bluuebunny/crossref_metadata_2025_split huggingface dataset:
The polychaete worm Nereis diversicolor increases mercury lability and methylation in intertidal mudflats
Authors: Sizmur Tom , Canário João , Edmonds Samuel , Godfrey Adam , O'Driscoll Nelson J. 
Published: April 2013

Abstract

The polychaete worm Nereis diversicolor engineers its environment by creating oxygenated burrows in anoxic intertidal sediments. The authors carried out a laboratory microcosm experiment to test the impact of polychaete burrowing and feeding activity on the lability and methylation of mercury in sediments from the Bay of Fundy, Canada. The concentration of labile inorganic mercury and methylmercury in burrow walls was elevated compared to worm-free sediments. Mucus secretions and organic detritus in worm burrows increased labile mercury concentrations. Worms decreased sulfide concentrations, which increased Hg bioavailability to sulfate-reducing bacteria and increased methylmercury concentrations in burrow linings. Because the walls of polychaete burrows have a greater interaction with organisms, and the overlying water, the concentrations of mercury and methylmercury they contain is more toxicologically relevant to the base of a coastal food web than bulk samples. The authors recommend that researchers examining Hg in marine environments account for sediment dwelling invertebrate activity to more fully assess mercury bioavailability. Environ Toxicol Chem 2013;32:1888–1895. © 2013 SETAC
Water Evolution in Direct Methanol Fuel Cell Cathodes Studied by Synchrotron X‐Ray Radiography
Authors: Schröder A. , Wippermann K. , Arlt T. , Sanders T. , Baumhöfer T. , Markötter H. , Mergel J. , Lehnert W. , Stolten D. , Manke I. , Banhart J. 
Published: April 2013

AbstractWater evolution, distribution, and removal in the cathodes of a running direct methanol fuel cell were investigated by means of synchrotron X‐ray radiography. Radiographs with a spatial resolution of around 5 μm were taken every 5 s. Special cell designs allowing for through‐plane and in‐plane viewing were developed, featuring two mirror‐symmetrical flow field structures consisting of one channel with the through‐plane design. Evolution and discharge of water droplets and the occurrence of water accumulations in selected regions of the channels were investigated. These measurements revealed a nonuniform distribution of water in the channels. Both irregular and periodic formation of water droplets were observed. In‐plane measurements revealed, that the droplets evolve between adjacent carbon fiber bundles of the gas diffusion layer. The water distribution within the channel cross‐section fits very well to the pressure difference between cathode channel inlet and outlet. The quick discharge of water droplets causes sudden decreases of the pressure difference up to 4.5 mbar.
Integration of microfluidic chip with biomimetic hydrogel for 3D controlling and monitoring of cell alignment and migration
Authors: Lee Kwang Ho , Lee Ki Hwa , Lee Jeonghoon , Choi Hyuk , Lee Donghee , Park Yongdoo , Lee Sang‐Hoon 
Published: April 2013

AbstractA biomimetic hydrogel was integrated into microfluidic chips to monitor glioma cell alignment and migration. The extracellular matrix‐based biomimetic hydrogel was remodeled by matrix metalloprotease (MMP) secreted by glioma cells and the hydrogel could thus be used to assess cellular behavior. Both static and dynamic cell growth conditions (flow rate of 0.1 mL/h) were used. Cell culture medium with and without vascular endothelial growth factor (VEGF), insensitive VEGF and tissue inhibitor of metalloproteinases (TIMP) were employed to monitor cell behavior. A concentration gradient formed in the hydrogel resulted in differences in cell behavior. Glioma cell viability in the microchannel was 75–85%. Cells in the VEGF‐loaded microchannels spread extensively, degrading the MMP‐sensitive hydrogel, and achieved cell sizes almost fivefold larger than seen in the control medium. Our integrated system can be used as a model for the study of cellular behavior in a controlled microenvironment generated by fluidic conditions in a biomimetic matrix. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1164–1172, 2014.
Suppression of autophagy by FIP200 deletion leads to osteopenia in mice through the inhibition of osteoblast terminal differentiation
Authors: Liu Fei , Fang Fang , Yuan Hebao , Yang Dongye , Chen Yongqiang , Williams Linford , Goldstein Steven A , Krebsbach Paul H , Guan Jun-Lin 
Published: April 2013

ABSTRACT

Autophagy is a conserved lysosomal degradation process that has important roles in both normal human physiology and disease. However, the function of autophagy in bone homeostasis is not well understood. Here, we report that autophagy is activated during osteoblast differentiation. Ablation of focal adhesion kinase family interacting protein of 200 kD (FIP200), an essential component of mammalian autophagy, led to multiple autophagic defects in osteoblasts including aberrantly increased p62 expression, deficient LC3-II conversion, defective autophagy flux, absence of GFP-LC3 puncta in FIP200-null osteoblasts expressing transgenic GFP-LC3, and absence of autophagosome-like structures by electron microscope examination. Osteoblast-specific deletion of FIP200 led to osteopenia in mice. Histomorphometric analysis revealed that the osteopenia was the result of cell-autonomous effects of FIP200 deletion on osteoblasts. FIP200 deletion led to defective osteoblast terminal differentiation in both primary bone marrow and calvarial osteoblasts in vitro. Interestingly, both proliferation and differentiation were not adversely affected by FIP200 deletion in early cultures. However, FIP200 deletion led to defective osteoblast nodule formation after initial proliferation and differentiation. Furthermore, treatment with autophagy inhibitors recapitulated the effects of FIP200 deletion on osteoblast differentiation. Taken together, these data identify FIP200 as an important regulator of bone development and reveal a novel role of autophagy in osteoblast function through its positive role in supporting osteoblast nodule formation and differentiation. © 2013 American Society for Bone and Mineral Research.
Switching between seismic and seismo‐acoustic harmonic tremor simulated in the laboratory: Insights into the role of open degassing channels and magma viscosity
Authors: Lyons John J. , Ichihara Mie , Kurokawa Aika , Lees Jonathan M. 
Published: April 2013

AbstractSwitching between seismic‐only harmonic tremor (SHT) and seismo‐acoustic harmonic tremor (SAHT) has been reported at few volcanoes worldwide, but its occurrence may indicate important changes in shallow conduit conditions. Switching was simulated in a laboratory experiment in which harmonic signals were produced with a flow‐driven valve and compressed air. The harmonic signals were passed through a tank of shear‐thinning viscoelastic fluid, and the resulting signals were recorded. At high fluid stiffness, a stable, open conduit was produced, and the harmonic signals generated within the experimental apparatus were efficiently transmitted into the atmosphere. At lower fluid stiffness, bubbling dominated the activity, stable pathways were not generated in the fluid, and HT was not recorded in the atmosphere. These results are compared to observations of switching at Fuego volcano, Guatemala. We conclude that at intermediate magma viscosities, the development of stable degassing pathways open to the atmosphere will allow HT generated in the conduit to be transmitted into the atmosphere. Further, subtle changes in magma properties and supply rate may control whether SHT or SAHT is recorded, providing information about the state of the shallow conduit and vent at active volcanoes.
Land water contribution to sea level from GRACE and Jason‐1measurements
Authors: Jensen L. , Rietbroek R. , Kusche J. 
Published: April 2013

AbstractWe investigate the effect of water storage changes in the world's major hydrological catchment basins on global and regional sea level change at seasonal and long‐term time scales. In a joint inversion using GRACE and Jason‐1 data, we estimate the time‐dependent sea level contributions of 124 spatial patterns (“fingerprints”) including glacier and ice sheet melting, thermal expansion, changes in the terrestrial hydrological cycle, and glacial isostatic adjustment. Particularly, for hydrological storage changes, we derive fingerprints of the 33 world's largest catchment basins, assuming mass distributions derived from the leading EOFs of total water storage in the WaterGap Global Hydrological Model (WGHM). From our inversion, we estimate a contribution of terrestrial hydrological cycle changes to global mean sea level of − 0.20 ± 0.04 mm/yr with an annual amplitude of 6.6 ± 0.5 mm for August 2002 to July 2009. Using only GRACE data in the inversion and comparing to hydrological changes derived from GRACE data directly using a basin averaging method shows a good agreement on a global scale, but considerable differences are found for individual catchment basins (up to 180%). Hydrological storage change estimates in 33 basins from the GRACE/Jason fingerprint inversion indicate a trend 46% smaller and an annual amplitude 43% bigger compared to WGHM‐derived storage changes. Mapping the hydrological trends to regional sea level reveals the strongest sea level rise along the coastlines of South America (max 0.9 mm/yr) and West Africa (max 0.4 mm/yr), whereas around Alaska and Australia, we find the hydrological component of sea level falling (min −2.0 mm/yr and −0.9 mm/yr).
Simulating the formation and fate of dense water in a midlatitude marginal sea during normal and warm winter conditions
Authors: Querin Stefano , Cossarini Gianpiero , Solidoro Cosimo 
Published: April 2013

AbstractDense shelf water production and the deep convection process in the Adriatic Sea are investigated, considering two case studies: the first is representative of the present climatic situation, whereas the second may be expected in a scenario characterized by mild winter conditions over the basin. Dense water production and spreading are studied using a high‐resolution implementation of the Massachusetts Institute of Technology general circulation model that is initialized and forced with realistic conditions. This paper provides qualitative and quantitative information on mass transport, dense water pathways, thermohaline structures, and the mixing properties of the basin. In the northern Adriatic shelf, seawater temperature is the key element for winter dense water production because it contributes more relevantly than salinity in determining density. In the southern Adriatic Sea, a small amount of dense water that cascades directly into the pit can be formed on the narrow western shelf only during cold winter conditions. Moreover, open ocean deepwater formation occurs in the middle of the southern basin. In late winter and spring, although only when winter conditions have been sufficiently cold, northern Adriatic dense shelf water forms a subsurface stream of which the densest part rapidly sinks in the southern pit along the shelf break, whereas its lighter part flows southward and reaches the Otranto Strait. The frequent occurrence of mild winter conditions could lead to lower dense water production, with a reduced dense water flow from the Adriatic Sea to the Ionian Sea and a potential great impact on the eastern Mediterranean thermohaline circulation.
An assemblage of lava flow features on Mercury
Authors: Byrne Paul K. , Klimczak Christian , Williams David A. , Hurwitz Debra M. , Solomon Sean C. , Head James W. , Preusker Frank , Oberst Jürgen 
Published: April 2013

AbstractIn contrast to other terrestrial planets, Mercury does not possess a great variety of volcanic features, its history of volcanism instead largely manifest by expansive smooth plains. However, a set of landforms at high northern latitudes on Mercury resembles surface flow features documented on Earth, the Moon, Mars, and Venus. The most striking of such landforms are broad channels that host streamlined islands and that cut through the surrounding intercrater plains. Together with narrower, more sinuous channels, coalesced depressions, evidence for local flooding of intercrater plains by lavas, and a first‐order analysis of lava flow rates, the broad channels define an assemblage of flow features formed by the overland flow of, and erosion by, voluminous, high‐temperature, low‐viscosity lavas. This interpretation is consistent with compositional data suggesting that substantial portions of Mercury's crust are composed of magnesian, iron‐poor lithologies. Moreover, the proximity of this partially flooded assemblage to extensive volcanic plains raises the possibility that the formation of these flow features may preface total inundation of an area by lavas emplaced in a flood mode and that they escaped complete burial only due to a waning magmatic supply. Finally, that these broad channels on Mercury are volcanic in nature yet resemble outflow channels on Mars, which are commonly attributed to catastrophic water floods, implies that aqueous activity is not a prerequisite for the formation of such distinctive landforms on any planetary body.
Ultrastructure of the spermatozoon of the digenean Plagiorchis elegans (Rudolphi, 1802) (Plagiorchioidea, Plagiorchiidae)
Authors: Ndiaye Papa Ibnou , Quilichini Yann , Tkach Vasyl V. , Greiman Stephen E. , Bâ Cheikh Tidiane , Marchand Bernard 
Published: April 2013

ABSTRACTThe ultrastructure of the mature spermatozoon of the type genus of the Plagiorchiidae Plagiorchis elegans (Rudolphi, 1802), a parasite of the Golden hamster, Mesocricetus auratus is described. This study is the first ultrastructural study of the spermatozoon of a Plagiorchis, the second of a plagiorchiid species and only the third in the Plagiorchioidea. Previously data on spermatozoon ultrastructure existed only for the plagiorchiid Enodiotrema reductum and the omphalometrid Rubenstrema exasperatum. The mature spermatozoon of P. elegans exhibited the general pattern described in most digenean species, namely two axonemes of the 9 + “1” Trepaxonemata pattern, nucleus, mitochondria, external ornamentation of the plasma membrane, spine‐like bodies, and glycogen granules. However, the rather typical expansion of the plasma membrane is not found in P. elegans. Another peculiarity of the spermatozoon of P. elegans is the presence of a structure called thin cytoplasm termination. Spermatozoon ultrastructure of P. elegans is compared with that of E. reductum and R. exasperatum. Spermatozoon of P. elegans conforms to the general pattern described in E. reductum. Thus, this study further expands our knowledge on the spermatozoon ultrastructure among the members of the Plagiorchioidea, one of the most phylogenetically derived groups of the digenea. J. Morphol. 274:965–972, 2013. © 2013 Wiley Periodicals, Inc.
Primary homologies of the circumorbital bones of snakes
Authors: Palci Alessandro , Caldwell Michael W. 
Published: April 2013

ABSTRACTSome snakes have two circumorbital ossifications that in the current literature are usually referred to as the postorbital and supraorbital. We review the arguments that have been proposed to justify this interpretation and provide counter‐arguments that reject those conjectures of primary homology based on the observation of 32 species of lizards and 81 species of snakes (both extant and fossil). We present similarity arguments, both topological and structural, for reinterpretation of the primary homologies of the dorsal and posterior orbital ossifications of snakes. Applying the test of similarity, we conclude that the posterior orbital ossification of snakes is topologically consistent as the homolog of the lacertilian jugal, and that the dorsal orbital ossification present in some snakes (e.g., pythons, Loxocemus, and Calabaria) is the homolog of the lacertilian postfrontal. We therefore propose that the terms postorbital and supraorbital should be abandoned as reference language for the circumorbital bones of snakes, and be replaced with the terms jugal and postfrontal, respectively. The primary homology claim for the snake “postorbital” fails the test of similarity, while the term “supraorbital” is an unnecessary and inaccurate application of the concept of a neomorphic ossification, for an element that passes the test of similarity as a postfrontal. This reinterpretation of the circumorbital bones of snakes is bound to have important repercussions for future phylogenetic analyses and consequently for our understanding of the origin and evolution of snakes. J. Morphol. 274:973–986, 2013. © 2013 Wiley Periodicals, Inc.
Sleep loss and its effects on health of family caregivers of individuals with primary malignant brain tumors
Authors: Pawl Jean D. , Lee Shih‐Yu , Clark Patricia C. , Sherwood Paula R. 
Published: April 2013

AbstractSleep loss places caregivers at risk for poor health. Understanding correlates of sleep loss and relationships to health may enable improvement of health of caregivers of individuals with primary malignant brain tumors (PMBT). In this cross‐sectional, descriptive study of 133 caregivers, relationships were examined between sleep loss and physical, mental, emotional, and social health at time of patient diagnosis. Sleep loss was not related to physical health. Shorter total sleep time was associated with greater fatigue and social support. Sleep quality was positively associated with quality of life. Further study is needed of the role of sleep loss in the PMBT caregiving trajectory and its long‐term relationship with health outcomes. © 2013 Wiley Periodicals, Inc. Res Nurs Health 36: 386–399, 2013
Analysis of mexicanolide‐ and phragmalin‐type limonoids from Heynea trijuga using high‐performance liquid chromatography/electrospray tandem mass spectrometry
Authors: Yang Wei , Fang Dong‐Mei , He Hong‐Ping , Hao Xiao‐Jiang , Wu Zhi‐Jun , Zhang Guo‐Lin 
Published: April 2013

RATIONALELimonoids, a class of tetranortriterpenoids, exhibit various biological effects, including acting as potent antifeedants and insect growth‐regulators against various pests. The analysis of phragmalin‐ and mexicanolide‐type limonoids by collision‐induced dissociation tandem mass spectrometry (CID‐MS/MS) has not been reported.METHODSA high‐performance liquid chromatography/electrospray ionization (HPLC/ESI)‐MS/MS method was developed to investigate the fragmentation patterns of [M+NH4]+ ions for nine reference phragmalin‐ and mexicanolide‐type limonoids. The method was also used in the identification of limonoid compounds in botanic extracts of Heynea trijuga.RESULTSThe losses of side chains and the furan part were the major fragmentation patterns. However, there was variation in the relative abundances of product ions resulting from the same fragmentation pathways. A total of 89 phragmalin‐ and mexicanolide‐type limonoids in botanic extracts of Heynea trijuga were detected and 50 of these compounds were identified or tentatively characterized based on elemental constituents, fragmentation pathways, and the profile of the major product ions of reference compounds. In addition, the isomers could be tentatively distinguished.CONCLUSIONSAn HPLC/ESI‐MS/MS method was developed and could be used to simultaneously identify and screen phragmalin‐ and mexicanolide‐type limonoids in botanic extracts of Heynea trijuga. Copyright © 2013 John Wiley & Sons, Ltd.
A formal model for the creation and evaluation of steganographic solutions based in lexical–semantic substitutions: a case applied to Spanish
Authors: Muñoz Alfonso , Argüelles Irina , Sánchez Sergio 
Published: April 2013

ABSTRACTThis paper develops a formal model that allows research, development and evaluation from a functional point of view and attending to security needs, of the different parts in the process of creation of a linguistic steganographic system based on the lexical–semantic substitution of words by their synonyms. The advantages and drawbacks of this type of steganographic technique and the procedure to evaluate its usefulness in a given language are discussed. As a case study, the application of this model is carried out in the Spanish language based on the development of the tool Lexical Substitution in Spanish. This tool allows the testing of the substitution of words with their synonyms in Spanish. A hiding capacity of at least 0.1864 bits/word, resulting in 68.33% of the stegotexts created being invisible to the attacks analysed. This hiding capacity is useful enough to send Internet addresses, GPS coordinates, brief mobility messages, signatures on text, control messages, and so forth. All these uses are in fact very practical within the area of telecommunication networks. From the point of view of corporate network security, stegotexts make possible, for example, the control of a botnet without any knowledge on the part of the network administrators. Copyright © 2013 John Wiley & Sons, Ltd.
Zac1 Regulates Astroglial Differentiation of Neural Stem Cells Through Socs3
Authors: Schmidt-Edelkraut Udo , Hoffmann Anke , Daniel Guillaume , Spengler Dietmar 
Published: April 2013

Abstract
Cell-fate decisions and differentiation of embryonic and adult neural stem cells (NSC) are tightly controlled by lineage-restricted and temporal factors that interact with cell-intrinsic programs and extracellular signals through multiple regulatory loops. Imprinted genes are important players in neurodevelopment and mental health although their molecular and cellular functions remain poorly understood. Here, we show that the paternally expressed transcriptional regulator Zac1 (zinc finger protein regulating apoptosis and cell cycle arrest) is transiently induced during astroglial and neuronal differentiation of embryonic and adult NSC lines. Thereby, Zac1 transactivates Socs3 (suppressor of cytokine signaling 3), a potent inhibitor of prodifferentiative Jak/Stat3 signaling, in a lineage-specific manner to prevent precocious astroglial differentiation. In vivo, Zac1 and Socs3 colocalize in the neocortical ventricular zone during incipient astrogliogenesis. Zac1 overexpression in primary NSCs delays astroglial differentiation whereas knockdown of Zac1 or Socs3 facilitates formation of astroglial cells. This negative feedback loop is unrelated to Zac1′s cell cycle arrest function and specific to the Jak/Stat3 pathway. Hence, reinstating Jak/Stat3 signaling in the presence of increased Zac1 expression allows for timely astroglial differentiation. Overall, we suggest that the imprinted gene Zac1 curtails astroglial differentiation of NSCs in the developing and adult brain.