bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical impedance spectroscopy study of electron transfer at poly(3,4-ethylenedioxythiophene) containing gold nanoparticles coating
Authors: Lupu Stelian
Published: December 2011

Electrochemical impedance spectroscopy (EIS) was used for characterization of electron transfer in various redox probes, such as the redox couple ferrocyanide-ferricyanide, ferrocene, ferrocenemethanol, and the poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer containing gold nanoparticles. The PEDOT coating was deposited onto platinum (Pt) and glassy carbon (GC) electrodes by galvanostatic electrochemical polymerization from an aqueous solution containing 10–2 M EDOT and 10–1 M LiClO4 as supporting electrolyte. The PEDOT-Au nanoparticles composite coating was prepared by droplet deposition of Au nanoparticles on top of the Pt/PEDOT and GC/PEDOT modified electrodes. The pure PEDOT and PEDOT-Au nanoparticles composite coatings were investigated using EIS and cyclic voltammetry (CV) in 10–1 M LiClO4 solution containing various redox probes. The impedance spectra were recorded at the formal redox potential of the redox probes. The charge transfer resistance (Rct), solution resistance (Rs), exchange current density (i0), standard rate constant (k0), and double-layer capacitance (Cdl) were calculated from the EIS data.
The endoscopically normal colon: when is mapping biopsy histopathologically justifiable?: Table 1
Authors: Elliot V J , Bateman A C , Green B
Published: December 2011

Objective

Mapping biopsy of endoscopically normal colon is a contentious area and generates considerable work for histopathology services. Managing demand for pathological testing is a current healthcare priority. In this retrospective audit, the authors aimed to establish diagnostic yield of mapping biopsy in this specific subgroup and identify situations where practice could be safely streamlined.

Design

Cases were retrieved over a 10-month period. Histopathology results were correlated with relevant endoscopy reports. The data were anonymised and analysed.

Setting

Department of Cellular Pathology, Southampton General Hospital, UK.

Results

717 cases were retrieved. 308 (43%) cases were reported as endoscopically normal. 278 (90%) cases with endoscopically normal/near normal mucosa showed normal/near normal histology. 30/308 (9.7%) endoscopically normal cases showed pathological abnormalities. 9/308 (2.9%) cases of microscopic colitis were detected. Of the 30 cases with pathological abnormalities, 20 (66.7%) presented with change in bowel habit and 6 (20%) had a pre-existing diagnosis of inflammatory bowel disease.

Conclusions

Pathological abnormalities in endoscopically normal colon are found most frequently in those who present with change in bowel habit or a known history of inflammatory bowel disease. The authors support biopsy in these individuals and believe that mapping biopsy of endoscopically normal colon in patients referred for other reasons (eg, bright red rectal bleeding or iron deficiency anaemia) should not be performed routinely as diagnostic yields are very low. Guidelines on appropriate use of mapping biopsy in this setting are limited. Streamlining patients based on reason for referral or presenting symptoms may be a useful step towards more effective management of histopathological demand.
Role of routine neuropathological examination for determining cause of death in sudden unexpected deaths in infancy (SUDI)
Authors: Pryce J W , Paine S M L , Weber M A , Harding B , Jacques T S , Sebire N J
Published: December 2011

Background

Current guidelines for the investigation of sudden unexpected death in infancy (SUDI) include full neuropathological examination with recommendations for brain fixation for 1–2 weeks. Little evidence is available regarding the yield of such examination in determining cause of death in clinical practice. This study examines the frequency of neuropathological findings determining cause of death at postmortem examination in SUDI in relation to clinical and macroscopic features.

Methods

All postmortem examinations performed for the indication of SUDI at a single specialist centre over a 14-year period were reviewed, including clinical history, macroscopic and neuropathological findings.

Results

6% of postmortem examinations performed for cases of SUDI demonstrated a neuropathological cause of death; in almost all (>90%) the clinical history and/or macroscopic examination suggested the cause of death. In 2% of all cases the cause of death was determined by histological neuropathological examination, but there were no cases in which histological neuropathological examination of a macroscopically normal brain revealed the cause of death in the absence of a ‘neurological history’. Macroscopic brain abnormalities and the presence of a ‘neurological history’ were significantly more likely to yield histological brain abnormalities (11-fold and fourfold, respectively).

Conclusions

Histological neuropathological examination rarely determines the cause of death in SUDI in the absence of macroscopic abnormalities or neurological clinical history. A macroscopically abnormal brain and the presence of a clinical history of possible neurological disease or of inflicted injury are significantly more likely to be associated with significant histological brain abnormalities.
Evaluation of spinosad for the oral treatment and control of flea infestations on dogs in Europe
Authors: Wolken S. , Franc M. , Bouhsira E. , Wiseman S. , Hayes B. , Schnitzler B. , Jacobs D. E.
Published: December 2011

The novel ectoparasiticide spinosad is a naturally occurring mixture of spinosyns A and D formed during a fermentation process. The spinosyns are tetracyclic macrolides with a unique ring system. Their mode of action differs from that of other commercially available insecticides. Laboratory and field trials were conducted to evaluate the use of spinosad in a chewable tablet at a dose range of 45 to 70 mg/kg for the treatment and control of flea infestations on dogs in Europe. Laboratory studies with artificially infested dogs confirmed persistent activity against Ctenocephalides felis of higher than 99 per cent at three weeks post‐treatment with values of 96.5 to 97.8 per cent at four weeks. Two multicentric field trials with naturally infected client‐owned animals in five European countries used selamectin as comparator. Monthly doses were given during the summer when many homes were heavily infested. Households with spinosad‐treated dogs showed cumulative benefits with flea burdens reduced by about 97 per cent at 14 and 30 days and by 99.6 per cent at 60 and 90 days. Corresponding figures for selamectin were significantly lower (P<0.05) at all time points: between 88.5 and 91 per cent at 14 and 30 days, then 97.8 and 98.2 per cent at 60 and 90 days. Thus, the performance of spinosad compared favourably with that of the established reference product.
Comparison of homoeologous chromosome pairing between hybrids of wheat genotypes Chinese Springph1band Kaixian-luohanmai with rye
Authors: Hao Ming , Luo Jiangtao , Yang Min , Zhang Lianquan , Yan Zehong , Yuan Zhongwei , Zheng Youliang , Zhang Huaigang , Liu Dengcai
Published: December 2011

The ph-like genes in the Chinese common wheat landrace Kaixian-luohanmai (KL) induce homoeologous pairing in hybrids with alien species. In the present study, meiotic phenotypic differences on homoeologous chromosome pairing at metaphase I between hybrids of wheat genotypes Chinese Spring ph1b (CSph1b) and KL with rye were studied by genomic in situ hybridization (GISH). The frequency of wheat–wheat associations was higher in CSph1b × rye than in KL × rye. However, frequencies of wheat–rye and rye–rye associations were higher in KL × rye than in CSph1b × rye. These differences may be the result of different mechanisms of control between the ph-like gene(s) controlling homoeologous chromosome pairing in KL and CSph1b. Wheat–wheat associations were much more frequent than wheat–rye pairing in both hybriods. This may be caused by lower overall affinity, or homoeology, between wheat and rye chromosomes than between wheat chromosomes.
Measurement of the interaction of aqueous copper(II) with a model amyloid-β protein fragment — Interference from buffers
Authors: Benn Michael H. , Rauk Arvi , Swaddle Thomas W.
Published: December 2011

For the formation of a complex of Cu2+ with the amyloid-β (Aβ) proxy N-α-dihydrourocanylhistamine (L) in unbuffered aqueous solution (pH ∼ 5.7, 25.0 °C), UV spectrophotometric measurements give a stability constant of 3.8 × 105 L mol–1. This stability constant is within the lower limit of the range of stability constants reported in the literature for complexes of Aβ with Cu2+ — as expected, in view of the smaller number of coordination sites in L. Computer modeling indicates that the Cu2+–L complex is CuL(H2O)22+, with terdentate L bound to Cu2+ via two Nπ atoms and the O atom of the peptide link. Attempts to make stability constant measurements for Cu2+ with L in aqueous solution buffered with Tris/TrisH+/ClO4– to pH near 7.2 were unsuccessful because the Tris base when in large excess over CuL2+ promoted its dissociation to Cu2+ + L by scavenging free Cu2+ as Cu(Tris)(TrisH–1)+, or when in roughly equimolar concentrations formed a ternary adduct, CuL(Tris)2+. The interactions of Cu2+ with Tris buffer were re-examined spectrophotometrically and with the aid of computations that show that the most stable Cu2+–Tris complexes are the syn- and anti-isomers of Cu(Tris)22+, but in the experimental pH ranges these are present as Cu(Tris)(TrisH–1)+. Since Cu2+(aq) is strongly complexed by almost any base capable of forming a buffer system with near-physiological pH, stability constants reported for Cu2+–Aβ complexes in any buffer solution should be regarded with skepticism unless interactions of the buffer with Cu2+ and with CuAβ2+ are taken quantitatively into account. Moreover, in vivo, biological buffers will reduce the physiological importance of Aβ–Cu2+ complexes by competing with Aβ for Cu2+.
First-principles computational studies of the torsional potential energy surface of the sec-butyl radical
Authors: Chen Ya Kun , Wang Yan Alexander
Published: December 2011

First-principles calculations were carried out to investigate the torsional potential energy surface (PES) of the sec-butyl radical. All the wave function methods employed predict a cis-like stable conformation with a dihedral angle of about 47° in addition to the trans-like global minimum conformation and a gauche conformation. However, most of the popular density functional approaches predict only the latter two local minima and lack the cis conformation that was experimentally observed. On the other hand, some density functional methods that incorporate the exact exchange and asymptotically corrected correlation functionals can locate the cis conformation successfully. The basis-set effect was also measured using popular B3LYP and MP2 Hamiltonians: only moderate shape changes were found for PES profiles upon basis-set variations. The stationary structures and their Hessians were obtained at both MP2 and B3LYP levels, with or without incorporating the zero-point energies. Opposite to the relative stability within the Born–Oppenheimer approximation, the cis conformation is more stable than the gauche conformation upon the zero-point correction, consistent with the experiment observations.
A common synthetic route to homochiral tetracycles related to pillaromycinone and premithramycinone
Authors: Hill Bryan , Jordan Robert , Qu Yang , Assoud Abdeljalil , Rodrigo Russell
Published: December 2011

Homochiral AB segments for (+)- and (–)-pillaromycinone were prepared in 11 steps from 2-acetylfuran. The synthesis featured an intramolecular Diels–Alder reaction of a 2,5-disubstituted furan and a hydroxyl-directed homogeneous hydrogenation of the tetrasubstituted alkene double bond of two enones. The CD segment was attached by a modified Staunton–Weinreb annulation to produce the desired homochiral tetracycle 21c related to (+)-pillaromycinone. An unusual acetonide migration enabled the synthesis of a tetracyclic model for premithramycinone.
Density functional theory study of the vertical ionization energies of the valence and core electrons of cyclopentadiene, pyrrole, furan, and thiophene
Authors: Chong Delano P.
Published: December 2011

The procedure abbreviated as ΔPBE0(SAOP)/et-pVQZ, based on density functional theory, was developed recently for the calculation of vertical ionization energies of the valence electrons of organic and other small molecules and succeeded in giving results with an average absolute deviation of 0.21 eV from experiment for a collection of 115 reliable test cases of nonperhalo molecules. The objective of this work is to add a number of test cases to the benchmark database. We chose the set of molecules cyclo-C4H4X, with X = CH2, NH, O, and S, previously studied by many workers both experimentally and theoretically. The results show that the ΔPBE0(SAOP)/et-pVQZ procedure is not only as good as ab initio methods such as SAC-CI, OVGF, and ADC(3) in performance, but also handles inner valence ionized cations more efficiently. Although the core-electron binding energies of the titled molecules have not been as well investigated theoretically, we apply the methods we developed in recent years to calculate the binding energies of C1s, N1s, O1s, S1s, and S2p, which compare well with available experimental data.
Synthesis of an iridium porphyrin amido complex
Authors: Tsang Jenkins Yin Ki , Chan Kin Shing
Published: December 2011

A synthetic route for iridium porphyrin amido complexes has been established. Treatment of a THF solution of Ir(ttp)(CO)Cl (1) (ttp = 5,10,15,20-tetrakis(p-tolyl)porphyrinato dianion) with an aqueous mixture of NaOH and NaBH4, followed by 2-iodoethanol leads to the clean formation of the β-hydroxyethyl complex Ir(ttp)(C2H4OH) (2) in 92% yield. Heating a pyridine solution of complex 2 in the presence of ca. 5–10 equiv. of phthalimide (HNC8H4O2; HPhth) leads to the formation of Ir(ttp)(C5H5N)(CH2CH2Phth) (3). The replacement of pyridine by THF as the reaction solvent leads to the formation of the THF adduct Ir(ttp)(THF)(Phth) (4), which has been characterized spectroscopically. Heating a solution of 4 in pyridine leads to the formation of Ir(ttp)(C5H5N)(Phth) (5), which has been isolated in 72% yield. Complexes 3 and 5 have been characterized by X-ray crystallographic studies. Complexes 4 and 5 are rare examples of monomeric late transition metal-amido complexes and are the first examples of iridium-amido complexes featuring a porphyrin as a supporting ligand.
Theoretical study on chemical bond parameters and properties of LnAl3(BO3)4
Authors: Li Zhiping , Gao Faming
Published: December 2011

The detailed chemical bond parameters of LnAl3(BO3)4 crystals were calculated using the chemical bond theory of complex crystals. Results indicated that Ln–O bonds are ionic and B–O bonds possess higher covalency. The environment factor defined by electron polarizabilities and covalency was employed to predict Racah parameters. The hardness of YAl3(BO3)4 was predicted using Gao’s model, which is also in agreement with the experimental value.
Ruthenium-catalyzed [2+2] cycloaddition reactions of a 2-oxa-3-azabicyclo[2.2.1]hept-5-ene with unsymmetrical alkynes
Authors: Durham Robin , Mandel Jérémie , Blanchard Nicolas , Tam William
Published: December 2011

Ruthenium-catalyzed [2+2] cycloaddition reactions of a 2-oxa-3-azabicyclo[2.2.1]hept-5-ene with unsymmetrical alkynes were investigated. Yields of up to 90% were obtained though regioselectivity was modest. Select cycloadducts could be separated and used to access a highly functionalized [3.2.0] bicyclic structure through reductive cleavage of the N–O bond. These ring-opened products displayed a chemical exchange phenomenon in 1D carbon NMR and required characterization by 2D NMR techniques.
Modulation of indium–tin oxide work function by a versatile self-assembled monolayer measured with the scanning Kelvin nanoprobe
Authors: Blaszykowski Christophe , Cheran Larissa-Emilia , Thompson Michael
Published: December 2011

In molecular optoelectronics, high-quality contacts at electrode|organics interfaces are crucial for charge carriers to efficiently flow through and therefore play a critical role on device performance. Electrode surface morphology, adhesibility, wettability, and work function are thus many parameters that must be accurately controlled, which is achievable using self-assembling monolayer (SAM) surface chemistry. Herein, we employ this technique to alter the electronic and surface energy-related properties of indium–tin oxide (ITO). In comparison to unmodified ITO, the newly introduced SAM-derivatized surface exhibits limited wettability and considerably higher work function (ΔΦ = ~1.2 eV). Several applications are proposed for this organic coating, notably at the anode of organic light-emitting diode (OLED) devices for decreasing the hole injection barrier or as an atmospherically stable protective layer in the coatings industry.
Nest-site selection in the Canada Warbler (Wilsonia canadensis) in central New Hampshire
Authors: Goodnow M.L. , Reitsma L.R.
Published: December 2011

Reproductive success in birds is largely influenced by nest-site selection. Nest predators are the greatest source of nest failure for most species of birds. Species that nest on the ground may be particularly adapted to maximally conceal nests to reduce the risk of loss to predators. Little is known about nest-site selection in the Canada Warbler ( Wilsonia canadensis (L., 1766)), a small ground-nesting Neotropical migrant. We predicted higher amounts of vegetative cover at successful nests of Canada Warblers compared with unsuccessful nests because detection by predators would decrease with greater cover. We measured vegetative characteristics (concealment, stem densities, ground cover) around each nest and compared these variables between successful and unsuccessful nests and between actual nests and mock nest sites on and off territories. Greater concealment and higher stem densities were the main features surrounding a successful nest site. Nest sites had significantly greater concealment when compared with both random mock nest sites on and off territories. Thus, concealment is important for this ground nester and achieved primarily through thick cover and strategic nest placement in vertical substrate with an inconspicuous opening to the nest cup. Forests with complex ground structure and thickets of small-stemmed woody plants should be targets of conservation when considering how to manage this declining species.
Diet and energetic constraints of an earthworm specialist, the Mesa Central Blotched Garter Snake (Thamnophis scaliger)
Authors: Reguera S. , Santos X. , Feriche M. , Mociño-Deloya E. , Setser K. , Pleguezuelos J.M.
Published: December 2011

Optimal diet theory predicts that predators optimize energy intake by balancing costs and benefits of foraging. One extreme strategy of snake foraging ecology is shown by specialist species that forage on low-energy prey, such as Thamnophis scaliger (Jan, 1863) which feeds almost exclusively on earthworms. Compared with other prey types such as small mammals, lizards, or arthropods, earthworms are low-energy prey because of their small size and high water content. Given the importance of energy acquisition for fueling snake reproduction, we expect that a low-energy dietary specialist such as T. scaliger needs to forage frequently to store enough fat to reproduce. The high frequency of snakes containing prey, the presence of multiple earthworms in snakes, and the fact that females continue to feed when gravid suggest that T. scaliger is a voracious consumer of earthworms. Despite these foraging behaviours, females did not reproduce in sequential years, suggesting constraints in energy input to reproduce more frequently. A meta-analysis of the diet, body size, and reproductive frequency of some species of the genus Thamnophis Fitzinger, 1843 confirms that consumption of invertebrate prey is associated with small snake size, but not with biennial reproductive frequency within the genus.
In the shallow end: diving behaviour of recolonising female New Zealand sea lions (Phocarctos hookeri) around the Otago Peninsula
Authors: Augé Amélie A. , Chilvers B. Louise , Davis Lloyd S. , Moore Antoni B.
Published: December 2011

Female New Zealand sea lions ( Phocarctos hookeri (Gray, 1844)) at the Auckland Islands (remnant populations) are the deepest and longest diving otariids. These remnant populations are found at the margin of the historical range of the species. We hypothesized that diving behaviours of animals in the core of their historical range is less extreme owing to a better marine habitat. All female New Zealand sea lions (n = 13, aged 2–14 years) born on the Otago Peninsula (initial recolonising population) were equipped with time–depth recorders during April and May 2008, 2009, and 2010. The mean dive depth was 20.2 ± 24.5 m and mean dive duration was 1.8 ± 1.1 min, some of the lowest values reported for otariids. Otago female New Zealand sea lions did not exhibit two distinct diving specialisations as reported at the Auckland Islands. Otago adult females exceeded calculated aerobic dive limits in 7.1% of dives compared with 68.7% at the Auckland Islands. The contrasting differences in diving behaviour between Otago and the Auckland Islands suggest that Otago represents a better marine habitat for New Zealand sea lions, with food easily accessible to animals of all ages.
Movement of small mammals across divided highways with vegetated medians
Authors: McLaren Ashley A.D. , Fahrig Lenore , Waltho Nigel
Published: December 2011

Previous studies suggest the gap in forest cover generated by roads contributes to the barrier effect of roads on movement of forest-dwelling small mammals. However, it is not known if vegetated medians of divided highways affect movement of small mammals by reducing the effective highway width. The purpose of our study was to determine whether the type of vegetation cover in the median (treed or grassy) or median width affects small-mammal crossings of divided highways. At 11 study sites varying in median cover type and width, we live-trapped small mammals next to one side of the highway and translocated them to the opposite side of the highway using a standardized translocation distance. In total, 24% of translocated individuals were recaptured on the side of the highway of initial capture, i.e., they had moved across the entire highway. This was significantly lower than what would have been expected in the absence of the highway (58%). The overall probability of recapturing a translocated individual was not significantly related to median cover type or width. Our results suggest that efforts to mitigate the barrier effect of highways on small mammals cannot be accomplished by altering median vegetation type and width.
An experimental test of facilitation between non-native earthworms
Authors: Cameron Erin K. , Bayne Erin M.
Published: December 2011

Invasional meltdowns, in which facilitation between species causes an accelerating increase in the number of introduced species or impacts, can cause large impacts in invaded systems. Earthworm invasion of northern forests has been suggested as a meltdown, with litter-dwelling species altering soil structure and facilitating mineral-soil or deep-burrowing earthworms that may be less capable of invading intact forest floors. We examined facilitation and synergistic effects of a litter-dwelling species ( Dendrobaena octaedra Savigny, 1826) and a deep-burrowing species ( Lumbricus terrestris L., 1758). Boreal forest soil cores were inoculated with D. octaedra, L. terrestris, both species, a higher density of L. terrestris, or no worms. After 4.5 months, we found no differences in survival or biomass between treatments for either species. Cocoon production did not differ for L. terrestris, but D. octaedra produced significantly fewer cocoons with L. terrestris. The two species had an additive effect on organic horizon depths and bulk densities. Thus, they did not appear to facilitate each other or have synergistic effects as would be predicted in an invasional meltdown.
Porphyrin-appended phosphapalladacycle precatalysts: effects of central metals on the catalytic activity in a high-temperature Heck reaction
Authors: Matano Yoshihiro , Matsumoto Kazuaki , Shibano Tarou , Imahori Hiroshi
Published: December 2011

The synthesis and the catalytic activity of bis(μ-chloro)-bridged, phosphapalladacycle-fused diporphyrins (M-porphyrin-appended phosphapalladacycles: M = Zn , Ni , free-base), as well as the coordinating ability of their precursors, meso-phosphanylporphyrins are reported. Treatment of meso-phosphanylporphyrinatozinc(II) with an equimolar amount of PdCl2(NCPh)2 caused regioselective β-C–H activation of the porphyrin ring to produce bis(μ-chloro)-bridged Zn -porphyrin-appended phosphapalladacycle, which was further converted to the free-base- and Ni -porphyrin-appended analogs. The UV-vis absorption spectra of these palladium complexes showed weak exciton coupling between two porphyrin chromophores connected by the μ-chloro bridges. The M-porphyrin-appended phosphapalladacycles behaved as precatalysts for a high temperature Heck reaction between p-bromobenzaldehyde and butyl acrylate. In a range of the catalyst-loading of 0.05–0.005 mol.%, the catalytic activity was found to significantly depend on the central metal incorporated at the porphyrin core. The Ni -porphyrin-appended phosphapalladacycle showed considerably higher turnover frequency than did the Zn -porphyrin- and free-base-porphyrin-appended counterparts. This trend in the catalytic activity does not simply correlate with the σ-donating ability of the phosphorus center and the electron-donating ability of the porphyrin π-systems. Instead, it is related to the durability of the precatalysts under the reaction conditions employed. The observed results corroborate that the central metal of the meso-phosphanylporphyrin ligands plays a crucial role in the active Pd(0) catalyst-loading from the porphyrin-appended phosphapalladacycles at constant efficiency.
Synthesis and electrochemical properties of meso-phenyl substituted copper corroles: Solvent effect on copper oxidation state
Authors: Lu Guifen , Lin Wensheng , Fang Yuanyuan , Zhu Weihua , Ji Xuelin , Ou Zhongping
Published: December 2011

Two meso-phenyl chloro-substituted copper corroles were synthesized and characterized by a variety of spectroscopic techniques. The investigated compounds are represented as ((ClPh)3Cor)Cu and ((Cl2Ph)3Cor)Cu , where (ClPh)3Cor and (Cl2Ph)3Cor are the trianions of the 5,10,15-tri- (4-chlorophenyl)corrole and 5,10,15-tri(2,4-dichlorophenyl)corrole, respectively. UV-visible and ESR spectroscopy revealed that the electronic ground state of each copper corrole is solvent dependent. Both compounds contain Cu(III) corroles in the solid state and in solutions of CH2Cl2 , but an equilibrium exists between Cu(III) and its Cu(II) form in pyridine, DMSO or DMF. The Cu(II) corrole could also be generated by controlled potential reduction in a thin-layer cell, which is reversible in CH2Cl2 or DMF containing 0.1 M TBAP. The structure of ((ClPh)3Cor)Cu was determined by a single-crystal X-ray study.
Geology of the earthquake source: an introduction
Authors: Fagereng Åke , Toy Virginia G.
Published: December 2011

Earthquakes arise from frictional ‘stick–slip’ instabilities as elastic strain is released by shear failure, almost always on a pre-existing fault. How the faulted rock responds to applied shear stress depends on its composition, environmental conditions (such as temperature and pressure), fluid presence and strain rate. These geological and physical variables determine the shear strength and frictional stability of a fault, and the dominant mineral deformation mechanism. To differing degrees, these effects ultimately control the partitioning between seismic and aseismic deformation, and are recorded by fault-rock textures. The scale-invariance of earthquake slip allows for extrapolation of geological and geophysical observations of earthquake-related deformation. Here we emphasize that the seismological character of a fault is highly dependent on fault geology, and that the high frequency of earthquakes observed by geophysical monitoring demands consideration of seismic slip as a major mechanism of finite fault displacement in the geological record.
Petrological evidence for co-seismic slip in extending middle–lower continental crust: Heier's zone of pseudotachylyte, north Norway
Authors: Moecher D. P. , Steltenpohl M. G.
Published: December 2011

Multiple generations of pseudotachylyte occur in the normal, shallowly dipping (30°NW) Eidsfjord and Fiskfjord shear zones, northern Norway, which developed during late- to-post-Caledonian crustal extension of Precambrian crystalline basement. Garnet-bearing amphibolite-facies mineral assemblages occur in metamorphosed pseudotachylyte and in sheared meta-anorthosite. Similar mineral assemblages (+clinopyroxene) occur in mylonitized pseudotachylyte cut by normal shear bands at Fiskfjord. These assemblages permit calculation via geothermobarometry of pressure and temperature for the crustal level at which pseudotachylyte was repeatedly generated by co-seismic slip during crustal extension. Equilibration conditions at Eidsfjord of 700±50 MPa and 650±25 °C correspond to
z
=22–29 km; conditions for Fiskfjord of 950±200 MPa and 640±50 °C correspond to
z
=30–40 km. Both ranges are significantly greater than the standard depth of the seismogenic zone. Creep at depth in the normal fault accumulated elastic strain in the shallower levels of the fault, which upon release initiated rupture downwards into the ductile regime at high strain rates resulting in frictional sliding and the generation of pseudotachylyte. Garnet-bearing ultramylonitic pseudotachylytes attest to a return to steady-state creep following co-seismic slip at depths well below the standard seismogenic zone.
Evolution of fluid chemistry and fluid-flow pathways during folding and faulting: an example from Taemas, NSW, Australia
Authors: Barker Shaun L. L. , Cox Stephen F.
Published: December 2011

In the Taemas area, New South Wales, Australia, a swarm of hydrothermal calcite and quartz veins is hosted in upright, open to close folded limestones and shales. Overprinting relationships and vein geometries demonstrate that the vein swarm formed progressively during fold growth and associated reverse faulting. Textures preserved in veins reveal that veins formed via hundreds to thousands of individual dilation and mineral precipitation events. Bedding-parallel flexural slip during fold growth was associated with laminated vein development, and limb-parallel stretching during fold growth was associated with the formation of bedding-orthogonal extension veins. The presence of subhorizontal extension fractures and severely misoriented reverse faults imply that fluid pressures exceeded lithostatic levels, at least transiently, during the development of the vein swarm.

Vein δ
18
O compositions increase upwards through the Murrumbidgee Group in response to a progressive reaction of an externally derived, upwards-flowing low-δ
18
O fluid (of probable meteoric origin) with host limestones. Vein δ
18
O and
87
Sr/
86
Sr compositions vary spatially and temporally within the same outcrop, and within individual veins. These variations are inferred to be caused by the ascent of packages of fluid along constantly changing flow pathways caused by multiple permeability creation–destruction cycles associated with fault slip and fault sealing. Vein trace and rare earth element (REE) concentrations are more variable, probably reflecting rapid rock buffering along fluid pathways on length scales of less than 10 m. Our results indicate that fluid-flow pathways change dynamically during crustal shortening, with pathways switching between states of low and high permeability during episodic fault slip and associated fracture development.

Supplementary material:

Two appendices are available at
http://www.geolsoc.org.uk/SUP18492
.
Visualizing and quantifying the suppressive effects of glucocorticoids on the tadpole immune system in vivo
Authors: Schreiber Alexander M.
Published: December 2011

A challenging topic in undergraduate physiology courses is the complex interaction between the vertebrate endocrine system and the immune system. There are relatively few established and accessible laboratory exercises available to instructors to help their students gain a working understanding of these interactions. The present laboratory module was developed to show students how glucocorticoid receptor activity can be pharmacologically modulated in Xenopus laevis tadpoles and the resulting effects on thymus gland size visualized and quantified in vivo. After treating young tadpoles with a cortisol receptor agonist (dexamethasone) for 1 wk, students can easily visualize the suppressive effects of glucocorticoids on the intact thymus gland, which shrinks dramatically in size in response to this steroid hormone analog. However, the suppressive effect of dexamethasone is nullified in the presence of the glucocorticoid receptor antagonist RU-486, which powerfully illustrates the specific effects of glucocorticoid receptor inhibition on the immune system. Image analysis and statistics software are used to quantify the effects of glucocorticoid modulation on thymus size.
Development of a model for whole brain learning of physiology
Authors: Eagleton Saramarie , Muller Anton
Published: December 2011

In this report, a model was developed for whole brain learning based on Curry's onion model. Curry described the effect of personality traits as the inner layer of learning, information-processing styles as the middle layer of learning, and environmental and instructional preferences as the outer layer of learning. The model that was developed elaborates on these layers by relating the personality traits central to learning to the different quadrants of brain preference, as described by Neethling's brain profile, as the inner layer of the onion. This layer is encircled by the learning styles that describe different information-processing preferences for each brain quadrant. For the middle layer, the different stages of Kolb's learning cycle are classified into the four brain quadrants associated with the different brain processing strategies within the information processing circle. Each of the stages of Kolb's learning cycle is also associated with a specific cognitive learning strategy. These two inner circles are enclosed by the circle representing the role of the environment and instruction on learning. It relates environmental factors that affect learning and distinguishes between face-to-face and technology-assisted learning. This model informs on the design of instructional interventions for physiology to encourage whole brain learning.
Effect of selected “desirable difficulty” learning strategies on the retention of physiology information
Authors: Dobson John L.
Published: December 2011

The purpose of this study was to examine the effects of interleaving and expanding retrieval on the retention of physiology concepts. Participants ( n = 189) read and then reread 30 immunology and reproductive physiology passages. Half of the participants read and then reread the passages in a blocked manner (e.g., a1 a2 a3 b1 b2 b3), and the other half did so in an interleaved manner (e.g., a1 b1 b2 a2 a3 b3). Participants were then repeatedly assessed, without feedback, after either a uniform or an expanding series of intervals. Half of the students from both the blocked and interleaved groups completed the assessments 1, 2, and 3 days after rereading the passages (uniform), whereas the other half completed the assessments immediately and 1 and 3 days after rereading the passages (expanding). All participants completed a final assessment 10 days after rereading the passages. There were no significant differences between the blocked and interleaved groups on any of the assessments, nor were there any significant interactions between the groups on any of the assessments. Those in the expanding retrieval group scored significantly higher than those in the uniform group on all four assessments (ANOVA; assessment 1: F = 35.12, P = 0.00; assessment 2: F = 13.88, P = 0.00; assessment 3: F = 10.87, P = 0.00; and assessment 4: F = 6.79, P = 0.01). Mean final assessment scores were 47.58 ± 19.81 and 40.50 ± 17.17 for the expanding and uniform groups, respectively. The results indicate that participants benefited more from expanding retrieval practice.
United States Army Research Institute of Environmental Medicine: Warfighter research focusing on the past 25 years
Authors: Pandolf Kent B. , Francesconi Ralph , Sawka Michael N. , Cymerman Allen , Hoyt Reed W. , Young Andrew J. , Zambraski Edward J.
Published: December 2011

The United States Army Research Institute of Environmental Medicine (USARIEM) celebrated its 50th anniversary on July 1, 2011. This article reviews its history, evolution, and transition of its research programs as well as its scientific and military accomplishments, emphasizing the past 25 yr. During the 1990s, USARIEM published a series of pocket guides providing guidance for sustaining Warfighter health and performance in Southwest Asia, Somalia, the former Republic of Yugoslavia, Rwanda, and Haiti. Issues identified during Operation Desert Storm elicited research that improved nutritional guidelines for protracted desert operations; safer use of nuclear, chemical, and biological protective clothing; equipment, development, and fielding of efficient microclimate cooling systems; and effective evaluation of pharmaceuticals to protect soldiers from chemical and biological threats. During the first decade of the 21st century, USARIEM and the Department of the Army published official medical/performance doctrines for operations in the heat and cold and at high altitude. The current Global War on Terrorism focused research to improve doctrines for hot, cold, and high-altitude operations, reduce musculoskeletal training injuries, provide improved field nutrition, more efficient planning for operational water requirements, and improve both military clothing and materiel. This article also describes the critically important interactions and communications between USARIEM and deployed units and the benefits to Warfighters from this association. This report presents USARIEM's unique and world-class facilities, organizational changes, scientific and support personnel, and major research accomplishments, including the publication of 2,200 scientific papers over the past 25 yr.
Steps to pluripotent learning: provocative teaching
Authors: Rangachari P. K.
Published: December 2011

Education involves interactions between students and teachers in a societal framework. Teachers can best serve their students and society by making students flexible enough to thrive under uncertain conditions. They should, in a sense, nourish, nurture, provoke, and stimulate pluripotent “educatoblasts.”
Origin, utilization, and recycling of nucleosides in the central nervous system
Authors: Ipata Piero Luigi
Published: December 2011

The brain relies on the salvage of preformed purine and pyrimidine rings, mainly in the form of nucleosides, to maintain its nucleotide pool in the proper qualitative and quantitative balance. The transport of nucleosides from blood into neurons and glia is considered to be an essential prerequisite to enter their metabolic utilization in the brain. Recent lines of evidence have also suggested that local extracellular nucleoside triphosphate (NTP) degradation may contribute to brain nucleosides. Plasma membrane-located ectonucleotidases, with their active sites oriented toward the extracellular space, catalyze the successive hydrolysis of NTPs to their respective nucleosides. Apart from the well-established modulation of ATP, ADP, adenosine (the purinergic agonists), UTP, and UDP (the pyrimidinergic agonists) availability at their respective receptors, ectonucleotidases may also serve the local reutilization of nucleosides in the brain. After their production in the extracellular space by the ectonucleotidase system, nucleosides are transported into neurons and glia and converted back to NTPs via a set of purine and pyrimidine salvage enzymes. Finally, nucleotides are transported into brain cell vescicles or granules and released back into the extracellular space. The key teaching concepts to be included in a two-to three-lecture block on the molecular mechanisms of the local nucleoside recycling process, based on a cross talk between the brain extracellular space and cytosol, are discussed in this article.
Subtotal nephrectomy plus coronary ligation leads to more pronounced damage in both organs than either nephrectomy or coronary ligation
Authors: Bongartz Lennart G. , Joles Jaap A. , Verhaar Marianne C. , Cramer Maarten J. , Goldschmeding Roel , Tilburgs Chantal , Gaillard Carlo A. , Doevendans Pieter A. , Braam Branko
Published: December 2011

Coexistence of chronic kidney disease (CKD) and heart failure (HF) in humans is associated with poor outcome. We hypothesized that preexistent CKD worsens cardiac outcome after myocardial infarction, and conversely that ensuing HF worsens progression of CKD. Subtotally nephrectomized (SNX) or sham-operated (CON) rats were subjected to coronary ligation (CL) or sham surgery in week 9 to realize four groups: CON, SNX, CON + CL, and SNX + CL. Blood pressure and renal function were measured in weeks 8, 11, 13, and 15. In week 16, cardiac hemodynamics and end-organ damage were assessed. Blood pressure was significantly lower in SNX + CL vs. SNX. Despite this, glomerulosclerosis was more severe in SNX + CL vs. SNX. Two weeks after CL, SNX + CL had more cardiac dilatation compared with CON + CL (end-diastolic volume index: 0.28 ± 0.04 vs. 0.19 ± 0.03 ml/100 g body wt; mean ± SD, P < 0.001), although infarct size was similar. During follow-up in SNX + CL, ejection fraction declined. Mortality was only observed in SNX + CL (2 out of 9). In SNX + CL, end-diastolic pressure (18 ± 4 mmHg) and tau (29 ± 9 ms), the time constant of active relaxation, were significantly higher compared with SNX (13 ± 3 mmHg, 20 ± 4 ms; P < 0.01) and CON + CL (11 ± 5 mmHg, 17 ± 2 ms; P < 0.01). The diameter of small arterioles in the myocardium was significantly decreased in SNX + CL vs. CON + CL ( P < 0.01). Urinary excretion of NO metabolites was significantly lower in SNX + CL compared with both CL and SNX. This study demonstrates the existence of more heart and more kidney damage in a new model of combined CKD and HF than in the individual models. Such enhanced damage appears to be separate from systemic hemodynamic changes. Reduced nitric oxide availability may have played a role in both worsened glomerulosclerosis and cardiac diastolic function and appears to be a connector in the cardiorenal syndrome.
Changes in eNOS phosphorylation contribute to increased arteriolar NO release during juvenile growth
Authors: Kang Lori S. , Nurkiewicz Timothy R. , Wu Guoyao , Boegehold Matthew A.
Published: December 2011

Nitric oxide (NO) mediates a major portion of arteriolar endothelium-dependent dilation in adults, but indirect evidence has suggested that NO contributes minimally to these responses in the young. Isolated segments of arterioles were studied in vitro to verify this age-related increase in NO release and investigate the mechanism by which it occurs. Directly measured NO release induced by ACh or the Ca2+ ionophore A-23187 was five- to sixfold higher in gracilis muscle arterioles from 42- to 46-day-old (juvenile) rats than in those from 25- to 28-day-old (weanling) rats. There were no differences between groups in arteriolar endothelial NO synthase (eNOS) expression or tetrahydrobiopterin levels, and arteriolar l-arginine levels were lower in juvenile vessels than in weanling vessels (104 ± 6 vs.126 ± 3 pmol/mg). In contrast, agonist-induced eNOS Thr495 dephosphorylation and eNOS Ser1177 phosphorylation (events required for maximal activity) were up to 30% and 65% greater, respectively, in juvenile vessels. Juvenile vessels did not show increased expression of enzymes that mediate these events [protein phosphatases 1 and 2A and PKA and PKB (Akt)] or heat shock protein 90, which facilitates Ser1177 phosphorylation. However, agonist-induced colocalization of heat shock protein 90 with eNOS was 34–66% greater in juvenile vessels than in weanling vessels, and abolition of this difference with geldanamycin also abolished the difference in Ser1177 phosphorylation between groups. These findings suggest that growth-related increases in arteriolar NO bioavailability may be due at least partially to changes in the regulation of eNOS phosphorylation and increased signaling activity, with no change in the abundance of eNOS signaling proteins.
The heart-specific NH2-terminal extension regulates the molecular conformation and function of cardiac troponin I
Authors: Akhter Shirin , Zhang Zhiling , Jin J.-P.
Published: December 2011

In addition to the core structure conserved in all troponin I isoforms, cardiac troponin I (cTnI) has an ∼30 amino acids NH2-terminal extension. This peptide segment is a heart-specific regulatory structure containing two Ser residues that are substrates of PKA. Under β-adrenergic regulation, phosphorylation of cTnI in the NH2-terminal extension increases the rate of myocardial relaxation. The NH2-terminal extension of cTnI is also removable by restrictive proteolysis to produce functional adaptation to hemodynamic stresses. The molecular mechanism for the NH2-terminal modifications to regulate the function of cTnI is not fully understood. In the present study, we tested a hypothesis that the NH2-terminal extension functions by modulating the conformation of other regions of cTnI. Monoclonal antibody epitope analysis and protein binding experiments demonstrated that deletion of the NH2-terminal segment altered epitopic conformation in the middle, but not COOH-terminal, region of cTnI. PKA phosphorylation produced similar effects. This targeted long-range conformational modulation corresponded to changes in the binding affinities of cTnI for troponin T and for troponin C in a Ca2+-dependent manner. The data suggest that the NH2-terminal extension of cTnI regulates cardiac muscle function through modulating molecular conformation and function of the core structure of cTnI.
Secondhand tobacco smoke, arterial stiffness, and altered circadian blood pressure patterns are associated with lung inflammation and oxidative stress in rats
Authors: Gentner Nicole J. , Weber Lynn P.
Published: December 2011

Chronic smoking and secondhand tobacco smoke exposure are major risk factors for cardiovascular disease that are known to adversely alter the structural and mechanical properties of arteries. The objective of this study was to determine the effects of subchronic secondhand tobacco smoke exposure on circadian blood pressure patterns, arterial stiffness, and possible sources of oxidative stress in conscious, unsedated radiotelemetry-implanted rats. Pulse wave change in pressure over time (dP/d t) was used an indicator of arterial stiffness and was compared with both structural (wall thickness) and functional (nitric oxide production and bioactivity and endothelin-1 levels) features of the arterial wall. In addition, histology of lung, heart, and liver was examined as well as pulmonary and hepatic detoxifying enzyme activity (cytochrome P450, specifically CYP1A1). Subchronic secondhand tobacco smoke exposure altered the circadian pattern of heart rate and blood pressure, with a loss in the normal dipping pattern of blood pressure during sleep. Secondhand tobacco smoke exposure also increased pulse wave dP/d t in the absence of any structural modifications in the arterial wall. Furthermore, although nitric oxide production and endothelin-1 levels were not altered by secondhand tobacco smoke, there was increased inactivation of nitric oxide as indicated by peroxynitrite production. Increased lung neutrophils or pulmonary CYP1A1 may be responsible for the increase in oxidative stress in rats exposed to secondhand tobacco smoke. In turn, this may be related to the observed failure of blood pressure to dip during periods of sleep and a possible increase in arterial stiffness.