bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementing accountability for reasonableness – the case of pharmaceutical reimbursement in Sweden
Authors: JANSSON SANDRA
Published: July 2007

This paper aims to describe the priority-setting procedure for new original pharmaceuticals practiced by the Swedish Pharmaceutical Benefits Board (LFN), to analyse the outcome of the procedure in terms of decisions and the relative importance of ethical principles, and to examine the reactions of stakeholders. All the ‘principally important’ decisions made by the LFN during its first 33 months of operation were analysed. The study is theoretically anchored in the theory of fair and legitimate priority-setting procedures by Daniels and Sabin, and is based on public documents, media articles, and semi-structured interviews. Only nine cases resulted in a rejection of a subsidy by the LFN and 15 in a limited or conditional subsidy. Total rejections rather than limitations gave rise to actions by stakeholders. Primarily, the principle of cost-effectiveness was used when limiting/conditioning or totally rejecting a subsidy. This study suggests that implementing a priority-setting process that fulfils the conditions of accountability for reasonableness can result in a priority-setting process which is generally perceived as fair and legitimate by the major stakeholders and may increase social learning in terms of accepting the necessity of priority setting in health care. The principle of cost-effectiveness increased in importance when the demand for openness and transparency increased.
Simulation chamber investigation of the reactions of ozone with short‐chained alkenes
Authors: Wegener Robert , Brauers Theo , Koppmann Ralf , Rodríguez Bares Sonia , Rohrer Franz , Tillmann Ralf , Wahner Andreas , Hansel Armin , Wisthaler Armin
Published: July 2007

Reaction rate coefficients and product yields in the gas phase reaction of O3 with the short‐chained alkenes ethene, propene, 1‐butene, isobutene, (E)‐butene, and (Z)‐butene were determined by Simulation of Atmospheric Photochemistry in a Large Reaction Chamber (SAPHIR). In a first set of experiments, reaction rate coefficients were acquired in an absolute reaction rate study from the measured concentration time profiles of ozone and the alkenes with side reactions being suppressed by adding a radical scavenger. The rate coefficients obtained agree well with literature data; for all but one alkene, the deviation was less than 10%. In a second set of experiments, OH yields were derived from the additional alkene turnover in the absence of a radical scavenger. In contrast to other studies, the OH yields determined in the dry chamber (propene, 0.10 ± 0.07; 1‐butene, 0.00 ± 0.08, isobutene, 0.30 ± 0.14; (Z)‐butene, 0.18 ± 0.09; and (E)‐butene, 0.70 ± 0.12) differed from the yields obtained under humid conditions (propene, 0.30 ± 0.08; 1‐butene, 0.30 ± 0.09; isobutene, 0.80 ± 0.10; (Z)‐butene, 0.40 ± 0.05; and (E)‐butene, 0.60 ± 0.12). The only exception was ethene ozonolysis, where no OH production was observed. HO2 yields (propene, 1.50 ± 0.75; 1‐butene, 1.60 ± 0.80; and isobutene, 2.00 ± 1.00) estimated from the additional ozone turnover compared to the experiments where radicals were not scavenged are reported here for the first time. Furthermore, the yields of the stable ozonolysis products CO, acetaldehyde, and formaldehyde were acquired by monitoring the concentration time profile of the respective compound.
On return stroke currents and remote electromagnetic fields associated with lightning strikes to tall structures: 1. Computational models
Authors: Pavanello D. , Rachidi F. , Rubinstein M. , Bermudez J. L. , Janischewskyj W. , Shostak V. , Nucci C. A. , Hussein A. M. , Chang J. S.
Published: July 2007

In this paper, analytical expressions relating far fields and currents associated with lightning strikes to tall towers are derived. The derived equations are general and can be used with any engineering model. It is shown that the far field can be decomposed into three terms, namely (1) contribution of the main return stroke pulse along the lightning channel, (2) contribution of the multiple‐reflection process along the elevated strike object, including the contribution of upward propagating pulses transmitted into the channel, and (3) contribution of the so‐called “turn‐on” terms, associated with the current discontinuity at the return stroke wavefront. This discontinuity is associated with neglecting reflections at the upward moving front. It is also shown that only the first term is model‐dependent and that the far field–current relationship does not significantly depend on the adopted engineering model. It is therefore possible to use the analytical equation relating the current peak and the associated distant electric or magnetic fields, derived by Bermudez et al. (2005) for the transmission line (TL) model, for any engineering model extended to include a tall strike object. It is also shown that the peak amplitude of the electromagnetic field radiated by a lightning strike to a tall structure is relatively insensitive both to the value of the return stroke speed and the top reflection coefficient. These results and findings of this paper emphasize the key differences between return strokes initiated at ground level (or from short strike objects) and those striking tall towers: (1) The electromagnetic field from lightning strikes to tall towers is largely determined by the tower and only to a lesser extent by the channel, (2) electromagnetic fields associated with tall strike objects are less model‐sensitive than those corresponding to a strike to ground; in particular, the early time response of the field is nearly model‐independent, and (3) unlike ground‐initiated strikes, for which the far field peak is strongly dependent on the return stroke speed (proportional according to the TL model), far field peaks associated with strikes to tall strike objects are little sensitive to the return stroke speed. This is a particularly interesting result when lightning currents are measured directly on instrumented towers to calibrate the performance of lightning location systems, since in most practical cases the value of the return stroke speed is unknown. Note that points (2) and (3) can be considered as corollaries of point (1).
A time‐dependent multiple scattering theory for a pulsed radar with a finite beam width
Authors: Kobayashi Satoru , Ito Shigeo , Tanelli Simone , Oguchi Tomohiro , Im Eastwood
Published: July 2007

Multiple scattering returns from spherical water particles of uniform diameter are studied for pulsed radar operation. The Gaussian transverse beam‐profile and the rectangular pulse‐duration are taken into account. A second‐order analytical solution is derived for a single layer structure, based on the time‐dependent radiative transfer theory. The method itself can be extended to higher‐order scatterings in a multiple layered structure with general drop size distributions. The calculation results show that the effect of second‐order scattering becomes larger, as the footprint radius, range, and range resolution, which are normalized by the mean free path, increase.
Seawater isotope constraints on tropical hydrology during the Holocene
Authors: Oppo Delia W. , Schmidt Gavin A. , LeGrande Allegra N.
Published: July 2007

Paleoceanographic data from the low latitude Pacific Ocean provides evidence of changes in the freshwater budget and redistribution of freshwater within the basin during the Holocene. Reconstructed Holocene seawater δ18O changes compare favorably to differences predicted between climate simulations for the middle Holocene (MH) and for the pre‐Industrial late Holocene (LH). The model simulations demonstrate that changes in the tropical hydrologic cycle affect the relationship between δ18Osw and surface salinity, and allow, for the first time, quantitative estimates of western Pacific salinity change during the Holocene. The simulations suggest that during the MH, the mean salinity of the Pacific was higher because less water vapor was transported from the Atlantic Ocean and more was transported to the Indian Ocean. The salinity of the western Pacific was enhanced further due both to the greater advection of salt to the region by ocean currents and to an increase in continental precipitation at the expense of maritime precipitation, the latter a consequence of the stronger Asian summer monsoon.
Particulate organic acids and overall water‐soluble aerosol composition measurements from the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)
Authors: Sorooshian Armin , Ng Nga L. , Chan Arthur W. H. , Feingold Graham , Flagan Richard C. , Seinfeld John H.
Published: July 2007

The Center for Interdisciplinary Remotely‐Piloted Aircraft Studies (CIRPAS) Twin Otter participated in the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) mission during August–September 2006. A particle‐into‐liquid sampler (PILS) coupled to ion chromatography was used to characterize the water‐soluble ion composition of aerosol and cloud droplet residual particles (976 5‐min PM1.0samples in total). Sulfate and ammonium dominated the water‐soluble mass (NH4++ SO42−= 84 ± 14%), while organic acids contributed 3.4 ± 3.7%. The average NH4+:SO42−molar ratio was 1.77 ± 0.85. Particulate concentrations of organic acids increased with decreasing carbon number from C9to C2. Organic acids were most abundant above cloud, presumably as a result of aqueous phase chemistry in cloud droplets, followed by subsequent droplet evaporation above cloud tops; the main product of this chemistry was oxalic acid. The evolution of organic acids with increasing altitude in cloud provides evidence for the multistep nature of oxalic acid production; predictions from a cloud parcel model are consistent with the observed oxalate:glyoxylate ratio as a function of altitude in GoMACCS cumuli. Suppressed organic acid formation was observed in clouds with relatively acidic droplets, as determined by high particulate nitrate concentrations (presumably high HNO3levels too) and lower liquid water content, as compared to other cloud fields probed. In the Houston Ship Channel region, an area with significant volatile organic compound emissions, oxalate, acetate, formate, benzoate, and pyruvate, in decreasing order, were the most abundant organic acids. Photo‐oxidation ofm‐xylene in laboratory chamber experiments leads to a particulate organic acid product distribution consistent with the Ship Channel area observations.
Sch35966 is a potent, selective agonist at the peripheral cannabinoid receptor (CB2) in rodents and primates
Authors: Gonsiorek W , Lunn C A , Fan X , Deno G , Kozlowski J , Hipkin R W
Published: July 2007

Background and purpose:

The peripheral cannabinoid receptor (CB2) is expressed on peripheral immune cells and is thought to have a role in the immunosuppressive effects of cannabinoids. Historically, there have been few potent, CB2‐selective agonists to assess the contribution of CB2to this phenomenon. The studies presented here describe the synthesis of 8,10‐bis[(2,2‐dimethyl‐1‐oxopropyl)oxy]‐11‐methyl‐1234‐tetrahydro‐6H‐benzo[β]quinolizin‐6‐one (Sch35966), which binds with low nanomolar potency to CB2in both primates and rodents.

Experimental approach:

The affinity, potency and efficacy of Sch35966 and other cannabinoid ligands at CB2was assessed using competition binding assays vs [3H]CP55,940, [35S]GTPγS exchange, cAMP accumulation and cell chemotaxis assays.

Key results:

We showed that Sch35966 has >450‐fold selectivity for CB2binding vs the central cannabinoid receptor (CB1) in primates (humans and cynomolgus monkeys) and rodents (rats and mice). Sch35966 is an agonist as it effectively inhibited forskolin‐stimulated cAMP synthesis in CHO‐hCB2cells, stimulated [35S]GTPγS exchange and directed chemotaxis in cell membranes expressing CB2. In all species examined, Sch35966 was more potent, more efficacious and more selective than JWH‐015 (a commonly used CB2‐selective agonist).

Conclusions and implications:

Taken together, the data show that Sch35966 is a potent and efficacious CB2‐selective agonist in rodents and primates.

British Journal of Pharmacology(2007)151, 1262–1271; doi:10.1038/sj.bjp.0707336
The potential of high‐content high‐throughput microscopy in drug discovery
Authors: Starkuviene V , Pepperkok R
Published: July 2007

Fluorescence microscopy is a powerful method to study protein function in its natural habitat, the living cell. With the availability of the green fluorescent protein and its spectral variants, almost any gene of interest can be fluorescently labelled in living cells opening the possibility to study protein localization, dynamics and interactions. The emergence of automated cellular systems allows rapid visualization of large groups of cells and phenotypic analysis in a quantitative manner. Here, we discuss recent advances in high‐content high‐throughput microscopy and its potential application to several steps of the drug discovery process.

British Journal of Pharmacology (2007) 152, 62–71; doi:10.1038/sj.bjp.0707346
In vitroandin vivoantiproliferative and trypanocidal activities of ruthenium NO donors
Authors: Silva J J N , Osakabe A L , Pavanelli W R , Silva J S , Franco D W
Published: July 2007

Background and purpose:

Many compounds liberating NO (NO donors) have been used as therapeutic agents. Here we test two ruthenium nitrosyls, which release NO when activated by biological reducing agents, for their effectsin vitroandin vivoagainstTrypanasoma cruzi, the agent responsible for the American trypanosomiasis (Chagas’ disease).

Experimental approach:

Ruthenium NO donors were incubated with a partially drug‐resistant strain ofT. cruziand the anti‐proliferative and trypanocidal activities evaluated. In a mouse model of acute Chagas’ disease, trypanocidal activity was evaluated by measuring parasitemia, survival rate of infected mice and elimination of amastigotes in myocardial tissue.

Key results:

In vitro, the observed anti‐proliferative and trypanocidal activities of trans‐[Ru(NO)(NH3)4isn](BF4)3andtrans‐[Ru(NO)(NH3)4imN](BF4)3were due to NO liberated upon reduction of these nitrosyls. Ru(NO)isn had a lower IC50epi(67μM) than the NO donor, sodium nitroprusside (IC50epi=244μM) and Ru(NO)imN (IC50try=52μM) was more potent than gentian violet (IC50try=536μM), currently used in the treatment of blood. Both ruthenium nitrosyls eliminated,in vivo, extracellular as well as intracellular forms ofT. cruziin the bloodstream and myocardial tissue and allowed survival of up to 80% of infected mice at a dose (100 nmol kg−1day−1) much lower than the optimal dose for benznidazole (385μmol kg−1day−1).

Conclusions and implications:

Our data strongly suggest that NO liberated is responsible for the anti‐proliferative and trypanocidal activities of the ruthenium NO donors and that these compounds are promising leads for novel and effective anti‐parasitic drugs.

British Journal of Pharmacology(2007)152, 112–121; doi:10.1038/sj.bjp.0707363
Novel uses for anti‐platelet agents as anti‐inflammatory drugs
Authors: Pitchford S C
Published: July 2007

An alteration in the character and function of platelets is manifested in patients with inflammatory diseases, and these alterations have been dissociated from the well‐characterized involvement of platelets in thrombosis and haemostasis. Recent evidence reveals platelet activation is sometimes critical in the development of inflammation. The mechanisms by which platelets participate in inflammation are diverse, and offer numerous opportunities for future drug intervention. There is now acceptance that platelets act as innate inflammatory cells in immune responses, with roles as sentinel cells undergoing surveillance, responding to microbial invasion, orchestrating leukocyte recruitment, and migrating through tissue, causing damage and influencing repair processes in chronic disease. Some of these processes are targeted by drugs that are being developed to target platelet participation in atherosclerosis. The actions of platelets therefore influence the pathogenesis of diverse inflammatory diseases in various body compartments, encompassing parasitic and bacterial infection, allergic inflammation (especially asthma and rhinitis), and non‐atopic inflammatory conditions, for example, chronic obstructive pulmonary disease (COPD), rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and atherosclerosis. This review will first discuss the evidence for platelet activation in these various inflammatory diseases, and secondly discuss the mechanisms by which this pathogenesis occurs and the various anti‐platelet agents which have been developed to combat platelet activation in atherosclerosis and their potential future use for the treatment of other inflammatory diseases.

British Journal of Pharmacology(2007)152, 987–1002; doi:10.1038/sj.bjp.0707364; published online 2 July 2007
Myosin light chain kinase‐independent inhibition by ML‐9 of murine TRPC6 channels expressed in HEK293 cells
Authors: Shi J , Takahashi S , Jin X‐H , Li Y‐Q , Ito Y , Mori Y , Inoue R
Published: July 2007

Background and purpose:

Myosin light chain kinase (MLCK) plays a pivotal role in regulation of cellular functions, the evidence often relying on the effects of extracelluarly administered drugs such as ML‐9. Here we report that this compound exerts non‐specific inhibitory actions on the TRPC6 channel, a transient receptor potential (TRP) protein.

Experimental approach:

Macroscopic and single channel currents were recorded from transfected HEK293 cells by patch‐clamp techniques.

Key results:

Cationic currents elicited by carbachol (CCh; 100 μM) in HEK293 cells overexpressing murine TRPC6 (ITRPC6) were dose‐dependently inhibited by externally applied ML‐9 (IC50=7.8 μM). This inhibition was voltage‐dependent and occurred as fast as external Na+ removal. Another MLCK inhibitor, wortmannin (3 μM), and MLCK inhibitory peptides MLCK‐IP11‐19 (10 μM) and ‐IP480‐501 (1 μM) showed little effects on ITRPC6 density and the inhibitory efficacy of ML‐9. The extent of the inhibition also unchanged with co‐expression of wild‐type or a dominant negative mutant of MLCK. Inhibitory effects of ML‐9 on ITRPC6 remained unaffected whether TRPC6 was activated constitutively or by a diacylglycerol analogue OAG (100 μM). Similar rapid inhibition was also observed with a ML‐9 relative, ML‐7. Intracellular perfusion of ML‐9 via patch pipette, dose‐dependently suppressed ITRPC6. In inside‐out patch configuration, bath application of ML‐9 (and ML‐7) rapidly diminished ∼35pS single TRPC6 channel activities. Contrarily, currents due to TRPC7 expression were rapidly enhanced by externally applied ML‐9 and ML‐7, which was not prevented by MLCK inhibitory peptides.

Conclusion and implications:

These results strongly suggest that ML compounds inhibit TRPC6 channels via a mechanism independent of inhibition of MLCK activity.

British Journal of Pharmacology (2007) 152, 122–131; doi:10.1038/sj.bjp.0707368
Interrelation between Lignin Deposition and Polysaccharide Matrices during the Assembly of Plant Cell Walls
Authors: Ruel K. , Montiel M.‐D. , Goujon T. , Jouanin L. , Burlat V. , Joseleau J.‐P.
Published: July 2007

Abstract: The modifications caused by genetic down‐regulation of the enzyme cinnamoyl CoA reductase (CCR) from monolignol biosynthetic pathways on tobacco and Arabidopsis thaliana were investigated at the ultrastructural level. A typical result was that the same transformation led to similar abnormality in secondary wall formation of fibres in both plants. The cell wall alterations mainly consisted in an important disorganization and loosening of cellulose microfibrils in the inner part of the S2 layer. This inability of the transformants to form a coherent cell wall coincided with a lack of synthesis of non‐condensed forms of lignin in this disorganized region of the wall, as demonstrated by immunolabelling of lignin subunits. A similar disorganization was observed during fibre wall formation in the differentiating tissues of young Populus and A. thaliana plants. The transitory lack of organization of cellulose microfibrils, also coincided with a depletion in non‐condensed forms of lignins. These results suggest that such lignin substructures may be involved in the cohesion of secondary walls during cell wall biogenesis. The mutual influence of the cellulose‐hemicellulose environment and monolignol local polymerization is discussed.
On the Cytochemistry of Cell Wall Formation in Poplar Trees
Authors: Grünwald C. , Ruel K. , Kim Y. S. , Schmitt U.
Published: July 2007

Abstract: The ultrastructure of cell walls and the mechanisms of cell wall formation are still not fully understood. The objective of our study was therefore to obtain additional fine structural details on the deposition of cell wall components during the differentiation of xylem cells in hybrid aspen (Populus tremula L. ×P. tremuloides Michx.) we used as a model tree. At the electron microscope level, PATAg staining revealed a successive deposition of polysaccharides with increasing distance from the cambium. Staining with potassium permanganate and UV microspectrophotometry showed that the cell walls were lignified, with some delay to the deposition of polysaccharides. Immunogold labelling of three lignin types in developing cell walls varied with progressive deposition of cell wall layers. Condensed lignin subunits were localized in corners of cells adjacent to the cambium prior to S1 formation, whereas non‐condensed lignin subunits became labelled only in later stages ‐ in secondary walls near cell corners and simultaneously with the completion of S1 formation. As S2 polysaccharide deposition progressed, the labelling extended towards the lumen. Labelling of peroxidases revealed their presence in cell corner regions of young xylem cells, still lacking a secondary wall, implying that peroxidases are incorporated into the developing cell wall at early developmental stages. A weak labelling of middle lamella regions and secondary walls could also be seen at later stages. The results are discussed in relation to current knowledge on the succession of polysaccharide and lignin deposition in woody cell walls.
Nutrients Induce an Increase in Inositol 1,4,5‐Trisphosphate in Soybean Cells: Implication for the Involvement of Phosphoinositide‐Specific Phospholipase C in DNA Synthesis
Authors: Shigaki T. , Bhattacharyya M. K.
Published: July 2007

Abstract: Phosphoinositide‐specific phospholipase C (PI‐PLC) hydrolyzes the membrane lipid phosphatidylinositol 4,5‐bisphosphate (PtdInsP2) to generate 1,2‐diacylglycerol (DAG) and inositol 1,4,5‐trisphosphate (InsP3). Both molecules serve as second messengers to carry out various cellular functions in mammals. In the present study, we demonstrate that many organic and inorganic nutrients cause the elevation of InsP3 concentrations in cultured soybean cells. This elevation of InsP3 content is sustained for several hours following treatment with Murashige‐Skoog (MS) inorganic nutrients. Phosphate and calcium are the major components in MS salts responsible for the increase in InsP3 levels. DNA synthesis, a measure of cell growth, was significantly suppressed by the PI‐PLC‐specific inhibitor 1‐(6‐{[17β‐3‐methoxyestra‐1,3,5(10)‐trien‐17‐yl]amino}hexyl)‐1H‐pyrrole‐2,5‐dione (U‐73122), whereas its near‐identical analogue 1‐(6‐{[17β‐3‐methoxyestra‐1,3,5(10)‐trien‐17‐yl]amino}hexyl)‐2,5‐pyrrolidinedione did not cause any suppression. Activation of PI‐PLC by MS salts increased DNA synthesis and abolished the suppression of DNA synthesis caused by U‐73122. Thus, we conclude that the higher cellular concentration of InsP3 induced by MS treatment is involved in DNA synthesis.
Distribution of Adult Male and FemaleBaccharis concinna(Asteraceae) in the Rupestrian Fields of Serra Do Cipó, Brazil
Authors: Marques A. R. , Fernandes G. W. , Reis I. A. , Assunç;ão R. M.
Published: July 2007

Abstract:This study focuses on the sex ratio and spatial distribution of males and females in three populations of the endemic and restricted tropical dioecious shrub,Baccharis concinna(Asteraceae) in the mountainous region of Serra do Cipó, southeastern Brazil. The proportion of female plants in the population at lower elevation (1000 m a.s.l.) was significantly greater than of male plants. At this elevation of P/N and Ca/Al ratios in the soil were also greater indicating better nutritional status of the soils. The concentration of aluminium increased significantly with the elevation (p< 0.001), perhaps rendering soils less conducive to female plants at higher elevations. Female plants are possibly adversely affected to a greater extent by soil quality than male plants. The spatial distribution of the populations within habitat was tested by the K(t) function, where the neighbourhood of a given individual was defined by a circle with a radius (t) up to 3 m. Despite the strong tendency for aggregation, the distribution of the sexes within habitats was random and the hypothesis was not supported. The independent distribution of the sexes within habitats may be explained by nutrient homogeneity of the soils, as well as by an absence of antagonism between the sexes. Nevertheless, we found a trend for males and females to be aggregated according to their gender.
Bienertia cycloptera Bunge ex Boiss., Chenopodiaceae, another C4 Plant without Kranz Tissues286
Authors: Freitag H. , Stichler W.
Published: July 2007

Abstract: Following up an earlier study on Borszczowia aralocaspica, a second C4 leaf type without Kranz tissues is described from Bienertia cycloptera Bunge ex Boiss. The species belongs also to tribe Suaedeae and grows in similar temporarily wet saline habitats in southwestern C Asia. Like Borszczowia, the species has the ability to perform C4 photosynthesis in single chlorenchyma cells but the cytological compartmentation differs. Evidence is cited from anatomy (cytoplasmic compartmentation, starch formation), from carbon isotope composition and from indirect sources. It is documented by micrographs and δ13C values (mean ‐ 14.7 %). Variations of the δ13C values subsequently found in newly formed leaves of the same greenhouse plants (‐ 15.5 to ‐ 21.1 %) support the hypothesis that Bienertia is a facultative C4/C3 species. The new described bienertioid leaf type differs from the leaves of C3 species in Suaeda by strict separation of the mesophyll into a central aqueous tissue without chloroplasts and a peripheral 1 ‐ 3 layered chlorenchyma with elaborate cytoplasmic compartmentation. Each cell of the latter contains a peripheral cytoplasmic layer with scattered chloroplasts and a large globular cytoplasmic body located in the central vacuole which is densely packed with starch producing chloroplasts, and joined by the nucleus. Comparative studies on different leaves of the same individuals of ordinary C4 species demonstrated a remarkable range of variation, from 1.0 % in Salsola tragus up to 2.5 % in Petrosimonia sibirica. This corresponds well with the variance in data from different individuals and populations. For explaining the larger interspecific variation from about 23 other species of Salsoloideae, the hypothesis is developed that in species or groups of taxa specific leakages of their C4 systems do occur. By three characters unique in tribe Suaedeae and detected during the study, Bienertia is confirmed as well separated from Suaeda and as a monotypic genus.
Flavor group Δ(3n2)
Authors: Luhn Christoph , Nasri Salah , Ramond Pierre
Published: July 2007

The large neutrino mixing angles have generated interest in finite subgroups of SU(3), as clues towards understanding the flavor structure of the standard model. In this work, we study the mathematical structure of the simplest non-Abelian subgroup, Δ(3n2). Using simple mathematical techniques, we derive its conjugacy classes and character table, and build its irreducible representations, their Kronecker products, and its invariants.
High (1GHz) repetition rate compact femtosecond laser: A powerful multiphoton tool for nanomedicine and nanobiotechnology
Authors: Ehlers A. , Riemann I. , Martin S. , Le Harzic R. , Bartels A. , Janke C. , König K.
Published: July 2007

Multiphoton tomography of human skin and nanosurgery of human chromosomes have been performed with a 1GHz repetition rate laser by the use of the commercially available femtosecond multiphoton laser tomograph DermaInspect as well as a compact galvoscanning microscope. We performed the autofluorescence tomography up to 100μm in the depth of human skin. Submicron cutting lines and hole drillings have been conducted on labeled human chromosomes.
Computation and interpretation of molecular Omega intracules
Authors: Crittenden Deborah L. , Gill Peter M. W.
Published: July 2007

The Omega intracule is a three-dimensional function that describes the relative positions, momenta, and directions of motion of pairs of electrons in a system. In this paper, we describe the computation of the Omega intracule for a molecular system whose electronic wave function is expanded in a Gaussian basis set. This is followed by implementation details and numerical tests. Finally, we use the Omega intracules of a number of small systems to illustrate the power of this function to extract simple physical insights from complicated wave functions.
Weak binding between two aromatic rings: Feeling the van der Waals attraction by quantum Monte Carlo methods
Authors: Sorella Sandro , Casula Michele , Rocca Dario
Published: July 2007

We report a systematic study of the weak chemical bond between two benzene molecules. We first show that it is possible to obtain a very good description of the C2 dimer and the benzene molecule by using pseudopotentials for the chemically inert 1s electrons and a resonating valence bond wave function as a variational ansatz, expanded on a relatively small Gaussian basis set. We employ an improved version of the stochastic reconfiguration technique to optimize the many-body wave function, which is the starting point for highly accurate simulations based on the lattice regularized diffusion Monte Carlo method. This projection technique provides a rigorous variational upper bound for the total energy, even in the presence of pseudopotentials, and substantially improves the accuracy of the trial wave function, which already yields a large fraction of the dynamical and nondynamical electron correlation. We show that the energy dispersion of two benzene molecules in the parallel displaced geometry is significantly deeper than the face-to-face configuration. However, contrary to previous studies based on post-Hartree-Fock methods, the binding energy remains weak (≃2kcal∕mol) also in this geometry, and its value is in agreement with the most accurate and recent experimental findings [H. Krause et al., Chem. Phys. Lett. 184, 411 (1991)].
Thermal diffusion measurements and simulations of binary mixtures of spherical molecules
Authors: Polyakov Pavel , Zhang Meimei , Müller-Plathe Florian , Wiegand Simone
Published: July 2007

Thermal diffusion forced Rayleigh scattering measurements on binary mixtures of carbon tetrabromide (CBr4), tetraethylsilane, and di-tert-butylsilane in carbon tetrachloride (CCl4) are reported at different temperatures and concentrations. The Soret coefficient of CBr4 in CCl4 is positive and ST of both silanes in CCl4 is negative, which implies that the heavier component always moves to the cold side. This is the expected behavior for unpolar simple molecules. Both silanes have the same mass so the influence of the difference in shape and moment of inertia could be studied. For all three systems, ST decreases with decreasing CCl4 concentration. The results are discussed in the framework of thermodynamic theories and the Hildebrand parameter concept. Additionally, the Soret coefficients for both silane∕CCl4 systems were determined by nonequilibrium molecular-dynamics calculations. The simulations predict the correct direction of the thermophoretic motion and reflect the stronger drive toward the warm side for di-tert-butylsilane compared to the more symmetric tetraethylsilane. The values deviate systematically between 9% and 18% from the experimental values.
Using redundant coordinates to represent potential energy surfaces with lower-dimensional functions
Authors: Manzhos Sergei , Carrington Tucker
Published: July 2007

We propose a method for fitting potential energy surfaces with a sum of component functions of lower dimensionality. This form facilitates quantum dynamics calculations. We show that it is possible to reduce the dimensionality of the component functions by introducing new and redundant coordinates obtained with linear transformations. The transformations are obtained from a neural network. Different coordinates are used for different component functions and the new coordinates are determined as the potential is fitted. The quality of the fits and the generality of the method are illustrated by fitting reference potential surfaces of hydrogen peroxide and of the reaction OH+H2→H2O+H.
Production yields of H(D) atoms in the reactions of N2(AΣu+3) with C2H2, C2H4, and their deuterated variants
Authors: Umemoto Hironobu
Published: July 2007

The production yields of H(D) atoms in the reactions of N2(AΣu+3) with C2H2, C2H4, and their deuterated variants were determined. N2(AΣu+3) was produced by excitation transfer between Xe(6s[3∕2]1) and ground-state N2 followed by collisional relaxation. Xe(6s[3∕2]1) was produced by two-photon laser excitation of Xe(6p[1∕2]0) followed by concomitant amplified spontaneous emission. H(D) atoms were detected by using vacuum-ultraviolet laser-induced fluorescence (LIF). The H(D)-atom yields were evaluated from the LIF intensities and the overall rate constants for the quenching, which were determined from the temporal profiles of the NO tracer emission. The absolute yields were evaluated by assuming that the yield for NH3(ND3) is 0.9. Although no H∕D isotope effects were observed in the overall rate constants, there were isotope effects in the H(D)-atom yields. The H-atom yields for C2H2 and C2H4 were 0.52 and 0.30, respectively, while the D-atom yields for C2D2 and C2D4 were 0.33 and 0.13, respectively. The presence of isotope effects in yields suggests that H2(D2) molecular elimination processes are competing and that molecular elimination is more dominant in deuterated species than in hydrides.
Acoustic band gaps in periodically and quasiperiodically modulated waveguides
Authors: King P. D. C. , Cox T. J.
Published: July 2007

We report experimental observation of the formation of phononic band structure in one-dimensional periodically and quasiperiodically (based on the Fibonacci and Thue-Morse number sequences) area modulated waveguide structures. The experimental results are compared to model calculations considering the interference of multiply reflected waves using a transfer matrix method formulation. It was found that both the scattering due to the changes in area (causing an impedance discontinuity) and also the radiation impedance acting at each area discontinuity must be considered to accurately model the experimental results. For the quasiperiodic structures, complicated transmission spectra are seen to result, characterized by wide acoustic pseudo-band-gaps interrupted by narrow defect modes around the center of the gap.
Structure factor and thermodynamics of rigid dendrimers in solution
Authors: Harnau L. , Rosenfeldt S. , Ballauff M.
Published: July 2007

The “polymer reference interaction site model” (PRISM) integral equation theory is used to determine the structure factor of rigid dendrimers in solution. The theory is quite successful in reproducing experimental structure factors for various dendrimer concentrations. In addition, the structure factor at vanishing scattering vector is calculated via the compressibility equation using scaled particle theory and fundamental measure theory. The results as predicted by both theories are systematically smaller than the experimental and PRISM data for platelike dendrimers.
Anomalous Hall effect in anatase Co:TiO2 ferromagnetic semiconductor
Authors: Ramaneti R. , Lodder J. C. , Jansen R.
Published: July 2007

The observation of the anomalous Hall effect (AHE) in Co-doped TiO2 ferromagnetic semiconductor in the anatase phase is reported. An AHE is observed with magnetic hysteresis consistent with remanence and coercivity obtained from magnetometry data. The anatase films also have reasonable mobility (∼17cm2∕Vs) at room temperature and carrier density of ∼5×1018cm−3. The AHE in such films with relatively low carrier density gives prospects to test whether the ferromagnetism in this oxide semiconductor is carrier mediated using a field effect device configuration.
High-energy collision induced dissociation fragmentation pathways of peptides, probed using a multiturn tandem time-of-flight mass spectrometer “MULTUM-TOF/TOF”
Authors: Toyoda Michisato , Giannakopulos Anastassios E. , Colburn Alex W. , Derrick Peter J.
Published: July 2007

A new multiturn tandem time-of-flight (TOF) mass spectrometer “MULTUM-TOF/TOF” has been designed and constructed. It consists of a matrix-assisted laser desorption/ionization ion source, a multiturn TOF mass spectrometer, a collision cell, and a quadratic-field ion mirror. The multiturn TOF mass spectrometer can overcome the problem of precursor ion selection in TOF, due to insufficient time separation between two adjacent TOF peaks, by increasing the number of cycles. As a result, the total TOF increases with the increase in resolving power. The quadratic-field ion mirror allows temporal focusing for fragment ions with different kinetic energies. Product ion spectra from monoisotopically selected precursor ions of angiotensin I, substance P, and bradykinin have been obtained. The fragment ions observed are mainly the result of high-energy collision induced dissociation.
Wide-spectrum, ultrasensitive fluidic sensors with amplification from both fluidic circuits and metal oxide semiconductor field effect transistors
Authors: Xu Dongyan , Kang Yuejun , Sridhar Manoj , Hmelo Anthony B. , Feldman Leonard C. , Li Dongqing , Li Deyu
Published: July 2007

The authors report a sensing scheme to detect the translocation of small particles through a fluidic channel. The device connects the gate of a metal oxide semiconductor field effect transistor (MOSFET) with a fluidic circuit and monitors the FET’s drain current to detect particles. They demonstrate that amplification can be achieved from both the fluidic circuit and the MOSFET. The results show that a 0.7% volume ratio of the particle to the sensing microchannel can lead to 28%–56% modulation of the MOSFET’s drain current. The minimum volume ratio detected is 0.006%, which is about ten times smaller than the lowest detectable volume ratio reported in the literature.
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Ohmic contacts to n-AlGaN∕GaN heterostructures with a thin GaN cap
Authors: Miller M. A. , Mohney S. E.
Published: July 2007

Silver is studied as a replacement for Au in V- and Ti-based Ohmic contacts to GaN-capped n-Al0.27Ga0.73N∕GaN heterostructures for high electron mobility transistors. An optimized V∕Al∕V∕Ag contact provided a low contact resistance of 0.27Ωmm and specific contact resistance of 1.7×10−6Ωcm2, and was much smoother than analogous Au-bearing metallizations. Transmission electron microscopy reveals a very limited reaction of the annealed metallization and semiconductor, leaving the Al0.27Ga0.73N layer intact. The majority of the Al0.27Ga0.73N interface is contacted by Ag-bearing phases. Silver has a lower work function than Au and facilitates the formation of a low-resistance Ohmic contact.
Local dielectric spectroscopy of polymer films
Authors: Crider P. S. , Majewski M. R. , Zhang Jingyun , Oukris H. , Israeloff N. E.
Published: July 2007

A noncontact scanning probe microscopy method of probing local frequency-dependent dielectric spectroscopy is described. Dielectric spectra can be measured with this technique from 0.01to100Hz, in nanometer-scale near-surface regions of materials. The technique is applied to polymer films (polyvinyl acetate), in order to determine if polymer glassy dynamics are altered near a free surface. A small reduction in glass transition temperature and a moderate narrowing of the distribution of relaxation times are found within 20nm of a free surface.
Heavy hole doping of epitaxial thin films of a wide gap p-type semiconductor, LaCuOSe, and analysis of the effective mass
Authors: Hiramatsu Hidenori , Ueda Kazushige , Ohta Hiromichi , Hirano Masahiro , Kikuchi Maiko , Yanagi Hiroshi , Kamiya Toshio , Hosono Hideo
Published: July 2007

The high density hole doping (1.7×1021cm−3) for a wide gap (Eg=∼2.8eV) p-type semiconductor was achieved on 40nm thick Mg-doped LaCuOSe epitaxial films. These films exhibited distinct free carrier absorption, and the effective mass and momentum relaxation time were analyzed. Its small hole mobility [∼3.5cm2∕(Vs)] compared to the electron mobilities of wide gap n-type semiconductors is attributed to a heavy effective mass of 1.6±0.2me. Regardless of the heavy hole doping, a band filling effect was not observed. These results are discussed with a rigid band model and an acceptor band model.
Phase change nanodot arrays fabricated using a self-assembly diblock copolymer approach
Authors: Zhang Yuan , Wong H.-S. Philip , Raoux Simone , Cha Jennifer N. , Rettner Charles T. , Krupp Leslie E. , Topuria Teya , Milliron Delia J. , Rice Philip M. , Jordan-Sweet Jean L.
Published: July 2007

Self-assembling diblock copolymer, polystyrene-b-poly-4-vinylpyridine (PS-b-P4VP), was used as the template for fabricating phase change nanostructures. The high density GeSb nanodots were formed by etching into an amorphous GeSb thin film using silica hard mask which was patterned on top of polymer. The nanodot arrays are 15nm in diameter with 30nm spacing. This is smaller than most structures obtained by e-beam lithography. Time-resolved x-ray diffraction studies showed that the phase transition occurred at 235°C, which is 5°C lower than blanket GeSb film but higher than that of Ge2Sb2Te5 (150°C). GeSb showed good temperature stability for fabrication of small memory devices.
Russia leads international team on revived UV space telescope
Authors: Feder Toni
Published: July 2007

Thanks to an upswing in Russia’s economy, a long-dormant plan for a UV space telescope is now taking shape.
Control ofC. eleganshermaphrodite gonad size and shape byvab-3/Pax6-mediated regulation of integrin receptors
Authors: Meighan Christopher M. , Schwarzbauer Jean E.
Published: July 2007

Integrin receptors for extracellular matrix are critical for cell motility, but the signals that determine when to stop are not known. Analysis of distal tip cell (DTC) migration during gonadogenesis inCaenorhabditis eleganshas revealed the importance of transcription factorvab-3/Pax6 in regulating the α integrin genes,ina-1andpat-2. Utilizingvab-3mutants, we show that the down-regulation ofina-1is necessary for DTC migration cessation and the up-regulation ofpat-2is required for directionality. These results demonstrate concomitant, but distinct roles in migration for each integrin. Notably, transcriptional control of migration termination provides a new mechanism for regulation of morphogenesis and organ size.
Transcription termination factor Pcf11 limits the processivity of Pol II on an HIV provirus to repress gene expression
Authors: Zhang Zhiqiang , Klatt Alicia , Henderson Andrew J. , Gilmour David S.
Published: July 2007

Many elongation factors in eukaryotes promote gene expression by increasing the processivity of RNA polymerase II (Pol II). However, the stability of RNA Pol II elongation complexes suggests that such complexes are not inherently prone to prematurely terminating transcription, particularly at physiological nucleotide concentrations. We show that the termination factor, Pcf11, causes premature termination on an HIV provirus. The transcription that occurs when Pcf11 is depleted from cells or an extract is no longer sensitive to 6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB), a compound that causes premature termination. Hence, Pcf11 can act as a negative elongation factor to repress RNA Pol II gene expression in eukaryotic cells.
The molecular signature and cis-regulatory architecture of a C. elegans gustatory neuron
Authors: Etchberger John F. , Lorch Adam , Sleumer Monica C. , Zapf Richard , Jones Steven J. , Marra Marco A. , Holt Robert A. , Moerman Donald G. , Hobert Oliver
Published: July 2007

Taste receptor cells constitute a highly specialized cell type that perceives and conveys specific sensory information to the brain. The detailed molecular composition of these cells and the mechanisms that program their fate are, in general, poorly understood. We have generated serial analysis of gene expression (SAGE) libraries from two distinct populations of single, isolated sensory neuron classes, the gustatory neuron class ASE and the thermosensory neuron class AFD, from the nematode Caenorhabditis elegans. By comparing these two libraries, we have identified >1000 genes that define the ASE gustatory neuron class on a molecular level. This set of genes contains determinants of the differentiated state of the ASE neuron, such as a surprisingly complex repertoire of transcription factors (TFs), ion channels, neurotransmitters, and receptors, as well as seven-transmembrane receptor (7TMR)-type putative gustatory receptor genes. Through the in vivo dissection of the cis-regulatory regions of several ASE-expressed genes, we identified a small cis-regulatory motif, the “ASE motif,” that is required for the expression of many ASE-expressed genes. We demonstrate that the ASE motif is a binding site for the C2H2 zinc finger TF CHE-1, which is essential for the correct differentiation of the ASE gustatory neuron. Taken together, our results provide a unique view of the molecular landscape of a single neuron type and reveal an important aspect of the regulatory logic for gustatory neuron specification in C. elegans.
T7-Based RNA Amplification for Genotyping from Maize Shoot Apical Meristem
Authors: Ohtsu Kazuhiro , Schnable Patrick S.
Published: July 2007

INTRODUCTION

The use of RNA for genotyping analysis can be advantageous because transcriptomes are significantly smaller than genomes and typically contain far fewer repetitive sequences. Laser capture microdissection (LCM) has been used successfully to isolate sequences (especially rare transcripts) that accumulate in specific tissues. The amount of RNA collected in a standard microdissection is often insufficient for global gene expression analysis but can be increased via linear amplification. Upon conversion to cDNA, the product serves as template for 454 sequencing to produce expressed sequence tags for subsequent SNP analysis and detection. This protocol describes how to amplify RNA extracted from laser-dissected and captured tissues and cells.
In Vivo Electroporation of Neurons
Authors: Price Stephen R.
Published: July 2007

INTRODUCTION

This protocol describes the electroporation of DNA constructs to drive in vivo gene expression in neurons during early chick development. Electroporation is a method of physically introducing DNA constructs into cells through the application of an electric field. This simple method is important as it allows the ectopic expression of transgenes with relative ease in most neurons.
Using a FASTA Sequence Database Similarity Search
Authors: Mount David W.
Published: July 2007

INTRODUCTION

FASTA is a program for rapid alignment of pairs of protein and DNA sequences. Rather than comparing individual residues in the two sequences, FASTA searches for matching sequence patterns or words, calledk-tuples. These patterns comprisekconsecutive matches of letters in both sequences. The program then attempts to build a local alignment based on these word matches. Due to the ability of the algorithm to find matching sequences in a sequence database with high speed, FASTA is useful for routine database searches of this type. Comparable methods are the BLAST program, which is faster than FASTA, is of comparable sensitivity for protein queries, and also does DNA searches, and programs that use the Smith-Waterman dynamic programming algorithm for protein and DNA searches, which are slower but more sensitive when full-length protein sequences are used as queries.