bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of Neotyphodium endophyte infection in ageing seed pools: incidence of differential viability loss of endophyte, infected seed and non‐infected seed
Authors: Gundel P.E. , Martínez‐Ghersa M.A. , Batista W.B. , Ghersa C.M.
Published: December 2009

Symbiotic associations between grasses and vertically transmitted endophytic fungi are widespread in nature. Within grass populations, changes in the frequency of infected plants are driven by influence of the endophyte on the fitness of their hosts and by the efficiency of endophyte transmission from parent plants to their offspring. During the seed stage, the endophyte might influence the fitness of its host by affecting the rate of seed viability loss, whereas the efficiency of endophyte transmission is affected by losses of viability of the fungus within viable seeds. We assessed the viability losses of Lolium multiflorum seeds with high and low level of infection of the endophyte Neotyphodium occultans, as well as the loss of viability of the fungus itself, under accelerated seed ageing and under field conditions. Starting with high endophyte‐infected accessions of L. multiflorum, we produced their low endophyte‐infected counterparts by treating seeds with a fungicide, and subsequently multiplying seeds in adjacent plots allowing pollen exchange. In our accelerated ageing experiments, which included three accessions, high endophyte‐infected seeds lost viability significantly faster than their low endophyte‐infected counterpart, for only one accession. High endophyte‐infected seeds of this particular accession absorbed more water than low endophyte‐infected seeds. In contrast, the endophyte lost viability within live seeds of all three accessions, as the proportions of viable seeds producing infected seedlings decreased over time. In our field experiment, which included only one accession, high endophyte‐infected seed lost viability significantly but only slightly faster than low endophyte‐infected seed. In contrast, the loss of viability of the endophyte was substantial as the proportions of viable seeds producing infected seedlings decreased greatly over time. Moving the seeds from the air to the soil surface (simulating seed dispersion off the spikes) decreased substantially the rate of seed viability loss, but increased the rate of endophyte viability loss. Our experiments suggest that, in ageing seed pools, endophyte viability loss and differential seed mortality determine decreases in the proportions of endophyte‐infected seeds in L. multiflorum. Endophyte viability loss within live seeds contributes substantially more to infection frequency changes than differential viability losses of infected and non‐infected seeds.
Some insights into how barnacles survive as sessile organisms
Authors: BUCKERIDGE John S. , REEVES Jessica M.
Published: December 2009

During routine chemical analyses of the stalked ibliform barnacle Chaetolepas calcitergum Buckeridge & Newman 2006, peaks of more than 7% (by dry mass) of bromine were detected. Although bromine ions occur in seawater (up to 66 ppm), this level of accumulation, in the soft tissue of the barnacle, is extraordinary. Organic concentration of bromine compounds occurs in a number of invertebrates, such as algae and sponges, but this is the first record of elevated bromine in goose barnacles. The high accumulation of bromine compound(s) is most likely a defense mechanism. The present paper includes a review of the mechanisms deployed by barnacles to repel predators.

in my countrey are trees that beare fruit, that become byrds flying, and they are good to eate, and that that falleth on the water, liveth, and that that falleth on the earth, dyeth.

Sir John Mandeville, circa 1322–1356
Biochronology, paleobiogeography and faunal turnover in western Mediterranean Cenozoic mammals
Authors: PALOMBO Maria R.
Published: December 2009

Cenozoic terrestrial mammals from Sardinia contribute substantial information for reconstructing the complex history of the western Mediterranean. The occurrence of endemic perissodactyls in Eocene marine and marsh deposits suggests the existence of ecological or physical barriers between the Corso‐Sardinian massif and the Iberian‐Occitanic area. At the end of the Oligocene, isolation of Sardinia was almost complete, although a migration from Europe occurred at the beginning of the Early Miocene, as indicated by the unbalanced endemic fauna from Oschiri. During the Late Miocene, the Tusco‐Sardinian palaeobioprovince came into existence as an isolated region inhabited by the quite diversified, but notably endemic, Oreopithecus fauna. Sardinia was definitely isolated from Tuscany by the Messinian, but temporary connections with the European mainland possibly allowed the colonization of forerunners of some Sardinian Pliocene taxa. During the Plio‐Pleistocene, Sardinia maintained permanent isolation. However, sea level drop, resulting in a relatively short distance between Sardinia and the European mainland, allowed different migratory events. From the Late Pliocene to the Late Pleistocene‐Holocene, two main mammalian faunal complexes (FC) can be recognized: the Nesogoral FC (Late Pliocene‐Early Pleistocene) and the Microtus (Tyrrhenicola) FC (late Early Pleistocene‐Early Holocene). At the transition from Nesogoral to Microtus (Tyrrhenicola) FC, approximately 47% of the genera and 76% of the species disappeared, while approximately 58% of the genera and 71% of the species appeared. A noticeable turnover followed the arrival of Neolithic man and his accompanying fauna. Nonetheless, Praemegaceros was still present at about 7000 years BP, while Microtus (Tyrrhenicola) and Prolagus are respectively recorded in the Bronze and Iron Ages.
Different infection routes of avian influenza A (H5N1) virus in mice
Authors: SUN Ruiqin , LUO Jing , GAO Yunying , HE Hongxuan
Published: December 2009

The continuing outbreaks of avian influenza A H5N1 virus infection in Asia and Africa have caused worldwide concern because of the high mortality rates in poultry, suggesting its potential to become a pandemic influenza virus in humans. The transmission route of the virus among either the same species or different species is not yet clear. Broilers and BABL/c mice were inoculated with the H5N1 strain of influenza A virus isolated from birds. The animals were inoculated with 0.1 mL 106.83 TCID50 of H5N1 virus oronasally, intraperitoneally and using eye drops. The viruses were examined by virological and pathological assays. In addition, to detect horizontal transmission, in each group, healthy chicks and mice were mixed with those infected. Viruses were detected in homogenates of the heart, liver, spleen, kidney and blood of the infected mice and chickens. Virus antigen was not detected in the spleen, kidney or gastrointestinal tract, but detected by Plaque Forming Unit (PFU) assay in the brain, liver and lung without degenerative change in these organs (in the group inoculated using eye drops. The detection results for mice inoculated using eye drops suggest that this virus might have a different tissue tropism from other influenza viruses mainly restricted to the respiratory tract in mice. All chicken samples tested positive for the virus, regardless of the method of inoculation. Avian influenza A H5N1 viruses are highly pathogenic to chickens, but its virulence in other animals is not yet known. To sum up, the results suggest that the virus replicates not only in different animal species but also through different routes of infection. In addition, the virus was detection not only in the respiratory tract but also in multiple extra‐respiratory tissues. This study demonstrates that H5N1 virus infection in mice can cause systemic disease and spread through potentially novel routes within and between mammalian hosts.
Surveillance for highly pathogenic avian influenza in wild birds in the USA
Authors: DELIBERTO Thomas J. , SWAFFORD Seth R. , NOLTE Dale L. , PEDERSEN Kerri , LUTMAN Mark W. , SCHMIT Brandon B. , BAROCH John A. , KOHLER Dennis J. , FRANKLIN Alan
Published: December 2009

As part of the USA's National Strategy for Pandemic Influenza, an Interagency Strategic Plan for the Early Detection of Highly Pathogenic H5N1 Avian Influenza in Wild Migratory Birds was developed and implemented. From 1 April 2006 through 31 March 2009, 261 946 samples from wild birds and 101 457 wild bird fecal samples were collected in the USA; no highly pathogenic avian influenza was detected. The United States Department of Agriculture, and state and tribal cooperators accounted for 213 115 (81%) of the wild bird samples collected; 31, 27, 21 and 21% of the samples were collected from the Atlantic, Pacific, Central and Mississippi flyways, respectively. More than 250 species of wild birds in all 50 states were sampled. The majority of wild birds (86%) were dabbling ducks, geese, swans and shorebirds. The apparent prevalence of low pathogenic avian influenza viruses during biological years 2007 and 2008 was 9.7 and 11.0%, respectively. The apparent prevalence of H5 and H7 subtypes across all species sampled were 0.5 and 0.06%, respectively. The pooled fecal samples (n= 101 539) positive for low pathogenic avian influenza were 4.0, 6.7 and 4.7% for biological years 2006, 2007 and 2008, respectively. The highly pathogenic early detection system for wild birds developed and implemented in the USA represents the largest coordinated wildlife disease surveillance system ever conducted. This effort provided evidence that wild birds in the USA were free of highly pathogenic avian influenza virus (given the expected minimum prevalence of 0.001%) at the 99.9% confidence level during the surveillance period.
Hole-Drilling Strain-Gauge Method: Residual Stress Measurement With Plasticity Effects
Authors: Vangi D. , Tellini S.
Published: December 2009

When measuring residual stresses using the hole-drilling strain-gauge method, plasticity effects arise if the residual stress level exceeds about 60% of the material yield strength. In this case the classical methods, which are based on the linear elastic material behavior, do not work properly and residual stresses are overestimated. This paper presents a numerical study of the influence of plasticity on residual stress measurement by using the hole-drilling strain-gauge method in those cases in which stress does not vary with depth. The study investigates the effects of the most important loading, measuring, geometry, and material variables. An iterative method, which can be applied to obviate these errors, is then presented. The method was implemented in ANSYS using the APDL macrolanguage (ANSYS Parametric Design Language Guide, Documentation for ansys 11.0) to automatically execute the procedure steps. A finite element model of the hole, which allows for plasticity, is requested. Employing the readings of a standard three elements strain-gauge rosette, the method makes it possible to extend the measurement limit in comparison to that of the ASTM E837 standard (ASTM E837-08, “Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gauge Method”).
The Anomalous Redundant Deformation and Work Hardening of the AISI 420 Stainless Steel During Axisymmetric Drawing
Authors: Santos C. A. , Corrêa E. C. S. , Aguilar M. T. P. , Andrade M. S. , Cetlin P. R.
Published: December 2009

The cold axisymmetric drawing of metals leads to effective strains that increase from the centerline to the surface of the material cross section. This strain heterogeneity depends on the die semi-angle and reduction in area related through a “Δ” parameter. The average strain in the product is evaluated through a redundant deformation coefficient, “ϕ,” which has a minimum value of unity and rises as Δ is increased. Anomalous experimental results for this relationship (ϕ values below unity and insensitive to variations in Δ) have been reported for the AISI 420 stainless steel. Strain path affects the work hardening of metals during sheet forming, where some materials harden more and others less than under pure tension, for the same strain path. The present paper analyses the possibility that a similar dependence of the work hardening on the strain path, during the axisymmetric drawing of AISI 420 stainless steel causes the anomalous ϕ versus Δ relationship. The strain path followed along various material streamlines in axisymmetric drawing involves the superposition of a radially varying reversed shear strain on a basic radial compression/longitudinal tension pattern. A new method was developed for the determination of the effective stress versus effective strain curves of the material along three material streamlines, located close to the material surface, along its centerline and following a midcourse between these two flow lines. A relationship between the local microhardness of the material and its flow stress was established and visioplasticity was employed for the determination of local strains in the deformation region. Data were obtained for six situations resulting from the combinations of two reductions of area (8% and 20%) and three die semi-angles (3 deg, 8 deg, and 15 deg). The various strain paths followed in axisymmetric drawing of AISI 420 stainless steel led to effective stress versus effective strain curves tending to be often lower than that obtained in pure tension. The degree of lowering seems to depend on the reduction in area and die semi-angle. The effect of strain path on the work hardening during axisymmetric drawing causes the anomalous experimental results for the ϕ versus Δ relationship of the AISI 420 stainless steel. The present paper seems to be the first report in literature covering such effects under cold bulk forming conditions.
Finite-Volume
Formulation and Solution of the P3
Equations of Radiative Transfer on Unstructured
Meshes
Authors: Ravishankar Mahesh , Mazumder Sandip , Kumar Ankan
Published: December 2009

The method of spherical harmonics (or PN) is a popular method for approximate solution of the radiative transfer equation (RTE) in participating media. A rigorous conservative finite-volume (FV) procedure is presented for discretization of the P3 equations of radiative transfer in two-dimensional geometry—a set of four coupled, second-order partial differential equations. The FV procedure presented here is applicable to any arbitrary unstructured mesh topology. The resulting coupled set of discrete algebraic equations are solved implicitly using a coupled solver that involves decomposition of the computational domain into groups of geometrically contiguous cells using the binary spatial partitioning algorithm, followed by fully implicit coupled solution within each cell group using a preconditioned generalized minimum residual solver. The RTE solver is first verified by comparing predicted results with published Monte Carlo (MC) results for two benchmark problems. For completeness, results using the P1 approximation are also presented. As expected, results agree well with MC results for large/intermediate optical thicknesses, and the discrepancy between MC and P3 results increase as the optical thickness is decreased. The P3 approximation is found to be more accurate than the P1 approximation for optically thick cases. Finally, the new RTE solver is coupled to a reacting flow code and demonstrated for a laminar flame calculation using an unstructured mesh. It is found that the solution of the four P3 equations requires 14.5% additional CPU time, while the solution of the single P1 equation requires 9.3% additional CPU time over the case without radiation.
Effect on Radiant Heat Transfer at the Surface of a Pool Fire Interacting With a Water Mist
Authors: Garo J. P. , Vantelon J. P. , Lemonnier D.
Published: December 2009

It is well established that the use of water mist can be an attractive alternative to gaseous suppression agents to extinguish fires for specific scenarios. Among the main mechanisms, which act together to extinguish fires when using a water mist: heat extraction, oxygen displacement, and radiant heat attenuation, the last one has received the less attention, especially regarding the energy balance at the fuel surface and, therefore, the rate of generation of flammable vapors. The objective of this work is to analyze, on the one hand, the perturbing influence of a mist addition as an opposed flow to a small-scale liquid (heptane) pool fire structure, especially at its base, the more interesting zone regarding the mechanisms of flame stabilization and extinction and, on the other hand, the effect on the surface radiant heat feedback. Experiments conducted give an order of magnitude estimate in essential agreement with a radiation computation, based on the mappings, previously obtained, of the two major parameters: temperature and extinction coefficient, that determine the thermal radiation of the flame. The important information is the confirmation that radiation attenuation cannot be identified as a predominant mechanism of extinguishment.
A Hybrid Coil/Polymer Device for Occlusion of Cerebral Aneurysms
Authors: Xu Fangmin , Hart Kevin , Flanagan Claire E. , Nacker John C. , Moftakhar Roham , Aagaard-Kienitz Beverly , Consigny Daniel W. , Grinde Julie R. , Crone Wendy C. , Masters Kristyn S.
Published: December 2009

The treatment of cerebral aneurysms is frequently accomplished via endovascular delivery of metal coils in order to occlude the aneurysm and prevent rupture. This procedure involves imprecise packing of large lengths of wire into the aneurysm and often results in high rates of aneurysm recanalization. Over time, this incomplete aneurysm occlusion can lead to aneurysm enlargement, which may have fatal consequences. This report describes the fabrication and preliminary testing of a novel aneurysm occlusion device composed of a single metal coil surrounded by a biocompatible polymer shell. These coil-in-shell devices were tested under flow conditions in synthetic in vitro models of saccular aneurysms and deployed in vivo in a short-term porcine aneurysm model to study occlusion efficacy. A single nickel titanium shape memory wire was used to deploy a biocompatible, elastic polymeric shell, leading to aneurysmal sac filling in both in vitro and in vivo aneurysm models. The deployment of this coil-in-shell device in synthetic aneurysm models in vitro resulted in varying degrees of aneurysm occlusion, with less than 2% of trials resulting in significant leakage of fluid into the aneurysm. Meanwhile, in vivo coil-in-shell device implantation in a porcine aneurysm model provided proof-of-concept for successful occlusion, as both aneurysms were completely occluded by the devices. Both in vitro and in vivo studies demonstrated that this coil-in-shell device may be attractive as an alternative to traditional coil embolization methods in some cases, allowing for a more precise and controlled aneurysm occlusion.
A Parametric Case Study in Radiative Heat Transfer Using the Reverse Monte-Carlo Ray-Tracing With Full-Spectrum k-Distribution Method
Authors: Sun Xiaojing , Smith Philip J.
Published: December 2009

A combined method of reverse Monte-Carlo ray-tracing with full-spectrum k-distribution (FSK) for computing the radiative heat transfer is applied to an extreme nonhomogeneous case (both temperature and gas mixture composition vary with positions) with an absorbing, emitting media. The parameter studies of the scaled FSK (FSSK) and correlated FSK (FSCK) methods for the case, such as g point resolution, mesh resolution, reference states, and integration quadratures, are carried out. The results from the FSSK and FSCK are only affected by the chosen reference states and are not sensitive to other parameters.
A Narrow Band-Based Multiscale Multigroup Full-Spectrum k-Distribution Method for Radiative Transfer in Nonhomogeneous Gas-Soot Mixtures
Authors: Pal Gopalendu , Modest Michael F.
Published: December 2009

The full-spectrum k-distribution (FSK) approach has become a promising method for radiative heat transfer calculations in strongly nongray participating media, due to its ability to achieve high accuracy at a tiny fraction of the line-by-line (LBL) computational cost. However, inhomogeneities in temperature, total pressure, and component mole fractions severely challenge the accuracy of the FSK approach. The objective of this paper is to develop a narrow band-based hybrid FSK model that is accurate for radiation calculations in combustion systems containing both molecular gases and nongray particles such as soot with strong temperature and mole fraction inhomogeneities. This method combines the advantages of the multigroup FSK method for temperature inhomogeneities in a single species, and the modified multiscale FSK method for concentration inhomogeneities in gas-soot mixtures. In this new method, each species is considered as one scale; the absorption coefficients within each narrow band of every gas scale are divided into M exclusive spectral groups, depending on their temperature dependence. Accurate and compact narrow band multigroup databases are constructed for combustion gases such as CO2 and H2O. Sample calculations are performed for a 1D medium and also for a 2D axisymmetric combustion flame. The narrow band-based hybrid method is observed to accurately predict heat transfer from extremely inhomogeneous gas-soot mixtures with/without wall emission, yielding close-to-LBL accuracy.
A Sensorized Instrument for Skills Assessment and Training in Minimally Invasive Surgery
Authors: Trejos A. L. , Patel R. V. , Naish M. D. , Lyle A. C. , Schlachta C. M.
Published: December 2009

Minimally invasive surgery (MIS) is carried out using long, narrow instruments and significantly reduces trauma to the body, postoperative pain, and recovery time. Unfortunately, the restricted access conditions, limited instrument motion, and degraded sense of touch inherent in MIS result in new perceptual-motor relationships, which are unfamiliar to the surgeon and require training to overcome. Current training methods do not adequately address the needs of surgeons interested in acquiring these skills. Although a significant amount of research has been focused on the development of sensorized systems for surgery, there is still a need for a system that can be used in any training scenario (laparoscopic trainer, animal laboratories, or real surgery) for the purpose of skills assessment and training. A sensorized laparoscopic instrument has been designed that is capable of noninvasively measuring its interaction with tissue in the form of forces or torques acting in all five degrees-of-freedom (DOFs) available during MIS. Strain gauges attached to concentric shafts within the instrument allow the forces acting in different directions to be isolated. An electromagnetic tracking system is used for position tracking. Two prototypes of the sensorized instrument were constructed. Position calibration shows a maximum root mean square (RMS) error of 1.3 mm. The results of the force calibration show a maximum RMS error of 0.35 N for the actuation force, 0.07 N in the x and y directions, and 1.5 N mm for the torque calibration with good repeatability and low hysteresis. Axial measurements were significantly affected by drift, noise, and coupling leading to high errors in the readings. Novel sensorized instruments for skills assessment and training have been developed and a patent has been filed for the design and operation. The instruments measure forces and torques acting at the tip of the instrument corresponding to all five DOFs available during MIS and provide position feedback in six DOFs. The instruments are similar in shape, size, and weight to traditional laparoscopic instruments allowing them to be used in any training environment. Furthermore, replaceable tips and handles allow the instruments to be used for a variety of different tasks.
Characterization of Plastic Hypodermic Needles
Authors: Busillo Eric , Colton Jonathan S.
Published: December 2009

A significant potential for plastic hypodermic needles exists as an alternative to current steel needles. This paper presents the design and testing of one type of plastic hypodermic needle. The buckling and penetration characteristics of the needles were modeled and analyzed analytically and by finite element analyses. Experimental penetration tests using plastic and steel control hypodermic needles with skin mimics, specifically polyurethane film and pig skin, were performed to determine penetration and friction forces. Lubricated plastic needles achieved successful penetrations in 25–75% of the tests in both polyurethane film and pig skin with penetration forces ranging from 7 N to 10 N. Penetration tests into butyl rubber stoppers also were conducted with lubricated plastic needles penetrating in 75% of the tests with an average penetration force of 8.3 N. Various lubricants, including silicone oil and a medical grade silicone dispersion, were also studied. In addition, the needles underwent successful perpendicular bending tests and cannula stiffness tests. Finally, fluid flow tests determined fluid flow rates through the needles. Experimental results were compared with each other and to finite element analyses and are discussed.
Numerical Investigation of Coil Configurations That Provide Ultrahigh Packing Density of Saccular Aneurysms
Authors: Sadasivan Chander , Lieber Baruch B.
Published: December 2009

The long-term outcome of endovascular coiling of cerebral aneurysms is directly related to the packing density at the time of treatment. In general, the highest packing density achievable is only about 45% due to the quasirandom distribution of currently available coils within aneurysms. We investigated whether packing densities could be maximized via more ordered coil configurations. Three different coil configurations—circular loops, planar spirals, and spherical helices—were investigated. The packing densities achievable in maximally filling the volume of an exemplar human basilar aneurysm with each coil configuration were calculated numerically. Coil packing simulations were also carried out for aneurysms idealized as spheres over diameters ranging from 2 mm to 30 mm. The packing densities with the loop, spiral, and spherical helix configurations were 82%, 60%, and 73%, respectively, for the human aneurysm model; the numbers of coils required were 693, 34, and 13, respectively. Simulations within idealized aneurysms suggest that aneurysms cannot be packed to more than 91% with coils of constant circular cross section. The spherical helix configuration provides a constant packing density (coefficient of variation of 0.4%) over the range of aneurysm diameters studied as compared to the two other configurations (coefficients of variation of 9% and 8%). Coil configurations that allow for ordered filling of cerebral aneurysms can potentially provide packing densities that are twice those currently achieved. The spherical helix configuration seems to be the most technically feasible and stable configuration of the three coil types investigated.
Lipids Link Membrane Molecules
Authors: VanHook Annalisa M.
Published: December 2009

Patched-mediated modulation of membrane lipid composition may regulate Smoothened trafficking.
ABA Receptor Up Close
Authors: Hines Pamela
Published: December 2009

The plant hormone responsible for drought tolerance signals by inducing conformational changes in its dimeric protein receptor.
Better Alzheimer’s Options
Authors: Gough Nancy R.
Published: December 2009

Drugs that specifically antagonize NMDA receptors with the NR2B subunit prevent Aβ-mediated inhibition of long-term potentiation.
Medulloblastoma and Atoh1
Authors: Hines Pamela
Published: December 2009

A transcription factor regulates signaling in the developing mouse cerebellum and also influences cancer formation.
To Be γδ or Not to Be γδ? Signaling Pathways in αβ Versus γδ T Cell Maturation
Authors: Archbold Julia K.
Published: December 2009

The role of Notch signaling in human T cell maturation is substantially different from that in the mouse.
Cracking the Phosphatase Code: Docking Interactions Determine Substrate Specificity
Authors: Roy Jagoree , Cyert Martha S.
Published: December 2009

Studies of the motifs that guide interactions between phosphatases and cellular proteins provide insight into phosphatase selectivity.
A Role for
VAV1
in Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis
Authors: Jagodic Maja , Colacios Celine , Nohra Rita , Dejean Anne S. , Beyeen Amennai Daniel , Khademi Mohsen , Casemayou Audrey , Lamouroux Lucille , Duthoit Christine , Papapietro Olivier , Sjöholm Louise , Bernard Isabelle , Lagrange Dominique , Dahlman Ingrid , Lundmark Frida , Oturai Annette B. , Soendergaard Helle B. , Kemppinen Anu , Saarela Janna , Tienari Pentti J. , Harbo Hanne F. , Spurkland Anne , Ramagopalan Sreeram V. , Sadovnick Dessa A. , Ebers George C. , Seddighzadeh Maria , Klareskog Lars , Alfredsson Lars , Padyukov Leonid , Hillert Jan , Clanet Michel , Edan Gilles , Fontaine Bertrand , Fournié Gilbert J. , Kockum Ingrid , Saoudi Abdelhadi , Olsson Tomas
Published: December 2009

VAV1
plays a role in regulating proinflammatory cytokines, which underlie the susceptibility for developing experimental autoimmune encephalomyelitis and multiple sclerosis.
Protonation effects on dynamic flux properties of aqueous metal complexes
Authors: Van Leeuwen Herman P. , Town Raewyn M.
Published: December 2009

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.
Irregular polarographic currents obey Feigenbaum universality route from order to chaos
Authors: Pospíšil Lubomír , Hromadová Magdaléna , Gál Miroslav , Valášek Michal , Fanelli Nicolangelo , Kolivoška Viliam
Published: December 2009

The DC polarograms of an oligomer with four repetitive units of ‘extended viologen’ yield in part irregular current fluctuation. The analysis of the current–time transients at different potentials confirms the periodicity, the period doubling and transfer to chaos. The periodicity doubling obeys the universal route to chaos. The estimated value of the Feigenbaum constant 4.68 is very close to the theoretical value δ = 4.6692...
Increased rate of whole body lipolysis before and after 9 days of bed rest in healthy young men born with low birth weight
Authors: Alibegovic A. C. , Højbjerre L. , Sonne M. P. , van Hall G. , Alsted T. J. , Kiens B. , Stallknecht B. , Dela F. , Vaag A.
Published: December 2009

Individuals born with low birth weight (LBW) are at risk of developing type 2 diabetes mellitus (T2D), which may be precipitated by physical inactivity. Twenty-two LBW subjects and twenty-three controls were studied before and after bed rest by the hyperinsulinemic euglycemic clamp combined with indirect calorimetry and infusion of stable isotope tracers and preceded by an intravenous glucose tolerance test. LBW subjects had a similar body mass index but elevated abdominal obesity compared with controls. The basal rate of whole body lipolysis (WBL) was elevated in LBW subjects with and without correction for abdominal obesity before and after bed rest (all P = 0.01). Skeletal muscle hormone-sensitive lipase (HSL) protein expression and phosphorylation at Ser565 were similar in the two groups. Bed rest resulted in a decrease in WBL and an increased skeletal muscle HSL Ser565 phosphorylation indicating a decreased HSL activity in both groups. All subjects developed peripheral insulin resistance in response to bed rest (all P < 0.0001) with no differences between groups. LBW subjects developed hepatic insulin resistance in response to bed rest. In conclusion, increased WBL may contribute to the development of hepatic insulin resistance when exposed to bed rest in LBW subjects. Nine days of bed rest causes severe peripheral insulin resistance and reduced WBL and skeletal muscle HSL activity, as well as a compensatory increased insulin secretion, with no differences in LBW subjects and controls.
Prolonged moderate-intensity aerobic exercise does not alter apoptotic signaling and DNA fragmentation in human skeletal muscle
Authors: Quadrilatero Joe , Bombardier Eric , Norris Sarah M. , Talanian Jason L. , Palmer Matthew S. , Logan Heather M. , Tupling A. Russell , Heigenhauser George J. F. , Spriet Lawrence L.
Published: December 2009

Apoptosis in skeletal muscle plays an important role in age- and disease-related tissue dysfunction. Physical activity can influence apoptotic signaling; however, this process has not been well studied in human skeletal muscle. The purpose of this study was to perform a comprehensive analysis of apoptosis-related proteins/enzymes, DNA fragmentation, and oxidative stress in skeletal muscle of humans during an acute bout of prolonged moderate-intensity exercise. Eight healthy, recreationally active individuals (age 20.8 ± 0.5 yr, V̇o2peak 51.2 ± 0.9 ml · kg−1 · min−1, BMI 21.5 ± 0.8 kg/m2) exercised on a cycle ergometer at ∼60% V̇o2peak for 2 h. Muscle biopsies were obtained at rest as well as at 60 and 120 min of exercise. Although exercise was associated with a significant whole body and muscle metabolic response, there were no significant changes in the content of antiapoptotic (ARC, Bcl-2, Hsp70, XIAP) and proapoptotic (AIF, Bax, Smac) proteins, activity of proteolytic enzymes (caspase-3, caspase-8, caspase-9), DNA fragmentation, or TUNEL-positive nuclei in skeletal muscle. Furthermore, the protein levels of several antioxidant enzymes (catalase, CuZnSOD, MnSOD), concentrations of GSH and GSSG, and degree of ROS generation in skeletal muscle were not altered by exercise. Fiber type-specific analysis also revealed that ARC ( P < 0.001) and Hsp70 ( P < 0.05) protein were significantly higher in type I compared with type IIA and type IIAX/X fibers; however, protein levels were not affected by exercise. These findings suggest that a single bout of prolonged moderate-intensity aerobic exercise is not sufficient to alter apoptotic signaling in skeletal muscle of healthy humans.
Exercise maintains euglycemia in association with decreased activation of c-Jun NH2-terminal kinase and serine phosphorylation of IRS-1 in the liver of ZDF rats
Authors: Király Michael A. , Campbell Jon , Park Edward , Bates Holly E. , Yue Jessica T. Y. , Rao Venket , Matthews Stephen G. , Bikopoulos George , Rozakis-Adcock Maria , Giacca Adria , Vranic Mladen , Riddell Michael C.
Published: December 2009

Stress-activated systems and oxidative stress are involved in insulin resistance, which, along with β-cell failure, contribute to the development of type 2 diabetes mellitus (T2DM). Exercise improves insulin resistance and glucose tolerance, and these adaptations may, in part, be related to reductions in inflammation and oxidative stress. We investigated circulating and tissue-specific markers of inflammation and oxidative stress and insulin-signaling pathways in a rodent model of T2DM, the Zucker diabetic fatty rat, with and without voluntary exercise. At 5 wk of age, Zucker diabetic fatty rats ( n = 8–9/group) were divided into basal (B), voluntary exercise (E), and sedentary control (S) groups. B rats were euthanized at 6 wk of age, and S and E rats were euthanized 10 wk later. E rats ran ∼5 km/day, which improved insulin sensitivity and maintained fed and fasted glucose levels and glucose tolerance. Ten weeks of exercise also decreased whole body markers of inflammation and oxidative stress in plasma and liver, including lowered circulating IL-6, haptoglobin, and malondialdehyde levels, hepatic protein oxidation, and phosphorylated JNK, the latter indicating decreased JNK activity. Hepatic phosphoenolpyruvate carboxykinase levels and Ser307-phosphorylated insulin receptor substrate-1 were also reduced in E compared with S rats. In summary, we show that, in a rodent model of T2DM, voluntary exercise decreases circulating markers of inflammation and oxidative stress and lowers hepatic JNK activation and Ser307-phosphorylated insulin receptor substrate-1. These changes in oxidative stress markers and inflammation are associated with decreased hyperglycemia and insulin resistance and reduced expression of the main gluconeogenic enzyme phosphoenolpyruvate carboxykinase.
Developmental Alteration of Endocannabinoid Retrograde Signaling in the Hippocampus
Authors: Zhu Ping Jun , Lovinger David M.
Published: December 2009

Endocannabinoids are lipid derivatives that mediate paracrine and juxtacrine signaling between cells. In the hippocampal CA1 region, a retrograde endocannabinoid signal suppresses GABA release by acting on presynaptic cannabinoid receptor-1 (CB1) and can be functionally manifested as depolarization-induced suppression of inhibition (DSI). In the present study, whole cell patch-clamp recordings in hippocampal slices were made to examine DSI in rats from P7–P21. Robust DSI develops in rat hippocampus at postnatal ages greater than two weeks, but only modest DSI is observed in P7-9 rat. DSI in neonatal rats can be enhanced by activation of group I metabotropic glutamate receptors (mGluRs) or muscarinic acetylcholine receptors in those neonatal rats. The DSI is also enhanced by sustained low-frequency (1 Hz) stimulation (5 min). This stimulus-enhanced DSI was prevented in the presence of 6-methyl-2-(phenylethynyl)-pyridine (10 μM), a group I mGluR antagonist. WIN55212-2, a synthetic CB1 agonist, produced a similar level of inhibition of GABAergic synaptic transmission at different postnatal time points. Therefore postsynaptic mechanisms appear to be mainly responsible for developmental changes in DSI, although presynaptic mechanisms cannot be ruled out entirely. We have also obtained evidence that tonic endocannabinoid release suppresses GABAergic transmission in the mature but not the neonatal hippocampus. The differential DSI magnitude at different stages of maturation could alter synaptic plasticity and learning and memory during hippocampal development.
Proteomic profiling of nuclei from native renal inner medullary collecting duct cells using LC-MS/MS
Authors: Tchapyjnikov Dmitry , Li Yuedan , Pisitkun Trairak , Hoffert Jason D. , Yu Ming-Jiun , Knepper Mark A.
Published: December 2009

Vasopressin is a peptide hormone that regulates renal water excretion in part through its actions on the collecting duct. The regulation occurs in part via control of transcription of genes coding for the water channels aquaporin-2 ( Aqp2) and aquaporin-3 ( Aqp3). To identify transcription factors expressed in collecting duct cells, we have carried out LC-MS/MS-based proteomic profiling of nuclei isolated from native rat inner medullary collecting ducts (IMCDs). To maximize the number of proteins identified, we matched spectra to rat amino acid sequences using three different search algorithms (SEQUEST, InsPecT, and OMSSA). All searches were coupled to target-decoy methodology to limit false-discovery identifications to 2% of the total for single-peptide identifications. In addition, we developed a computational tool ( ProMatch) to identify and eliminate ambiguous identifications. With this approach, we identified >3,500 proteins, including 154 proteins classified as “transcription factor” proteins (Panther Classification System). Among these, are members of CREB, ETS, RXR, NFAT, HOX, GATA, EBOX, EGR, MYT1, KLF, and CP2 families, which were found to have evolutionarily conserved putative binding sites in the 5′-flanking region or first intron of the Aqp2 gene, as well as members of EBOX, NR2, GRE, MAZ, KLF, and SP1 families corresponding to conserved sites in the 5′-flanking region of the Aqp3 gene. In addition, several novel phosphorylation sites in nuclear proteins were identified using the neutral loss-scanning LC-MS3technique. The newly identified proteins have been incorporated into the IMCD Proteome Database ( http://dir.nhlbi.nih.gov/papers/lkem/imcd/ ).
Effect of pregnancy and progesterone concentration on expression of genes encoding for transporters or secreted proteins in the bovine endometrium
Authors: Forde N. , Spencer T. E. , Bazer F. W. , Song G. , Roche J. F. , Lonergan P.
Published: December 2009

The objective of this study was to determine the temporal and spatial expression patterns of genes encoding transporters, as well as selected secreted proteins that may be regulated by progesterone (P4) and/or the presence of the conceptus in the bovine endometrium. Estrus-synchronized beef heifers were randomly assigned to either: 1) pregnant, high P4; 2) pregnant, normal P4; 3) cyclic, high P4; or 4) cyclic, normal P4. Uteri were collected on days 5, 7, 13, and 16 of the estrous cycle or pregnancy. Localization of mRNAs for ANPEP, CTGF, LPL, LTF, and SLC5A1 in the uteri was determined by radioactive in situ hybridization, and expression quantified in the endometria by quantitative real-time PCR. ANPEP localized to luminal (LE) and superficial glandular (sGE) epithelia of all heifers on days 5 and 7 only. SLC5A1 mRNA was detected in the LE and sGE on days 13 and 16 in all heifers, and expression increased on day 16 in pregnant groups. CTGF localized weakly to the LE and GE on days 5 and 7 but increased on days 13 and 16 with an increase ( P < 0.05) in CTGF expression in high P4 ( day 7) and pregnant heifers ( day 16). Both LPL and LTF localized to the GE only on days 5 and 7. In conclusion we have characterized the temporal expression pattern of these genes and modulation of their transcript abundance by P4 ( CTGF, LPL) and/or the conceptus ( CTGF, SLC5A1) likely modifies the uterine microenvironment, enhancing histotroph composition and contributing to advanced conceptus elongation.
Differential effects of leptin receptor mutation on male and female BBDR.Gimap5−/Gimap5− spontaneously diabetic rats
Authors: Moralejo Daniel H. , Hansen Carl T. , Treuting Piper , Hessner Martin J. , Fuller Jessica M. , Van Yserloo Brian , Jensen Richard , Osborne William , Kwitek Anne E. , Lernmark Åke
Published: December 2009

Rodents homozygous for autosomal leptin receptor gene mutations not only become obese, insulin resistant, and hyperleptinemic but also develop a dysregulated immune system. Using marker-assisted breeding to introgress the Koletsky rat leptin receptor mutant ( lepr−/lepr−), we developed a novel congenic BBDR. lepr−/lepr− rat line to study the development of obesity and type 2 diabetes (T2D) in the BioBreeding (BB) diabetes-resistant (DR) rat. While heterozygous lepr (−/+) or homozygous (+/+) BBDR rats remained lean and metabolically normal, at 3 wk of age all BBDR. lepr−/lepr− rats were obese without hyperglycemia. Between 45 and 70 days of age, male but not female obese rats developed T2D. We had previously developed congenic BBDR. Gimap5−/Gimap5− rats, which carry an autosomal frameshift mutation in the Gimap5 gene linked to lymphopenia and spontaneous development of type 1 diabetes (T1D) without sex differences. Because the autoimmune-mediated destruction of pancreatic islet β-cells may be affected not only by obesity but also by the absence of leptin receptor signaling, we next generated BBDR. lepr−/lepr−,Gimap5−/Gimap5− double congenic rats carrying the mutation for Gimap5 and T1D as well as the Lepr mutation for obesity and T2D. The hyperleptinemia rescued end-stage islets in BBDR. lepr−/lepr−,Gimap5−/Gimap5− congenic rats and induced an increase in islet size in both sexes, while T1D development was delayed and reduced only in females. These results demonstrate that obesity and T2D induced by introgression of the Koletsky leptin receptor mutation in the BBDR rat result in islet expansion associated with protection from T1D in female but not male BBDR. lepr−/lepr−,Gimap5−/Gimap5− congenic rats. BBDR. lepr−/lepr−,Gimap5−/Gimap5− congenic rats should prove valuable to study interactions between lack of leptin receptor signaling, obesity, and sex-specific T2D and T1D.
Generalized Levitin-Polyak Well-Posedness of Vector Equilibrium Problems
Authors: Peng Jian-Wen , Wang Yan , Zhao Lai-Jun
Published: December 2009

We study generalized Levitin-Polyak well-posedness of vector equilibrium problems with functional constraints as well as an abstract set constraint. We will introduce several types of generalized Levitin-Polyak well-posedness of vector equilibrium problems and give various criteria and characterizations for these types of generalized Levitin-Polyak well-posedness.
Synthesis and Characterizations of Bare CdS Nanocrystals Using Chemical Precipitation Method for Photoluminescence Application
Authors: Lee H. L. , Issam A. M. , Belmahi M. , Assouar M. B. , Rinnert H. , Alnot M.
Published: December 2009

Bare cadmium sulfide (CdS) nanocrystals were successfully synthesized by the thermolysis of a single‐source organometallic precursor, cadmium chloride hemipentahydrate (CdCl2 · 2.5H2O) with thiourea in ethanol. The microstructure of the CdS samples was characterized using XRD, TEM, and Raman spectroscopy. The XRD′s results showed that there was a transformation from cubic to hexagonal crystalline phase when higher mass of CdCl2 · 2.5H2O was used. Further experimental with different Cd2+ source showed ion Cl− originated from CdCl2 · 2.5H2O attributed to this crystalline phase transformation. The UV‐Visible analysis indicated that quantum confinement effect took place when compared to the bulk CdS. However, the photoluminescence experiments revealed that the red‐light emission was observed in all samples. This finding could be ascribed to deep trap defects that were due to sulfur vacancies as suggested by XPS and also the fact that the bare CdS nanoparticles are in contact with each other as shown in the TEM images.
Differential Destruction of Stem Cells: Implications for Targeted Cancer Stem Cell Therapy
Authors: Sehl Mary E. , Sinsheimer Janet S. , Zhou Hua , Lange Kenneth L.
Published: December 2009

Cancer stem cells represent a novel therapeutic target. The major challenge in targeting leukemic stem cells (LSC) is finding therapies that largely spare normal hematopoietic stem cells (HSC) while eradicating quiescent LSCs. We present a mathematical model to predict how selective a therapy must be to ensure that enough HSCs survive when LSCs have been eradicated. Stem cell population size is modeled as a birth-death process. This permits comparison of LSC and HSC eradication times under therapy and calculation of the number of HSCs at the time of LSC eradication for varied initial population sizes and stem cell death rates. We further investigate the effects of LSC quiescence and resistance mutations on our predictions. From a clinical point of view, our models suggest criteria by which cancer stem cell therapy safety can be assessed. We anticipate that in conjunction with experimental observation of cancer stem cell killing rates, our results will be useful in screening targeted therapies for both hematologic and solid tumor malignancies. [Cancer Res 2009;69(24):9481–9]