bluuebunny/crossref_metadata_2025 huggingface dataset:
Kissing Interaction between 3′ Noncoding and Coding Sequences Is Essential for Porcine Arterivirus RNA Replication
Authors: Verheije M. H. , Olsthoorn R. C. L. , Kroese M. V. , Rottier P. J. M. , Meulenberg J. J. M.
Published: October 2010

We used an infectious cDNA clone of
Porcine reproductive and respiratory syndrome virus
(PRRSV) to investigate the presence of essential replication elements in the region of the genome encoding the structural proteins. Deletion analysis showed that a stretch of 34 nucleotides (14653 to 14686) within ORF7, which encodes the nucleocapsid protein, is essential for RNA replication. Strand-specific reverse transcription-PCR analysis of viral RNA isolated from transfected BHK-21 cells revealed that this region is required for negative-strand genomic RNA synthesis. The 34-nucleotide stretch is highly conserved among PRRSV isolates and folds into a putative hairpin. A 7-base sequence within the loop of this structure was suggested to base-pair with a sequence present in the loop of a hairpin located in the 3′ noncoding region, resulting in a kissing interaction. Mutational analyses confirmed that this kissing interaction is required for RNA replication.
Second-Site Mutation Outside of the U
S
10-12 Domain of Δγ
1
34.5 Herpes Simplex Virus 1 Recombinant Blocks the Shutoff of Protein Synthesis Induced by Activated Protein Kinase R and Partially Restores Neurovirulence
Authors: Cassady Kevin A. , Gross Martin , Gillespie G. Yancey , Roizman Bernard
Published: October 2010

Earlier studies have shown that herpes simplex virus type 1 (HSV-1) activated protein kinase R (PKR) but that the product of the product of the γ
1
34.5 gene binds and redirects the host phosphatase 1 to dephosphorylate the α subunit of eukaryotic translation initiation factor 2 (eIF-2α). In consequence, the γ
1
34.5 gene product averts the threatened shutoff of protein synthesis caused by activated PKR. Serial passages of Δγ
1
34.5 mutants in human cells led to isolation of two classes of second-site, compensatory mutants. The first, reported earlier, resulted from the juxtaposition of the α promoter of the U
S
12 gene to the coding sequence of the U
S
11 gene. The mutant blocks the phosphorylation of eIF-2α but does not restore the virulence phenotype of the wild-type virus. We report another class of second-site, compensatory mutants that do not map to the U
S
10-12 domain of the HSV-1 genome. All mutants in this series exhibit sustained late protein synthesis, higher yields in human cells, and reduced phosphorylation of PKR that appears to be phosphatase dependent. Specific dephosphorylation of eIF-2α was not demonstrable. At least one mutant in this series exhibited a partial restoration of the virulence phenotype characteristic of the wild-type virus phenotype. The results suggest that the second-site mutations reflect activation of fossilized functions designed to block the interferon response pathways in cells infected with the progenitor of present HSV.
Small DNA Hairpin Negatively Regulates In Situ Priming during Duck Hepatitis B Virus Reverse Transcription
Authors: Habig Jeffrey W. , Loeb Daniel D.
Published: October 2010

There are two mutually exclusive pathways for plus-strand DNA synthesis in hepadnavirus reverse transcription. The predominant pathway gives rise to relaxed circular DNA, while the other pathway yields duplex linear DNA. Both pathways use the same RNA primer, which is capped and 18 or 19 nucleotides in length. At the completion of minus-strand DNA synthesis, the final RNase H cleavage generates the plus-strand primer. To make relaxed circular DNA, primer translocation must occur, resulting in the transfer of the primer generated at DR1 to the acceptor site (DR2) near the opposite end of the minus-strand DNA. A small fraction of viruses instead make duplex linear DNA after initiating plus-strand DNA synthesis from DR1, a process called in situ priming. We are interested in understanding the mechanism of discrimination between these two pathways. Some variants of duck hepatitis B virus exhibit high levels of in situ priming due to
cis-
acting mutations. The mechanism by which these mutations act has been obscure. Sequence inspection predicted formation of a small DNA hairpin in the region overlapping these mutations. We have shown that substitutions disrupting base pairing potential in this hairpin led to increased levels of in situ priming. The introduction of compensatory changes to restore base pairing potential led to reduced levels of in situ priming. Thus, formation of the small DNA hairpin overlapping the 5′ end of DR1 in the minus strand contributes to the regulation of primer translocation, at least, through inhibition of in situ priming by making the 3′ end of the minus-strand DNA a poor template for initiation.
Phosphorylation of the Epstein-Barr Virus (EBV) DNA Polymerase Processivity Factor EA-D by the EBV-Encoded Protein Kinase and Effects of the
l
-Riboside Benzimidazole 1263W94
Authors: Gershburg Edward , Pagano Joseph S.
Published: October 2010

A member of the family of
l
-riboside benzimidazole compounds, 1263W94, was shown recently to inhibit replication of Epstein-Barr virus (EBV) (V. L. Zacny, E. Gershburg, M. G. Davis, K. K. Biron, and J. S. Pagano, J. Virol. 73:7271–7277, 1999). In the present report the effect of 1263W94 on the phosphorylation pattern of the EBV DNA polymerase processivity factor, EA-D, during viral reactivation in latently EBV-infected Akata cells is analyzed. This pattern specifically changes with progression of cytolytic infection. In the presence of 1263W94 the appearance of the hyperphosphorylated form of EA-D is mainly affected. Next, coexpression of the cloned EBV-encoded protein kinase (EBV PK), BGLF4, with EA-D demonstrated the ability of EBV PK to phosphorylate EA-D to its hyperphosphorylated form in transient assays. However, the phosphorylation of EA-D was not directly inhibited by 1263W94 in these coexpression assays. The results indicate that the EBV PK appears to be responsible for the hyperphosphorylation of EA-D, imply that the phosphorylation status of EA-D is important for viral replication, and suggest that 1263W94 acts at a level other than direct inhibition of EA-D phosphorylation by EBV PK.
Analysis of the C-Terminal Membrane Anchor Domains of Hepatitis C Virus Glycoproteins E1 and E2: toward a Topological Model
Authors: Charloteaux Benoit , Lins Laurence , Moereels Henri , Brasseur Robert
Published: October 2010

The hepatitis C virus (HCV) glycoproteins E1 and E2 should be anchored in the viral membrane by their C-terminal domains. During synthesis, they are translocated to the endoplasmic reticulum (ER) lumen where they remain. The 31 C-terminal residues of the E1 protein and the 29 C-terminal residues of the E2 protein are implicated in the ER retention. Moreover, the E1 and E2 C termini are implicated in E1-E2 heterodimerization. We studied the E1 and E2 C-terminal sequences of 25 HCV strains in silico using molecular modeling techniques. We conclude that both C-terminal domains should adopt a similar and peculiar configuration: one amphipathic α-helix followed by a pair of transmembrane β-strands. Several three-dimensional (3-D) models were generated. After energy minimization, their ability to interact with membranes was studied using the molecular hydrophobicity potentials calculation and the IMPALA procedure. The latter simulates interactions with a membrane by a Monte Carlo minimization of energy. These methods suggest that the β-hairpins could anchor the glycoproteins in the ER membrane at least transiently. Anchoring could be stabilized by the adsorption of the nearby amphipathic α-helices at the membrane surface. The 3-D models correlate with experimental results which indicate that the E1-E2 transmembrane domains are involved in the heterodimerization and have ER retention properties.
Estimating the Standing Biomass of Aquatic Macrophytes
Authors: Downing John A. , Anderson M. Robin
Published: October 2010

The accuracy, precision, and cost-efficiency of estimation techniques for macrophyte standing biomass are examined, and solutions are offered to problems encountered in the design of efficient sampling programs. Five sizes of quadrats (100 cm2 to 1 m2) were compared on seven occasions and ail five yielded equivalent biomass estimates in six of these tests. Published and unpublished values of biomass sampling variance measured around the world were predictable from average standing biomass and size of sampler. The sampling cost was predictable from sampler size. Analysis of these relationships allows optimization of sampling design. The use of small quadrat samplers with great replication is recommended. Adherence to this protocol can result in a 30-fold reduction in sampling cost. Recommendations are compared with techniques actually used by aquatic ecologists. A brief analysis of spatial heterogeneity of aquatic macrophyte biomass is presented.
Interactive Effects of Cadmium, Polychlorinated Biphenyls, and Fuel Oil on Experimentally Exposed English Sole (Parophrys vetulus)
Authors: Rhodes Linda , Casillas Edmundo , McKnight Barbara , Gronlund William , Myers Mark , Olson O. Paul , McCain Bruce
Published: October 2010

Investigation of the interactive effects of representatives of three classes of compounds was performed, using English sole (Parophrys vetulus) as the test organism, juvenile fish were exposed orally to cadmium chloride and Aroclor 1254 (PCB), either independently or simultaneously, for a 4-wk period, followed by exposure to seawater-accommodated No. 2 diesel fuel for 2 wk. Blood was collected for analysis of serum constituents, and tissue samples were examined for histological changes. Hepatocellular necrosis, regeneration, and karyomegaly were observed. Differential lesion prevalences were observed among the exposure groups, with high proportions among cadmium-exposed fish, low proportions among PCB-exposed fish, and intermediate proportions in combination cadmium- plus PCB-exposed fish. Levels of aspartate aminotransferase activity and magnesium in the sera of these groups exhibited similar patterns. Depressed serum calcium levels in both PCB-exposed and cadmium- plus PCB-exposed groups were found after the first week, and lower serum albumin concentrations occurred in all cadmium- and PCB-exposed groups following the third week. Subsequent exposure to No. 2 diesel fuel produced few effects in any of the exposure groups. The observed antagonistic effect of Aroclor 1254 against cadmium toxicity emphasizes the importance of employing multiple as well as single contaminant exposure in toxicity studies.
Foraging Behavior of Hatchery-Produced Coho Salmon (Oncorhynchus kisutch) Smolts on Live Prey
Authors: Paszkowski Cynthia A. , Olla Bori L.
Published: October 2010

We presented three groups of naive hatchery-produced, pellet-reared coho salmon (Oncorhynchus kisutch) with live, natural prey and observed their foraging behavior. Of 26 individuals examined, 20 captured one or more Crangon (sand shrimp) within 1 h of their first exposure to these prey. Six older [Formula: see text] accelerated smolts (underyearlings) displayed improved foraging performances with experience, capturing their first Crangon sooner during their second, compared with their first, exposure. Four of five of these fish successfully captured sand lance (Ammodytes hexapterus) within 1 h of their first presentation. Two groups of 10 recently smolted fingerlings (< 190 mm TL), one accelerated and one conventionally reared (yearlings), were used in choice experiments and simultaneously offered equal masses of Crangon and pellets. Six of the accelerated and seven of the conventionally reared fish ate larger amounts of Crangon than pellets, with all 20 fish striking more at Crangon than at pellets. Our results suggest that a majority of hatchery-produced coho salmon smolts readily recognize, capture, and ingest natural prey and seem capable of foraging successfully upon release into the marine environment.
Effects of Successive Flow Perturbations on Stream Invertebrates
Authors: Irvine J. R.
Published: October 2010

Initial stream flow changes after a period of constant flow have a much larger effect on invertebrate drift than subsequent changes. Constant discharge was maintained in two man-made streams for several months, after which discharge was kept constant on one stream (control) while in the other (treatment) it was increased fivefold and then returned to its original state three times between 17:00 and 21:00 in 1 d. This treatment was repeated on four successive days each week for 3 wk. On the first day of treatment the density of invertebrate drift increased in the treatment stream during the changes in discharge, the increase being less with each successive change. By the final day of treatment, however, the changes in discharge did not cause increases in drift, and this result is attributed to depletion of the benthos by repeated fluctuations in discharge. Surber sample estimates of benthic invertebrate density declined following flow changes. Many of the invertebrates displaced by flow changes were probably resident in sloughed off filamentous algae. I conclude that it is necessary to know the flow history of a river before being able to predict effects of flow perturbations.
Biological Control of Excessive Phytoplankton Growth and the Enhancement of Aquacultural Production
Authors: Smith Daniel Wilkins
Published: October 2010

A method is proposed to control phytoplankton biomass in aquacultural ponds, using both zooplankton and filter-feeding silver carp (Hypophthalmichthys molitrix). The technique maintains co-existence of zooplankton and filter-feeding fish by excluding the fish from part of the water column. Zooplankton, which feed on smaller algal species, and silver carp, which feed on large algae and zooplankton, together can consume all sizes of phytoplankton, thus controlling algal biomass. This technique was tested in 1000-L tanks, some containing channel catfish (Ictalurus punctatus) alone, some both catfish and silver carp, and others catfish and silver carp with a zooplankton refuge. The refuge permitted coexistence of high densities of large zooplankters with the filter-feeding fish. This combination of filter-feeders reduced algal biomass by as much as 99%, increased phytoplankton diversity, and showed a trend toward improved silver carp growth compared with treatments without a refuge. The proposed technique could be applied to both intensive and extensive aquacultural systems.
Variation in Body Morphology Among British Columbia Populations of Coho Salmon, Oncorhynchus kisutch
Authors: Taylor Eric B. , McPhail J. D.
Published: October 2010

Ten populations of juvenile coho salmon, Oncorhynchus kisutch, from streams tributary to the upper Fraser River, the lower Fraser River, and the Strait of Georgia region were morphologically compared. Juveniles from coastal streams (Fraser River below Hell's Gate and the Strait of Georgia) were more robust (deeper bodies and caudal peduncles, shorter heads, and larger median fins) than interior Juveniles. Discriminant function analysis indicated that juvenile coho could be identified as to river of origin with 71% accuracy. Juvenile coho from coastal streams were less successfully classified as to stream of origin; however, juveniles could be successfully identified as either coastal or interior with 93% accuracy. Juvenile coho from north coastal British Columbia, Alaska, and the upper Columbia system also fitted this coastal and interior grouping. This suggests that a coastwide coastal–interior dichotomy in juvenile body form exists. Three populations (one interior and two coastal) were studied in more detail. In these populations the coastal versus interior morphology was consistent over successive years, and was also displayed in individuals reared from eggs in the laboratory. Adult coho salmon also showed some of the coastal–interior morphological differences exhibited by juveniles. We concluded that the morphological differences between coastal and interior coho salmon are at least partially inherited.
Variation in Burst and Prolonged Swimming Performance Among British Columbia Populations of Coho Salmon,Oncorhynchus kisutch
Authors: Taylor Eric B. , McPhail J. D.
Published: October 2010

Burst swimming tests, using both wild and laboratory-reared juvenile coho salmon, Oncorhynchus kisutch, from three streams (two south coastal British Columbia and one interior), indicated that in the first few hundredths of a second of a "fast-start" the coastal juveniles attain greater burst velocities than similar sized interior juveniles. Interior (Coldwater River) juveniles had greater swimming stamina than individuals from the two coastal streams: Wade and Morrison creeks. The differences in stamina performance were demonstrated to be inherited. The differences in swimming performance between coastal and interior are related to differences in body form; coastal coho have deep, robust bodies, while interior juveniles are more fusiform. The differences in swimming performance between coastal and interior coho salmon are probably adaptive and related to differences in the energetic demands of their freshwater migrations and perhaps to different levels of predation in coastal and interior streams.
Seaweeds, Sea Urchins, and Lobsters: A Reappraisal
Authors: Miller Robert J.
Published: October 2010

A popular hypothesis, that on the south coast of Nova Scotia the green sea urchin (Strongylocentrotus droebachiensis) has been released from control by predators, is critically reviewed. Predator control is given the functional definition of limiting sea urchin grazing sufficient to permit abundant growth of seaweed. Of the predators identified, the American lobster (Homarus americanus) is the least likely to have been important in sea urchin control in recent decades. Feeding rates, stomach contents, and field biomass are available for this species. A smaller amount of data available for the rock crab (Cancer irroratus) and benthic feeding fish points to the conclusion that they likewise cannot control urchin populations. Among other temperate sea urchin species the case is strongest for sea otter control of Strongylocentrotus sp. in some areas of the west coast of North America. The formation of sea urchin grazing fronts, a usual step in the destruction of seaweed beds, has been explained as a behavioral response to predators. This may in fact be merely a response to the location of food. Evidence for suspected enhancement of lobster production by seaweeds is equivocal, and comparative field data collected in and out of seaweed beds (e.g. lobster abundance, food, growth, and survival) have not been published.
The internal evolution of black holes
Authors: Bonanno Alfio , Droz Serge , Israel Werner , Morsink Sharon
Published: October 2010

Determining the inner structure of a black hole is really an evolutionary problem, with precisely known initial data. The evolution can in principle be followed to within Planck distances of the singularity at the inner horizon, using only well-established physical laws. This article is a progress report and a review of open questions.
What astronomy has learned from observations of
Authors: Miller Steven , Lam Hoanh An , Tennyson Jonathan
Published: October 2010

We review the uses to which [Formula: see text] astronomical observations have been put, in the five years since the first detection of this molecular ion in the aurorae of Jupiter. Spectroscopy of Jupiter shows that the ionospheric temperature is high (~1000 K) compared with the lower atmosphere and that auroral column densities are between 1012 and 1013 cm−2. The molecule is also distributed widely across the planet in concentrations about 10% of peak auroral densities. Imaging in [Formula: see text]-sensitive wavelengths links the aurorae to open magnetic field lines, rather than those encompassing the Io plasma torus. Uranus shows [Formula: see text] emission intensities of a few percent of the peak jovian auroral lines, with somewhat weaker emission from Saturn. On Uranus, [Formula: see text] is distributed fairly evenly across the planet, with some indication that auroral enhancement is not more than a factor of two. Saturnine [Formula: see text] appears to be concentrated more towards the magnetic poles. The identification of [Formula: see text] in the spectrum of the type II supernova SN1987a constrains models of the explosion to avoid microscopic mixing during much of the first year of the event. So far no reliable detection of [Formula: see text] in the interstellar medium has been reported.
Numerical study of the properties of the real part of the Heisenberg–Euler effective Lagrangian
Authors: Valluri S. R. , Mielniczuk W. J. , Lamm D. R.
Published: October 2010

Convenient series representations for both the real and imaginary parts of the Heisenberg–Euler Lagrangian of quantum electrodynamics for constant electric, E, and magnetic, B, fields of arbitrary relative angle have been presented previously by Valluri et al. along with numerical results for the real and imaginary parts of the Lagrangian for its approximate valid range of [Formula: see text] and [Formula: see text], where Ecr ≈ 1.7 × 1016 V cm−1 and Bcr ≈ 4.4 × 1013 G. These series representations are applied to the calculation of the Hamiltonian energy, polarization, and magnetization densities for the chargeless vacuum, and numerical results and plots are presented for the specific cases of parallel and perpendicular E and B fields. The series representation of the Heisenberg–Euler Lagrangian is then applied to the energy momentum tensor, Tμν, to calculate the nonlinear corrections to the Maxwell terms of this tensor. Strong and weak field corrections are calculated and the latter are compared to Schwinger's weak field corrections for Tμν.
Multiphoton LIF in atomic 6Li
Authors: Ballard M. K. , Hoobler R. J. , He Chun , Gold L. P. , Bernheim R. A. , Bicchi P.
Published: October 2010

The multiphoton laser-induced fluorescence excitation spectrum of 6Li vapor has been measured with a tunable, pulsed, nanosecond laser scanned between 13 600 and 14 500 cm−1. Two- and three-photon allowed excitation transitions originating from the 22S and 22P levels were observed, the latter likely originating from photodissociation products of Li2. Laser polarization and power dependencies are consistent with the multiphoton transition probabilities. Evidence for a parity "forbidden" multiphoton transition is also present.
Cinématographie ultrarapide dans le domaine des courtes longueurs d'onde
Authors: Côté C. Y. , Nantel M. , Gauthier J. , Kieffer J. C.
Published: October 2010

We present some recent results on the temporal evolution of X-ray images and spectra of laser produced plasmas. These results illustrate our progress in the development of a new technology for subpicosecond cinematography. We discuss the perspectives of such a technology for the control and optimization of ultrashort X-ray sources.[Journal translation]
General methods for evaluating matrix elements of singular operators in two-electron systems
Authors: Yan Zong-Chao , Drake G. W. F.
Published: October 2010

Due to the recent advances in both theory and experiment for the fine structure of two-electron atomic systems, it is necessary to include quantum electrodynamic (QED) effects through orders α6mc2, α7ln(Zα)mc2, and α7mc2, in order to match the experimental precision. These effects can be expressed in terms of a sum of singular operators. A general scheme is given for the evaluation of a wide range of matrix elements of high-order singular QED operators for two-electron atomic systems in Hylleraas coordinates. The scheme presented here can be applied to triplet states with arbitrary angular momentum. A number of useful expressions for the analytical evaluation of radial integrals are derived. An example is given in calculating the Douglas and Kroll terms, and the numerical values of the reduced matrix elements are presented for the 2 3PJ states of helium.
A BOXCARS investigation of the V–V energy transfer from highly excited SF6 to CS2 and the sensitized photodissociation of CS2
Authors: Wang L. , Jones W. E.
Published: October 2010

The BOXCARS technique was used to investigate the vibrational energy transfer between highly excited SF6 and CS2, and for the sensitized photodissociation of CS2. The analysis of data, as reported in our previous studies, to extract vibrational temperature from the CARS signal has been revised in the present work to adjust for the fact that the ground-state population may not be constant. The current investigation suggests that IR laser excitation of SF6 and the energy exchange between excited SF6 and CS2 create a high-lying vibrational energy reservoir in the CS2 vibrational manifold. The rate of energy transfer depends on the partial pressures of SF6 and CS2, and the excitation intensity. The transfer rate shows greater dependence on the partial pressure of SF6 than on the partial pressure of CS2. At higher excitation energies, the energy reservoir leads to photofragmentation products.
The B′ 1Σu+ → X 1Σg+ and D 1Πu → X 1Σg+ band systems of molecular hydrogen
Authors: Abgrall Hervé , Roueff Evelyne , Launay Françoise , Roncin Jean-Yves
Published: October 2010

Spectral line positions and emission probabilities of the B′ 1Σu+ → X 1Σg+ and D 1Πu → X 1Σg+ band systems of molecular hydrogen have been calculated by solving a system of four coupled Schrödinger equations. A great number of rotational lines, emitted by a low-pressure electric discharge in H2, have been identified from 122 nm down to 78 nm. All the 69 bands of the B′ 1Σu+ → X 1Σg+ system and many high-J lines of 145 bands of the D 1Πu → X 1Σg+ system are reported for the first time. Improved molecular constants are derived for the (unperturbed) electronic excited state D 1Πu−.
Spectroscopy of pendular molecules in strong parallel electric and magnetic fields
Authors: Friedrich Bretislav , Slenczka Alkwin , Herschbach Dudley
Published: October 2010

We report high-resolution laser-induced fluorescence spectra of the A3Π1, [Formula: see text] ν″ = 0 system of ICl subjected to strong parallel electric and magnetic fields, scanned independently up to 50 kV cm−1 and 0.7 T. Either field induces coherent superposition or hybridization of the rotational states within the A3Π1 electronic state, which possesses both an electric and a magnetic dipole moment along the internuclear axis. Only the electric field induces such hybridization within the ground state [Formula: see text], since it is polar but diamagnetic. Comparisons with computed spectra illustrate several salient features. The hybridization creates directional pendular states in which the molecular axis is confined to librate over a limited angular range about the field direction. For a polar paramagnetic electronic state, such as the A state, parallel electric and magnetic fields conjoin in producing hybridization for half of the ensemble but they counteract for the other half. For the latter component, the electric and magnetic effects can be tuned to balance out, yet the concomitant field-induced hyperfine splitting remains, despite the resulting free rotation of the molecule. The dependence of the transition intensities on the combined fields provides an unequivocal means to determine the relative sign of the electric dipole moments in the upper and lower electronic states. We find that the sign is the same for the X and A states (chlorine more negative than iodine).
High-resolution study of the emission system of 80Se2 in the near infrared
Authors: Fink E. H. , Setzer K. D. , Ramsay D. A. , Zhu Q.-S.
Published: October 2010

The [Formula: see text] system of 80Se2 has been observed from a discharge flow system where [Formula: see text] molecules were excited by electronic energy transfer from metastable oxygen, O2(a1Δg), to ground state Se2. Emission spectra of the 0–0, 0–1, 0–2, 1–1, 1–2, 1–3, and 2–3 bands have been recorded at high resolution with a Bomem Fourier-transform spectrometer. The rotational structures of the bands are determined by magnetic dipole selection rules. Detailed analysis has yielded accurate molecular constants for the [Formula: see text] and X21g states of 80Se2.
Tunneling splittings in the rotational spectrum of
Authors: Bogey M. , Bolvin H. , Cordonnier M. , Demuynck C. , Destombes J. L. , Escribano R. , Gomez P. C.
Published: October 2010

The splitting of some rotational lines due to a predicted hydrogen atom migration in protonated acetylene, [Formula: see text], was not observed in the first pure rotational spectroscopy experiment in the vibrational ground state. An improvement of the spectral resolution of the spectrometer has allowed the observation of some of these small splittings. They have been interpreted within the semi-rigid bender model. Numerical results are presented for different values of the barrier height. Reasonable agreement between observed and calculated splittings is obtained with a barrier of about 1600 cm−1, which is 15% higher than the most recent ab initio value.
The infrared vibration–rotation spectrum of the molecular ion: extension to higher vibrational and rotational quantum numbers
Authors: Amano T. , Chan M.-C. , Civis S. , McKellar A. R. W. , Majewski W. A. , Sadovskii D. , Watson J. K. G.
Published: October 2010

The assigned infrared spectrum of the [Formula: see text] molecular ion is extended from 84 to 529 lines by three types of spectroscopic measurements on hollow-cathode electrical discharges through deuterium gas: (i) emission from a small hollow cathode, in which the [Formula: see text] lines were distinguished from the electronic transitions of D2 by the pressure dependence of their intensities; (ii) absorption in the same hollow cathode with discharge amplitude modulation; and (iii) absorption in a larger hollow cathode cell with discharge amplitude modulation. The observed lines belong mainly to the [Formula: see text] fundamental and its hot bands [Formula: see text], [Formula: see text] and [Formula: see text] in the 1330–2530 cm−1 region in experiments (i) and (ii), and to the first overtone band [Formula: see text] in the 3160–4000 cm−1 region in experiment (iii). The lines were assigned by means of calculations with a large vibration–rotation basis, using a Morse-based discrete variable representation for the vibrations. This method overcomes the convergence problems for the centrifugal terms in the effective Hamiltonian approach. Six coefficients in the Meyer–Botschwina–Burton ab initio potential were adjusted in order to fit these data with a standard deviation of 0.059 cm−1.
Diode-laser spectra of the ν4 Q branch of methyl isocyanide
Authors: Blanquet Ghislain , Walrand Jacques , Courtoy Charles P. , Dang-Nhu Mai
Published: October 2010

With a diode-laser spectrometer, we have recorded the Q branch of the ν4 fundamental band of CH3NC. A least-squares analysis provides the rovibrational constants. A list gives wave numbers and absolute intensities for each line as calculated from the observed band strength.
Sub-Doppler laser spectroscopy of H2 and D2 in the range 91–98 nm
Authors: Hinnen P. C. , Hogervorst W. , Stolte S. , Ubachs W.
Published: October 2010

The absorption spectra of hydrogen and deuterium have been measured in the range 91–98 nm. A narrowband extreme ultraviolet laser source is employed in combination with a molecular beam, allowing for sub-Doppler resolution and yielding linewidths of 0.23 cm−1. Transition frequencies of 291 lines of the Lyman and Werner bands are determined with an average absolute accuracy of 0.03 cm−1. The data are analyzed in a semi-empirical perturbation model, involving heterogeneous couplings between nearby lying levels of B1Σu+ and C1Πu states. This model is found to be accurate on the level of accuracy of the data obtained.
Single- and double-ionization potentials of polycyclic aromatic hydrocarbons and fullerenes by photon and electron impact
Authors: Tobita S. , Leach S. , Jochims H. W. , Rühl E. , Illenberger E. , Baumgärtel H.
Published: October 2010

Single- and double-ionization appearance potentials of 21 polycyclic aromatic hydrocarbons (PAHs) were determined by measurement of photoion yield curves using a synchrotron radiation source. Analogous measurements were made by electron impact on three PAHs. The origin of differences, of up to 4 eV, between appearance potentials for double ionization by photon and electron impact is discussed. The ratio of the double- to single-ionization potentials of PAHs was found to be 2.65 ± 0.06 for photon impact, significantly lower than for electron-impact and charge-stripping measurements. An electrostatic model, which considers that PAHs ionize like fragments of graphite, is applied to the PAHs studied and to data on the fullerenes C60 and C70. The validity and limitations of the model are discussed and its analytical and predictive propensities concerning multiple-ionization potentials and processes are demonstrated.
Molecular beam spectroscopy of the and transitions in Hg2
Authors: Koperski J. , Atkinson J. B. , Krause L.
Published: October 2010

Excitation and fluorescence spectra of Hg2 were produced in a pulsed supersonic molecular beam crossed with a pulsed laser beam. Well-resolved structures arising from [Formula: see text] and [Formula: see text] vibronic transitions were analyzed and yielded spectroscopic constants for the excited and ground states of the molecule.
Analysis of the A2Πi ~ X2Σ+ perturbations of the AlO radical
Authors: Ito Haruhiko
Published: October 2010

The A2Πi ~ X2Σ+ perturbations of the AlO radical were analyzed in the mixed levels of (νA, νX) = (0, 5), (1, 6), (2, 7), (3, 8), and (4, 9) by a simultaneous analysis of the reported D2Σ+–A2Πi transition wave numbers and the A2Πi–X2Σ+ energy level differences, the latter being evaluated by taking the differences of the reported wave numbers of the C2Πr–X2Σ+ and C2Πr–A2Πi transitions. The molecular constants for A2Πi, ν = 0–4; D2Σ+, ν = 0–5; and X2Σ+, ν = 8 and 9, and the perturbation constants were determined. The Rydberg–Klein–Rees (RKR) potentials of the A2Πi and D2Σ+ states were obtained using these molecular constants. The spin-orbit constants, Aν, for A2Πi are discussed in terms of the electronic structure of the A2Πi state.
Branch intensities and oscillator strengths for the Herzberg absorption systems in oxygen
Authors: Huestis David L. , Copeland Richard A. , Knutsen Karen , Slanger Tom G. , Jongma Rienk T. , Boogaarts Maarten G. H. , Meijer Gerard
Published: October 2010

We report two complementary experimental investigations of the absorption spectrum of molecular oxygen between 243 and 258 nm. In the first experiment, excitation of O2 is inferred by detecting oxygen atoms resulting from chemical reaction. In the second experiment, absorption by O2 is observed directly by cavity ring-down spectroscopy. Absorption strengths for the Herzberg I [Formula: see text], Herzberg II [Formula: see text], and Herzberg III [Formula: see text] band systems are modeled with the DIATOM spectral simulation computer program using the best available branch intensity formulas. Absolute oscillator strengths are derived for all three systems and compared with values in the literature.
Low vibrational levels of the ionic–covalent coupled state A0+ of NaI and its potential function
Authors: Lindner J. , Bluhm H. , Fleisch A. , Tiemann E.
Published: October 2010

The A0+ state of NaI was investigated towards the minimum of its potential using laser-induced fluorescence and Λ-type double resonance spectroscopy via the covalent C0+ state, because significantly different potential functions were proposed in the literature due to missing spectroscopic data. The vibrational interval νadia = 135–282 measured previously by Schaefer et al. was extended to vibrational levels as low as νadia = 40. Transitions to lower levels are masked by the very strong C0+–B1 transition. An improved potential curve for A0+ was derived. The uncertainty by the unknown lowest vibrational levels is discussed. A comparison of the new curve with others reported in the literature is given.
The high-resolution infrared spectrum of BrCl
Authors: Uehara Hiromichi , Konno Toichi , Ozaki Yasushi , Horiai Koui , Nakagawa Kuniaki , Johns J. W. C.
Published: October 2010

The high-resolution infrared spectrum of BrCl has been observed with a Fourier transform spectrometer. About 850 spectral lines for the Δν = 1 sequences of the four isotopic species, 79Br35Cl, 81Br35Cl, 79Br37Cl, and 81Br37Cl have been measured between 417 and 461 cm−1. They have been fitted with a standard deviation of 0.000 146 cm−1 to a Dunham potential function using eight coefficients that included two Watson-type Δ correction terms. Dunham Yij coefficients have been derived for each of the four isotopic species. The equilibrium internuclear distance re of BrCl is 2.136 053 28 (67) Å.
Infrared spectrum of CH3+ involving high rovibrationai levels
Authors: Jagod Mary-Frances , Gabrys Charles M. , Rösslein Matthias , Uy Dairene , Oka Takeshi
Published: October 2010

An extensive search of carbo-ion spectra in the infrared region from 3300 cm−1 to 2900 cm−1 has revealed many spectral lines of CH3+, the most fundamental hydrocarbon cation. Out of over 1000 spectral lines that were identified as due to CH3+from their plasma chemical behaviors and linewidths, 356 lines have been assigned to the CH stretch ν3 fundamental band. Most of the remaining lines are thought to belong to the hot bands ν2 + ν3 − ν2 and ν3 + ν4 − ν4. Their analysis was found to be difficult because of the large Coriolis interaction and the near degeneracy of ν2 and ν4. A series of spectral lines has been assigned to the ν3 + ν4 − ν4 band. The rovibrational temperature of CH3+ in the plasma has been determined from relative intensities of the spectral lines.
Microwave spectrum and molecular structure of silacyclopropenylidene c-C2H2Si
Authors: Izuha Mitsuaki , Yamamoto Satoshi , Saito Shuji
Published: October 2010

The rotational spectra of silacyclopropenylidene, c-C2H2Si, and its isotopic species (C2H229Si, C2D2Si, 13C2H2Si) were observed in the frequency region of 220–400 GHz by using a source-modulated microwave spectrometer combined with a free space absorption cell. c-C2H2Si was produced in the cell by discharging a mixture of SiH4, C2H2, and He. Least-squares analyses of the observed spectral lines yielded the rotational constants and the centrifugal distortion constants for the normal and its isotopic species. From the observed rotational constants, the rs structure was determined: rs (C=C) = 1.3458 Å, rs (C—Si) = 1.8200 Å rs (C—H) = 1.0795 Å, and [Formula: see text]. (1 Å = 10−10 m.)
High-resolution visible spectrum for the A3Π(l)–X1Σ+ system of IBr
Authors: Appadoo Dominique R. T. , Bernath Peter F. , Roy Robert J. Le
Published: October 2010

New high-resolution absorption and laser excitation spectra of the A3Π(1)–X1Σ+ system of IBr, consisting of approximately 4000 lines of over 40 bands spanning the vibrational range ν′ = 6–29 and ν″ = 1–4 for each of the two isotopomers, have been recorded and analyzed. Combined with previous microwave and infrared data and fluorescence progressions into the X state, and with new data obtained from laser excitation of the lowest levels of the A state, they formed the core of a global fit to mass-reduced Dunham expansions that yields new molecular constants for the A and X states of I79Br and I81Br. Inability to fully account for all data within the experimental uncertainties points to the existence of substantial perturbations or "non-mechanical" behaviour for A-state levels ν′ > 24.
Spectroscopy of metastable species in a free-jet expansion: the β ← A transition in IBr
Authors: Clevenger Jason O. , Ray Quentin P. , Tellinghuisen Joel , Zheng Xiaonan , Heaven Michael C.
Published: October 2010

The A 1(3Π) state of IBr is observed in a free-jet expansion of IBr in Ar, following photolysis with ArF laser irradiation. Laser excitation spectra are obtained for the β 1(3P2) ← A transition in medium (0.5 cm−1) and high (0.08 cm−1) resolution. Sixteen ν′–ν″ bands recorded in high resolution are rotationally analyzed, providing the first detailed characterization of the lowest three νlevels in the A state. An additional ~50 bandheads in the ν″ = 0 and 1 progressions are recorded for both I79Br and I81Br. The new data, which sample ν′ levels in the range 31–71, are combined with existing information for low ν in the β state to provide improved constants for the β state. These results are merged with least-squares parameters from a detailed reanalysis of existing data for the A and X(1Σ+) states to yield spectroscopic parameters valid for ν = 0–20 in the X state and ν = 0–26 in the A state. Among these results are the first precise estimates of the equilibrium parameters in the A state: Te = 12 369.68 (14) cm−1, ωe = 134.22 (13) cm−1, Be = 0.042 40 (5) cm−1, Re = 2.8583 (16) Å.
Rotational structure of the B–X system of Na3 from high-resolution resonant two-photon ionization spectroscopy
Authors: Ernst Wolfgang E. , Rakowsky Stefan
Published: October 2010

First investigations of the [Formula: see text] system of Na3 at rotational resolution are reported. Using resonant two-photon ionization and optical-optical double resonance spectroscopy, two vibronic bands were assigned and rotationally analyzed. In the B state, the three sodium nuclei perform a nearly free pseudorotational motion in the moat of a pseudo-Jahn–Teller potential that is characterized by a vibronic angular momentum quantum number j. In states with J > 0, each rotational level is split by Coriolis interaction. Rotational and Coriolis coupling parameters were determined and are discussed in terms of the dynamics of the vibronic coupling in this floppy molecule.
Sodium/glucose cotransporter-1, sweet receptor, and disaccharidase expression in the intestine of the domestic dog and cat: two species of different dietary habit
Authors: Batchelor D. J. , Al-Rammahi M. , Moran A. W. , Brand J. G. , Li X. , Haskins M. , German A. J. , Shirazi-Beechey S. P.
Published: October 2010

The domestic cat ( Felis catus ), a carnivore, naturally eats a very low carbohydrate diet. In contrast, the dog ( Canis familiaris ), a carno-omnivore, has a varied diet. This study was performed to determine the expression of the intestinal brush border membrane sodium/glucose cotransporter, SGLT1, sweet receptor, T1R2/T1R3, and disaccharidases in these species adapted to contrasting diets. The expression (this includes function) of SGLT1, sucrase, maltase and lactase were determined using purified brush border membrane vesicles and by quantitative immunohistochemistry of fixed tissues. The pattern of expression of subunits of the sweet receptor T1R2 and T1R3 was assessed using fluorescent immunohistochemistry. In proximal, middle, and distal small intestine, SGLT1 function in dogs was 1.9- to 2.3-fold higher than in cats ( P = 0.037, P = 0.0011, P = 0.027, respectively), and SGLT1 protein abundance followed an identical pattern. Both cats and dogs express T1R3 in a subset of intestinal epithelial cells, and dogs, but not cats, express T1R2. In proximal and middle regions, there were 3.1- and 1.6-fold higher lactase ( P = 0.006 and P = 0.019), 4.4- and 2.9-fold higher sucrase (both P < 0.0001), and 4.6- and 3.1-fold higher maltase activity ( P = 0.0026 and P = 0.0005), respectively, in the intestine of dogs compared with cats. Dogs have a potential higher capacity to digest and absorb carbohydrates than cats. Cats may suffer from carbohydrate malabsorption following ingestion of high-carbohydrate meals. However, dogs have a digestive ability to cope with diets containing significant levels of carbohydrate.
Folic acid supplementation inhibits NADPH oxidase-mediated superoxide anion production in the kidney
Authors: Hwang Sun-Young , Siow Yaw L. , Au-Yeung Kathy K. W. , House James , O Karmin
Published: October 2010

Hyperhomocysteinemia, a condition of elevated blood homocysteine (Hcy) levels, is a metabolic disease. It is a common clinical finding in patients with chronic kidney diseases and occurs almost uniformly in patients with end-stage renal disease. Hyperhomocysteinemia is also a risk factor for cardiovascular disease. Our recent studies indicate that hyperhomocysteinemia can lead to renal injury by inducing oxidative stress. Oxidative stress is one of the important mechanisms contributing to Hcy-induced tissue injury. Folic acid supplementation is regarded as a promising approach for prevention and treatment of cardiovascular disease associated with hyperhomocysteinemia due to its Hcy-lowering effect. However, its effect on the kidney is not clear. The aim of this study was to examine the effect of folic acid supplementation on Hcy-induced superoxide anion production via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in the kidney during hyperhomocysteinemia. Hyperhomocysteinemia was induced in male Sprague-Dawley rats fed a high-methionine diet for 12 wk with or without folic acid supplementation. A group of rats fed a regular diet was used as control. There was a significant increase in levels of superoxide anions and lipid peroxides in kidneys isolated from hyperhomocysteinemic rats. Activation of NADPH oxidase was responsible for hyperhomocysteinemia-induced oxidative stress in the kidney. Folic acid supplementation effectively antagonized hyperhomocysteinemia-induced oxidative stress via its Hcy-lowering and Hcy-independent effect. In vitro study also showed that 5-methyltetrahydrofolate, an active form of folate, effectively reduced Hcy-induced superoxide anion production via NADPH oxidase. Xanthine oxidase activity was increased and superoxide dismutase (SOD) activity was decreased in the kidney of hyperhomocysteinemic rats, which might also contribute to an elevation of superoxide anion level in the kidney. Folic acid supplementation attenuated xanthine oxidase activity and restored SOD activity in the kidney of hyperhomocysteinemic rats. These results suggest that folic acid supplementation may offer renal protective effect against oxidative stress.
Reorganization of Finger Coordination Patterns During Adaptation to Rotation and Scaling of a Newly Learned Sensorimotor Transformation
Authors: Liu Xiaolin , Mosier Kristine M. , Mussa-Ivaldi Ferdinando A. , Casadio Maura , Scheidt Robert A.
Published: October 2010

We examined how people organize redundant kinematic control variables (finger joint configurations) while learning to make goal-directed movements of a virtual object (a cursor) within a low-dimensional task space (a computer screen). Subjects participated in three experiments performed on separate days. Learning progressed rapidly on day 1, resulting in reduced target capture error and increased cursor trajectory linearity. On days 2 and 3, one group of subjects adapted to a rotation of the nominal map, imposed either stepwise or randomly over trials. Another group experienced a scaling distortion. We report two findings. First, adaptation rates and memory-dependent motor command updating depended on distortion type. Stepwise application and removal of the rotation induced a marked increase in finger motion variability but scaling did not, suggesting that the rotation initiated a more exhaustive search through the space of viable finger motions to resolve the target capture task than did scaling. Indeed, subjects formed new coordination patterns in compensating the rotation but relied on patterns established during baseline practice to compensate the scaling. These findings support the idea that the brain compensates direction and extent errors separately and in computationally distinct ways, but are inconsistent with the idea that once a task is learned, command updating is limited to those degrees of freedom contributing to performance (thereby minimizing energetic or similar costs of control). Second, we report that subjects who learned a scaling while moving to just one target generalized more narrowly across directions than those who learned a rotation. This contrasts with results from whole-arm reaching studies, where a learned scaling generalizes more broadly across direction than rotation. Based on inverse- and forward-dynamics analyses of reaching with the arm, we propose the difference in results derives from extensive exposure in reaching with familiar arm dynamics versus the novelty of the manual task.