bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensory integration across space and in time for decision making in the somatosensory system of rodents
Authors: Celikel Tansu , Sakmann Bert
Published: January 2007

Environment is represented in the brain by a neural code that is a result of the spatiotemporal pattern of incoming sensory information. Sensory neurons encode inputs across space and in time such that activity of a given cell inhibits the ability of near-simultaneously arriving sensory stimuli to excite the cell. At the behavioral level, consequences of such suppression are unknown. We investigated the contribution of spatially distributed, near-simultaneous sensory inputs to decision making in a whisker-dependent learning task. Mice learned the task with a single whisker or multiple whiskers alike. Both groups of mice had similar learning curves and final success rates. However, multiple-whisker animals had faster response times than single-whisker mice, requiring only about half the time to perform the task successfully. The results show that spatially distributed sensory inputs in a highly redundant sensory environment improve speed but not accuracy of the decisions made during simple sensory detection. Suppression of the near-simultaneous sensory inputs could, therefore, act to reduce the sensory redundancy.
RNA expression in a cartilaginous fish cell line reveals ancient 3′ noncoding regions highly conserved in vertebrates
Authors: Forest David , Nishikawa Ryuhei , Kobayashi Hiroshi , Parton Angela , Bayne Christopher J. , Barnes David W.
Published: January 2007

We have established a cartilaginous fish cell line [
Squalus acanthias
embryo cell line (SAE)], a mesenchymal stem cell line derived from the embryo of an elasmobranch, the spiny dogfish shark
S. acanthias
. Elasmobranchs (sharks and rays) first appeared >400 million years ago, and existing species provide useful models for comparative vertebrate cell biology, physiology, and genomics. Comparative vertebrate genomics among evolutionarily distant organisms can provide sequence conservation information that facilitates identification of critical coding and noncoding regions. Although these genomic analyses are informative, experimental verification of functions of genomic sequences depends heavily on cell culture approaches. Using ESTs defining mRNAs derived from the SAE cell line, we identified lengthy and highly conserved gene-specific nucleotide sequences in the noncoding 3′ UTRs of eight genes involved in the regulation of cell growth and proliferation. Conserved noncoding 3′ mRNA regions detected by using the shark nucleotide sequences as a starting point were found in a range of other vertebrate orders, including bony fish, birds, amphibians, and mammals. Nucleotide identity of shark and human in these regions was remarkably well conserved. Our results indicate that highly conserved gene sequences dating from the appearance of jawed vertebrates and representing potential cis-regulatory elements can be identified through the use of cartilaginous fish as a baseline. Because the expression of genes in the SAE cell line was prerequisite for their identification, this cartilaginous fish culture system also provides a physiologically valid tool to test functional hypotheses on the role of these ancient conserved sequences in comparative cell biology.
Structural analysis of Bub3 interactions in the mitotic spindle checkpoint
Authors: Larsen Nicholas A. , Al-Bassam Jawdat , Wei Ronnie R. , Harrison Stephen C.
Published: January 2007

The Mad3/BubR1, Mad2, Bub1, and Bub3 proteins are gatekeepers for the transition from metaphase to anaphase. Mad3 from
Saccharomyces cerevisiae
has homology to Bub1 but lacks a corresponding C-terminal kinase domain. Mad3 forms a stable heterodimer with Bub3. Negative-stain electron microscopy shows that Mad3 is an extended molecule (≈200 Å long), whereas Bub3 is globular. The Gle2-binding-sequence (GLEBS) motifs found in Mad3 and Bub1 are necessary and sufficient for interaction with Bub3. The calorimetrically determined dissociation constants for GLEBS-motif peptides and Bub3 are ≈5 μM. Crystal structures of these peptides with Bub3 show that the interactions for Mad3 and Bub1 are similar and mutually exclusive. In both structures, the GLEBS peptide snakes along the top surface of the β-propeller, forming an extensive interface. Mutations in either protein that disrupt the interface cause checkpoint deficiency and chromosome instability. We propose that the structure imposed on the GLEBS segment by its association with Bub3 enables recruitment to unattached kinetochores.
The neck of caveolae is a distinct plasma membrane subdomain that concentrates insulin receptors in 3T3-L1 adipocytes
Authors: Foti Michelangelo , Porcheron Geneviève , Fournier Margot , Maeder Christine , Carpentier Jean-Louis
Published: January 2007

Insulin receptors (IRs) segregate on plasma membrane microvilli, but in cells devoid of microvilli, such as adipocytes, the localization of IRs is a matter of controversy. In the present study, we examined the distribution of IRs in the plasma membrane of 3T3-L1 adipocytes. Quantitative electron microscopy indicates that IRs are predominantly associated with the neck, but not the bulb, of caveolae. Caveola necks represent distinct microdomains of the plasma membrane. Indeed, as shown by freeze–fracture analysis, intramembrane particles are concentrated as necklaces around the craters of caveolae. In addition, subcellular fractionation suggests that the neck and the bulb of caveolae present a different resistance to detergent solubility. Finally, cytoskeletal components, including actin, are highly enriched in the membrane area underlying the neck part of caveolae. IRs coimmunoprecipitate with cytoskeletal components, and disruption of the actin cytoskeleton alters IRs expression, localization, and signaling, thus supporting the notion that caveola necks are involved in intracellular signaling by IRs. Together, these results suggest that cytoskeletal proteins anchor IRs to microdomains in the caveola necks of 3T3-L1 adipocytes. By homology with IR localization in other cell types, we suggest that the necks of caveolae may represent the counterpart of microvillar domains in cells poor in microvilli such as adipocytes and that they play an important role as signaling platforms.
Wrinkled hard skins on polymers created by focused ion beam
Authors: Moon Myoung-Woon , Lee Sang Hoon , Sun Jeong-Yun , Oh Kyu Hwan , Vaziri Ashkan , Hutchinson John W.
Published: January 2007

A stiff skin forms on surface areas of a flat polydimethylsiloxane (PDMS) upon exposure to focused ion beam (FIB) leading to ordered surface wrinkles. By controlling the FIB fluence and area of exposure of the PDMS, one can create a variety of patterns in the wavelengths in the micrometer to submicrometer range, from simple one-dimensional wrinkles to peculiar and complex hierarchical nested wrinkles. Examination of the chemical composition of the exposed PDMS reveals that the stiff skin resembles amorphous silica. Moreover, upon formation, the stiff skin tends to expand in the direction perpendicular to the direction of ion beam irradiation. The consequent mismatch strain between the stiff skin and the PDMS substrate buckles the skin, forming the wrinkle patterns. The induced strains in the stiff skin are estimated by measuring the surface length in the buckled state. Estimates of the thickness and stiffness of the stiffened surface layer are estimated by using the theory for buckled films on compliant substrates. The method provides an effective and inexpensive technique to create wrinkled hard skin patterns on surfaces of polymers for various applications.
Cell cycle progression and de novo centriole assembly after centrosomal removal in untransformed human cells
Authors: Uetake Yumi , Lončarek Jadranka , Nordberg Joshua J. , English Christopher N. , La Terra Sabrina , Khodjakov Alexey , Sluder Greenfield
Published: January 2007

How centrosome removal or perturbations of centrosomal proteins leads to G1 arrest in untransformed mammalian cells has been a mystery. We use microsurgery and laser ablation to remove the centrosome from two types of normal human cells. First, we find that the cells assemble centrioles de novo after centrosome removal; thus, this phenomenon is not restricted to transformed cells. Second, normal cells can progress through G1 in its entirety without centrioles. Therefore, the centrosome is not a necessary, integral part of the mechanisms that drive the cell cycle through G1 into S phase. Third, we provide evidence that centrosome loss is, functionally, a stress that can act additively with other stresses to arrest cells in G1 in a p38-dependent fashion.
Detection of chromatin-associated single-stranded DNA in regions targeted for somatic hypermutation
Authors: Ronai Diana , Iglesias-Ussel Maria D. , Fan Manxia , Li Ziqiang , Martin Alberto , Scharff Matthew D.
Published: January 2007

After encounter with antigen, the antibody repertoire is shaped by somatic hypermutation (SHM), which leads to an increase in the affinity of antibodies for the antigen, and class-switch recombination (CSR), which results in a change in the effector function of antibodies. Both SHM and CSR are initiated by activation-induced cytidine deaminase (AID), which deaminates deoxycytidine to deoxyuridine in single-stranded DNA (ssDNA). The precise mechanism responsible for the formation of ssDNA in V regions undergoing SHM has yet to be experimentally established. In this study, we searched for ssDNA in mutating V regions in which DNA–protein complexes were preserved in the context of chromatin in human B cell lines and in primary mouse B cells. We found that V regions that undergo SHM were enriched in short patches of ssDNA, rather than R loops, on both the coding and noncoding strands. Detection of these patches depended on the presence of DNA-associated proteins and required active transcription. Consistent with this, we found that both DNA strands in the V region were transcribed. We conclude that regions of DNA that are targets of SHM assemble protein–DNA complexes in which ssDNA is exposed, making it accessible to AID.
The Location of a Closed Channel Gate in the GABAA Receptor Channel
Authors: Bali Moez , Akabas Myles H.
Published: January 2007

Considerable controversy surrounds the location of the closed channel gate in members of the Cys-loop receptor family of neurotransmitter-gated ion channels that includes the GABAA, glycine, acetylcholine, and 5-HT3 receptors. Cysteine-accessibility studies concluded that the gate is near the cytoplasmic end of the channel in acetylcholine and GABAA receptors but in the middle of the 5-HT3A receptor channel. Zn2+ accessibility studies in a chimeric 5-HT3-ACh receptor suggested the gate is near the channel's cytoplasmic end. In the 4-Å resolution structure of the acetylcholine receptor closed state determined by cryoelectron microscopy, the narrowest region, inferred to be the gate, is in the channel's midsection from 9' to 14' but the M1–M2 loop residues at the channel's cytoplasmic end were not resolved in that structure. We used blocker trapping experiments with picrotoxin, a GABAA receptor open channel blocker, to determine whether a gate exists at a position more extracellular than the picrotoxin binding site, which is in the vicinity of α1Val257 (2') near the channel's cytoplasmic end. We show that picrotoxin can be trapped in the channel after removal of GABA. By using the state-dependent accessibility of engineered cysteines as reporters for the channel's structural state we infer that after GABA washout, with picrotoxin trapped in the channel, the channel appears to be in the closed state. We infer that a gate exists between the picrotoxin binding site and the channel's extracellular end, consistent with a closed channel gate in the middle of the channel. Given the homology with acetylcholine and 5-HT3 receptors there is probably a similar gate in those channels as well. This does not preclude the existence of an additional gate at a more cytoplasmic location.
Mean Lives in Ne V, Mg VII, and Al VIII
Authors: L C McIntyre Jr  , D J Donahue  , E M Bernstein
Published: January 2007

Mean lives of five 2s2p3terms in each of the 6-electron ions Ne V, Mg VII, and Al VIII have been measured using the techniques of beam-foil spectroscopy. An ion beam energy of 2 MeV was used for Ne and 5 MeV for Mg and Al. The wavelength range covered was 245-575 Å. Experimental results are compared with predicted trends of oscillator strength as a function of 1/Z.
Threshold of Electromagnetic Instability in a Magnetic Neutral Sheet
Authors: K Yamanaka
Published: January 2007

The structure of electromagnetic perturbations in a magnetic neutral sheet is analyzed within the framework of a Vlasov-Maxwellian picture. In reference to Harris' equilibrium state, a boundary value problem is formulated and solved to give the possible existence of a low-frequency electromagnetic wave of compressional type, propagating along the electron-drift current in the sheet. The stability of this mode is critically dependent on the thickness parameter of the sheet. If the sheet is thin enough, the perturbation will grow even forTe=Ti. The critical thicknesses are calculated with regard to various temperature ratios and their values are found to be about 0.9r*Lior less, wherer*Limeans the ion Larmor radius just outside the sheet region.
Analytic Nuclear Level Density Formula with Shell and Pairing Effects
Authors: A S Jensen  , J Sandberg
Published: January 2007

For use in calculations and in analyses of experimental data an analytic approximation of the level density is worked out. This is done in two steps. First the level density is calculated in a simple but realistic model including both shell structure and pairing effects. Then it is approximated by an analytic function of the excitation energy together with a few parameters describing average properties of the single particle spectrum. The overall accuracy in the natural logarithm is, for realistic parameters, better than one unit, and for energies above around 5 MeV it is usually better than 0.5. A detailed prescription to obtain the necessary parameters is given in terms of experimental binding energies and the observed level density at the neutron binding energy. The resulting energy dependent level density is compared with observations available for energies below 8 MeV for several nuclei. Systematic deviations are found for the lighter nuclei. Very good agreement is obtained for heavier nuclei.
The Local Space Density of Quasars and Active Nuclei
Authors: Maarten Schmidt
Published: January 2007

Local space densities are given for quasars as a function of their optical and radio luminosities, radio galaxies, clusters of galaxies, Seyfert galaxies, giant elliptical galaxies, and field galaxies. The local space density of dead quasars is estimated. A substantial fraction of all galaxies may have a dead quasar as nucleus.
Extragalactic X-ray Sources
Authors: Riccardo Giacconi
Published: January 2007

Observations of X-ray emission from the nuclei of active galaxies are briefly summarized and their relevance to models for galactic nuclei discussed. Particular emphasis is given to the recent observations of X-ray emission from Seyfert Galaxies, their luminosity function, and the time-scale for variability.
Statistics of Absorption Lines and Line-Locking
Authors: R F Carswell
Published: January 2007

The location and nature of the clouds which cause absorption lines in the spectra of many high redshift QSOs remains controversial. Most statistical tests performed so far have been inconclusive, though there have been indications that the distribution of numbers of lines is not consistent with that expected from intervening galaxies. There also is a significant peak in numbers corresponding to a velocity difference between emission and absorption regions of about 0.1c. This type of behavior is consistent with radiation pressure driven outflow and `line-locking', though it is difficult to understand theoretically how the latter mechanism can operate in QSOs.
A Summary of the Properties of Zabs > Zem Systems and Some Comments on the Origins of QSO Absorption Line Systems
Authors: R J Weymann  , R E Williams
Published: January 2007

Z
abs > Z
em systems are "real" in the sense of not being artifacts of measuring errors, but Z
em may not represent the true Z of the QSO. However, a specific simple model involving occultation of outflowing gas by an opaque central object produces too much asymmetry in the emission lines. If Z
abs > Z
QSO systems truly exist the least objectionable model involves clouds of gas bound in an associated large cluster.

Lack of detectable C II fine structure in 3 objects (1225+31, 1331+17, 1756+23) suggests the absorbing material is ≳ 500 kpc from the QSO on the basis of ionization arguments, leading to unacceptably large kinetic energies if the absorption is "intrinsic". Defects in the ionization argument are considered.

Preliminary statistical results on low Z
ab Mg II systems require that the effective radius for producing such systems by intervening galaxies must be ∼ 5 times the Holmberg radius, but attempts to detect such galaxies have not been successful.

Finally, it is speculated that a correlation may exist between the column density of the strongest absorption system and multiplicity of absorption systems in a given object suggesting that systems like those in 1756+23 are intrinsic, despite the C II fine-structure argument.
On the Radiative Acceleration of Quasar Absorption Line Clouds
Authors: Peter Goldreich
Published: January 2007

Radiation may expel dense gas clouds from quasar emission line regions. Small clouds can be accelerated to velocities approaching c if they are confined so as to maintain high densities.

The kinetic energies, inferred from the spectra, of low to medium excitation quasar absorption clouds are too large for radiation pressure to have played a dominant role in their acceleration. If these clouds are physically associated with the quasars, they are probably accelerated by the same stresses that are responsible for their confinement.

Models for absorption clouds based on radiatively driven instabilities in expanding quasar envelopes predict column densities that are much larger than those deduced from observation.
Possible Use of Electronographically Recorded Low-dispersion Slitless Spectra in Optical Quasar Surveys
Authors: Bengt Strömgren
Published: January 2007

Uses of low-dispersion slitless spectra, recorded electronographically, in spectral classification are discussed, and a method of producing such spectra with a Fehrenbach-type prism placed about 20 cm in front of the focal plane of an f/8.6 reflector is described. A program of stellar classification of faint stars in specially selected areas of high galactic latitude is briefly referred to. Possible applications of the technique in quasar surveys are discussed on the basis of results obtained by P. Kjærgaard and J. Ravn (cf. their article in these proceedings, p. 341) by computer simulation of low-dispersion spectra of quasars and white dwarfs.
On the Volume and Structure Dependence of Electric Field Gradients in Close-packed Metals. II
Authors: T Butz
Published: January 2007

In an attempt to calculate the contributions to the electric field gradient in close-packed metals from all charge outside the central Wigner-Seitz cell, lattice sums over screened ions were performed using a Thomas-Fermi and a Hartree screened potential. The volume and structure dependence of these lattice sums is examined and compared to experimental observations. The role of lattice vibrations is also discussed.
Calculation of the Electron Double Ionization Cross Section of the K-shell in Cr and Fe
Authors: J Saijonmaa
Published: January 2007

Cross sections of double ionization of theK-shell by electron impact are calculated for Cr and Fe using Gryzinski's method and applying classical and quantum mechanical binary encounter approximations as developed by Gryzinski and Vriens. The average field of the nucleus is taken into account, and momentum transfer from impact electron to nucleus is found to decrease the cross sections near the threshold making them to agree better with measurements. It was found that the cross sections were not sensitive to momentum distributions of K-electrons, nor did the classical and quantum mechanical binary encounter approximations yield essentially different results. Within the present accuracy of measurements experiments and calculations are in good agreement.
Crystal structure prediction of organic pigments: quinacridone as an example
Authors: Panina N. , Leusen F. J. J. , Janssen F. F. B. J. , Verwer P. , Meekes H. , Vlieg E. , Deroover G.
Published: January 2007

The structures of the α, β and γ polymorphs of quinacridone (Pigment Violet 19) were predicted usingPolymorph Predictorsoftware in combination with X-ray powder diffraction patterns of limited quality. After generation and energy minimization of the possible structures, their powder patterns were compared with the experimental ones. On this basis, candidate structures for the polymorphs were chosen from the list of all structures. Rietveld refinement was used to validate the choice of structures. The predicted structure of the γ polymorph is in accordance with the experimental structure published previously. Three possible structures for the β polymorph are proposed on the basis of X-ray powder patterns comparison. It is shown that the α structure in the Cambridge Structural Database is likely to be in error, and a new α structure is proposed. The present work demonstrates a method to obtain crystal structures of industrially important pigments when only a low-quality X-ray powder diffraction pattern is available.
Multipattern Rietveld refinement of protein powder data: an approach to higher resolution
Authors: Von Dreele Robert B.
Published: January 2007

By using combinations of multiple protein powder diffraction patterns obtained from an image plate to ad-spacing of 2 Å, which differ by solvent-induced and radiation-damage-induced lattice strains, the powder overlap problem is partially resolved in a stereochemically restrained Rietveld refinement. The results for hen egg white lysozyme (HEWL) include, for the first time with powder data, placement of a substantial number of water molecules and structural results that approach the quality normally obtained by single-crystal methods. This study explores the lattice strains induced by changes in salt concentration, changes in solvent pH and the effect of low-dose radiation damage. For HEWL, lattice strains are not monotonic, so that with increasing NaCl concentration (0.25–1.25 M) theaaxis increases by ∼0.5%, while thecaxis decreases by ∼1.5%, and this variation is pH dependent. Low-dose radiation damage similarly induces non-monotonic lattice strains, similar but smaller than those arising from increased salt concentration. The effect of using these powder data in a combined Rietveld analysis is effectively to deconvolute the overlapping reflections by differing shifts in their relative positions.
Phase-object approximation in small-angle neutron scattering experiments on silicon gratings
Authors: de Haan Victor-O. , Plomp Jeroen , Bouwman Wim G. , Trinker Martin , Rekveldt M. Theo , Duif Chris P. , Jericha Erwin , Rauch Helmut , van Well Ad A.
Published: January 2007

The phase-object approximation for neutron scattering based on a one-dimensional dynamic forward scattering theory is discussed and used to calculate the differential cross section of an object. It is shown that this approximation is valid in ultra-small-angle neutron scattering (USANS) and spin-echo small-angle neutron scattering (SESANS) experiments on silicon gratings. In the weak scattering limit, the phase-object approximation reduces to the kinematic or first Born approximation. The spatial coherence function is used to describe instrumental resolution effects. Measurements on three different instruments are in good agreement with calculation results. In the experiment with a time-of-flight SESANS instrument, the effect ofPendellösungwith object size is observed.
Follicular cysts in dairy cows
Authors: ISOBE Naoki
Published: January 2007

Follicular cysts are the most critical reproductive disorder in dairy cows and disturb the normal ovarian cycle, resulting in a prolonged interval from calving to conception. Therefore, this condition causes significant economic losses to the dairy industry. Two direct causal factors for cysts are suggested in this review; ovulation disorder and the delay of regression. Ovulation disorder has been accepted to be a main etiology of cystic follicle. This seems to be caused by the deficiency of positive feedback of estrogen to the hypothalamus, leading to the lack of luteinizing hormone surge. On the other hand, if a large anovulatory follicle is regressed immediately after the failure of ovulation, its follicle does not continue to grow, resulting in no cystic follicle being formed. Therefore, it is proposed that another cause of a cystic follicle is the delay (or absence) of the degeneration system of the follicle. This review will introduce these two causes separately, referring to recent advances in understanding the follicular cyst in dairy cows.
Seasonal changes in digestibility, passage rate and rumen fermentation of alfalfa hay in sika deer (Cervus nippon) under restricted feeding
Authors: ASANO Sanae , IKEDA Shoshichi , KUROKAWA Yuzo , KANDA Shuhei , ITABASHI Hisao
Published: January 2007

To investigate seasonal variations in the digestive functions of sika deer, five female sika deer were provided with an amount of alfalfa hay cubes equivalent to voluntary food intake during winter. We measured the rate at which the food passed through the digestive tract, digestibility and rumen fermentation during the summer (August), autumn (November), winter (February) and spring (May). Total mean retention time in the digestive tract during summer and autumn was numerically longer than that in winter and spring, but the difference did not reach significance. Organic matter and fiber were less digestible in summer and autumn than in winter and spring (P < 0.05), whereas the digestibility of the dry matter tended to vary with the seasons (P < 0.1). Ruminal pH values seasonally changed (P < 0.01), and were the lowest in autumn. The concentration of ruminal ammonia‐nitrogen differed significantly among the seasons (P < 0.05), increasing in winter and decreasing during spring and summer. The numbers of protozoa changed significantly among the seasons (P < 0.05), being higher in autumn than in winter and spring, and intermediate in summer. The concentration of total volatile fatty acids was not seasonally affected, but the molar percentages of propionic acid and butyric acid significantly changed according to season (P < 0.05 and P < 0.01, respectively), and the ratio of acetic to propionic acid tended to change with the seasons (P < 0.1). The results of this study suggested that the digestive functions in sika deer, fed a commercial diet at a restricted level, differed notably among the seasons and these variations might partially be due to environmental effects.
Estimation of dietary lysine requirement using plasma amino acid concentrations in mature thoroughbreds
Authors: OHTA Yoshiyuki , YOSHIDA Tatsuyuki , ISHIBASHI Teru
Published: January 2007

Four experiments were conducted to estimate dietary lysine (Lys) requirements using plasma amino acid concentrations as a criterion in mature thoroughbreds. In each experiment four adult thoroughbreds were used. The changes in plasma Lys concentration after feeding were observed in Experiment 1. Blood samples were taken from the cervix vein 0.5 h before, and 1, 3, 5.5, and 10 h after feeding. The plasma Lys concentration increased and remained constant until 3 h after feeding, decreased until 5.5 h and remained constant after then. Therefore, the bleed was done at 3 h after feeding in all later experiments. To make sure of the response speed of the plasma Lys to changes of dietary Lys levels, dietary Lys levels were changed from high to low, and low to high levels in Experiment 2. Blood samples were taken just on the changing day and 1, 2 and 3 days after changing diets. The plasma Lys concentration decreased until 2 days after changing the diet, and then remained constant with advancing days after changing the diet from high Lys to low Lys. On the other hand, the plasma Lys increased until one day after changing the diet, and then remained constant with advancing days after changing dietary Lys levels. Thus, blood samples were taken 3 days after feeding in the next experiments. The possibility of estimating the Lys requirement for maintenance using plasma Lys concentration was elucidated by two methods in Experiments 3 and 4. In Experiment 3, the horses were fed a diet containing 0.33 percent Lys for 3 days. After this the diet was changed to diets containing higher levels of Lys to 0.40, 0.47, 0.54, and 0.61 percent every third day. The Lys requirement was estimated to be 0.46 percent of diet from the response of plasma Lys concentration of five Lys levels. In Experiment 4, a 4 × 4 Latin square design was used for four dietary Lys levels. The Lys requirement was estimated to be 0.47 percent of the diet with a plasma Lys concentration of four Lys levels.
Digestive enzyme activities of pancreas and intestinal digesta in streptozotocin‐induced diabetic piglets
Authors: MURAKAMI Hitoshi , MATSUMOTO Mitsuhito , INOUE Hiroaki , KAJI Yuji
Published: January 2007

Six (Landrace × Large White) × Duroc crossbred, castrated weanling piglets were used to evaluate the effect of a streptozotocin (STZ) injection to induce diabetes on the activities of digestive enzymes derived from the pancreas (lipase, amylase, trypsin and chymotrypsin) in the pancreas and intestinal digesta. Fasting plasma glucose after the administration of STZ was maintained at the level of 302–491 mg/dL during this experiment, compared with the level of 89–125 mg/dL in the control group, and they were defined as the STZ‐induced diabetic piglets for about 7 weeks. Although their bodyweight increased in proportion to a quadratic curve (P < 0.0001) during 49 days after the administration of STZ, the growth of the STZ‐induced diabetic piglets was slower compared with the control. The STZ‐injection did not affect the percentage of the pancreas in bodyweight. The administration of STZ in the piglets tended to accelerate the activity of lipase (P = 0.06) and depress the activity of amylase (P = 0.15) or chymotrypsin (P = 0.18), as units/kg bodyweight, in the pancreas. In the case of measurement as units/kg bodyweight, the activities of intestinal digesta in the STZ group showed a tendency to be higher than those in control group, irrespective of the sort of enzymes. In conclusion, STZ‐induced diabetic piglets have a moderate digestive ability and the administration of exogenous digestive enzymes is not necessary when they are used as a diabetic animal model.
Experience in adverse events detection in an emergency department: Nature of events
Authors: Hendrie James , Sammartino Luke , Silvapulle Mervyn J , Braitberg George
Published: January 2007

Objective:  The study was performed to determine the nature of adverse events in an ED.

Methods:  The methodology has been described in the accompanying paper. Two by two tables were analysed using the two‐tailed Fisher’s exact test. A P‐value of ≤0.05 was considered significant. Statistical analysis was performed using MINITAB.

Results:  One hundred and ninety‐four events were detected, from a sample of 3222 patients. Except where specified, events with management causation ≤3 were excluded. This excluded 24 events (12.4%) leaving 170 for analysis. Errors of commission occurred in 55% and omission in 45%. Errors of commission were significantly associated with prior events, errors of omission with ED events (P ≤ 0.0001, respectively). The most common cause of events was drug reactions. 1.35% had a Naranjo score ≥ 1, 0.54% ≥ 4. Prior events were significantly associated with adverse drug reactions (P ≤ 0.0001). Drug reactions were associated with a lower preventability score (P ≤ 0.0001). Diagnostic issues were present in 1.2%. All three categories, that is diagnosis not considered, diagnosis within the differential and seriousness not appreciated were associated preventability ≥4 (P ≤ 0.0001, P ≤ 0.02 and P ≤ 0.004, respectively). Diagnostic problems were significantly associated with ED events (P ≤ 0.0001).

Conclusion:  In conclusion, the data demonstrate that events fall into two sets: prior events which are associated with errors of commission, drug reactions and lower preventability; and ED events which are associated with errors of omission, diagnostic issues and high preventability.
Comparison between single‐dose oral prednisolone and oral dexamethasone in the treatment of croup: A randomized, double‐blinded clinical trial
Authors: Fifoot Allison A , Ting Joseph YS
Published: January 2007

Objective:  To compare the effectiveness of three corticosteroid regimens in children with mild to moderate croup.

Methods:  Double‐blinded, randomized comparative trial with parallel design, conducted in the ED of a paediatric tertiary care hospital. Children aged 6 months to 6 years presenting to the ED with croup were eligible for inclusion if their Westley croup score was 2 or more. They were randomized to receive a single oral dose of either prednisolone 1 mg/kg, dexamethasone 0.15 mg/kg or dexamethasone 0.6 mg/kg. Primary outcome measures were the magnitude and rate of reduction in Westley croup score, rate of return for medical care with ongoing croup, and further treatment with steroids in the week following index presentation. Secondary outcome measures were the proportion of subjects requiring admission or salvage therapy, such as nebulized adrenaline, during index presentation.

Results:  A total of 99 children, aged 6–79 months, were enrolled (mean age: 1.7 years). Thirty‐four patients were randomized to receive prednisolone 1 mg/kg, 34 to receive dexamethasone 0.15 mg/kg, and 31 to receive dexamethasone 0.6 mg/kg. Baseline characteristics of the three groups were similar. The parents of 86 patients (87%) were available for follow‐up telephone interview at 1 week. There were no significant differences in primary or secondary outcome measures between the three treatment groups.

Conclusions:  Both prednisolone 1 mg/kg and low‐dose dexamethasone (0.15 mg/kg) were found not to differ in efficacy from the currently recommended 0.6 mg/kg dexamethasone. The use of these corticosteroid regimens in treating patients with mild to moderate croup is thus supported.
Hsp70 Negatively Controls Rotavirus Protein Bioavailability in Caco-2 Cells Infected by the Rotavirus RF Strain
Authors: Broquet Alexis H. , Lenoir Christelle , Gardet Agnès , Sapin Catherine , Chwetzoff Serge , Jouniaux Anne-Marie , Lopez Susana , Trugnan Germain , Bachelet Maria , Thomas Ginette
Published: January 2007

Previous studies demonstrated that the induction of the heat shock protein Hsp70 in response to viral infection is highly specific and differs from one cell to another and for a given virus type. However, no clear consensus exists so far to explain the likely reasons for Hsp70 induction within host cells during viral infection. We show here that upon rotavirus infection of intestinal cells, Hsp70 is indeed rapidly, specifically, and transiently induced. Using small interfering RNA-Hsp70-transfected Caco-2 cells, we observed that Hsp70 silencing was associated with an increased virus protein level and enhanced progeny virus production. Upon Hsp70 silencing, we observed that the ubiquitination of the main rotavirus structural proteins was strongly reduced. In addition, the use of proteasome inhibitors in infected Caco-2 cells was shown to induce an accumulation of structural viral proteins. Together, these results are consistent with a role of Hsp70 in the control of the bioavailability of viral proteins within cells for virus morphogenesis.
Role of V1V2 and Other Human Immunodeficiency Virus Type 1 Envelope Domains in Resistance to Autologous Neutralization during Clade C Infection
Authors: Rong Rong , Bibollet-Ruche Frederic , Mulenga Joseph , Allen Susan , Blackwell Jerry L. , Derdeyn Cynthia A.
Published: January 2007

Biologically functional clade C envelope (Env) glycoproteins from the chronically (donor) and newly (recipient) infected partners of four heterosexual transmission pairs in Zambia were cloned and characterized previously. In each case, the donor viral quasispecies contained Envs that were resistant to autologous neutralization by contemporaneous plasma, while the recipient Envs were sensitive to neutralizing antibodies in this donor plasma sample. The donor Envs also varied in length, glycosylation, and amino acid sequence of the V1V2 hypervariable domain of gp120, while the recipient Envs were much more homogeneous. To assess the contribution of V1V2 to the neutralization phenotype of the donor Envs, V1V2 domains from neutralization-sensitive recipient Envs were replaced with donor V1V2 domains, and the autologous neutralization sensitivities of the chimeric Envs were evaluated using a virus-pseudotyping assay. Long donor V1V2 domains regulated sensitivity to autologous neutralization, although the effect was dependent on the Env background. Short donor V1V2 domains did not confer neutralization resistance. Primary sequence differences in V2 were also found to influence neutralization sensitivity in one set of recipient Envs. The results demonstrate that expansion of the V1V2 domain is one pathway to escape from autologous neutralization in subtype C Envs. However, V1V2-independent mechanisms of resistance also exist, suggesting that escape is multifaceted in chronic subtype C infection.
Exposure to mercury in the mine of Almadén
Authors: García Gómez Montserrat , Diego Caballero Klink José , Boffetta Paolo , Español Santiago , Sällsten Gerd , Gómez Quintana Javier
Published: January 2007

Objectives:To describe the process for obtaining mercury and the historical exposure of Almadén miners to mercury.

Methods:Information on every workplace and historical data on production, technological changes in the productive process and biological and environmental values of mercury was collected. A job-exposure matrix was built with these values and the exposure to inorganic mercury was estimated quantitatively as μg/l of urine mercury. A cumulative exposure index was calculated for every worker by adding the estimates for every year in the different workplaces.

Results:In the mine, the highest exposures occurred during drilling, with values up to 2.26 mg/m3in air, 2194 μg/l in urine and 374 μg/l in blood. Furnace operation and cleaning were the tasks with the highest values in metallurgy, peaking up to 3.37 mg/m3. The filling of bottles with mercury by free fall gave values within a range of 1.13–2.43 mg/m3in air; these values dropped to 0.32–0.83 mg/m3after introducing a new ventilation system. The toxicity effects of high doses of inorganic mercury on the central nervous and urinary systems have been known for decades.

Conclusions:The exposure of the workers in Almadén mines to mercury has been very high. The extremely high content cinnabar ore of the mine explains the increased concentrations of mercury in air at the work places. This, together with inadequate working conditions, explains the high mercury levels found in blood and urine during the study period.
The anatomy ofSantalum album(Sandalwood) haustoria
Authors: Tennakoon Kushan U. , Cameron Duncan D.
Published: January 2007

Structural attributes of Santalum album L. (Sandalwood) haustoria have been long overlooked in the literature. This is surprising since successful haustorial formation is key to the survival of individuals of this ecologically and economically important plant. We investigated the morphology of haustoria formed by S. album attached to one of its principal hosts Tithonia diversifolia (Hemsley) A. Gray. The bell-shaped mature haustoria were composed of a peripheral hyaline body and a centrally located penetration peg. The parasite penetration peg can penetrate the host by means of direct pressure and the secretion of cell-wall-degrading enzymes when forming a successful graft union. The latter mechanism is supported by this study as we observed no evidence of collapsed host cells as the result of parasite applied pressure. Upon reaching the xylem tissue of the host root, the penetration peg formed a thin ellipsoidal disc and the host–parasite interface was almost entirely composed of parenchymatous tissue. Luminal continuities were absent between the xylem conducting tissues of the partners, thus suggesting mass flow of solutes is unlikely to occur in this association. High densities of contact parenchyma were found at the host–parasite interface; thus it is probable that these are the principal structures formed by the parasite that facilitate the acquisition of host-derived xylem resources. This study therefore concludes that haustorial anatomy of S. album supports cross membrane (potentially selective) uptake of host-derived solutes as opposed to mass flow via vascular continuity.
Archean geochronological framework of the Bighorn Mountains, Wyoming
Authors: Frost Carol D , Fanning C Mark
Published: January 2007

The Bighorn Mountains of the central Wyoming Province expose a large tract of Archean crust that has been tectonically inactive and at relatively high crustal levels since ~2.7 Ga. Seven sensitive high-resolution ion microprobe (SHRIMP) U–Pb zircon and titanite age determinations on samples of the main lithologic units provide a geochronological framework for the evolution of this area. The oldest, precisely dated magmatic event occurred at 2950 ± 5 Ma, when diorite to granite dykes and sills intruded an older gneiss complex exposed in the central and southern Bighorn Mountains. Rocks as old as 3.25 Ga may be present in this gneissic basement, as indicated by the oldest dates obtained on areas of zircon grains that are interpreted as inherited cores. A tonalitic gneiss was intruded into the gneiss complex at 2886 ± 5 Ma. Deformation of the central and southern gneisses preceded the intrusion of the Bighorn batholith, a tonalitic to granitic intrusion that occupies the northern portion of the uplift. This composite batholith was intruded over the period 2.86–2.84 Ga. Ca. 3.0–2.8 Ga crust is also present in the Beartooth Mountains, the Washakie block of the northeastern Wind River Range, the Owl Creek Mountains, and the northern Granite Mountains, but late Archean deformation and plutonism has obscured much of the earlier history in the southern portion of this area. The entire area, referred to as the Beartooth–Bighorn Magmatic Zone, has been undeformed since 2.6 Ga. Proterozoic extension was focused in those parts of the Wyoming Province outside of this domain.
The Teton – Wind River domain: a 2.68–2.67 Ga active margin in the western Wyoming Province
Authors: Frost B Ronald , Frost Carol D , Cornia Mary , Chamberlain Kevin R , Kirkwood Robert
Published: January 2007

The Archean rocks in western Wyoming, including the Teton Range, the northern Wind River Range, and the western Owl Creek Mountains, preserve a record of a 2.68–2.67 Ga orogenic belt that has many of the hallmarks of modern plate tectonics. A 2683 Ma tholeiitic dike swarm is undeformed and unmetamorphosed in the western Owl Creek Mountains. In the Wind River Range, these dikes have been deformed and metamorphosed during thrusting along the west- to southwest-directed Mount Helen structural belt, which was active at the time that the 2.67 Ga Bridger batholith was emplaced. In the northern Teton Range, the Moose Basin gneiss, which contains relict granulite-facies assemblages, appears to have been thrust upon the amphibolite-grade layered gneiss. The syntectonic Webb Canyon orthogneiss was intruded into the thrust at or before 2673 Ma. We interpret these relations, along with isotopic data indicating that the layered gneiss in the Teton Range consists of juvenile components, to indicate that the western Wyoming Province was the site of active margin tectonics at 2.68–2.67 Ga. This involved a magmatic arc in the present Wind River Range and back-arc spreading in the Owl Creek Mountains. The immature, juvenile layered gneiss in the Teton Range probably represents an accretionary prism or fore-arc basin onto which high-pressure rocks containing a mature sedimentary sequence were thrust at 2.67 Ga. Although it may be questioned as to when modern-style plate tectonics began in other cratons, it was certainly operating in the Wyoming Province by 2.67 Ga.
In suspect terrane? Provenance of the late Archean Phantom Lake metamorphic suite, Sierra Madre, Wyoming
Authors: Souders A Kate , Frost Carol D
Published: January 2007

The 2.68 Ga Phantom Lake metamorphic suite of the Sierra Madre is a volcanogenic, volcaniclastic, and siliciclastic sequence that may have been deposited on or near the margin of the Wyoming Province or, alternatively, it may represent part of an exotic block accreted onto the southern margin of the Wyoming Province. The metamorphosed supracrustal rocks of the Phantom Lake metamorphic suite, along with quartzofeldspathic gneisses and granitoids of similar age, have light rare-earth element (LREE) – enriched REE patterns with little to no Eu-anomaly. These patterns are comparable to those of modern oceanic arc rocks and sediments. Both supracrustal and metaigneous rocks have radiogenic initial εNd from +4.5 to –2.5 and Nd crustal residence ages between 2.7 and 3.0 Ga. It is proposed that these juvenile rocks were part of an intra-oceanic arc system formed beyond the influence of detritus from the Wyoming Province and subsequently were accreted onto the southern Wyoming Province following intrusion of granitic gneisses in the Sierra Madre at ca. 2.64 Ga. The younger 2.43 Ga Baggot Rocks granite has less radiogenic εNd of –3.9 suggesting that the rocks of the Sierra Madre had accreted to the Wyoming Province by 2.43 Ga. The supracrustal sequences at South Pass, Bradley Peak, and the Rattlesnake Hills have similar, radiogenic initial Nd isotope compositions. Together with the Phantom Lake metamorphic suite, they represent juvenile additions to existing continental crust and provide evidence that lateral accretion of oceanic terranes was an important process of late Archean crustal growth in the Wyoming Province.
The relationship between Pacific hake (Merluccius productus) distribution and poleward subsurface flow in the California Current System
Authors: Agostini Vera N , Francis Robert C , Hollowed Anne B , Pierce Stephen D , Wilson Chris , Hendrix Albert N
Published: January 2007

In a search for ocean conditions potentially affecting the extent of Pacific hake (Merluccius productus) feeding migrations, we analyzed data collected in 1995 and 1998 by the National Marine Fisheries Service on abundance and distribution of hake (by echo integration), intensity and distribution of alongshore flow (from acoustic Doppler current profiler), and temperature (conductivity–temperature–depth profiles). Our results show that Pacific hake are associated with subsurface poleward flow and not a specific temperature range. Temporal and spatial patterns characterize both hake distribution and undercurrent characteristics during the two years of this study. We suggest that poleward flow in this area defines adult hake habitat, with flow properties aiding or impeding the poleward migration of the population. We conclude that although physical processes may not directly affect fish production, they may be the link between large-scale ocean–atmosphere variability and pelagic fish distribution.