bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical Studies on Sphingolipid ofArtemia franciscana(I) Isolation and Characterization of Sphingomyelin
Authors: Kojima Hisao , Inoue Takashi , Sugita Mutsumi , Itonori Saki , Ito Masahiro
Published: June 2010

Sphingomyelin was isolated from cysts of the brine shrimpArtemia franciscanausing QAE‐Sephadex A25, Florisil and Iatrobeads column chromatographies. The chemical structure was identified using thin‐layer chromatography, gas–liquid chromatography, infrared spectroscopy and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry. The ceramide moiety of sphingomyelin consisted of stearic, arachidic, and behenic acids as fatty acids, and hexadeca‐4‐ and heptadeca‐4‐sphingenines as sphingoids. By comparative analysis, the ceramide component ofArtemiasphingomyelin appears unique in invertebrates and vertebrates. Biological functions of sphingomyelin have largely been investigated using mammalian‐derived sphingomyelin. In mammals, a wide variety of molecular species of sphingomyelins have been reported, especially derived from nerve tissue, while the lower animalArtemiacontains this unusual sphingomyelin perhaps because of having a much simpler nervous system. The purified unusual sphingomyelin derived fromArtemia franciscanamight be a very useful tool in elucidating the functions and mechanisms of action of this mediator.
Inter-observer and intra-observer agreement in the radiographic diagnosis of avascular necrosis of the femoral head following slipped capital femoral epiphysis
Authors: Davidson Darin , Ghag Arvindera , Beauchamp Richard D. , Tredwell Stephen J. , Mulpuri Kishore
Published: June 2010

Introduction

Slipped capital femoral epiphysis (SCFE) is a common pediatric hip disorder. Avascular necrosis (AVN) of the femoral head is a devastating complication of SCFE. The frequency of this complication reported in the literature has been variable. It was the objective of this study to estimate the inter- and intra-observer agreement between two experienced pediatric orthopaedic surgeons for the radiographic diagnosis of AVN following SCFE.

Methods

A retrospective review of all cases of SCFE treated at our center between 1995 and 2005 was performed. All cases of AVN and a random sample of 19 of the remaining cases were selected for study. The most recent anteroposterior and lateral radiographs were presented to two experienced pediatric orthopaedic surgeons in a random order. Inter-observer reliability was determined by calculating the kappa statistic to assess for clinical agreement. Each observer repeated this process two weeks after the initial review.

Results

There were a total of 103 cases of SCFE, of which four were diagnosed with AVN. The inter-observer agreement in the first trial was 0.79. The intra-observer agreement for the first observer was 0.9 and for the second observer, it was 0.88.

Conclusion

The agreement, both inter- and intra-observer, for the radiographic diagnosis of AVN amongst adolescents with previous SCFE is very high. The results of this study suggest that the reported discrepancy of AVN in the literature following SCFE is not likely due to the lack of inter- and intra-observer agreement.
Effects of dietary fat modification on oxidative stress and inflammatory markers in the LIPGENE study
Authors: Petersson Helena , Risérus Ulf , McMonagle Jolene , Gulseth Hanne L. , Tierney Audrey C. , Morange Sophie , Helal Olfa , Shaw Danielle I. , Ruano Juan A. , López-Miranda José , Kieć-Wilk Beata , Gołąbek Iwona , Blaak Ellen E. , Saris Wim H. M. , Drevon Christian A. , Lovegrove Julie A. , Roche Helen M. , Basu Samar
Published: June 2010

Subjects with the metabolic syndrome (MetS) have enhanced oxidative stress and inflammation. Dietary fat quality has been proposed to be implicated in these conditions. We investigated the impact of four diets distinct in fat quantity and quality on 8-iso-PGF2α (a major F2-isoprostane and oxidative stress indicator), 15-keto-13,14-dihydro-PGF2α (15-keto-dihydro-PGF2α, a major PGF2α metabolite and marker of cyclooxygenase-mediated inflammation) and C-reactive protein (CRP). In a 12-week parallel multicentre dietary intervention study (LIPGENE), 417 volunteers with the MetS were randomly assigned to one of the four diets: two high-fat diets (38 % energy (%E)) rich in SFA or MUFA and two low-fat high-complex carbohydrate diets (28 %E) with (LFHCC n-3) or without (LFHCC) 1·24 g/d of very long chain n-3 fatty acid supplementation. Urinary levels of 8-iso-PGF2α and 15-keto-dihydro-PGF2α were determined by RIA and adjusted for urinary creatinine levels. Serum concentration of CRP was measured by ELISA. Neither concentrations of 8-iso-PGF2α and 15-keto-dihydro-PGF2α nor those of CRP differed between diet groups at baseline (P>0·07) or at the end of the study (P>0·44). Also, no differences in changes of the markers were observed between the diet groups (8-iso-PGF2α, P = 0·83; 15-keto-dihydro-PGF2α, P = 0·45; and CRP, P = 0·97). In conclusion, a 12-week dietary fat modification did not affect the investigated markers of oxidative stress and inflammation among subjects with the MetS in the LIPGENE study.
In Defence of Mercenarism
Authors: Fabre Cécile
Published: June 2010

The recent wars in Iraq and Afghanistan have been characterized by the deployment of large private military forces, under contract with the US administration. The use of so-called private military corporations (PMCs) and, more generally, of mercenaries, has long attracted criticisms. This article argues that under certain conditions (drawn from the Just War tradition), there is nothing inherently objectionable about mercenarism. It begins by exposing a weakness in the most obvious justification for mercenarism, to wit, the justification from freedom of occupational choice. It then deploys a less obvious, but stronger, argument – one that appeals to the importance of enabling just defensive killings. Finally, it rebuts five moral objections to mercenarism.
Correlation between the reproductive potential and the pyrethroid resistance in an Indian strain of filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae)
Authors: Kumar S. , Pillai M.K.K.
Published: June 2010

The laboratory studies were conducted to uncover the correlation between the levels of pyrethroid resistance and the reproductive potential of parent (SS) and resistant strains of Culex quinquefasciatus (RR) originating from Delhi, India and selected with deltamethrin (RDL) or the combination of deltamethrin and PBO (1:5) (RDP) at the larval stage and selected with deltamethrin at the adult stage (RDA). The reproductive potential was evaluated in terms of fecundity, fertility, egg hatchability and longevity of gonotrophic cycles. The RR strains exhibited 68–74% reduced duration of the gonotrophic cycles when compared with that of SS strain. The considerable decrease in the egg production, ranging from 45.4% to 61.6%, observed in the selected strains as compared to the SS strain, indicates the possible positive correlation between the levels of deltamethrin resistance and the reproduction disadvantage. This correlation was further confirmed by 24.6% to 53.6% decrease in the hatchability of eggs of the selected strains with respect to that of the parent strain. A worth-mentioning observation of the reduced reproductive fitness in RDP strains suggests the effectiveness of synergized deltamethrin selections in reducing the frequency of resistant individuals. The reproductive disadvantage in adult-selected strains possessing negligible resistance to deltamethrin implicates the efficacy of deltamethrin as an adulticide rather than as a larvicide against Cx. quinquefasciatus. The results suggest that the reduced reproductive fitness of resistant genotypes in the population can eliminate heterozygotes and resistant homozygotes by implementing different resistance-management strategies against Cx. quinquefasciatus.
The genusEumetula(Gastropoda: Caenogastropoda: Cerithiopsidae) in north European waters, with the description of a new species from the upper continental slope off Norway
Authors: Høisæter Tore
Published: June 2010

Eumetula vitrea, a new species of Cerithiopsidae, is described from the upper continental slope outside western Norway. The taxonomic status of theEumetulaspecies complex is discussed. WhileEumetula arcticais a shelf species rarely found in sub-zero waters,E. vitreais one of a group of species supposedly found only in negative temperature or water fluctuating between negative and positive temperatures (below ~570 m) in the bathyal around the Norwegian Sea.
Diet of the harbour seal (Phoca vitulina vitulina) in the west and south-west of Ireland
Authors: Kavanagh Ailbhe S. , Cronin Michelle A. , Walton Mike , Rogan Emer
Published: June 2010

Although the harbour seal (Phoca vitulina vitulina) is relatively common in coastal waters of the Republic of Ireland, it remains largely unstudied. Issues including potential interactions with coastal fisheries and the occurrence of phocine distemper virus outbreaks in 1988 and 2002 have highlighted the need to increase our knowledge of the ecology of these animals. The diet of harbour seals was investigated using a combination of approaches: hard-part analysis of scat contents and fatty-acid analysis. A total of 102 scat and 13 blubber samples were collected from two locations in Ireland and were analysed following standard methodologies. Results from scat analysis indicate that the seals are opportunistic, generalist feeders, and probably consume prey in relation to its availability. Eighteen prey species were identified, with sandeels (Ammodytidae spp.) constituting 55% of the prey items by number. Biomass of prey was reconstructed using otolith-length regression equations, with and without the application of digestion correction factors and sole (Solea solea) (16.1%), sandeels (15.2%), andTrisopterusspecies (12.4%) were found to be the most important species by weight. Rarefraction curves were used to determine prey species diversity on a sample site basis and we used accumulation curves to ascertain whether sampling was sufficient on a site basis. Sixty-four fatty acids were isolated from the blubber and analysis of the fatty-acid profiles revealed the possible influence of season, seal weight and sex on the seals' long-term diet. Some of the prey species recorded in the diet overlap with commercially and recreationally caught fish species in Ireland; however, there was little overlap with marketed size-ranges.
Lost in transmission: The case of the Pahlavi-Vīdēvdād manuscripts
Authors: Cantera Alberto
Published: June 2010

All extant Pahlavi-Vīdēvdād (PV) manuscripts derive from a single copy. The binding of this copy was damaged early on, and some folios were lost and others displaced. A detailed analysis of the extant manuscripts allows us to reconstruct the original order and to discover where some folios are lost, but in previous editions (especially of the Pahlavi translation), this fact was not always noted appropriately and numerous errors occurred. Moreover, other typical transmission errors in this common source have slipped into all extant PV manuscripts and caused omissions of several fragments of the Avestan text and its Pahlavi translation, hence the importance of the Sādes for the edition of the Avestan text of the Vīdēvdād. Geldner was, unfortunately, too confident in the quality of the PV manuscripts and omitted from his edition Avestan texts that should have been included. But not every difference between the Avestan text of the Sāde and Pahlavi manuscripts can be attributed to the transmission. One of the most important differences is the omission of fragard 12 in the Pahlavi-Vīdēvdād manuscripts. Since its omission cannot be attributed to transmission, an alternative explanation for this important difference is proposed.
Potential source regions of biogenic aerosol number concentration apportioning at King George Island, Antarctic Peninsula
Authors: Alencar Alexandre S. , Evangelista Heitor , Dos Santos Elaine A. , Correa Sergio M. , Khodri Myriam , Garcia Virginia M.T. , Garcia Carlos A.E. , Pereira Enio B. , Piola Alberto R. , Felzenszwalb Israel
Published: June 2010

Nowadays it is well accepted that background aerosols in the boundary layer over remote oceans are of marine origin and not aged continental. Particularly in the Atlantic sector of the Southern Ocean at least four main important regions exhibit significant ocean primary productivity. They are the Bellingshausen–Amundsen Sea, the Weddell Sea, the southern Argentinean shelf and the southern Chilean coast. In this work, we have combined ground-based continuous atmospheric sampling of aerosol number concentration (ANC), over-sea dimethyl sulphide (DMS) measurements, chlorophyll a (chl a) concentration provided by Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite images, in situ meteorological data and monthly regional NCEP-NCAR re-analysis wind fields in order to investigate the relative contribution of each of the above regions to the apportionment of the ANC at King George Island (KGI), South Shetland Islands. Our results suggest that, at least during the period from September 1998–December 1999, the southern Argentinean shelf acted as the main contributor to the ANC measured in KGI.
Short-term treatment with 6-DMAP and demecolcine improves developmental competence of electrically or Thi/DTT-activated porcine parthenogenetic embryos
Authors: Park Sol Ji , Koo Ok Jae , Kwon Dae Kee , Gomez Ma Ninia Limas , Kang Jung Taek , Atikuzzaman Mohammad , Kim Su Jin , Jang Goo , Lee Byeong Chun
Published: June 2010

Treatment with 6-dimethylaminopurine (6-DMAP) or demecolcine (DE) for several (at least 2) hours after artificial activation is known to improvein vitrodevelopment of porcine embryos. However, several reports have also shown that treatments with these chemicals induce apoptosis. The aim of this study was to find out whether short-term treatment with 6-DMAP and DE combined with electrical or thimerosal/dithiothreitol (Thi/DTT) activation had a beneficial effect on development of parthenogenetically activated porcine oocytes. We additionally treated embryos with 6-DMAP (2 mM) and/or DE (0.4 μg/ml) for a short time (40 min) after an electrical pulse (EP) or Thi/DTT. As a result, short-term treatment with 6-DMAP and DE successfully induced development of electrically or Thi/DTT-activated porcine parthenogenetic embryos with no significant difference in cleavage rate, blastocyst formation rate and total cell number compared with long-term treatment. To find optimal activation protocol, cleavage rate, blastocyst formation rate and total cell number were compared between EP and Thi/DTT treatments. Thi/DTT + 6-DMAP + DE showed significantly higher blastocyst formation rate (36.1 ± 3.5%) and total cell number (46.9 ± 1.0) than other groups (EP + 6-DMAP + DE, EP + Thi/DTT + 6-DMAP + DE: 23.3 ± 3.0%, 42.2 ± 1.1 and 17.2 ± 2.7%, 36.7 ± 1.5, respectively). In conclusion, this study demonstrates that short-term treatment with 6-DMAP and DE is as effective as the standard long-term treatment and Thi/DTT + 6-DMAP + DE exerts a synergistic effect.
Identification of a 2-cell stage specific inhibitor of the cleavage of preimplantation mouse embryos synthesized by rat hepatoma cells as 5′-deoxy-5′-methylthioadenosine
Authors: Kobayashi Masayuki , Saito Koichi , Tamogami Shigeru , Takashima Junko , Kasuga Kano , Kojima Ikuo
Published: June 2010

Rat hepatoma Reuber H-35 cells produce a unique compound designated as Fr.B-25, a 2-cell stage-specific inhibitor of the cleavage of preimplantation mouse embryos culturedin vitro. Here, we identified Fr.B-25 as a purine nucleoside, 5′-deoxy-5′-methylthioadenosine (MTA), by mass spectroscopic analysis. All of the biological activities examined of authentic MTA on the development of mouse zygotes were indistinguishable from those of Fr.B-25. The mechanism of MTA action in the development of preimplantation mouse embryos was probably different from those of hypoxanthine and adenosine, which are well-characterized purine nucleosides that act as inhibitors of the cleavage of mouse 2-cell embryos. From the shared molecular and biological properties of Fr.B-25 and MTA, we concluded that Fr.B-25 is MTA. To the best of our knowledge, this is the first delineation of the effect of MTA on the development of preimplantation mammalian embryos culturedin vitro.
Meiotic inhibition of bovine oocytes in medium supplemented with a serum replacer and hormones: effects on meiosis progression and developmental capacity
Authors: Barretto Letícia Siqueira Sá , Caiado Castro Viviane Sgobbi Dias , Garcia Joaquim Mansano , Mingoti Gisele Zoccal
Published: June 2010

Aiming to improve the developmental competence of bovine oocytes during meiotic block, this study evaluated the effects of a serum replacer (Knockout SR®) and hormones (gonadotropins and estradiol) supplementation of prematuration medium (TCM119 with 0.5 mM IBMX [IBMX group] or 25 μM roscovitine [ROSC group]) on the kinetics of oocyte nuclear maturation and embryo development. Most IBMX and ROSC oocytes prematured for 8 h culture remained in the GV stage (70.3% and 73.1%, respectively; p > 0.05) similar to Control 8 h (63.5%) and to control immature oocytes (Control 0 h, 92.5%). After prematuration for 16 h, no oocytes remained in the GV stage at similar rates to those recently aspirated (p < 0.05); GV rates in ROSC (32.4%) were higher (p < 0.05) than in the Control 16 h group (8.6%), but similar (p > 0.05) to IBMX (9.7%). After in vitro maturation (IMV) for 24 h, metaphase II (MII) rates for oocytes prematured during 8 h were similar (p > 0.05) between control and treatments (65.0–71.7%). Similarly, MII rates oocytes prematured during 16 h were similar (p > 0.05) between all groups (45.9–60.4%). Cleavage rates (67.8–78.2%), embryonic development in day-7 (25.0–35.6%) and hatching rates in day-8 (2.5–11.3%) oocytes blocked during 8 h were similar for all groups (p > 0.05). Results indicate that addition of Knockout SR® and hormones to meiotic block culture with IBMX and roscovitine negatively affected meiotic arrest, but did not impair oocyte nuclear maturation and acquisition of developmental competence.
Nek2 and its substrate, centrobin/Nip2, are required for proper meiotic spindle formation of the mouse oocytes
Authors: Sonn Seongkeun , Oh Goo Taeg , Rhee Kunsoo
Published: June 2010

A typical centrosome consists of a pair of centrioles embedded in a proteinous matrix called pericentriolar material. However, the centrosomes in the mouse oocytes and early embryos lack centrioles, but consist of the γ-tubulin-enriched vesicle aggregates. We previously revealed that Nek2 and centrobin/Nip2, a centrosomal substrate of Nek2, is critical for the mouse early embryogenesis, especially at the step of spindle assembly during mitosis. In order to expand our understanding of the biological functions of Nek2, we examined expression and knockdown phenotypes of Nek2 and its substrates, centrobin and C-Nap1, in the mouse oocyte. Nek2, centrobin and C-Nap1 in the mouse oocytes were also centrosomal. Suppression of Nek2 and its substrates did not affect meiotic resumption of the oocytes. However, meiosis of theNek2- andcentrobin-suppressed oocytes was not completed, but arrested with defects in spindle assembly. No visible phenotype was observed in theC-Nap1-suppressed oocytes. These results indicate that Nek2 is critical for proper assembly of the meiotic spindles. Centrobin may be a possible substrate of Nek2 responsible for the meiotic spindle assembly in the mouse oocytes.
Effect of trichostatin A on transfected donor cells and subsequent development of porcine cloned embryos
Authors: Bo Fu , Di Liu , Qing-chang Fang , Liang Ren , Hong Ma , Liang Wang , Zhen-hua Guo , Zhong-qiu Li
Published: June 2010

Transgenes integrated into mammalian cells are silenced rapidly. This phenomenon correlates with repressed chromatin structure marked by histone hypoacetylation. This study investigated the effect of trichostatin A (TSA; a histone-deacetylase inhibitor) on EGFP expression in transfected cells and embryonic development after somatic cell nuclear transfer (SCNT). Porcine adult fibroblasts were transfected with a pEGFP-C1 vector. Then transfected cells, donor cells for SCNT, were pretreated with TSA, with the untreated cells being used as the control. Expression of EGFP in donor cells and reconstructed embryos was detected when exposed to blue light. Results showed that the percentage of EGFP-positive cells significantly increased when the transfected cells were treated with TSA and the increased expression of EGFP was sustained to at least the morula stage. In addition, the cytotoxic effect of TSA on the transfected cells was dose dependent. In conclusion, TSA can rescue the silencedEGFPgene. Even after transferring the TSA-treated cells to enucleated recipient oocytes, TSA retained the ability to rescue a silencedEGFPgene. In addition, TSA had an impact on cell proliferation.
Gene therapy for bone healing
Authors: Evans Christopher H.
Published: June 2010

Clinical problems in bone healing include large segmental defects, spinal fusions, and the nonunion and delayed union of fractures. Gene-transfer technologies have the potential to aid healing by permitting the local delivery and sustained expression of osteogenic gene products within osseous lesions. Key questions for such an approach include the choice of transgene, vector and gene-transfer strategy. Most experimental data have been obtained using cDNAs encoding osteogenic growth factors such as bone morphogenetic protein-2 (BMP-2), BMP-4 and BMP-7, in conjunction with both nonviral and viral vectors using in vivo and ex vivo delivery strategies. Proof of principle has been convincingly demonstrated in small-animal models. Relatively few studies have used large animals, but the results so far are encouraging. Once a reliable method has been developed, it will be necessary to perform detailed pharmacological and toxicological studies, as well as satisfy other demands of the regulatory bodies, before human clinical trials can be initiated. Such studies are very expensive and often protracted. Thus, progress in developing a clinically useful gene therapy for bone healing is determined not only by scientific considerations, but also by financial constraints and the ambient regulatory environment.
Determinants of the generosity of pension plans for public school teachers, 1982–2006
Authors: CLARK ROBERT L. , CRAIG LEE A.
Published: June 2010

All states provide pension plans to their teachers and civil servants; however, these plans vary across the states. We present a history of the development of teacher retirement plans during the twentieth century, describe how teacher plans relate to retirement plans for other state employees, and assess the impact of teachers not being included in Social Security on the benefits they receive from their employer pension plan. Over the past 25 years, public school teacher retirement plans in the United States have increased in generosity as benefit formulas have been increased, salary averaging periods have been reduced, and the normal retirement age has been lowered. We employ data from retirement plans in the states to estimate the impact of social and economic factors on the replacement rates for teachers retiring with 30 years of service.
Constraints on upper mantle anisotropy surrounding the Cocos slab from SK(K)S splitting
Authors: Abt David L. , Fischer Karen M. , Abers Geoffrey A. , Protti Marino , González Victor , Strauch Wilfried
Published: June 2010

SKS and SKKS splitting observations are used to constrain the pattern of mantle flow in the Central American subduction zone beneath Costa Rica and Nicaragua. After removing the effects of shallow wedge anisotropy on SK(K)S waveforms, a best fitting model of anisotropy beneath the Cocos Plate and in the deeper mantle wedge is determined. Fast polarization directions and model symmetry axis orientations in both regions (as well as the shallow wedge) are dominated by roughly arc‐parallel azimuths and, therefore, are not consistent with sublithospheric mantle flow entrained by the subducting Cocos Plate or simple two‐dimensional corner flow in the wedge. In conjunction with geochemical data and local S splitting tomography, the SK(K)S splitting observations and anisotropy models are consistent with flow to the WNW within the mantle wedge on the Caribbean side of the Cocos Plate, possibly drawn through a slab window beneath Panama and southern Costa Rica. Anisotropy in the Pacific mantle beneath the Cocos Plate is also best explained by flow with a component that is roughly parallel to the strike of the slab, although the absolute direction of this flow is not uniquely constrained.
Lamé parameters of common rocks in the Earth's crust and upper mantle
Authors: Ji Shaocheng , Sun Shengsi , Wang Qian , Marcotte Denis
Published: June 2010

Lamé parameter (λ) and shear modulus (μ) are the most important, intrinsic, elastic properties of rocks. The Lamé parameter λ, which relates stresses and strains in perpendicular directions, is closely related to the incompressibility and contains a high proportion of information about the resistance to a change in volume caused by a change in pressure. Recent studies have emphasized the roles played by λ in the discrimination of gas sands from carbonates and shale in sedimentary basins and in the seismic reflection of crustal fault zones. Here we analyze the equivalent isotropic elastic data of 475 natural rocks in order to characterize λ values for common types of crystalline rocks in the Earth's crust and upper mantle and their variations with pressure (P), temperature (T), and mineralogical composition. When no partial melting, metamorphic reaction, dehydration, or phase transformation occurs, λ of a crystalline rock as a function of P and T can be described by λ = a + (dλ/dP)P − c exp(− kP) − (dλ/dT)T, where a is the projected λ value at zero pressure if microcracks were fully closed; dλ/dP is the pressure derivative in the linear elastic regime; c is the initial λ drop caused by the presence of microcracks at zero pressure; k is a decay constant of the λ drop in the nonlinear poroelastic regime; and dλ/dT is the temperature derivative. The parameter λ increases nonlinearly and linearly with increasing pressure at low (<∼300 MPa) and high (>∼300 MPa) pressures, respectively. In the regime of high pressures, λ decreases quasi‐linearly with increasing temperature with dλ/dT values in the range of 1–10 × 10−3 GPa/°C. Approaching the α‐β quartz transition temperature, quartzite displays negative λ values. In the λ‐ρ (density) and μ‐λ plots, the main categories of lithology can be clearly distinguished. The ultramafic rocks display systematic decreases in both μ and λ with increasing the degree of serpentinization. Eclogites, mafic rocks (gabbro, diabase, mafic granulite, and mafic gneiss), and felsic rocks (granite, diorite, felsic gneiss, intermediate gneiss, and metasediments) are characterized by high, moderate, and low μ and λ values, respectively. For pyroxene and olivine, both λ and ρ increase, but μ decreases with increasing the Fe/Mg ratios. In the plagioclase series, both λ and μ increases with increasing the anorthite content. Increases in the contents of garnets, sillimanite, rutile, zircon, ilmenite, and spinel result systematically in an increase in rock's λ and μ values. The present results provide improved constraints on the discrimination of composition for crustal and upper mantle rocks in terms of λ and μ.
Nonlinear terms in storm surge predictions: Effect of tide and shelf geometry with case study from Hurricane Rita
Authors: Rego João L. , Li Chunyan
Published: June 2010

This study applied the finite volume coastal ocean model (FVCOM) to the storm surge induced by Hurricane Rita along the Louisiana‐Texas coast. The model was calibrated for tides and validated with observed water levels. Peak water levels were shown to be lower than expected for a landfall at high tide. For low‐ and high‐tide landfalls, nonlinear effects due to tide‐surge coupling were constructive and destructive to total storm tide, respectively, and their magnitude reached up to 70% of the tidal amplitude in the Rita application. Tide‐surge interaction was further examined using a standard hurricane under idealized scenarios to evaluate the effects of various shelf geometries, tides, and landfall timings (relative to tide). Nonlinearity was important between landfall position and locations within 2.5 × radius of maximum winds. On an idealized wide continental shelf, nonlinear effects reached up to 80% of the tidal amplitude with an S2 tide and up to 47% with a K1 tide. Increasing average depths by 4 m reduced nonlinear effects to 41% of the tidal amplitude; increasing the slope by a factor of 3 produced nonlinearities of just 26% of tide (both with a K1 tide). The nonlinear effect was greatest for landfalls at low tide, followed by landfalls at high tide and then by landfalls at midebb or midflood.
Experimental investigation of the mechanical properties of synthetic magnesium sulfate hydrates: Implications for the strength of hydrated deposits on Mars
Authors: Grindrod Peter M. , Heap Michael J. , Fortes A. Dominic , Meredith Philip G. , Wood Ian G. , Trippetta Fabio , Sammonds Peter R.
Published: June 2010

We have carried out uniaxial compression experiments to determine the mechanical properties of three crystalline magnesium sulfate hydrates that may be present in the near‐surface environment of Mars. Our synthetic samples of kieserite (MgSO4 · H2O), epsomite (MgSO4 · 7H2O), and meridianiite (MgSO4 · 11H2O) have mean values of unconfined compressive strength of 6.3 ± 0.7, 12.9 ± 1.8, and 30.1 ± 4.5 MPa, respectively, Young's modulus of 0.8 ± 0.1, 2.9 ± 0.4, and 5.9 ± 0.8 GPa, respectively, and mean porosity values of 47.8% ± 0.5%, 11.1% ± 0.6%, and 2.9% ± 0.2%, respectively. Although our tests cannot quantify a systematic relationship between hydration state and mechanical properties, the different porosities produced by consistent sample preparation methods suggest that the addition of non‐cation‐coordinated water molecules likely reduces the strength of individual sulfate hydrate phases. However, the bulk mechanical properties of our synthetic specimens are instead controlled predominantly by the sample porosity; generally, the strength increases as the porosity decreases. We expect the mechanical properties of sulfate hydrate deposits on Mars to be governed by the bulk porosity rather than the strength of the pure solid phase. We have performed cyclic stressing tests, replicating possible periodic depositional and erosional periods on Mars resulting from obliquity changes. A gradual compaction and reduction in sample porosity, rather than an increase in crack damage, is observed with each loading cycle, suggesting that the evolution of mechanical properties will depend on local factors such as bulk density, in addition to the overall stress history.
A nonlocal theory of sediment transport on hillslopes
Authors: Foufoula‐Georgiou E. , Ganti V. , Dietrich W. E.
Published: June 2010

Hillslopes are typically shaped by varied processes which have a wide range of event‐based downslope transport distances, some of the order of the hillslope length itself. We hypothesize that this can lead to a heavy‐tailed distribution of displacement lengths for sediment particles. Here, we propose that such a behavior calls for a nonlocal computation of the sediment flux, where the sediment flux at a point is not strictly a function (linear or nonlinear) of the gradient at that point only but is an integral flux taking into account the upslope topography (convolution Fickian flux). We encapsulate this nonlocal behavior in a simple fractional diffusive model which involves fractional derivatives, with the order of differentiation (1 < α ≤ 2) dictating the degree of nonlocality (α = 2 corresponds to linear diffusion and strictly local dependence on slope). The model predicts an equilibrium hillslope profile which is parabolic close to the ridgetop and transits, at a short downslope distance, to a power law with an exponent equal to the parameter α of the fractional transport model. Hillslope profiles reported in previously studied sites support this prediction. Furthermore, we show that the nonlocal transport model gives rise to a nonlinear dependency on local slope and that variable upslope topography leads to widely varying rates of sediment flux for a given local hillslope gradient. Both of these results are consistent with available field data and suggest that nonlinearity in hillslope flux relationships may arise in part from nonlocal transport effects in which displacement lengths increase with hillslope gradient. The proposed hypothesis of nonlocal transport implies that field studies and models of sediment fluxes should consider the size and displacement lengths of disturbance events that mobilize hillslope colluvium.
Deformation textures and mechanical behavior of a hydrated amorphous silica formed along an experimentally produced fault in chert
Authors: Hayashi Nao , Tsutsumi Akito
Published: June 2010

We conducted a series of friction experiments on chert at intermediate to high slip velocities (V = 0.87 − 104 mm/s) and at low normal stress (σn = 1.5 MPa) to better understand the process of fault weakening by silica‐gel formation, as identified in previous friction experiments on quartz‐rocks. Fault weakening in chert samples occurred in association with the formation of a 0.1‐mm‐thick fault gouge layer that contains a thin, foliated layer of fine‐grained material and a cataclastically fragmented zone characterized by clast‐matrix texture. MFT‐IR and XRD analyses reveal that the fault gouge consists of a mixture of hydrated amorphous silica and quartz grains. The mechanical behavior of the fault gouge at a small magnitude of strain (γ = 0.008), as examined independently of the friction experiments using a rheometer, is characterized by a negative dependence of shear stress on strain rate with a notable hysteresis behavior.
Protective effect of melatonin against oxidative stress induced by ligature of extra‐hepatic biliary duct in rats: comparison with the effect of S‐adenosyl‐l‐methionine
Authors: Montilla López Pedro , Túnez Fiñana Isaac , Muñoz De Agueda M. Carmen , Cabrera Sánchez Emilio , Montilla Muñoz M. Carmen , Plascencia Álvarez Jaime , De La Torre Lozano Eugenio J.
Published: June 2010

In the present research, we studied the effect of the administration of melatonin or S‐adenosyl‐l‐methionine (S‐AMe) on oxidative stress and hepatic cholestasis produced by double ligature of the extra‐hepatic biliary duct (LBD) in adult male Wistar rats. Hepatic oxidative stress was evaluated by the changes in the amount of lipid peroxides and by the reduced glutathione content (GSH) in lysates of erythrocytes and homogenates of hepatic tissue. The severity of the cholestasis and hepatic injury were determined by the changes in the plasma enzyme activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AP), g‐glutamyl‐transpeptidase (GGT), and levels of albumin, total bilirubin (TB) and direct bilirubin (DB). Either melatonin or S‐AMe were administered daily 3 days before LBD, and for 10 days after biliary obstruction. LDB caused highly significant increases in plasma enzyme activities and in bilirubin and lipid peroxides levels in erythrocytes and hepatic tissue. At the same time, this procedure produced a notable decrease in the GSH pools in these biological media. Both melatonin and S‐AMe administration were effective as antioxidants and hepatoprotective substances, although the protective effects of melatonin were superior; it prevented the GSH decrease and reduced significantly the increases in enzyme activities and lipid peroxidation products produced by biliary ligature. S‐AMe did not modify the increased GGT activity nor did it decrease greatly the TB levels (43% melatonin vs. 14% S‐AMe). However, S‐AMe was effective in preventing the loss of GSH in erythrocytes and hepatic tissue, as was melatonin. The obtained data permit the following conclusions. First, the LDB models cause marked hepatic oxidative stress. Second, the participation of free radicals of oxygen in the pathogenecity and severity of cholestasis produced by the acute obstruction of the extra‐hepatic biliary duct is likely. Third, the results confirm the function of S‐AMe as an antioxidant and hepatoprotector. Finally, melatonin is far more potent and provides superior protection as compared to S‐AMe. Considering the decrease in oxidative stress and the intensity of cholestasis, these findings have interesting clinical implications for melatonin as a possible therapeutic agent in biliary cholestasis and parenchymatous liver injury.
Serum cholesterol and lipid peroxidation are decreased by melatonin in diet‐induced hypercholesterolemic rats
Authors: Hoyos Marta , Guerrero Juan M. , Perez‐Cano Ramon , Olivan Josefina , Fabiani Fernando , Garcia‐Pergañeda Antonio , Osuna Carmen
Published: June 2010

The purpose of this study was to investigate the effect of melatonin, at pharmacological doses, on serum lipids of rats fed with a hypercholesterolemic diet. Therefore, different groups of animals were fed with either the regular Sanders Chow diet or a diet enriched in cholesterol. Moreover, animals were treated with or without melatonin in the drinking water for 3 months. We show that melatonin treatment did not affect the levels of cholesterol or triglycerides in rats fed with a regular diet. However, the increase in total cholesterol and low‐density lipoprotein (LDL)‐cholesterol induced by a cholesterol‐enriched diet was reduced significantly by melatonin administration. On the other hand, melatonin administration prevented the decrease in high‐density lipoprotein (HDL)‐cholesterol induced by the same diet. No differences in the levels of very low‐density lipoprotein (VLDL)‐cholesterol and triglycerides were found. We also found that melatonin administration slightly decreased serum uric, bilirubin and increased serum glucose levels. Other biochemical parameters, including total proteins, creatinine, urea, phosphorus, calcium, glutamic oxalacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), Γ‐glutamyltranspeptidase (Γ‐GT), acetyl cholinesterase (AcCho), and alkaline phosphatase (ALP) were not modified by melatonin treatment. Finally, lipid peroxidation (LPO) was studied in membranes of liver, brain, spleen, and heart as an index of membrane oxidative damage. Results show that hypercholesterolemic diet did not modify the LPO status in any of the tissues studied. However, chronic melatonin administration significantly decreased LPO. Results confirm that melatonin participates in the regulation of cholesterol metabolism and in the prevention of oxidative damage to membranes.
Circadian rhythm of mt1 melatonin receptor expression in the suprachiasmatic nucleus of the C3H/HeN mouse1
Authors: Masana M.I. , Benloucif S. , Dubocovich M.L.
Published: June 2010

This report studied the diurnal and circadian rhythms of mt1
melatonin receptor expression in the SCN of C3H/HeN mice maintained in
either a light:dark (LD) cycle or in constant dark for a minimum of 6 wk.
Diurnal times (ZT) were assessed with reference to the onset of the light
period (ZT0) and circadian times (CT) were established by determining the
phase of wheel running activity of each mouse before sacrifice. 2‐[125I]‐Iodomelatonin binding in the SCN
revealed low amplitude diurnal and circadian rhythms with highest levels
of binding 2 hr after lights on (41.3±1.7 fmol/mg protein, n=5, at
ZT2) or at the beginning of the subjective day (48.6±2.1 fmol/mg
protein, n=6, CT2), respectively. The expression of mt1 mRNA,
determined by in situ hybridization with a 35
S‐labeled mouse mt1 riboprobe, showed robust diurnal
and circadian rhythms. In animals housed under a LD cycle, low levels of
expression were observed during the day, with a rapid rise in
mt1 melatonin receptor expression at the beginning of the dark
period (ZT14), coincident with an abrupt increase in levels of
circulating melatonin measured by radioimmunoassay. In animals housed
under constant dark conditions, a robust peak of mt1 mRNA
expression occurred in the middle of the subjective night (CT18), 8 hr
before the peak of protein expression, while the lowest levels of
mt1 mRNA expression were observed during the day (CT10).
Results suggest that mt1 melatonin receptor rhythm in the C3H/HeN mouse SCN is regulated both by light and by the biological clock as distinct rhythms of both mRNA and protein are differentially expressed under a LD cycle and constant dark conditions.
Metal chelating and hydrogen peroxide scavenging effects of melatonin
Authors: Gulcin İlhami , Buyukokuroglu Mehmet Emin , Kufrevioglu O. Irfan
Published: June 2010

Abstract: Antioxidant activity of a molecule is attributed to various mechanisms such as prevention of chain initiation, binding of transition metal ion catalysts and decomposition of peroxides. This study was aimed at evaluating the metal chelating and hydrogen peroxide (H2O2) scavenging activity of melatonin. The metal chelating and H2O2 scavenging activity increased with increasing concentrations of melatonin (20–60 μg/mL). α‐Tocopherol, butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) were used as standards. Sixty micrograms per milliliter concentration of melatonin exhibited 95% chelating effect on ferrous ions and scavenged 83% of H2O2. On the other hand, the same concentration of α‐tocopherol, BHA, and BHT exhibited 58, 61, and 72% inhibition, respectively, of the formation of the Fe2+–ferrozine complex and scavenged 48, 20, and 23%, respectively, of H2O2. Based on these results, it is concluded that melatonin is an effective metal chelating agent and scavenger of H2O2. These properties may be major reasons for the melatonin's ability to inhibit lipid peroxidation.
Melatonin in the duodenal lumen is a potent stimulant of mucosal bicarbonate secretion
Authors: Sjöblom Markus , Flemström Gunnar
Published: June 2010

Abstract: Melatonin, originating from intestinal enterochromaffin cells, mediates vagal and sympathetic neural stimulation of the HCO secretion by the duodenal mucosa. This alkaline secretion is considered the first line of mucosal defense against hydrochloric acid discharged from the stomach. We have studied whether luminally applied melatonin stimulates the protective secretion and whether a melatonin pathway is involved in acid‐induced stimulation of the secretion. Rats were anaesthetized (Inactin®) and a 12‐mm segment of proximal duodenum with an intact blood supply was cannulated in situ. Mucosal HCO secretion (pH‐stat) and the mean arterial blood pressure were continuously recorded. Luminal melatonin at a concentration of 1.0 μm increased (P < 0.05) the secretion from 7.20 ± 1.35 to 13.20 ± 1.51 μEq/cm/hr. The MT2 selective antagonist luzindole (600 nmol/kg, i.v.) had no effect on basal HCO secretion, but inhibited (P < 0.05) secretion stimulated by luminal melatonin. Hexamethonium (10 mg/kg i.v. followed by continuous i.v. infusion at a rate of 10 mg/kg/hr), abolishes neurally mediated rises in secretion and also inhibited (P < 0.05) the stimulation by luminal melatonin. Exposure of the lumen to acid containing perfusate (pH 2.0) for 5 min increased (P < 0.05) the HCO secretion from 5.85 ± 0.82 to 12.35 ± 1.51 μEq/cm/hr, and luzindole significantly inhibited (P < 0.05) this rise in secretion. The study thus demonstrates that luminal melatonin is a potent stimulant of duodenal HCO secretion and, furthermore, strongly suggests melatonin as an important mediator of acid‐induced secretion.
Necrostatin Decreases Oxidative Damage, Inflammation, and Injury after Neonatal HI
Authors: Northington Frances J , Chavez-Valdez Raul , Graham Ernest M , Razdan Sheila , Gauda Estelle B , Martin Lee J
Published: June 2010

Necrostatin-1 inhibits receptor-interacting protein (RIP)-1 kinase and programmed necrosis and is neuroprotective in adult rodent models. Owing to the prominence of necrosis and continuum cell death in neonatal hypoxia–ischemia (HI), we tested whether necrostatin was neuroprotective in the developing brain. Postnatal day (P)7 mice were exposed to HI and injected intracerebroventricularly with 0.1 μL of 80 μmol necrostatin, Nec-1, 5-(1H-Indol-3-ylmethyl)-(2-thio-3-methyl) hydantoin, or vehicle. Necrostatin significantly decreased injury in the forebrain and thalamus at P11 and P28. There was specific neuroprotection in necrostatin-treated males. Necrostatin treatment decreased necrotic cell death and increased apoptotic cell death. Hypoxia–ischemia enforced RIP1–RIP3 complex formation and inhibited RIP3–FADD (Fas-associated protein with death domain) interaction, and these effects were blocked by necrostatin. Necrostatin also decreased HI-induced oxidative damage to proteins and attenuated markers of inflammation coincidental with decreased nuclear factor-κB and caspase 1 activation, and FLIP ((Fas-associated death-domain-like IL-1β-converting enzyme)-inhibitory protein) gene and protein expression. In this model of severe neonatal brain injury, we find that cellular necrosis can be managed therapeutically by a single dose of necrostatin, administered after HI, possibly by interrupting RIP1–RIP3-driven oxidative injury and inflammation. The effects of necrostatin treatment after HI reflect the importance of necrosis in the delayed phases of neonatal brain injury and represent a new direction for therapy of neonatal HI.
Intact Memory in TGF-β1 Transgenic Mice Featuring Chronic Cerebrovascular Deficit: Recovery with Pioglitazone
Authors: Nicolakakis Nektaria , Aboulkassim Tahar , Aliaga Antonio , Tong Xin-Kang , Rosa-Neto Pedro , Hamel Edith
Published: June 2010

The roles of chronic brain hypoperfusion and transforming growth factor-beta 1 (TGF-β1) in Alzheimer's disease (AD) are unresolved. We investigated the interplay between TGF-β1, cerebrovascular function, and cognition using transgenic TGF mice featuring astrocytic TGF-β1 overexpression. We further assessed the impact of short, late therapy in elderly animals with the antioxidant N-acetyl–cysteine (NAC) or the peroxisome proliferator-activated receptor-γ agonist pioglitazone. The latter was also administered to pups as a prophylactic 1-year treatment. Elderly TGF mice featured cerebrovascular dysfunction that was not remedied with NAC. In contrast, pioglitazone prevented or reversed this deficit, and rescued the impaired neurovascular coupling response to whisker stimulation, although it failed to normalize the vascular structure. In aged TGF mice, neuronal and cognitive indices—the stimulus-evoked neurometabolic response, cortical cholinergic innervation, and spatial memory in the Morris water maze—were intact. Our findings show that impaired brain hemodynamics and cerebrovascular function are not accompanied by memory impairment in this model. Conceivably in AD, they constitute aggravating factors against a background of aging and underlying pathology. Our data further highlight the ability of pioglitazone to protect the cerebrovasculature marked by TGF-β1 increase, aging, fibrosis, and antioxidant resistance, thus of high relevance for AD patients.