bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein nanoarray on Prolinker™ surface constructed by atomic force microscopy dip‐pen nanolithography for analysis of protein interaction
Authors: Lee Minsu , Kang Dong‐Ku , Yang Hyun‐Kyu , Park Keun‐Hyung , Choe Soo Young , Kang ChangSoo , Chang Soo‐Ik , Han Moon Hi , Kang In‐Cheol
Published: January 2006

Protein nanoarrays are addressable ensembles of nano‐scale protein domain on solid surfaces. This method can serve as a useful platform for ultraminiaturized bioanalysis. In this study, we investigated single molecular nanopatterning and molecular interaction of proteins that were immobilized on Prolinker™ surface of gold‐coated silicon wafer by using dip‐pen nanolithography (DPN) method. Contact force and humidity were optimized at 0.01 nN and 80%, respectively. The domain features of protein nanoarrays were developed at the contact time of 5 s. The optimized conditions for the nanoarray process were applied to create protein nanoarray using integrin αvβ3 and angiogenin. Constructed protein nanoarrays using integrin αvβ3 have single molecular monolayer with regular domain shape (height 15 ± 5 nm). The changed height value due to the single molecular interaction between integrin αvβ3 and vitronectin was approximately 30 ± 5 nm on Prolinker™ surface as measured with atomic force microscopy tip. Taken together, these results suggest that protein nanoarray on Prolinker™ surface fabricated by well‐controlled DPN process can be used to analyze single molecular interaction of protein.
On the nature of the CP group adjacent to a valence‐deficient atom: phosphaethynyl substituent vs. phosphorus center
Authors: Pham‐Tran Nguyen‐Nguyen , Hou Xin Juan , Nguyen Minh Tho
Published: January 2006

On the basis of quantum chemical calculations (CCSD(T), CASSCF and B3LYP), we have demonstrated in this work that the CP group, when connected to a valence‐deficient center, in particular in a triplet state or a radical, its π‐electrons tend to move into other parts of the system, thus transforming the formal RCP system into a P‐centered RCP species. The CP group does not behave as a phosphaethynyl substituent, but rather as a P‐centered phosphinidene or a P‐radical. Copyright © 2006 John Wiley & Sons, Ltd.
The determinants of stability in the human prion protein: Insights into folding and misfolding from the analysis of the change in the stabilization energy distribution in different conditions
Authors: Colacino Stefano , Tiana Guido , Broglia Ricardo A. , Colombo Giorgio
Published: January 2006

The dynamic evolution of the PrPC from its NMR‐derived conformation to a β‐sheet‐rich, aggregation‐prone conformation is studied through all‐atom, explicit solvent molecular dynamics in different temperature and pH conditions. The trajectories are analyzed by means of a recently introduced energy decomposition approach aimed at identifying the key residues for the stabilization and folding of the protein. It is shown that under native conditions the stabilization energy is concentrated in regions of the helices H1 and H3, whereas under misfolding conditions (low pH, high temperature, or mutations in selected sites) it is spread out over helix H2. Misfolding appears to be a rearrangement of the chain that disrupts most of the native secondary structure of the protein, producing some β‐rich conformations with an energy distribution similar to that of the native state. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Deduction of functional peptide motifs in scorpion toxins
Authors: Tan Paul T. J. , Ranganathan Shoba , Brusic Vladimir
Published: January 2006

Scorpion toxins are important physiological probes for characterizing ion channels. Molecular databases have limited functional annotation of scorpion toxins. Their function can be inferred by searching for conserved motifs in sequence signature databases that are derived statistically but are not necessarily biologically relevant. Mutation studies provide biological information on residues and positions important for structure–function relationship but are not normally used for extraction of binding motifs. 3D structure analyses also aid in the extraction of peptide motifs in which non‐contiguous residues are clustered spatially. Here we present new, functionally relevant peptide motifs for ion channels, derived from the analyses of scorpion toxin native and mutant peptides. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Results of L‐[1‐13C]phenylalanine breath test with air isotope ratio mass spectrometry can reflect the activity of phenylalanine hydroxylase in cirrhotic rat liver
Authors: Yan Weili , Xiong Ping , Liu Zhengwei , Huang Gang
Published: January 2006

The L‐[1‐13C]phenylalanine breath test (PheBT) could potentially advance the evaluation of hepatocyte function and liver functional reserve. However, because the factors influencing PheBT results have not been clarified, the clinical application of the test has been limited. This study investigated the relationship between the parameters of PheBT, performed with air isotope ratio mass spectrometry, and the activity of phenylalanine hydroxylase (PAH), the phenylalanine metabolism rate‐limiting enzyme, in rat liver, and proposes valid parameters for the assessment of liver function. Chronic injury to the liver was induced by the administration of CCl4 to male Sprague‐Dawley rats for either 8 or 12 weeks. Livers from rats in the two cirrhotic groups were discolored, enlarged and roughly textured, with cells filled with fat granules of various sizes, pseudolobuli formations, and regenerated tubercles. Of the 12 parameters tested, only the unit liver weight (LW) breath test parameters, including the maximum abundance of 13C in breath (13Cmax/LW), 13C abundance in breaths 2 and 7 min after administration of L‐[1‐13C]phenylalanine (13C‐phe) (13C2/LW and 13C7/LW), cumulative 13C excretion 10 and 30 min after 13C‐phe administration (AUC10/LW and AUC30/LW), and the 13C excretion rate constant (PheBT‐k/LW) were significantly affected in the chronic liver injury groups. There was no significant difference in the total PAH activity in liver among the three groups, but there was significant difference in unit LW PAH activity. Total PAH activity in the liver was significantly correlated with 13Cmax, 13C2, 13C7, AUC10, AUC30 and PheBT‐k, while the unit LW PAH activity was significantly correlated with 13Cmax/LW, 13C2/LW, 13C7/LW, AUC10/LW, AUC30/LW and PheBT‐k/LW. PheBT‐k/LW was also correlated with biochemical indices that are used to assess liver function. The present findings indicate that the PheBT results based on air isotope ratio mass spectrometry can quantitatively reflect the change in total PAH activity in the livers of chronically injured rats. PheBT‐k and PheBT‐k/LW are the most sensitive among the test parameters, and can be used to assess liver functional reserve and hepatocyte damage at the molecular level. Copyright © 2006 John Wiley & Sons, Ltd.
Characterization of unusual alkenones and alkyl alkenoates by electron ionization gas chromatography/mass spectrometry
Authors: Rontani J.‐F. , Prahl F. G. , Volkman J. K.
Published: January 2006

Unusual long‐chain, diunsaturated alkenones and alkyl alkenoates exhibiting double bonds separated by three methylene units instead of the more usual five were characterized by electron ionization (EI) gas chromatography/mass spectrometry. In a first step, the positions of the double bonds of these compounds (isolated from Holocene Black Sea sediments) were confirmed after OsO4 treatment and silylation. Mass spectra of the resulting tetratrimethylsilyloxy derivatives allowed unambiguous determination of the positions of unsaturations. The EI mass spectra of the non‐derivatized compounds were then compared with those of the alkenones and alkyl alkenoates having double bonds separated by five methylene units. Specific fragment ions resulting from γ‐H rearrangements were found to be prominent in EI mass spectra of these unusual ‘Black Sea’ diunsaturated alkenones and alkyl alkenoates. These fragment ions can be used to characterize these compounds in natural samples without the need for laborious derivatization treatments. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of chemical lipid extraction and arithmetic lipid correction on stable isotope ratios of fish tissues
Authors: Sweeting C. J. , Polunin N. V. C. , Jennings S.
Published: January 2006

For accurate interpretation of fish trophodynamics from carbon stable isotope data it is necessary to extract tissue lipids. This is because lipid content varies within and among tissues in both space and time, and because lipids are 13C‐depleted relative to proteins. However, lipid extraction may affect δ15N, thus requiring costly and time‐consuming separation of δ13C and δ15N analyses. These problems have prompted the development of arithmetic correction techniques for δ13C, but the techniques and their underlying assumptions have not been systematically tested. This study compared the effects of lipid extraction and arithmetic correction techniques on δ13C and δ15N of European sea bass (Dicentrarchus labrax) tissues. Following Folch lipid extraction from muscle and liver, there was a mean increase in δ15N of 0.77‰, but enrichment varied with lipid content such that effects on δ15N were hard to predict. Changes in δ13C and C:N between untreated and lipid‐extracted samples reflected the quantity of lipid removed. The arithmetic correction techniques of mass balance and lipid correction were sensitive to the C:N of the lipid‐extracted tissue and to the assumed depletion of lipid δ13C relative to protein δ13C. However, the mass balance approach was appropriate for the mathematical correction of bulk tissue data in most circumstances, provided that the C:N of lipid‐extracted tissue could be determined for a small proportion of samples. Application of mass balance arithmetic correction can lead to significant time and cost savings in trophodynamic studies, because the majority of δ13C and δ15N analyses would not need to be run separately. Copyright © 2006 John Wiley & Sons, Ltd.
Optimal filtering for polynomial system states with polynomial multiplicative noise
Authors: Basin Michael , Perez Joel , Skliar Mikhail
Published: January 2006

In this paper, the optimal filtering problem for polynomial system states with polynomial multiplicative noise over linear observations is treated proceeding from the general expression for the stochastic Ito differential of the optimal estimate and the error variance. As a result, the Ito differentials for the optimal estimate and error variance corresponding to the stated filtering problem are first derived. The procedure for obtaining a closed system of the filtering equations for any polynomial state with polynomial multiplicative noise over linear observations is then established, which yields the explicit closed form of the filtering equations in the particular cases of a linear state equation with linear multiplicative noise and a bilinear state equation with bilinear multiplicative noise. In the example, performance of the designed optimal filter is verified for a quadratic state with a quadratic multiplicative noise over linear observations against the optimal filter for a quadratic state with a state‐independent noise and a conventional extended Kalman–Bucy filter. Copyright © 2006 John Wiley & Sons, Ltd.
Structural evolution and tectonic setting of the Porongos belt, southern Brazil
Authors: SAALMANN K. , REMUS M. V. D. , HARTMANN L. A.
Published: January 2006

The SW–NE-striking Porongos belt, located between juvenile Neoproterozoic rocks in the west and the Dom Feliciano belt, characterized by intense reworking of older crust, in the east, comprises a greenschist to amphibolite-facies metavolcano-metasedimentary succession (Porongos sequence) of unknown age with some exposures of Palaeoproterozoic gneisses (Encantadas gneisses). High-temperature ductile deformation of the basement gneisses comprises at least two magmatic events followed by three deformational phases including folding and shearing (DT1–DT3) and can be attributed to the Palaeoproterozoic Trans-Amazonian orogeny. The deformation of the Porongos sequence occurred during the Neoproterozoic Brasiliano orogeny and comprises four ductile deformation phases (DB1–DB4), including two phases of isoclinal folding associated with shearing recorded in mylonitic layers, followed by closed NW-vergent folding and thrusting leading to formation of a thrust stack. Uplift of the basement and formation of late tectonic sedimentary basins occurred as a result of semi-ductile to brittle block faulting in a sinistral strike-slip regime. The Porongos sequence can be subdivided into a southeastern and a northwestern part. Trace element analyses as well as Sm–Nd and Rb–Sr geochemical data indicate partial melting and significant contamination by old continental crust for the metavolcanic rocks. The metavolcanic rocks show εNd(t=780 Ma) values of −20.64 and −21.72 (northwestern units) and −6.87 (southeastern sequence). The metasedimentary rocks were derived from late Palaeoproterozoic to Archaean sources, and the data indicate different sources for the northwestern and southeastern rock units of the Porongos sequence. εNd(t=780 Ma) are −6.25 and −6.85 in the southeastern units, with TDM model ages between 1734 and 1954 Ma, and vary between −14.72 and −17.96 in the northwestern parts, which have TDM model ages between 2346 and 2710 Ma. High 87Sr/86Sr(t) values between 0.7064 and 0.7286 confirm reworking of older crust. Isotopic signatures of the Porongos sequence do not show indications for a significant contribution from a Neoproterozoic juvenile source. A passive margin or continental rift environment is suggested for the tectonic setting of the Porongos belt, which is compatible with both deposition of shallow marine to deep marine sediments and stretching of continental crust leading to volcanism which is characterized by significant contamination by old continental crust.
Selective attention for negative information and depression in schizophrenia
Authors: WATERS FLAVIE A. V. , BADCOCK JOHANNA C. , MAYBERY MURRAY T.
Published: January 2006

Objectives. Depression is a frequent feature of schizophrenia but the cognitive processes involved in its development and maintenance are unclear. Recent studies have shown that clinical depression is associated with faulty inhibitory mechanisms of selective attention for negative information. The current study examined whether patients with schizophrenia also have an attentional bias towards negative stimuli. The inhibitory processes of interference control and task-shifting abilities were also examined to assess whether patients would show a selective impairment.

Method. Forty-three patients with schizophrenia and 24 healthy controls completed the Affective Shifting Task.

Results. As a group, schizophrenia patients did not show an attentional bias for negative material. However, those patients with high levels of depression demonstrated faster latencies when negative words were the targets, and higher depression scores were found to be associated with an increasing number of false alarms for negative words when they were not the targets. The results also showed that patients had impaired interference control but intact task-shifting abilities.

Conclusions. Faulty inhibitory mechanisms of selective attention for negative information are not a general feature of schizophrenia but appear to be selective to those with a depressed mood. The results highlight the need for further studies examining the exact nature of the affective dysfunction in schizophrenia and the cognitive processes supporting negative emotions.
Observer-based control of a walking biped robot without orientation measurement
Authors: Lebastard V. , Aoustin Y. , Plestan F.
Published: January 2006

Two observers based on high order sliding mode approach are proposed to determine the absolute orientation of a walking biped robot without feet. Contrary to velocities observers which have been often designed for robot control, very few works have been proposed for the orientation estimation: in this paper, the estimation of all state variables are derived from only the actuated joint variables. Then the technology problem of the absolute measurement is avoided. This latter point is an original contribution of this paper. The observers and the control law converge in finite-time and are well adapted for analysis of the cyclic walking gait. Then, a second original contribution consists in adapting an existing “simplified” Poincaré's sections-based analysis of the stability of the walking to nonlinear systems with not fully available state variables.
Reports and Surveys
Authors: Rudall Brian H.
Published: January 2006

When John von Neumann gave his lecture on ‘General and Logical Theory of Automata’ in 1948 his ideas were met with some scepticism. The suggestion that life is a logical process which could result in making a new kind of creature, was the forerunner of all our discussions on whether ‘artificial life’ was at all possible.
Agent-oriented software engineering
Authors: BERNON CAROLE , COSSENTINO MASSIMO , PAVÓN JUAN
Published: January 2006

Considering the great number of agent-oriented methodologies that can be found in the literature, and the fact that each one defines its own concepts and system structure, one of the main challenges in agent-oriented software engineering (AOSE) research is how to make these methodologies interoperable. By defining concepts used in a specific domain in a non-ambiguous way, meta-modelling may represent a step towards such interoperability. Consequently the main objective of the AOSE TFG (Technical Forum Group) is to establish a strategy for identifying a common meta-model that could be widely adopted by the AOSE community. This paper sums up the approach used by this TFG which consists of (i) studying and comparing the meta-models related to some existing methodologies (ADELFE, Gaia, INGENIAS, PASSI, RICA and Tropos) in order to find commonalities and (ii) giving a clear and basic definition for the core concepts used in multi-agent systems for relating and positioning them in a unified MAS meta-model. The first proposal, set up by the working group, for this unified meta-model then concludes this paper.
Agents in bioinformatics
Authors: LUCK MICHAEL , MERELLI EMANUELA
Published: January 2006

The scope of the Technical Forum Group (TFG) on Agents in Bioinformatics (BIOAGENTS) was to inspire collaboration between the agent and bioinformatics communities with the aim of creating an opportunity to propose a different (agent-based) approach to the development of computational frameworks both for data analysis in bioinformatics and for system modelling in computational biology. During the day, the participants examined the future of research on agents in bioinformatics primarily through 12 invited talks selected to cover the most relevant topics. From the discussions, it became clear that there are many perspectives to the field, ranging from bio-conceptual languages for agent-based simulation, to the definition of bio-ontology-based declarative languages for use by information agents, and to the use of Grid agents, each of which requires further exploration. The interactions between participants encouraged the development of applications that describe a way of creating agent-based simulation models of biological systems, starting from an hypothesis and inferring new knowledge (or relations) by mining and analysing the huge amount of public biological data. In this report we summarize and reflect on the presentations and discussions.
The AgentLink III Technical Forums: Introduction to the Special Issue
Authors: OMICINI ANDREA , McBURNEY PETER
Published: January 2006

This paper introduces the Special Issue of The Knowledge Engineering Review devoted to reports arising from selected Technical Forum Groups at the First and Second AgentLink III Agent Technical Forums, held in 2004 and 2005.
Multiagent resource allocation
Authors: CHEVALEYRE YANN , DUNNE PAUL E. , ENDRISS ULLE , LANG JÉRÔME , MAUDET NICOLAS , RODRÍGUEZ-AGUILAR JUAN A.
Published: January 2006

Resource allocation in multiagent systems is a central research issue in the AgentLink community. The aim of the Technical Forum Group on Multiagent Resource Allocation (TFG-MARA) is to provide a venue for the exchange of ideas in this area and to foster collaboration between different research groups. In this article we report on the first meeting of TFG-MARA, which was held as part of the Second AgentLink III Technical Forum in Ljubljana.
Psychische Aspekte bei körperlichen Krankheiten
Authors: Rief Winfried
Published: January 2006

Zusammenfassung: Gerade bei chronischen körperlichen Krankheiten hängt der Krankheitsverlauf sowie die Beeinträchtigung durch die Erkrankung oftmals vom Verhalten und Erleben der Betroffenen ab. Dies ist auch Gegenstand der Verhaltensmedizin, die körperliche, psychische und soziale Faktoren bei körperlichen Krankheiten als Forschungsgegenstand hat. Bei Krankheitsbildern wie koronaren Herzkrankheiten, Diabetes mellitus Typ II, chronischen Schmerzsyndromen oder Krebs kann durch Verhaltens- oder Einstellungsänderung die Chronifizierung und assoziierte Einschränkungen der Lebensqualität positiv beeinflusst werden. Für diese Ansätze werden bisher entwickelte Leitlinien vorgestellt. Dabei ist im Besonderen darauf zu achten, dass gerade die psychologischen bzw. psychotherapeutischen Interventionen in optimaler Qualität durchgeführt werden, um die möglichen positiven Effekte zu erreichen. Abschließend werden Charakteristiken eines verhaltensmedizinischen Vorgehens zusammengefasst und es wird auf zentrale Konstrukte eingegangen (Motivationsanalyse, subjektives Krankheitsmodell, Krankheitseinstellungen, Krankheitsverhalten, Compliance/Adherence, emotionale Bewältigung, Ressourcenanalyse, Stressbewältigung, Biofeedback).
Investigation of the role of TASK‐2 channels in rat pulmonary arteries; pharmacological and functional studies following RNA interference procedures
Authors: Gönczi Mónika , Szentandrássy Norbert , Johnson Ian T , Heagerty Anthony M , Weston Arthur H
Published: January 2006

In the present study, we investigated the ability of RNA interference technology to suppress TASK‐2 potassium channel expression in human embryonic kidney (HEK293) cells stably transfected with TASK‐2 cDNA and in rat isolated intact pulmonary arteries.

Lipofectamine‐induced transfection of a specific siRNA sequence targeted against TASK‐2 resulted in a dose‐ and time‐dependent decrease in TASK‐2 channel protein expression. In siRNA‐transfected cells the TASK‐2 peak currents were significantly smaller than in control cells at every investigated pH, while the pH sensitivity was not altered. Using scrambled siRNA as a negative control, there were no significant changes in TASK‐2 protein expression or current compared to mock‐transfected cells.

In TASK‐2 siRNA‐transfected small pulmonary arteries, but not in scrambled siRNA‐treated vessels, myocyte resting membrane potential at pH 7.4 was significantly less negative and the hyperpolarisations in response to increasing pH from 6.4 to 8.4 were significantly smaller compared with control.

The application of levcromakalim (10 μM), NS1619 (33 μM) and a potassium channel inhibitor cocktail (5 mM 4‐aminopyridine, 10 mM tetraethylammonium chloride, 30 μM Ba2+ and 10 μM glibenclamide) had similar effects in control and in siRNA‐transfected vessels. The TASK‐1 (anandamide‐sensitive) contribution to resting membrane potential was comparable in each group. Clofilium (100 μM) generated significantly smaller responses in transfected artery segments.

These results suggest that RNA interference techniques are effective at inhibiting TASK‐2 channel expression in cultured cells and in intact vessels and that TASK‐2 channels have a functional role in setting the membrane potential of pulmonary artery myocytes.

British Journal of Pharmacology (2006) 147, 496–505. doi:10.1038/sj.bjp.0706649
Substance P‐induced cyclooxygenase‐2 expression in human umbilical vein endothelial cells
Authors: Gallicchio Margherita , Rosa Arianna Carolina , Benetti Elisa , Collino Massimo , Dianzani Chiara , Fantozzi Roberto
Published: January 2006

Substance P (SP) is a neuropeptide involved in neurogenic inflammation and an agonist for NK1, NK2, and NK3 receptors. SP induces prostaglandin (PG) production in various cell types, and these eicosanoids are responsible for numerous inflammatory and vascular effects.

Cyclooxygenase (COX) are needed to convert arachidonic acid to PGs. The study evaluated the effect of SP on COX expression in human umbilical vein endothelial cells (HUVEC).

COX‐2 protein expression was upregulated by SP with a peak at 100 nM and at 20 h; in the same experimental conditions COX‐1 protein expression was unchanged. A correlation between COX‐2 expression and PGI2 and PGE2 release was detected.

Dexamethasone (DEX) inhibited SP‐mediated COX‐2 expression. Mitogen‐activated protein kinases (MAPK) p38 and p42/44 were activated by SP, whereas SB202190 and PD98059, inhibitors of these kinases, blocked COX‐2 expression. 5,5‐dimethyl‐3‐(3‐fluorophenyl)‐4‐(4‐methylsulphonyl)phenyl‐2(5H)‐furanone (DFU), an experimental selective COX‐2 inhibitor, blocked SP‐induced PG release.

By RT–PCR and Western blot analysis, we demonstrated that NK1 and NK2 but not NK3 receptors are present on HUVEC. Selective NK1 and NK2 agonists, namely [Sar9, Met(O2)11]SP and [β‐Ala8] NKA(4–10), upregulated COX‐2 protein expression and PG production, whereas senktide (Suc–Asp–Phe–MePhe–Gly–Leu–Met–NH2), a selective NK3 agonist, was ineffective in this respect. The NK1 selective antagonist L703,606 ((cis)‐2‐(diphenylmethyl)‐N‐((2‐iodophenyl)‐methyl)‐1‐azabicyclo(2.2.2)octan‐3‐amine) and the NK2 selective antagonist SR 48,968 ((S)‐N‐methyl‐N‐(4‐(4‐acetylamino‐4‐phenylpiperidino)‐2‐(3,4 dichlorophenyl)butyl) benzamide) competitively antagonised SP‐induced effects.

The study shows HUVEC to possess functional NK1 and NK2 receptors, which mediate the ability of SP to induce expression of COX‐2 in HUVEC, thus showing a previously‐undetected effect of SP on endothelial cells.

British Journal of Pharmacology (2006) 147, 681–689. doi:10.1038/sj.bjp.0706660
Prostaglandin E2 activates EP2 receptors to inhibit human lung mast cell degranulation
Authors: Kay Linda J , Yeo Wilfred W , Peachell Peter T
Published: January 2006

The prostanoid, PGE2, is known to inhibit human lung mast cell activity. The aim of the present study was to characterize the EP receptor that mediates this effect.

PGE2 (pEC50, 5.8±0.1) inhibited the IgE‐mediated release of histamine from mast cells in a concentration‐dependent manner. Alternative EP receptor agonists were studied. The EP2‐selective agonist, butaprost (pEC50, 5.2±0.2), was an effective inhibitor of mediator release whereas the EP1/EP3 receptor agonist, sulprostone, and the EP1‐selective agonist, 17‐phenyl‐trinor‐PGE2, were ineffective.

The DP agonist PGD2, the FP agonist PGF2α, the IP agonist iloprost and the TP agonist U‐46619 were ineffective inhibitors of IgE‐mediated histamine release from mast cells.

PGE2 induced a concentration‐dependent increase in intracellular cAMP levels in mast cells.

The effects of the EP1/EP2 receptor antagonist, AH6809, and the EP4 receptor antagonist, AH23848, on the PGE2‐mediated inhibition of histamine release were determined. AH6809 (pKB, 5.6±0.1) caused a modest rightward shift in the PGE2 concentration–response curve, whereas AH23848 was ineffective.

Long‐term (24 h) incubation of mast cells with either PGE2 or butaprost (EP2 agonist), but not sulprostone (EP1/EP3 agonist), caused a significant reduction in the subsequent ability of PGE2 to inhibit histamine release.

Collectively, these data suggest that PGE2 mediates effects on human lung mast cells by interacting with EP2 receptors.

British Journal of Pharmacology (2006) 147, 707–713. doi:10.1038/sj.bjp.0706664
Systemic administration of β2‐adrenoceptor agonists, formoterol and salmeterol, elicit skeletal muscle hypertrophy in rats at micromolar doses
Authors: Ryall James G , Sillence Martin N , Lynch Gordon S
Published: January 2006

β2‐Adrenoceptor agonists provide a potential therapy for muscle wasting and weakness, but their use may be limited by adverse effects on the heart, mediated in part, by β1‐adrenoceptor activation.

Two β2‐agonists, formoterol and salmeterol, are approved for treating asthma and have an extended duration of action and increased safety, associated with greater β2‐adrenoceptor selectivity.

The pharmacological profiles of formoterol and salmeterol and their effects on skeletal and cardiac muscle mass were investigated in 12‐week‐old, male F344 rats. Formoterol and salmeterol were each administered via daily i.p. injection at one of seven doses (ranging from 1 to 2000 μg kg−1 day−1), for 4 weeks. Rats were anaesthetised and the EDL and soleus muscles and the heart were excised and weighed. Dose–response curves were constructed based on skeletal and cardiac muscle hypertrophy.

Formoterol was more potent than salmeterol, with a significantly lower ED50 in EDL muscles (1 and 130 μg kg−1 day−1, P <0.05), whereas salmeterol had greater intrinsic activity than formoterol in both EDL and soleus muscles (12% greater hypertrophy than formoterol). The drugs had similar potency and intrinsic activity in the heart, with a smaller leftward shift for formoterol than seen in skeletal muscle. A dose of 25 μg kg−1 day−1 of formoterol elicited greater EDL and soleus hypertrophy than salmeterol, but resulted in similar β‐adrenoceptor downregulation.

These results show that doses as low as 1 μg kg−1 day−1 of formoterol can elicit significant muscle hypertrophy with minimal cardiac hypertrophy and provide important information regarding the potential therapeutic use of formoterol and salmeterol for muscle wasting.

British Journal of Pharmacology (2006) 147, 587–595. doi:10.1038/sj.bjp.0706669
Cardiac implications for the use ofβ2‐adrenoceptor agonists for the management of muscle wasting
Authors: Molenaar Peter , Chen Lu , Parsonage William A
Published: January 2006

There are proposals for the implementation ofβ2‐adrenoceptor agonists for the management of muscle wasting diseases. The idea has been initiated by studies in animal models which show thatβ2‐adrenoceptor agonists cause hypertrophy of skeletal muscle. Their use in clinical practice will also need an understanding of possible effects of activation of human heartβ2‐adrenoceptors. Consequences could include an increased probability of arrhythmias in susceptible patients.

British Journal of Pharmacology(2006)147, 583–586. doi:10.1038/sj.bjp.0706670
Inhibition of classical PKC isoenzymes downregulates STAT1 activation and iNOS expression in LPS‐treated murine J774 macrophages
Authors: Salonen Tiina , Sareila Outi , Jalonen Ulla , Kankaanranta Hannu , Tuominen Raimo , Moilanen Eeva
Published: January 2006

Proinflammatory cytokines and bacterial products trigger inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in inflammatory and tissue cells. In inflammation, NO acts as an important mediator having both proinflammatory and destructive effects.

Protein kinase C (PKC) is a family of serine–threonine protein kinase isoenzymes involved in signal transduction pathways related to inflammatory responses. The aim of the present study was to investigate the role of classical PKC (cPKC) isoenzymes in the regulation of iNOS expression and NO production in murine J774 macrophages and the mechanisms involved.

RO318220 (inhibits PKCβ, PKCγ and PKCɛ), GÖ6976 (inhibits cPKC isoenzymes PKCα and PKCβ) and LY333531 (inhibits PKCβ) reduced lipopolysaccharide (LPS)‐induced NO production and iNOS expression in a dose‐dependent manner as did 6 h pretreatment with 1 μM phorbol 12‐myristate 13‐acetate (PMA) (which was shown to downregulate PKC expression).

PKC inhibitors also reduced LPS‐induced iNOS mRNA levels, but they did not affect the half‐life of iNOS mRNA. PKC inhibitors did not alter LPS‐induced activation of NF‐κB as measured by electrophoretic mobility shift assay.

All PKC inhibitors used and pretreatment with 1 μM PMA inhibited signal transducer and activator of transcription 1 (STAT1) activation as measured by the translocation of STAT1α from the cytosol to the nucleus by Western blot. In addition, inhibition of STAT1 activation by AG‐490, an inhibitor of JAK‐2, also reduced NO production.

These results suggest that cPKC isoenzymes, especially PKCβ, mediate the upregulation of iNOS expression and NO production in activated macrophages in an NF‐κB‐independent manner, possibly through the activation of transcription factor STAT1.

British Journal of Pharmacology (2006) 147, 790–799. doi:10.1038/sj.bjp.0706672
Magnetoresistive playback heads for bit-patterned medium recording applications
Authors: Smith Darren , E Chunsheng , Khizroev Sakhrat , Litvinov Dmitri
Published: January 2006

This work examines playback characteristics of common magnetoresistive heads applied in magnetic recording systems based on bit-patterned medium. Playback for different head designs is evaluated using the reciprocity principle. Analytical solution for a pointlike reader is used to elucidate the playback resolution limits for a given patterned medium morphology. Various recording system design parameters including recording layer design (thickness, bit geometry, and bit-to-bit spacing), exchange/buffer layer thickness, soft underlayers, and fly height are examined. Differential readers are shown to offer significantly higher spatial resolution, higher signal amplitude, and the weakest dependence on fly-height variations and bit geometry. For example, for a 1Tb∕in2 reader design considered, D50 is 1.46 and 2.64Tb∕in2 for shielded and differential readers, respectively; differential readers have more than 35% higher playback amplitude than equivalent shielded readers. The loss in playback amplitude can be as high 18% due to bit-corner rounding (lithography imperfections) for shielded readers; differential readers exhibit only a weak dependence on bit-corner rounding (±2%–3%). Pseudodifferential readers with a single-sensor element are shown to offer advantages similar to the advantages of conventional double-sensor differential readers while addressing manufacturability issues.
Unraveling the deposition mechanism in a-C:H thin-film growth: A molecular-dynamics study for the reaction behavior of C3 and C3H radicals with a-C:H surfaces
Authors: Neyts E. , Bogaerts A. , van de Sanden M. C. M.
Published: January 2006

In this molecular-dynamics study, we present the simulated growth of thin a-C:H films using the Brenner [(Phys. Rev. B 42, 9458 (1990)] potential. These simulations are relevant for the growth of thin films, grown using low-energy hydrocarbons. In this work, we investigate the reaction mechanisms of both the linear and the cyclic isomers of C3 and C3H on an a-C:H surface. We found that the cyclic species are always more reactive as compared to the linear species, due to their lower stability. The C3 species are found to be more reactive than the C3H species, due to steric hindrance of the H atom, shielding the C atom from the surface. The different mechanisms are discussed. The resulting film properties for different flux ratios of C3 and C3H have also been investigated. It is shown that films as deposited from C3 and C3H have a low density and show low cross-linking. A clear change in microstructure is observed as the ratio between the cyclic and the linear species changes. These simulations provide insights into the reaction behavior of the investigated species, and how this influences the resulting film properties.
Anneal-induced interdiffusion in 1.3-μmGaInNAs∕GaAs quantum well structures grown by molecular-beam epitaxy
Authors: Liu H. F. , Dixit V. , Xiang N.
Published: January 2006

High-resolution x-ray diffraction (HRXRD) and photoluminescence (PL) have been used to study the diffusion of atoms in 8-nm Ga0.628In0.372N0.015As0.985∕GaAs quantum well, with and without dielectric encapsulants. These samples were repeatedly annealed in the temperature range of 680–800 °C over times of up to 16 000 s. HRXRD simulations, by using dynamic scattering theory and Fick’s diffusion model with a constant diffusion coefficient, demonstrate that the diffusion lengths are shorter than 2 nm under the annealing conditions studied. In this range of diffusion lengths, the transition energy Ee1−Hh1, numerically calculated from the Schrödinger equation using a potential derived from the diffusion equation, increases linearly as the square of the diffusion length. The steady-state PL blueshifts, after a fast initial blueshift due to the rearrangement of local nitrogen bonding configurations N–GamIn4−m(0⩽m⩽4), otherwise known as short-range order, as a function of annealing time are well fitted by using the linear function. The values of ΔESRO and diffusion coefficients obtained are 18–28 meV and 3.0×10−20–3.5×10−18cm2∕s, respectively. The activation energy characterized from the diffusion coefficients at different temperatures is 3.25 eV and is not affected by the dielectric encapsulates.
Photomodification of CdSe nanocrystals incorporated in a poly(butylmethacrylate) polymer film
Authors: Kovalevskij V. , Gulbinas V. , Scholes G. D.
Published: January 2006

We report a study of the influence of high intensity laser light on the optical properties and exciton relaxation dynamics in CdSe nanocrystals passivated by tri-n-octylphosphine oxide and dispersed in the optically clear poly(butylmethacrylate) polymer. Sample irradiation by 3ps duration laser pulses at 527nm leads to the blueshift of the maximum of the lowest-energy exciton absorption band and to the disappearance of a long-wavelength absorption slope in the 600–800nm region that we attribute to Rayleigh scattering. The photomodification rate is approximately proportional to the second to third power of the light intensity and strongly temperature dependent. The shift of the absorption band is related to the reduction of the nanocrystal (NC) size. The disappearance of the Rayleigh scatter is explained as a modification of the NC surface ligands and their immediate surroundings due to an increase in the local temperature.
Interband absorption of multiple quantum wells including diluted magnetic semiconductors in magnetic fields
Authors: Guo X. G. , Cao J. C.
Published: January 2006

We have investigated theoretically the interband excitonic absorption spectra and the coupling behaviors of coupled symmetric triple Zn1−xCdxSe∕ZnSe quantum wells with diluted Mn doping in the central well under external magnetic field. The results show that the magnetic field can effectively adjust the energy levels and the optical properties of the coupled multiple quantum wells (CMQWs). The coupling behaviors of the CMQWs are very sensitive to the central well depth. The effect of the magnetic-field-introduced parabolic-confined potential on the main features of the absorption spectra can be neglected at moderate magnetic-field densities.
Electronic properties of the Sm∕4H-SiC surface alloy
Authors: Kildemo M. , Grossner U. , Juel M. , Samuelsen B. , Svensson B. G. , Raaen S.
Published: January 2006

The formation of a samarium on silicon carbide (Sm∕SiC) alloy after deposition of 2–3 monolayers of Sm in ultrahigh vacuum on clean reconstructed carbon(000-1)- and silicon(0001)-terminated SiC surfaces is studied by x-ray photoemission spectroscopy, ultraviolet photoemission spectroscopy, and low-energy electron diffraction (LEED). The measured work function together with core-level spectroscopy is used to differentiate the formation of samarium silicide carbide (Sm–Si–C) surface alloys on both polar faces of 4H-SiC. Both naturally n-type-doped bulk Si-face and low-doped epilayer Si-face SiC were studied. A (1×1) LEED pattern is obtained on the C-face Sm–Si–C alloy and on the Si-face epilayer Sm–Si–C alloy. Flatband voltages are estimated as a function of annealing, from the shift in the C1s and Si2p bulk core-level positions. The valency of Sm is estimated during the formation of the Sm–Si–C surface alloy. The valence of the Sm overlayer after deposition at room temperature is estimated to be approximately 2.75, while upon annealing, the Sm∕SiC surface alloys on the bulk crystal become predominately 3+ valent. In the case of the Sm∕SiC surface alloy on the Si-face epilayer, the (1×1) surface alloy is of mixed valency (2.84). In all the cases studied, the Sm 3d peak undergoes a major shift of 1.8eV accompanied with a change in the Sm 3d multiplet spectrum.
The Einstein relation in systems with trap-controlled transport
Authors: Neumann F. , Genenko Y. A. , von Seggern H.
Published: January 2006

The applicability of the Einstein relation considering diffusivity and mobility of charge carriers with respect to disordered systems has been a matter of serious discussion in recent years. Here the validity of the Einstein relation, using the generalized form, is checked for two specific density-of-states functions within a multiple trapping model and the mobility edge concept. It is shown that the classical Einstein relation is valid for almost all charge-carrier densities relevant for experimental purposes. It is demonstrated that this result is dependent on the charge-carrier mobility definition.
One-dimensional diffusion of colloids in polymer solutions
Authors: Chou C.-Y. , Eng B. C. , Robert M.
Published: January 2006

For colloid-polymer systems confined in one-dimensional channels, the diffusion of the colloidal particles is obtained by tracking individual particles using enhanced video microscopy and digital image analysis. For short times, the diffusion is normal, of the Fickian type, with mean-squared displacement varying linearly with time. For long times, however, the mean-squared displacement is found to increase more slowly with time, being proportional to the square root of time, in agreement with the theoretical prediction for diffusion of hard rods in one dimension in which mutual crossing of the particles cannot take place. The crossover from short-time to long-time diffusion is observed and is found to depend on the colloid and polymer concentrations. Unexpectedly, for small polymer-to-colloid size ratios, it is the polymer rather than the colloid concentration which has a leading effect on the colloid diffusion.
Fracture toughness of low-pressure chemical-vapor-deposited polycrystalline silicon carbide thin films
Authors: Hatty V. , Kahn H. , Trevino J. , Zorman C. A. , Mehregany M. , Ballarini R. , Heuer A. H.
Published: January 2006

The fracture toughness of thin-film polycrystalline silicon carbide (poly-SiC) deposited on silicon (Si) wafers via low-pressure chemical-vapor deposition (LPCVD) has been measured on a scale useful for micromachined devices; the results are compared to previous studies on poly-SiC thin films deposited by atmospheric pressure chemical-vapor deposition (APCVD) [Bellante et al., Appl. Phys. Lett. 86, 071920 (2005)]. Samples in this study included those with and without silicon dioxide (SiO2) sacrificial release layers. The LPCVD processing technique induces residual tensile stresses in the films. Doubly clamped microtensile specimens were fabricated using standard micromachining processes, and microindentation was used to initiate atomically sharp precracks. The residual stresses in the films create stress intensity factors K at the crack tips; upon release, the precracks whose K exceeded a critical value, KIC, propagated to failure. The fracture toughness KIC was the same for both types of devices, 2.9±0.2MPam1∕2 for the SiC on Si samples and 3.0±0.2MPam1∕2 for the SiC on SiO2∕Si samples, and similar to that found for APCVD poly-SiC, 2.8⩽KIC⩽3.4MPam1∕2 [Bellante et al., Appl. Phys. Lett. 86, 071920 (2005)], indicating that KIC is truly a structure-insensitive material property. The fracture toughness of poly-SiC compares favorably with that for polysilicon, 0.85±0.05MPam1∕2 [Kahn et al., Science 298, 1215 (2002)].
Correlation of the electrical and optical properties of p-type CdGeAs2
Authors: Bai Lihua , Xu Chunchuan , Giles N. C. , Nagashio K. , Feigelson R. S.
Published: January 2006

Cd Ge As 2 crystals typically exhibit an absorption band near 5.5μm that limits their use as a nonlinear frequency-conversion material in high-power infrared laser systems. This absorption band is related to the p-type nature of the as-grown bulk crystals. We correlate the electrical properties, as determined using van der Pauw Hall measurements, with optical absorption and photoluminescence data. The samples are all p type at room temperature with hole concentrations varying from 1×1015to2×1017cm−3. High-absorption samples have two acceptor levels, while low-absorption samples have one deep acceptor. A linear correlation between absorption at 5.5μm and hole concentration (p) is established. Also, we account for ambipolar conduction and explain possible discrepancies which may arise when comparing hole concentrations and optical data in low-absorption CdGeAs2 samples. We correlate the variation in activation energy with p, and also with NA and find excellent agreement with theory. An ionization energy is obtained for the deep acceptor.
Analysis of uncompensated Langmuir probe characteristics in radio-frequency discharges revisited
Authors: Oksuz L. , Soberón F. , Ellingboe A. R.
Published: January 2006

Measurements of the electron temperature, plasma density, and floating and plasma potentials with Langmuir probes in radio-frequency discharges often represent a challenge due to rf oscillations of the plasma potential. These oscillations distort the probe characteristic, resulting in wrong estimates of the plasma parameters. Both active and passive rf compensation methods have previously been used to eliminate rf fluctuation effects on the electron current drawn by an electrostatic probe. These effects on an uncompensated probe have been theoretically and experimentally studied by Garscadden and Emeleus [Proc. Phys. Soc. London 79, 535 (1962)], Boschi and Magistrelli [Nuovo Cimento 29, 487 (1963)], and Crawford [J. Appl. Phys. 34, 1897 (1963)]. They have shown theoretically that, assuming a Maxwellian distribution and sinusoidal plasma-potential oscillation, the electron temperature can be deduced directly from an uncompensated Langmuir probe trace, by taking the natural logarithm of the electron current. It is the purpose of this paper to bring back the attention onto this result, which shows that under certain discharge conditions it is not necessary to build any rf compensation in a Langmuir probe system. Here we present and reference experimental data found on the literature which support this result. Also computational data are presented.
Semiconductor superlattice in a biharmonic field: Absolute negative conductivity and static electric-field generation
Authors: Romanov Yuriy A. , Romanova Julia Yu. , Mourokh Lev G.
Published: January 2006

We analyze the transport properties of a semiconductor superlattice in the presence of a biharmonic electric field. The modification of current-voltage characteristics induced by the biharmonic radiation is obtained. The conditions for absolute negative conductivity and for the spontaneous generation of a significant static electric field are determined. We also show that a simple harmonic field can experience nonlinear amplification even when the differential superlattice dc conductivity is positive, and we determine the corresponding range of parameters.