bluuebunny/crossref_metadata_2025 huggingface dataset:
Through the service operations strategy looking glass: Influence of industrial sector, ownership, and service offerings on B2B e‐marketplace failures
Authors: Rosenzweig Eve D. , Laseter Timothy M. , Roth Aleda V.
Published: April 2010

This paper contributes to the emerging area of e‐service strategy in the context of business‐to‐business (B2B) e‐marketplaces, which we view as Internet‐based service delivery systems that link sellers’ offerings to buyers. Although a myriad of new B2B e‐marketplaces were launched over the past decade, a substantial number failed shortly after the peak of the NASDAQ in 2000. The bursting of the Internet bubble provides a setting for assessing salient, theory‐based determinants of failure—and success. Accordingly, we apply a service operations strategy lens and complementary organizational theories to explain how three strategic factors—industrial sector characteristics, ownership structure, and functionality of service offering—may have influenced B2B e‐marketplaces’ odds of survival after the bubble. We empirically test these factors using logistic regression analysis on a sample of 854 B2B e‐marketplaces.

Consistent with emerging e‐services literature, our empirical results indicate that B2B e‐marketplaces serving industrial sectors that are a better fit with the Internet service delivery systems—by high information dependence and low information tacitness—have the highest likelihood of success, as do e‐marketplaces with service offerings that facilitate collaboration among multiple buyers and sellers. We also demonstrate the positive influence of consortium ownership structure on B2B e‐marketplace survival, albeit not for first‐mover consortia‐backed e‐marketplaces. Our findings contribute to the service operations strategy literature and provide direction for managers in the areas of e‐service strategy and investment.
Sources of social support for China’s current political order: The “thick embeddedness” of private capital holders
Authors: McNally Christopher A. , Wright Teresa
Published: April 2010

In recent years, scholars have puzzled over the fact that China’s increased economic privatization and marketization since the early 1990s have not triggered a simultaneous advance in political liberalization. Many have sought to explain why – despite a marked upsurge in popular unrest – sources of social support for the political order have remained sizeable. Seeking to shed light on this debate, this article investigates the nature and implications of the political embeddedness of China’s private capital holders. The embeddedness of these individuals is “thick” in the sense that it encompasses an inter-twined amalgam of instrumental ties and affective links to the agents and institutions of the party-state. Thick embeddedness therefore incorporates personal links that bind private capital holders to the party-state through connections that are layered with reciprocal affective components. Such close relations work against the potential interest that private capital holders might have in leading or joining efforts to press for fundamental political liberalization. Drawing on these findings, the article places China’s economic and political development in comparative perspective, and lays out the most likely scenarios for China’s future.
Lithospheric structure and Mesozoic geodynamics of the eastern Central Asian orogen
Authors: Didenko A.N. , Kaplun V.B. , Malyshev Yu.F. , Shevchenko B.F.
Published: April 2010

The lithospheric structure of several marginal and interior units of the eastern Central Asian orogen has been explored in 2D geophysical models. The obtained constraints on effective parameters (density, resistivity, temperature) of lithospheric blocks and their boundaries allowed correlation of geophysical structures to tectonic settings. The geological and geophysical (including paleomagnetic) data were used jointly to model the present structure of the lithosphere along 126° E between 56° N and 40° N and to construct a palinspastic model of the same area for the latest Early Jurassic (175 Ma).
Biogenic sedimentation factors of mineralization in the Neoproterozoic strata of the Baikal–Patom region
Authors: Nemerov V.K. , Stanevich A.M. , Razvozzhaeva E.A. , Budyak A.E. , Kornilova T.A.
Published: April 2010

The formation environments of stratiform ore deposits in the Neoproterozoic Baikal–Patom region (BPR) have been considered. A model for the formation of the Sukhoi Log gold ore deposit in the Bodaibo zone has been put forward. The first stage is gold concentration by a chemolithotrophic bacterial community. Independently established facts suggest that bacterial communities may also have contributed to initial metal accumulation in the sediments of the Kholodnaya Pb–Zn deposit. The ore beds occur in the high-carbon sediments of the side and trough of a back-arc basin. Sedimentation (Dal’nyaya Taiga and Zhuya regional horizons) took place during the “back-arc basin–foreland basin” transition. This transition is characterized by increased sediment bioproductivity, which is clearly evidenced from the increased biophile-element content and taxonomic diversity of organic remains. Hundreds of microfossil sites in the Neoproterozoic BPR host littoral benthos (cyanobacteria and brown algae) and plankton (green algae). Most microfossils in the outer shelf, on the basin side, and in its trough belong to chemolithotrophic bacteria. These bacteria are assumed to have accumulated metals in the vent field of the back-arc basin. Studies showed the ability of microorganisms (bacteria, algae, fungi, etc.) to accumulate Fe, Mn, Au, Pb, Zn, and other metals. Bacterial communities are particularly important for metal accumulation in the vent fields of rift zones and areas of arc volcanism. All these conditions were observed in the Neoproterozoic BPR.
High-density lipoprotein subclasses are a potential intermediary between alcohol intake and reduced risk of cardiovascular disease: The Rancho Bernardo Study
Authors: Muth Natalie D. , Laughlin Gail A. , von Mühlen Denise , Smith Sidney C. , Barrett-Connor Elizabeth
Published: April 2010

We conducted a cross-sectional study of NMR-derived HDL subclasses and alcohol intake among 2171 community-dwelling older adults with a large proportion of daily or near-daily alcohol consumers (44 %). We aimed to assess whether, in addition to increasing total HDL, alcohol may induce a beneficial shift in HDL particle size distribution. Participants were categorised based on reported alcohol intake (g per week) and on frequency (none, < 3 times/week, 3–4 times/week, ≥ 5 times/week). The association between alcohol intake and lipoprotein fractions was examined using sex-specific linear regression models adjusted for age, BMI, diabetes, current smoking, exercise and hormone therapy in women. There was a stepwise gradient with the highest weekly alcohol consumption associated with the highest total HDL size and greatest number of medium and large HDL particles, as well as higher total HDL concentrations (allP < 0·001); total small HDL did not differ. Alcohol–HDL size associations were similar in both sexes and did not differ by use of hormone replacement therapy in women. In conclusion, regular alcohol consumers had a higher number and percentage of large HDL particles than non-drinkers. These results suggest that one way that alcohol may decrease CVD is through potentially favourable changes in lipoprotein subclass composition.
Paediatric aerodigestive foreign bodies: remember the nasopharynx
Authors: MacNeil S D , Moxham J P , Kozak F K
Published: April 2010

Introduction:

Nasopharyngeal foreign bodies are relatively uncommon, compared with other aerodigestive sites. They may mimic a lower airway location, or may be coughed up into the nasopharynx prior to endoscopic evaluation.

Objective:

To describe our experience with nasopharyngeal foreign bodies mimicking a more distal airway location.

Method:

Case series from a tertiary referral children's hospital.

Results:

We present a series of four children who were initially thought to have a lower aerodigestive tract foreign body (three respiratory, one oesophageal), but who were finally diagnosed with nasopharyngeal foreign body. The concept of panendoscopy at all foreign body removals is suggested as a means to avoid a missed nasopharyngeal foreign body.

Conclusion:

Although nasopharyngeal foreign bodies are uncommon, their rare ability to mimic distal sites mandates a thorough endoscopic approach to ensure that all sites (i.e. larynx, lungs, oesophagus and nasopharynx) are evaluated endoscopically.
Evaluation of computed tomography virtual bronchoscopy in paediatric tracheobronchial foreign body aspiration
Authors: Bhat K V , Hegde J S , Nagalotimath U S , Patil G C
Published: April 2010

Objective:

Virtual bronchoscopy is a noninvasive technique which provides an intraluminal view of the tracheobronchial tree. This study aimed to evaluate this technique in comparison with rigid bronchoscopy, in paediatric patients with tracheobronchial foreign bodies undetected by plain chest radiography.

Methods:

Plain chest radiography was initially performed in 40 children with suspected foreign body aspiration. Computed tomography virtual bronchoscopy was performed in the 20 in whom chest radiography appeared normal. Virtual bronchoscopic images were obtained. All patients underwent rigid bronchoscopy performed by an otolaryngologist blinded to the computed tomography virtual bronchoscopy findings, within 24 hours. Virtual bronchoscopic findings were then compared with the results of rigid bronchoscopy.

Results:

In 12 patients, foreign bodies detected by virtual bronchoscopy were confirmed by rigid bronchoscopy. In one case, a mucous plug was perceived as a foreign body on virtual bronchoscopy. In another case, a minute foreign body was missed on virtual bronchoscopy. The following parameters were calculated: sensitivity, 92.3 per cent; specificity, 85.7 per cent; validity, 90 per cent; positive likelihood ratio, 6.45; and negative likelihood ratio, 0.089.

Conclusion:

In the presence of a positive clinical diagnosis and negative chest radiography, computed tomography virtual bronchoscopy must be considered in all cases of tracheobronchial foreign body aspiration, in order to avoid needless rigid bronchoscopy. Computed tomography virtual bronchoscopy is particularly useful in screening cases of occult foreign body aspiration, as it has high sensitivity, specificity and validity.
Radiological airway changes following bipolar radiofrequency volumetric tissue reduction
Authors: Heywood R L , Khalil H M B , Kothari S , Chawda S , Kotecha B T
Published: April 2010

Objective:

To characterise the appearance of lesions of the tongue base and soft palate induced by bipolar radiofrequency volumetric tissue reduction, using magnetic resonance imaging up to six weeks post-procedure.

Methods:

Five men with sleep-disordered breathing were treated with one session of bipolar radiofrequency volumetric tissue reduction to a number of sites, including the tongue base and soft palate. Magnetic resonance imaging was performed pre-operatively and one week and six weeks after surgery.

Results:

Lesions were visible from day one. T1 (spine lattice relaxation Time)-weighted images demonstrated areas of central hyperintensity, reflecting haemorrhagic, coagulative necrosis, surrounded by hypointensity, representing oedema; corresponding short tau inversion recovery (STIR) sequences showed central hypointensity with surrounding high signal. The lesions expanded up to day three and then gradually diminished, but were still evident at week six on short tau inversion recovery images.

Conclusion:

The characterisation of lesions induced by bipolar radiofrequency volumetric tissue reduction enables us to elucidate the pathophysiology of this procedure, to optimise treatment benefits and clinical outcomes, and to explain patient symptoms.
Changing sink demand of developing shoot affects transitory starch biosynthesis in embryonic tissues of germinating rice seeds
Authors: Liu Shiang-Lin , Siao Wei , Wang Shu-Jen
Published: April 2010

The mechanism of starch metabolism in the endosperm of germinating rice (Oryza sativaL.) seed (caryopsis) has been well studied; however, little is known about the occurrence and function of transitory starch in germinating rice embryos. During rice seed germination and seedling establishment, starch in the endosperm is hydrolysed to glucose, which is taken up by scutellar epithelial cells, converted to sucrose, and transported through vascular bundles to other embryonic tissues, such as growing shoots and roots. In this study, we found that soluble sugar was converted to starch in the scutellum 6 d after imbibition (DAI). Starch appeared primarily in cells surrounding the vascular bundles of the embryonic axis 12 DAI. The removal of growing shoots caused hyper-accumulation of starch in embryonic tissues, including the scutellum. In contrast, placing seedlings in the dark, which reduced photosynthetic efficiency, lowered starch levels in the embryonic axis cells. The disappearance of transitory starch from embryonic tissues of dark-grown seedlings was accompanied by a reduction of soluble sugar content and the down-regulation of the expression and activity of starch biosynthesis enzymes. These results suggest that the amount of transitory starch in embryonic tissues was dependent on the demand of growing sink tissues.
Global distribution and long‐term fate of anthropogenic 129I in marine and surface water reservoirs
Authors: Snyder Glen , Aldahan Ala , Possnert Göran
Published: April 2010

Since the advent of the nuclear age in the mid‐1940s, the mass of radioactive 129I (t1/2 = 15.7 Myr) circulating in the Earth's hydrosphere has increased nearly fortyfold from its natural background level of 140 kg. Nuclear fuel reprocessing has been by far the major contributor, responsible for releasing 5400 kg of 129I, primarily into the North Atlantic Ocean. Regional and global trends in the distribution of the 129I inventory are elucidated from an examination of more than 600 determinations of 129I in environmental samples from around the world. Because the major point sources are located in Europe and the United States, more than 99% of the present 129I reservoir is distributed in the Northern Hemisphere, where both 129I concentrations and 129I/I ratios in rivers, lakes, and shallow seawater are several orders of magnitude above the preanthropogenic background. Downwelling in the North Atlantic presently provides a major sink for marine 129I; however, marine upwelling along the margins of the Pacific will eventually return part of this anthropogenic input to the ocean surface, where it will find its way back into surface waters and the atmosphere. Iodine‐129 has a long half‐life (15.7 Myr), and consequently, there is also the possibility that climate change will influence the dynamics of iodine transfer in surface reservoirs. We model the effect of a collapse in thermohaline circulation and project a concentration increase of more than 3 orders of magnitude in shallow oceans over the 10,000 years that follow if nuclear reprocessing is to continue at the present rate.
Wave‐turbulence interaction and its induced mixing in the upper ocean
Authors: Huang Chuan Jiang , Qiao Fangli
Published: April 2010

In the ocean, interaction among the mean current, the surface waves, and turbulence is a major mechanism for energy transfer from surface waves to the turbulence field. This process is associated with attenuation of surface waves. This paper deals with wave‐turbulence interaction and its induced mixing using field observations and a one‐dimensional, level 2.5 turbulence closure model. The results show that both the turbulence kinetic energy dissipation rate and the vertical mixing induced by wave‐turbulence interaction are a function of us0u*2 and wave parameters, where us0 is the Stokes drift at the sea surface and u* is the friction velocity in water. The former decays with the depth away from the surface in the form of e2kz, while the latter decays as e3kz (k is the wave number). We also analyze the wave decay induced by wave‐turbulence interaction. The decay time scale is in proportion to cL/u*2, while in inverse proportion to , where c is a phase speed, L is a wavelength, and δ is a wave steepness. A series of numerical experiments are performed to evaluate the effects of wave‐turbulence interaction. The results from the cases with effects of wave‐turbulence interaction show significant improvement in simulation of turbulence characteristics compared to the cases in the absence of surface waves. This implies that wave‐turbulence interaction is a significant mechanism for generation of turbulence kinetic energy in the upper ocean and plays an important role in regulating vertical mixing and surface wave decay.
Effects of interactive global changes on methane uptake in an annual grassland
Authors: Blankinship Joseph C. , Brown Jamie R. , Dijkstra Paul , Hungate Bruce A.
Published: April 2010

The future size of the terrestrial methane (CH4) sink of upland soils remains uncertain, along with potential feedbacks to global warming. Much of the uncertainty lies in our lack of knowledge about potential interactive effects of multiple simultaneous global environmental changes. Field CH4 fluxes and laboratory soil CH4 consumption were measured five times during 3 consecutive years in a California annual grassland exposed to 8 years of the full factorial combination of ambient and elevated levels of precipitation, temperature, atmospheric CO2 concentration, and N deposition. Across all sampling dates and treatments, increased precipitation caused a 61% reduction in field CH4 uptake. However, this reduction depended quantitatively on other global change factors. Higher precipitation reduced CH4 uptake when temperature or N deposition (but not both) increased, and under elevated CO2 but only late in the growing season. Warming alone also decreased CH4 uptake early in the growing season, which was partly explained by a decrease in laboratory soil CH4 consumption. Atmospheric CH4 models likely need to incorporate nonadditive interactions, seasonal interactions, and interactions between methanotrophy and methanogenesis. Despite the complexity of interactions we observed in this multifactor experiment, the outcome agrees with results from single‐factor experiments: an increased terrestrial CH4 sink appears less likely than a reduced one.
Continual influences of tropical waves on the genesis and rapid intensification of Typhoon Durian (2006)
Authors: Yanase Wataru , Satoh Masaki , Yamada Hiroyuki , Yasunaga Kazuaki , Moteki Qoosaku
Published: April 2010

Using a global cloud‐system resolving model (GCRM), we examined the external influence of tropical waves on the life‐cycle of a tropical cyclone (TC). The GCRM successfully simulated the genesis and rapid intensification of Typhoon Durian (2006). Sensitivity experiments demonstrated that the genesis of Durian was triggered by a distinct westward‐propagating tropical wave. Furthermore, the subsequent rapid intensification of Durian was affected by an eastward‐propagating tropical wave. These results not only support the tropical cyclogenesis process proposed by observational studies, but also indicates that life‐cycles of TCs may be continually influenced by several tropical waves with different origins. Thus, a GCRM is advantageous in simulating a TC genesis and the subsequent life‐cycle, in cases where a TC is influenced by external disturbances moving long distances.
Temporal Trends in Generic and Brand Prices of Antiretroviral Medicines Procured with Donor Funds in Developing Countries
Authors: Waning Brenda , Kaplan Warren , Fox Matthew P , Boyd-Boffa Mariah , King Alexis C , Lawrence Danielle A , Soucy Lyne , Mahajan Sapna , Leufkens Hubert G , Gokhale Manjusha
Published: April 2010

Pharmaceutical markets in low resource settings are imperfect. Suppliers provide information on ‘suggested’ medicine prices, but actual purchase prices vary substantially across purchasers and these prices paid are typically unavailable. Public procurement databases now, however, provide timely market intelligence on prices for antiretroviral (ARV) medicines purchased with donor funds, allowing for careful examination of market trends. We used data posted by the World Health Organization to create a longitudinal database of 15 111 ARV procurements from 2002–2008. We noted dramatic price reductions for ARVs over this 6-year time period. Most generic ARVs were cheaper than branded counterparts, with the exception of protease inhibitors (PIs) in which some generic versions were more expensive than branded counterparts. Less price variation was noted for ARVs in low-income countries than middle-income countries where price variations of threefold or greater were noted in five of 28 (18 per cent) generic and 15 of 25 (60 per cent) brand dosage forms. In order to meet global goals of universal access to HIV/AIDS treatment, further price reductions are needed for abacavir, tenofovir and PIs. New approaches are needed to create incentives for generic manufacturers of these ARVs to enter the market and create price competition with these medicines.
Creating Sustainable European Health-Care Systems through the Increased Use of Generic Medicines: A Policy Analysis
Authors: Simoens Steven
Published: April 2010

The increased use of generic medicines can play a role in creating sustainable health-care systems in Europe. However, differences in generic medicine market shares between countries indicate that Europe is not maximizing its full potential with respect to generic medicines. This article aims to identify the conditions for a successful generic medicines policy by reviewing the policy tools that European countries have used to strengthen their generic medicines market. A search of the international peer-reviewed literature and relevant documents was carried out. The findings indicated that a country needs to introduce a key policy driver, that is a balanced policy based on proven methods, in order to encourage the use of generic medicines. However, the type of driver may vary between countries and needs to be adapted to local demographic, cultural, economic and institutional constraints. Additional supply-side and demand-side measures are likely to be needed for the key policy driver to be effective. Furthermore, a country needs to implement a long-term generic medicines policy which ensures that supply-side and demand-side measures reinforce each other and are part of a coherent policy.
High integrity metal/organic device interfaces via low temperature buffer layer assisted metal atom nucleation
Authors: Maitani Masato M. , Allara David L. , Ohlberg Douglas A. A. , Li Zhiyong , Williams R. Stanley , Stewart Duncan R.
Published: April 2010

The ability to generate sharp, high integrity metal/organic film interfaces is demonstrated by the use of a buffer layer of Xe condensate during the vapor deposition of Au atoms onto a CH3(CH2)11S-/Au{111} self-assembled monolayer (SAM), a normally highly permeable film for the metal atoms in spite of the high degree of molecular organization and ordering. Atomic force microscopy conductance and topographic imaging reveals the intervening buffer can result in complete elimination of typical electrically shorting metal filaments and metal atom penetration into the SAM over large area contacts. This deposition method provides a highly reproducible way to form high integrity top metal contacts for demanding applications such as molecular electronic devices.
Modeling extreme ultraviolet suppression of electrostatic analyzers
Authors: Gershman Daniel J. , Zurbuchen Thomas H.
Published: April 2010

In addition to analyzing energy-per-charge ratios of incident ions, electrostatic analyzers (ESAs) for spaceborne time-of-flight mass spectrometers must also protect detectors from extreme ultraviolet (EUV) photons from the Sun. The required suppression rate often exceeds 1:107 and is generally established in tests upon instrument design and integration. This paper describes a novel technique to model the EUV suppression of ESAs using photon ray tracing integrated into SIMION, the most commonly used ion optics design software for such instruments. The paper compares simulation results with measurements taken from the ESA of the Mass instrument flying onboard the Wind spacecraft. This novel technique enables an active inclusion of EUV suppression requirements in the ESA design process. Furthermore, the simulation results also motivate design rules for such instruments.
Realization of submicrometer structures by a confocal system on azopolymer films containing photoluminescent chromophores
Authors: Ambrosio A. , Camposeo A. , Carella A. , Borbone F. , Pisignano D. , Roviello A. , Maddalena P.
Published: April 2010

The mass migration phenomenon occurring on the free surface of azobenzene-containing polymers illuminated by light of appropriate wavelength is employed to pattern polymeric films constituted by an azopolymer doped with photoluminescent chromophore. Different topographical features are obtained by adjusting the laser scanning parameters, in particular the laser polarization direction. A detailed microscopic analysis of the patterned samples, based on atomic force microscopy and spectral confocal imaging, evidences the photobleaching of the emitting chromophore in the exposed regions, whereas the emitting features of the chromophore are preserved by the mass migration process. Our results are important for the design of nanostructured light emitting photonic devices based on azopolymers.
Magnetothermal instability in weakly magnetized plasmas with anisotropic resistivity and viscosity
Authors: Ren Haijun , Wu Zhengwei , Cao Jintao , Chu Paul K. , Li Ding
Published: April 2010

The linear buoyancy instability in magnetized plasmas is investigated in the presence of anisotropic resistivity and viscosity. The magnetic field is assumed to be horizontal and the background heat flux is not taken into account. That is, the magnetic field lines are initially isothermal. The heat is assumed to be primarily transported along the magnetic force lines. The general dispersion relationship of the thermal convective instability in the presence of anisotropic resistive and viscous dissipative effects is derived and discussed in detail in weak magnetic field limit. Our results show that the perturbation is damped when the temperature decreases in the direction of gravity due to the resistive or viscous effect while this situation results in pure oscillation modes in the ideal MHD case. The resistive and viscous effects are shown to reduce the growth rate of the magnetothermal instability when the temperature increases in the direction of gravity.
High temperature magnetic properties of cobalt ferrite nanoparticles
Authors: Franco A. , e Silva F. C.
Published: April 2010

Cobalt ferrite materials have a wide variety of technological applications that requires temperatures higher than room temperature. Thus the magnetic properties such as saturation magnetization, Ms remanent magnetization, Mr, coercivitty, Hc, and Curie temperature, Tc, of nanoparticles of CoFe2O4 were studied in a broad range of temperature varying from room temperature to 870 K. It was observed that, for temperatures 100 K above room temperature, these magnetic properties are still the same as at room temperature. The results were discussed in terms of interparticle interactions induced by the thermal fluctuations, cation distribution, and other imperfections that exert fields on Co2+ ions could increase with temperature.
Superfine open pulled straws vitrification of porcine blastocysts does not require pretreatment with cytochalasin B and/or centrifugation
Authors: Cuello C. , Sanchez-Osorio J. , Almiñana C. , Gil M. A. , Parrilla I. , Roca J. , Vazquez J. M. , Martinez E. A. , Rodriguez-Martinez H.
Published: April 2010

The present study investigated the in vitro development of and cytoskeletal disruption suffered by in vivo-derived porcine blastocysts subjected to superfine open pulled straws (SOPS) vitrification. Blastocysts were either untreated prior to SOPS vitrification or were subjected to one of the following three pretreatment protocols: (1) centrifugation (12 min, 13 000g); (2) 25 min equilibration with 7.5 μg mL–1 cytochalasin B; or (3) equilibration with cytochalasin B followed by centrifugation. After 24 h culture, fresh (n = 32) and vitrified–warmed (n = 188) blastocysts were evaluated by stereomicroscopy, with survival and hatching rates recorded. Some blastocysts were stained with 4′,6′-diamidino-2-phenylindole and processed for cytoskeletal evaluation. Three cytoskeletal patterns were identified: Grade I, intact cytoskeleton; Grade II, gross maintenance of integrity, but with some clumps of actin within the cytoplasm; and Grade III, a highly disrupted cytoskeleton. There were no differences in the survival, hatching and cell death rats, total cell number or cytoskeletal integrity between the different vitrification groups. Cell death was greater for vitrified blastocysts than for fresh blastocysts (3.6 ± 0.4% v. 0.4 ± 0.7%, respectively; P < 0.05) and the percentage of blastocysts with a Grade I cytoskeletal pattern was lower for vitrified compared with fresh blastocysts (60.8% v. 92%, respectively; P < 0.05). The vitrified–warmed blastocysts that hatched during culture exhibited a Grade I cytoskeletal pattern. In conclusion, successful SOPS vitrification of porcine blastocysts does not require pretreatment with cytochalasin B and/or centrifugation.
Production and binding of endothelin-2 (EDN2) in the rat ovary: endothelin receptor subtype A (EDNRA)-mediated contraction
Authors: Bridges Phillip J. , Jo Misung , Al Alem Linah , Na Giyoun , Su Wen , Gong Ming C. , Jeoung Myoungkun , Ko CheMyong
Published: April 2010

Endothelin-2 (EDN2)-mediated contraction has been proposed as a final mechanical signal facilitating ovulation. The objectives herein were to determine (1) whether ovarian endothelins were increased before ovulation; (2) whether a specific endothelin-converting enzyme (ECE) was mediating their production; (3) which receptor was facilitating ovarian contraction; and (4) whether receptor-specific antagonism affected ovulation. Follicular development was induced in immature rats with 10 IU pregnant mare serum gonadotrophin (PMSG) and the ovulatory cascade was initiated 48 h later with 10 IU human chorionic gonadotrophin (hCG). In Experiment 1, an immunoassay revealed that the ovarian concentration of endothelin peptide was increased 7-fold 12 h after hCG when compared with 48 h after PMSG (P < 0.05). In Experiment 2, real-time PCR indicated that mRNA for Ece1, but not Ece2, was increased in granulosa cells collected 12 h after hCG when compared with those collected before the ovulatory stimulus (P < 0.05). In Experiment 3, isometric tension analysis revealed that the contractile effect of EDN2 was mediated by endothelin receptor A (EDNRA), not B (EDNRB). In Experiment 4, no effect was observed on the rate of ovulation when rats were treated with an antagonist specific to EDNRA (BQ123) or EDNRB (BQ788), or when mice were treated with BQ123, BQ788 or BQ123 + BQ788. In conclusion, endothelin peptide is produced before ovulation and the contractile action of EDN2 within the ovary is facilitated via EDNRA. In addition, findings of this study indicate synergistic interactions among contractile factors affect ovulatory outcome, while the role of EDNRB alone in the process of ovulation requires further investigation.
Incidence, causes and consequences of pregnancy failure in viviparous lizards: implications for research and conservation settings
Authors: Hare Kelly M. , Cree Alison
Published: April 2010

Research on the causes of pregnancy failure in vertebrates has historically been mammal-focussed. However, live-birth (viviparity) has evolved multiple times, and is present in all other vertebrate taxa except Aves and Agnatha. Viviparous lizards (O. Squamata, excluding snakes and amphisbaenians) provide a valuable experimental group when studying major evolutionary events and some are also species of high conservation value. Consequently, both researchers and herpetoculturists often require high reproductive output from captive-held lizards. We reviewed the literature to determine potential or known causes of pregnancy failure for captive lizards. Pregnancy success across species averages ~86%, but varies extensively and does not appear to be related to embryonic stage when brought into captivity or level of placentation. Causes of pregnancy failure also vary among species, but correct thermal environments are vital to success, and providing adequate nutrition before vitellogenesis increases the number of viable offspring. A coordinated sequence of hormonal changes involving both pro-pregnancy and pro-labour factors is important for successful pregnancies, although uncertainty remains around the maternal concentrations of corticosterone that allow successful development. Several research areas commonly studied in mammals have yet to be explored or fully addressed in pregnant lizards, including impacts of toxins, parasites, UV light and nutritional quality. As viviparity has evolved over 100 times in lizards, and many different levels of placentation exist, pregnant lizards provide valuable models for studies in ecology and evolution and offer a useful comparison for studies on other viviparous vertebrates.
Improving the effect of incubation and oxidative stress on thawed spermatozoa from red deer by using different antioxidant treatments
Authors: Domínguez-Rebolledo Álvaro E. , Fernández-Santos María R. , Bisbal Alfonso , Ros-Santaella José Luis , Ramón Manuel , Carmona Manuel , Martínez-Pastor Felipe , Garde J. Julián
Published: April 2010

Antioxidants could improve sperm media, extending the viability of spermatozoa and protecting their DNA. The protective ability of lipoic acid, melatonin, Trolox and crocin was tested on red deer spermatozoa incubated at 37°C. Cryopreserved spermatozoa were thawed and incubated with 1 mM or 0.1 mM of each antioxidant, with or without oxidative stress (100 μM Fe2+). Motility (CASA), viability, mitochondrial membrane potential and acrosomal status were assessed. Lipoperoxidation (malondialdehyde production), intracellular reactive oxygen species (ROS) and DNA status (TUNEL) were checked at 4 h. Incubation alone increased ROS and decreased motility. Oxidative stress intensified these effects, increasing lipoperoxidation and DNA damage. Lipoic acid had little protective effect, whereas 1 mM melatonin showed limited protection. Trolox lowered ROS and lipoperoxidation both in oxidised and non-oxidised samples. In oxidised samples, Trolox prevented DNA and acrosomal damage, and ameliorated motility. Crocin at 1 mM showed similar results to Trolox, but noticeably stimulated motility and had no effect on lipoperoxidation. In a second experiment, a broader range of crocin and melatonin concentrations were tested, confirming the effects of crocin (positive effects noticeable at 0.5–0.75 mM), but showing an increase in lipoperoxidation at 2 mM. Melatonin was increasingly effective at 2.5 and 5 mM (ROS, lipoperoxidation and DNA status). Crocin seems a promising new antioxidant, but its particular effects on sperm physiology must be further studied, especially the consequences of motility stimulation and confirming its effect on lipoperoxidation. Melatonin might be useful at relatively high concentrations, compared to Trolox.
An insight into testis and gubernaculum dynamics of INSL3 - RXFP2 signalling during testicular descent in the dog
Authors: Arrighi S. , Bosi G. , Groppetti D. , Aralla M. , Cremonesi F.
Published: April 2010

Insulin-like 3 (INSL3) plays a prominent role in male development and is supposed to induce the growth of the gubernaculum testis (g.t.), thus being directly involved in testicular descent in humans and rodents. This happens through activation of the RXFP2 receptor (GREAT or LGR8). The INSL3–RXFP2 complex is reputed to play an additional paracrine role in the testis, possibly acting as part of an autocrine feedback loop. The present work provides evidence of the immunolocalisation of INSL3 in the Leydig cells of canine fetuses and of the expression of RXFP2 receptor in different tissues of the g.t. of the same specimens. RXFP2 was localised at the cell membrane of g.t. muscle and connective cells, as well as in the epithelial cells of the developing excurrent ducts. Notably, RXFP2 immunoreactivity of the g.t. was limited to fetuses at ~35–45 days of gestation, which is also the fetal period when the endocrine compartment of the dog testis is active endocrinologically, as confirmed by the anti-P450c17 and anti-INSL3 immunoreactivities of the fetal Leydig cells, and by anti-Müllerian hormone immunoreactivity of the Sertoli cells. The same immunoreactivities were also evaluated in the testes of cryptorchid dogs of different ages. RXFP2 immunoreactivity was absent from genital tracts of cryptorchid testes and g.t. remnants.
Maturation, fertilisation and culture of bovine oocytes and embryos in an individually identifiable manner: a tool for studying oocyte developmental competence
Authors: Matoba Satoko , Fair Trudee , Lonergan Patrick
Published: April 2010

The ability to successfully culture oocytes and embryos individually would facilitate the study of the relationship between follicle parameters and oocyte developmental competence, in order to identify markers of competent oocytes, as well as the ability to use small numbers of oocytes from an individual donor such as when ovum pick-up is carried out. Using a total of 3118 oocytes, the aim of the present study was to develop a system capable of supporting the development of immature bovine oocytes to the blastocyst stage in an individually identifiable manner. Initially, post-fertilisation embryo culture in the Well-of-the-Well (WOW) system, on the cell adhesive Cell-Tak or in polyester mesh was tested and shown to result in similar development to embryos cultured in standard group culture. The results demonstrate that it is possible to culture bovine oocytes to the blastocyst stage in an individually identifiable manner in all three culture systems with comparable success rates. This permits the localisation and identification of individual embryos throughout preimplantation development in vitro while retaining the developmental benefits of group culture. In terms of ease of preparation and use, culture in isolation within the strands of a polyester mesh is preferable.
The NADPH Oxidase Subunit NOX4 Is a New Target Gene of the Hypoxia-inducible Factor-1
Authors: Diebold Isabel , Petry Andreas , Hess John , Görlach Agnes
Published: April 2010

NADPH oxidases are important sources of reactive oxygen species (ROS), possibly contributing to various disorders associated with enhanced proliferation. NOX4 appears to be involved in vascular signaling and may contribute to the response to hypoxia. However, the exact mechanisms controlling NOX4 levels under hypoxia are not resolved. We found that hypoxia rapidly enhanced NOX4 mRNA and protein levels in pulmonary artery smooth-muscle cells (PASMCs) as well as in pulmonary vessels from mice exposed to hypoxia. This response was dependent on the hypoxia-inducible transcription factor HIF-1α because overexpression of HIF-1α increased NOX4 expression, whereas HIF-1α depletion prevented this response. Mutation of a putative hypoxia-responsive element in the NOX4 promoter abolished hypoxic and HIF-1α–induced activation of the NOX4 promoter. Chromatin immunoprecipitation confirmed HIF-1α binding to the NOX4 gene. Induction of NOX4 by HIF-1α contributed to maintain ROS levels after hypoxia and hypoxia-induced proliferation of PASMCs. These findings show that NOX4 is a new target gene of HIF-1α involved in the response to hypoxia. Together with our previous findings that NOX4 mediates HIF-1α induction under normoxia, these data suggest an important role of the signaling axis between NOX4 and HIF-1α in various cardiovascular disorders under hypoxic and also nonhypoxic conditions.
Limited dispersal in mobile hunter–gatherer Baka Pygmies
Authors: Verdu Paul , Leblois Raphaël , Froment Alain , Théry Sylvain , Bahuchet Serge , Rousset François , Heyer Evelyne , Vitalis Renaud
Published: April 2010

Hunter–gatherer Pygmies from Central Africa are described as being extremely mobile. Using neutral genetic markers and population genetics theory, we explored the dispersal behaviour of the Baka Pygmies from Cameroon, one of the largest Pygmy populations in Central Africa. We found a strong correlation between genetic and geographical distances: a pattern of isolation by distance arising from limited parent–offspring dispersal. Our study suggests that mobile hunter–gatherers do not necessarily disperse over wide geographical areas.
Diversity dynamics of Miocene mammals in relation to the history of tectonism and climate
Authors: Finarelli John A. , Badgley Catherine
Published: April 2010

Continental biodiversity gradients result not only from ecological processes, but also from evolutionary and geohistorical processes involving biotic turnover in landscape and climatic history over millions of years. Here, we investigate the evolutionary and historical contributions to the gradient of increasing species richness with topographic complexity. We analysed a dataset of 418 fossil rodent species from western North America spanning 25 to 5 Ma. We compared diversification histories between tectonically active (Intermontane West) and quiescent (Great Plains) regions. Although diversification histories differed between the two regions, species richness, origination rate and extinction rate per million years were not systematically different over the 20 Myr interval. In the tectonically active region, the greatest increase in originations coincided with a Middle Miocene episode of intensified tectonic activity and global warming. During subsequent global cooling, species richness declined in the montane region and increased on the Great Plains. These results suggest that interactions between tectonic activity and climate change stimulate diversification in mammals. The elevational diversity gradient characteristic of modern mammalian faunas was not a persistent feature over geologic time. Rather, the Miocene rodent record suggests that the elevational diversity gradient is a transient feature arising during particular episodes of Earth's history.
Epstein–Barr virus strains defined by the latent membrane protein 1 sequence characterize Thai ethnic groups
Authors: Saechan Vannarat , Settheetham-Ishida Wannapa , Kimura Ryosuke , Tiwawech Danai , Mitarnun Winyou , Ishida Takafumi
Published: April 2010

Epstein–Barr virus (EBV) is ubiquitous in the human population and seroepidemiological studies have revealed that more than 90 % of adults are infected with the virus in Thailand. It has been suggested that latent membrane protein 1 (LMP1) variants may differ in their tumorigenicity and geographical localization. The distribution of LMP1 variants of EBV in the Thai population was studied. A total of 259 LMP1 sequences from ten Thai ethnic groups (Lahu, Lisu, Shan, Red Karen, White Karen, Hmong, Akha, Mlabri, Moken and Urak Lawoi) were studied using direct PCR sequencing. Nucleotide sequences corresponding to the C terminus of the LMP1, including previously published sequences from central and southern Thais, were used in the phylogenetic analysis. Five strains – the B95-8 prototype, China 1, China 2, Mediterranean (Med) and SEA 2 – were identified in ethnic groups in Thailand. The major strain and the distribution pattern differed by group and location. When the ethnic groups were classified by linguistic group, the prevalence of the SEA 2 strain was significantly different between Austro-Thais and other linguistic groups (P=0.0001), whereas, among Tibeto-Burman linguistic groups, the prevalence of the Med strain was different between matrilocal and patrilocal groups (P=0.0245). The distribution of LMP1 strains in ethnic minorities in Thailand is associated with ethnogeographical factors and the social/marriage system. This study thus provides evidence for the importance of interactions between populations in virus diversity.
Mouse sarcoma L1 cell line holoclones have a stemness signature
Authors: Miloszewska J. , Gos M. , Przybyszewska M. , Trembacz H. , Koronkiewicz M. , Janik P.
Published: April 2010

Accumulating data suggest that cancers contain a fraction of cells called cancer stem cells (CSCs), that may be responsible for upkeep and relapses of disease. In experimental settings, CSCs are regarded as most effective at tumour initiation in in vivo assays. Since the first isolation of cancer stem cells from acute myeloid leukaemia in 1994, cancer stem cells have been identified in human solid tumours and they have also been found in the established cell lines, based on ability of CSCs to form in vitro colonies of a specific morphology, called holoclones. Our study examined the ability of a mouse sarcoma cell line, derived from a lung metastasis of a BALB/c mouse and established as a stably growing line (L1), to produce holoclones in vitro. We aimed to verify a stemness signature of the holoclone cells. The L1 cell line was found to form holoclone colonies in vitro, which were shown to contain a percentage of CSC‐like cells. A fraction of the L1 cells was able to repopulate the original cell line, and presented an increased clonogenic and metastatic potential (18th passage). In addition, MTT assay and flow cytometry of the side population fraction revealed that these cells were more resistant to chemotherapeutic drugs than the original cell line, and over‐expressed the anti‐apoptotic genes, GRP78 and GADD153. We conclude that mouse L1 sarcoma cell line contains CSC‐like cells.
Epidermal kinetic alterations required to generate the psoriatic phenotype: a reappraisal
Authors: Simonart T. , Heenen M. , Lejeune O.
Published: April 2010

Objectives:  Although there have been major advances in understanding immunopathogenesis of psoriasis, the basic processes causing psoriatic morphology remain to be identified.

Materials and methods:  Our group has designed a systematic review of studies (1962–2009) on keratinocyte kinetics in psoriasis. We obtained data from MEDLINE, PubMed, Current Contents, reference lists and specialist textbooks. A general equation for evolution of the differentiated epidermis has been analysed. Necessary conditions for observed qualitative change in homeostasis between normal skin and established psoriatic lesions were determined.

Results and discussion:  Increase in the number of cell divisions (or imbalance in symmetric division rates of committed progenitor cells) and/or decrease in physiological apoptosis in the germinative compartment, together with feedback loops that limit thickening of the skin, are required to generate psoriatic morphology, that is, to increase the absolute size but decrease relative size of the differentiated cell compartment with respect to the germinative compartment.
What's in a service?
Authors: Axford Nick
Published: April 2010

The measurement of ‘service’ in children's services is highly varied. We do not know in a meaningful sense what services children and families get. This paper sets out why it is important to measure services well. It outlines the dimensions of ‘service’, how they have been measured in research, policy and practice contexts, and the strengths and weaknesses of these approaches. It then explores implications for the field and identifies potential applications of a more nuanced and consistent approach to measuring services.