bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of De Geer moraines and implications for deglaciation dynamics
Authors: Larsen Eiliv , Longva Oddvar , Follestad Bjørn A.
Published: February 2007

De Geer moraines are very common in the Møre area, western Norway. These moraines occur below the marine limit and outside the Younger Dryas ice limit and occupy tributaries that connect the main fjords through the mountain passes. During deglaciation, ice in these tributaries flowed to the major ice streams.

Sections across three De Geer moraines show that the ridges are composed of diamictons and fine‐grained sediment, partly in stacked sequences. The diamicton units are interpreted as being composed of water‐lain tills, lodgements tills and subaqueous flow deposits. The fine‐grained sediment is though to have formed in a proglacial marine environment. Clast fabric of diamictons and deformation structures in underlying sands show that depositional directions for diamicton units and the direction of deformation for the sands is perpendicular to the ridge crests. Mainly based on this evidence, the ridges are thought to have formed by push at the glacier grounding line. The formation of transverse ridges (relative to ice flow) do occur in basal crevasses on modern glaciers, as do swarms of ridges along the front of retreating glaciers. The first mechanism of deposition does not seem to explain the ridges studied in the present paper and hence the importance of this process in the formation of De Geer moraines is questioned.

The De Geer moraines were deposited by ice lobes advancing from one main fjord into another; therefore by studying the drainage pattern of the tributary lobes and their sequence of deglaciation, many features of the style of deglaciation of the ice sheet across the area can be determined.

The northwestern part of the area was deglaciated earliest. After that, deglaciation proceeded to the southwest parallel to the coast. Subsequently the outer and the central part of Romsdalsfjorden were deglaciated causing ice to drain towards this fjord from both the north and south. The last fjord to be deglaciated was Storfjorden in the south.
The extension of the Late Weichselian/Late Devensian ice sheets in the North Sea Basin
Authors: Ehlers Jürgen , Wingfield Robin
Published: February 2007

The distribution of large channel‐like features, comprising Weichselian/Devensian incisions, in the western North Sea provides evidence for a much larger extension of the last ice sheet than currently assumed. Morphological comparison of the incisions with those in North Germany and Poland reveals a striking similarity in shape and distribution. The features on the North Sea floor are interpreted as being formed by meltwater erosion within the margin of the ice sheet. The widespread absence of Weichselian/Devensian till in the area under consideration may be attributed to later erosion. Large‐scale reworking and redistribution of sediments is indicated by the complete sediment infill of the majority of the incisions.
Glacier response to climatic change during the Loch Lomond Stadial and early Flandrian: Geomorphological and palynological evidence from the Isle of Skye, Scotland
Authors: Benn Douglas I. , Lowe J. John , Walker Michael J. C.
Published: February 2007

The deglaciation of Skye at the close of the Loch Lomond Stadial is assessed on the basis of detailed geomorphological mapping and pollen‐stratigraphic correlations. It is concluded that deglaciation proceeded in two distinct stages. The first was marked by numerous glacier stillstands and readvances, while uninterrupted retreat and local glacier stagnation occurred during the second and final stage. The pollen evidence indicates that the first stage was well advanced before the marked thermal improvement at the start of the Flandrian, and it is inferred that initial glacier retreat occurred in response to a decline in precipitation in the later part of the Loch Lomond Stadial. The first stage of glacier retreat continued into the early Flandrian, during which climatic amelioration was interrupted briefly. Final deglaciation appears to have occurred rapidly in response to sustained temperature increases. The collective evidence also indicates spatial variations in the timing of deglaciation, which appear to reflect differences in glacier morphology.
Mineral magnetic analyses as a means of lithostratigraphic correlation and provenance indication of glacial diamicts: Intra‐ and interunit variation
Authors: Walden John , Smith John P. , Dackombe Roger V.
Published: February 2007

Mineral magnetic analyses are applied to a series of diamict samples taken from the Quaternary sequence in the Isle of Man in order to assess the relative magnitude of the intra‐and inter‐unit variation of the magnetic properties. The results are analysed both qualitatively and quantitatively and show that the level of intra‐unit variation is significantly less than the level of inter‐unit variation. The intra‐unit variation detected appears to show some relationship to the basic stratigraphy. Previous correlations based upon field evidence of diamict units exposed upon the east and west coasts of the Isle of Man are supported by their mineral magnetic properties. The statistically significant differences in the magnetic mineralogy of the stratigraphically lower Wyllin and Shellag Tills and the upper Orrisdale, Ballavarkish and Ballaquark Tills suggests distinct provenances for these two suites of sediments, allowing potential source areas to be suggested. These source areas are consistent with published data on ice flow directions in the Irish Sea Basin during the Devensian.
Foraminifera from the Irish Sea glacigenic deposits at Aberdaron, western Lleyn, North Wales: Palaeoenvironmental implications
Authors: Austin William E. N. , McCarroll Danny
Published: February 2007

In a sequence of glacigenic sediments at Aberdaron, Foraminifera were obtained from samples located specifically in order to differentiate between opposing models of depositional environment. All the diamict samples yielded remarkably uniform assemblages, with similar numbers of benthic specimens and benthic species per unit weight of sediment, similar planktic : benthic ratios, and similar ratios of clearly allochthonous to possibly autochthonous elements. This is precisely as predicted by the terrestrial model of sedimentation, where all of the sediments are interpreted as being derived from the melting of glacier ice rich in marine debris entrained during passage along the Irish Sea Basin. The results lend no support to a glacial marine model, since no faunal responses to increasingly distal sedimentary environments are observed. However, the fauna is dominated by the Foraminifera Elphidium excavatum (Terquem) forma clavata Cushman, which is commonly assumed to indicate glacial marine conditions. The modern distribution of similar assemblages suggests that it is just as likely to represent the cold, reduced salinity conditions that would have prevailed in the northern Irish Sea Basin for much of the Quaternary.
The magnetic properties of Quaternary and Tertiary sediments in the southern North Sea
Authors: Thompson R. , Cameron T. D. J. , Schwarz C. , Jensen K. A. , Maenhaut Lemberge V. Van , Sha L. P.
Published: February 2007

Cores from boreholes penetrating late Quaternary, glacial, interglacial and postglacial sediments and the underlying late Cenozoic delta complex of the southern North Sea have been examined for their magnetic properties. A magnetic polarity stratigraphy has been established as an aid to biostratigraphic dating of the sediments; the Kaena‐Gauss and Gauss—Matuyama transitions and the base and top of the Olduvai subchron have been identified. The strength and stability of laboratory‐induced isothermal remanent magnetisation display clear magneto‐petrological variations, which match lithostratigraphic changes in the cores. Principal component analysis has picked out a basin‐wide and palaeoenvironmental consistency in the magnetic data. Large, multi‐domain magnetite grains predominate in the post‐deltaic and fluvio‐deltaic sediments, whereas smaller greigite or titanomagnetite grains are concentrated in the intertidal and marine deltaic facies. Since heavy mineral analysis indicates that most of the deltaic detritus derived from common source areas, the differences in magnetic mineralogy have probably been caused by the sediment transport processes operating within the delta complex.
Periglacial microjointing and faulting in Weichselian fluvio‐aeolian deposits
Authors: Mol Joanne , Vandenberghe Jef , Kasse Kees , Stel Harry
Published: February 2007

A Weichselian Late Pleniglacial fluvio‐aeolian deposit has been investigated in the southern Netherlands. Three main structural lineaments have been distinguished: (1) very small, vertical platy structures (microjoints), in a parallel and a columnar configuration; (2) large joints and normal faults with minor displacement (‘Grubbenvorst type’), arranged in a conjugate fault‐system; (3) large joints and normal faults (‘wedge‐type’), located adjacent to ice‐wedge casts.

Since clay is absent, the occurrence of the vertical platy structures cannot be attributed to desiccation cracking. The vertical platy structures are interpreted as the result of thermal contraction cracking of a relatively thin layer, due to a sudden temperature drop.

The large joints and normal faults of the Grubbenvorst type are the result of failure of the sediment due to the melting of the permafrost in the Late Pleniglacial, just before the formation of the Beuningen Gravel Bed. In other areas large periglacial convolutions have been formed during the same period. The normal faults and joints of the wedge type are more generally known. They are the result of failure of the sediment adjacent to a melting ice wedge.
The distinction between postcranial bones of Bos primigenius Bojanus, 1827 and Bison priscus Bojanus, 1827 from the British pleistocene and the taxonomic status of Bos and Bison
Authors: Gee Henry
Published: February 2007

The study of British Pleistocene mammal faunas has been hampered by the difficulty of telling the difference between the postcranial elements of the often abundant remains of the large bovids Bos primigenius Bojanus, 1827 and Bison priscus Bojanus, 1827. Here I present qualitative and morphometric criteria whereby Bos primigenius and Bison priscus radii, metacarpals, tibiae, astragali and metatarsals can be told apart using British Pleistocene material.
Land snails from the last glacial maximum on Andikithira, southern Greece and their palaeoclimatic implications
Authors: Gittenberger Edmund , Goodfriend Glenn A.
Published: February 2007

An assemblage of land snails from an aeolianite deposit on the coast of the southern Greek island of Andikithira is shown to date to 16 000 yr BP and thus represents the period of the last glacial maximum (LGM; Oxygen Isotope Stage 2). The assemblage has no modern analogue. Five of the ten species are extinct on the island and some of these now live only at high elevations (> 950 m). Significantly cooler temperatures, some 5‐8°C below present, and slightly drier moisture conditions (lower rainfall, partially offset by reduced evapotranspiration at the lower temperature) are inferred. The large temperature depression at the LGM, well documented in northern and central Europe, extended also to the Mediterranean climate of southern Europe. Late Quaternary climatic changes had a considerable impact on the fauna of this isolated island.
Till in the marine environment
Authors: King Lewis H.
Published: February 2007

Till is of common occurrence in the marine environment and can be both subglacial and proglacial in origin. Former glacial margins are often represented by till tongues, that are interbedded with stratified glaciomarine sediment, and the relationship is readily mappable using seismic reflection techniques. It is inferred that within individual till tongues, sediment‐gravity flow deposits form transitional contacts with till of subglacial origin, but these contacts cannot be distinguished on seismic profiles. These unstratified, gravity‐induced deposits formed in close proximity to the glacial source at the grounding line are considered to be secondary tills (flow‐till complex) in terms of the INQUA classification of tills.

Till‐tongue successions and till deltas are large, ice‐marginal depocentres associated with floating front ice‐margins, and appear to be closely related in origin.

Tabular and hummocky moraines of the mid‐Norwegian Shelf also are considered to be products of floating‐front margins and represent a large proportion of the retreat tills formed during ice recession.

Seismostratigraphic evidence for channelisation in ice‐marginal deposits appears to provide a means of distinguishing between former tidewater and floating‐front margins.
A high‐resolution record of Lateglacial and early Holocene marine sediments from southwestern Sweden; with special emphasis on environmental changes close to the Pleistocene‐Holocene transition and the influence of fresh water from the Baltic basin
Authors: Bergsten Helene
Published: February 2007

A high‐resolution study of a marine depositional record (43 m long), dated by accelerator mass spectrometry, from Göteborg (Gothenburg), southwestern Sweden, shows biostratigraphical and sedimentological changes of environmental significance during the Lateglacial and early Holocene. High accumulation rates are recorded from the onset of the deglaciation of the area, ca. 13 500 yr BP, until 10 300 yr BP, by which time approximately 100 m of marine sediments were deposited. The early Holocene is represented by 10 m only of sediment.

The influence on the Skagerrak‐Kattegat coastal area of the dramatic, final drainage of the Baltic Ice Lake, at 10 300 yr BP, is re‐evaluated. Its impact on the distal Swedish west coast was limited and sediments that were previously related to this drainage are reinterpreted. Here, it is suggested they reflect resuspension and redeposition of sediments from the large inland Lake Vänern basin between ca. 9500 and 9000 yr BP. At 10 200 yr BP a general climatic change and a sudden incursion of warm and saline Atlantic water into the Norwegian Sea occurred and the Skagerrak altered environmental conditions, with more temperate bottom‐water conditions in the investigation area.
Late Quaternary evolution of Lake Urana, New South Wales, Australia
Authors: Page Kenneth , Dare‐Edwards Anthony , Nanson Gerald , Price David
Published: February 2007

Lake Urana is a well‐preserved relict lake in the semi‐arid Riverine Plain of southeastern Australia. A compound lunette at its eastern shoreline consists of a quartz‐sand‐dominated unit (Bimbadeen Formation), thermoluminescence (TL) dated at 30 ka to 12 ka, and a clay and sand facies unit (Coonong Formation), dated at 55 ka to 35 ka. The intervening period indicates a phase of periodically exposed lake floor and soil formation. The older wet phase conforms well with similar environments recorded from the same period at Lake Mungo. However, the return to high water levels from 30 ka to 12 ka departs sharply from the generally accepted palaeoclimatic model from Australia, which demands severe glacial maximum desiccation and widespread construction of clay lunettes. Although hydrological budgets calculated for Lake Urana and nearby Lake Cullivel require high glacial maximum water levels they do not support higher precipitation.
Wisconsinan Late‐glacial environmental change in Nova Scotia: A regional synthesis
Authors: Mott R. J.
Published: February 2007

A synthesis of the interpreted vegetational and climatic history of Nova Scotia during the Wisconsinan Late‐glacial period (14‐9 ka BP) is presented and described in 500‐year intervals. The concomitant regional deglaciation history of the region is also described. A synthesis chart is provided which includes a qualitative curve of temperature reconstructions for the Lateglacial period.
Wisconsinan Late‐glacial environmental change in Newfoundland: A regional review
Authors: Anderson T. W. , Macpherson J. B.
Published: February 2007

The distribution of 75 lake and bog sites, from which pollen stratigraphical evidence relevant to the late Quaternary of Newfoundland has been obtained, is presented. The detailed records of lithology, pollen and diatoms, supplemented by geochemical data, are discussed for three of the sites — Southwest Brook Lake, Woody Hill Brook Pond and Leading Tickles — and interpretations made are based on vegetational history, relative climatic changes and extent of ice cover. Radiocarbon data from 14 sites are summarised. A summary chart of Late‐glacial environmental changes, including a qualitative palaeotemperature curve, is provided.
Hierarchical biostratigraphical classification of long pollen sequences
Authors: Tzedakis P. C.
Published: February 2007

The biostratigraphical classification of long pollen sequences in relation to the definition of pollen assemblage biozones according to the International Stratigraphic Guide is examined. To facilitate the description and organization of pollen stratigraphical data the concept of a ‘pollen assemblage superzone’ is introduced. A hierarchical approach relying on superzones, zones and subzones appears to be better suited to the different levels of variation encountered in long pollen sequences and is here applied to a recored from the loannina basin, northwest Greece.
Degree of rock surface weathering as an indicator of ice‐sheet thickness along an east—west transect across southern Norway
Authors: Nesje Atle , McCarroll Danny , Dahl Svein Olaf
Published: February 2007

Rock surface weathering, as reflected by rock surface hardness and roughness, was measured at six mountains along an east‐west transect across southern Norway. At most sites the results show significant differences in rock surface weathering across the autochthonous blockfield boundary, suggesting that the areas above the boundary have been exposed to subaerial weathering for a considerably longer time span that the areas below. The results are interpreted as reflecting the surface profile of an asymmetric, west‐centred, low‐gradient ice sheet.
Stratigraphy and sedimentology of Devensian (Dimlington Stadial) glacial deposits, east Yorkshire, England
Authors: Evans David J. A. , Owen Lewis A. , Roberts David
Published: February 2007

The stratigraphy and sedimentology of the glacial deposits exposed along the coast of east Yorkshire are reviewed. Critical sections at Filey Brigg, Barmston and Skipsea are examined to reassess the stratigraphy of Devensian Dimlington Stadial glacial deposits in the light of recent developments in glacial sedimentology. Sedimentary and glaciotectonic structures studied in the field and by using scanning electron microscopy are emphasised. Two hypotheses are considered for the genesis of the interbedded diamictons and stratified sediments. The first involves the deposition of lodgement till and/or deformation till followed by meltout till, which was overridden to produce more deformation till, reflecting periods of ice stagnation punctuated by glacier thickening. The second hypothesis, which is favoured on the basis of field evidence and micromorphology, involves the vertical accretion of a deforming till layer associated with cavity/channel or tunnel valley fills, beneath active ice. At Barmston the upper part of the diamicton contains elongate pendant structures containing gravels, indicating that the diamicton was saturated and able to flow. The diamictons, therefore, represent a complex sequence of tills deposited and deformed by active ice during the Dimlington Stadial. Previously published stratigraphical schemes involving classifications of multiple tills in east Yorkshire should be simplified and it is more appropriate to assign these to a single formation, the Skipsea Till Formation. Rhythmic glaciolacustrine and proglacial glaciofluvial sediments overlie the tills at Barmston and Skipsea. These were deposited in sag basins during deglaciation as the tills settled and deformed under thickening sediment and as buried ice melted out. Extensive sands and gravels cap the succession and were deposited on a sandur during the later stages of deglaciation.
Patterned fen development in northern Scotland: Hypothesis testing and comparison with ombrotrophic blanket peats
Authors: Charman Daniel J.
Published: February 2007

Patterned fens are part of the diverse Holocene peatland landscape of the Flow Country, northern Scotland. Their present vegetation and morphology allies them with boreal systems in Scandinavia and North America. However, previous work has shown that their mode of formation is rather different and has suggested a developmental model in which the poor fens have formed only recently and have arisen as a result of local hydrological change. These ideas are tested here by morphological, stratigraphical and macrofossil studies on three additional patterned fens covering a wider geographical and ecological range. Two sites corroborate the hypotheses of the earlier study, and one site which refutes the earlier findings can be shown to be dependent on different topographic controls. A comparison of two patterned fens with an ombrotrophic mire site in the same area shows that hydroseral processes dominate the early development of individual components of the mire complex. The time of initiation of patterned fens coincides with increasing surface wetness on the ombrotrophic mire. This may be due to climatic change and/or the coalescence of the constituent parts of the present integrated blanket mire system. The hydrological changes arising from this led to the emergence of the springs that currently supply the patterned fens with their water and elevated nutrient levels. The study supports the idea that landscape‐scale research and conservation are essential for the understanding and hydrological integrity of blanket mire landscapes such as the Flow Country.
Last interglacial and Holocene climatic development in the Norwegian Sea region: Ocean front movements and ice‐core data
Authors: Sejrup Hans Petter , Haflidason Haflidi , Kristensen Dorthe Klitgaard , Johnsen Sigfus J.
Published: February 2007

Planktonic foraminiferal evidence suggests that the ocean front systems between Polar and Atlantic surface waters in the Norwegian Sea generally were located closer to Greenland during Oxygen Isotope Substage 5e than in the Holocene. During both these periods oscillations have occurred in the position of the fronts. In the western Norwegian Sea region, the substage 5e influence of warm Atlantic waters was interrupted by a return to polar conditions. These findings support both ice‐core data and evidence from Europe that the last interglacial was a period of rapid climatic shifts.
Composite Hydrogels: Robust Carriers for Catalytic Nanoparticles
Authors: Lu Yan , Spyra Paul , Mei Yu , Ballauff Matthias , Pich Andrij
Published: February 2007

A new type of composite hydrogel have been synthesized in which “nano‐tree” type polymer brush particles have been chemically entrapped in a poly(vinyl alcohol) (PVA) matrix by means of the disulfone reaction. This reaction leads to a chemical crosslinking of the nano‐tree brush particles within the PVA hydrogel. Obtained composite hydrogels can be successfully used as template for the deposition of Ag nanoparticles. Field‐emission scanning electron microscopy (FESEM) images demonstrate that monodisperse Ag nanoparticles (ca. 35 nm) are embedded into the composite hydrogel: Most of the silver nanoparticles were generated on the surface of the brush particles while a small amount of Ag nanoparticles was found to be entrapped within the PVA polymer network. We demonstrate that the resulting composite hydrogels can be used as a robust carrier for generation and immobilization of catalytically active Ag nanoparticles. The catalytic activity is investigated by monitoring the reduction of 4‐nitrophenol by NaBH4 in the presence of such a kind of composite hydrogel. The hybrid hydrogels can be easily reused many times as a catalyst and the catalytic activity can be retained over several months.

magnified image
Retirement and transition phenomena in the family purchase process
Authors: Stammerjohan Claire Allison , Capella Louis M. , Taylor Ronald D.
Published: February 2007

Research is needed on the family purchase process of retirement‐age couples, because 78 million baby boomers are rapidly approaching retirement age. Both boomers and the retirement‐age couples in this study present special opportunities to marketers through new roles adopted in retirement. This study reports on perceptions of family purchase process participation among retirement‐age couples. Results indicate that transition retirees' family purchase process participation differs from that of post‐transition retirees. This finding has managerial implications for marketers wishing to serve desirable segments of current and future retirement‐age consumers. © 2007 Wiley Periodicals, Inc.
Effect of caffiene on microsurgical technical performance
Authors: Urso‐Baiarda Fulvio , Shurey Sandra , Grobbelaar Adriaan O.
Published: February 2007

Microsurgeons may choose to avoid caffeine to prevent potentially deleterious caffeine tremor, although an adverse effect on surgical skill has never been shown. This double‐blind placebo‐controlled crossover study investigated the effect of moderate caffeine intake on microsurgical ability among microsurgical training course attendees. Subjects were randomized to receive either morning placebo and afternoon caffeine, or the reverse, thereby acting as their own controls. Performance in end‐to‐end vessel anastomosis was graded by a single observer during both sessions using a global rating scale. Subjects consuming caffeine in the morning demonstrated significantly improved scores from morning to afternoon, whereas subjects consuming caffeine in the afternoon showed no such improvement. These results are consistent with an adverse effect of caffeine on microsurgical skill combined with a learning curve among the study population of novice microsurgeons, and support the view that caffeine has a detrimental effect on microsurgical ability among this study group. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Selection of the sacral nerve posterior roots to establish skin–CNS–bladder reflex pathway: An experimental study in rats
Authors: Wang Jinwu , Hou Chunlin , Jiang Jia , Li Qi , Zhang Feng
Published: February 2007

The purpose of this study was to explore the innervations of different sacral nerve posterior roots to bladder, and to provide evidence for further study of skin–CNS–bladder reflex pathway in the spinal cord injury patient. Spinal cord injury was produced in 10 rats. The bilateral spinal posterior roots of S1–S4 were electrically stimulated, and the bladder plexus action, bladder smooth muscle complex action potential, and intravesical pressure were examined and measured. The results showed that all the sacral nerve posterior roots were involved in innervations of bladder in rats. Among them, the S2 sacral nerve is the dominant nerve in innervations of bladder, followed by S1, S3, and S4 sacral nerve posterior roots. This study has provided valuable information for selection of sacral nerve posterior root for further study of the artificial bladder reflex arc for improving the micturition function in spinal cord injury patients. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Responsiveness of rabbits to superovulation treatment by a single injection of follicle‐stimulating hormone with aluminum hydroxide gel
Authors: Hashimoto Shu , Kimura Koji , Kuramochi Takashi , Aoyagi Kazuki , Hirako Makoto , Kawaguchi Mamoru , Iwata Hisataka , Hirao Masao , Kitada Kensaku , Hirasawa Kazuo , Ueda Masatsugu
Published: February 2007

Aluminum hydroxide gel (Al‐gel), which is used as an adjuvant, can absorb macromolecules. We investigated the applicability of Al‐gel to the sustained release of follicle‐stimulating hormone (FSH) as a simplified method of superovulation (SOV) in rabbits. The responsiveness of rabbits to SOV by a single injection of FSH dissolved in Al‐gel suspension (3.2 mg Al/ml) and in 10% (w/v) polyvinylpyrrolidone (PVP), and by multiple injections of FSH in saline was examined. The numbers of total and fertilized eggs recovered from rabbits treated with FSH in Al‐gel (40.5 and 26.3, respectively) were similar to multiple injections (47.4 and 28.6, respectively) and were significantly greater (P < 0.05) than single injection of FSH with PVP (17.3 and 11.5, respectively). We also compared the plasma FSH levels of rabbits which were induced SOV by multiple or a single injection of Al‐gel. Al‐gel provided sustained release of FSH to the blood stream at a high enough dose for SOV. Moreover, the developmental competence of the pups of DNA‐injected embryos from rabbits treated with a single injection of FSH mixed with Al‐gel (18%) was similar to that of DNA‐injected embryos, recovered from rabbits treated with FSH dissolved in saline (21%). Two transgenic pups were obtained from embryos recovered from rabbits by a single injection of FSH with Al‐gel. These results indicate that a single injection of FSH with Al‐gel is an effective method for SOV of rabbit and that this technique is applicable to research requiring large numbers of rabbit embryos such as the production of transgenic rabbits. Mol. Reprod. Dev. 74: 1208–1212, 2007. © 2007 Wiley‐Liss, Inc.
High mobility group box 1 (HMGB1) is implicated in preimplantation embryo development in the mouse
Authors: Cui Xiang‐Shun , Shen Xing‐Hui , Kim Nam‐Hyung
Published: February 2007

High mobility group box 1 (HMGB1) regulates multiple cell functions, including transcription, DNA repair, differentiation, and apoptosis. In order to obtain insight into the role of HMGB1 in embryo development, we first evaluated its gene expression levels in mouse preimplantation embryos. Quantitative real‐time reverse transcription‐polymerase chain reaction (RT‐PCR) revealed high expression levels in zygotes, and expression steadily increased after zygotic genome activation when normalized to the rabbit Globin mRNA. Indirect immunocytochemistry showed that the HMGB1 protein was also produced in mouse embryos. Injection of a small interfering RNA (siRNA) specific for HMGB1 into zygotes specifically reduced both mRNA expression (P < 0.001) and protein synthesis of HMGB1 in early embryos developed in vitro. Injection of siRNA into the zygote did not affect development to the blastocyst stage, but significantly decreased cell numbers (P < 0.01) in the blastocyst and increased caspase3 (Casp3, P < 0.05) gene expression and apoptosis (P < 0.005). Addition of recombinant HMGB1 (Sigma, H‐4652) into the culture medium enhanced the development of zygote stage mouse embryos to blastocysts, in the absence of BSA supplementation. These findings suggest that endogenous and exogenous HMGB1 are implicated in preimplantation embryo development in the mouse. Mol. Reprod. Dev. 75: 1290–1299, 2008. © 2007 Wiley‐Liss, Inc.
Distinct responses of human granulosa lutein cells after hCG or LH stimulation in a spheroidal cell culture system
Authors: Becker Julia , Walz Andrea , Daube Stefanie , Keck Christoph , Pietrowski Detlef
Published: February 2007

The growth and development of the corpus luteum (CL) is regulated by gonadotropic hormones. It is formed by granulosa cells (GCs), theca cells, and endothelial cells, and is the primary source of circulating progesterone. During early pregnancy only human chorionic gonadotropin (hCG) but not luteinizing hormone (LH) extends the life span of the CL, although hCG and LH interact with the same receptor and have similar actions on the CL. In this study a recently by our group established spheroidal GC culture assay served as a model of CL development on which we compared the actions of the gonadotropic hormones LH and hCG. To find out which signal pathways take part in the hormonal regulation of GC we stimulated GC‐spheroids with modulators of protein kinases A and C dependent signaling cascades and determined their impact on sprout forming activity in GC. Our results indicate that PKA‐dependent signaling pathways play a major role in mediating the hormonal‐induced signaling cascades leading to sprouting in GC. Furthermore, this study strongly indicates that the different effects of hCG and LH in the maintenance of the CL may be reasoned in different signal transduction pathways triggered by hCG or LH. Mol. Reprod. Dev. 74: 1312–1316, 2007. © 2007 Wiley‐Liss, Inc.
Polypeptide backbone derived from carboxyl terminal of mouse ZP3 inhibits sperm‐zona binding
Authors: Li Ding , Cao Shaofeng , Xu Chen
Published: February 2007

For mammalian organism, fertilization begins with species‐specific recognition between sperm and egg, a process depending upon egg zona pellucida glycoproteins and putative sperm interacting protein(s). In mouse, zona pellucida glycoprotein ZP3 is believed to be the primary receptor for sperm and inducer of sperm acrosomal reaction, and its function has been attributed to the specific O‐linked oligosaccharides attached to polypeptide backbone. While lots of reports have focused on the role of ZP3's oligosaccharides in fertilization, there are few concerning its polypeptide backbone. To investigate whether mZP3 polypeptide backbone is involved in sperm‐egg recognition, three partially overlapping cDNA fragments, together covering entire mouse ZP3, were cloned, expressed and purified under denaturing condition. Although all three refolded proteins possess native conformation, only one derived from the carboxyl terminal showed inhibitory effect to the sperm‐zona binding during in vitro fertilization. This phenomenon could not be explained by enhanced acrosomal exocytosis rate, in that the acrosomal reaction assay demonstrated its inability to induce the acrosomal reaction. Our results suggest that the carboxyl terminal of mZP3 polypeptide backbone interacts with sperm and such interaction plays a significant role in sperm‐zona binding, ultimately successful fertilization. Mol. Reprod. Dev. 74: 1327–1336, 2007. © 2007 Wiley‐Liss, Inc.
A natural neighbour method for linear elastic problems based on Fraeijs de Veubeke variational principle
Authors: Cescotto Serge , Li Xiang
Published: February 2007

The natural neighbour method can be considered as belonging to the meshless methods. Classically, the development of this method is based on the virtual work principle. In the present paper, we use the natural neighbour method for 2D domains starting from the Fraeijs de Veubeke variational principle and we approximate separately the displacement field, the stress field and the strain field: the assumed strains and the assumed stresses are constant over each Voronoi cell, the assumed surface reactions are constant along the edge where the displacements are imposed, while the assumed displacements are interpolated by Laplace interpolants. In the absence of body forces, it is shown that the calculation of integrals on the area of the solid domain can be avoided: only integrals on the edges of the Voronoi cells are necessary. On the other hand, displacements can be imposed in the average sense on some boundaries of the domain. Patch tests and some applications in the elastic domain are given in the paper and show the effectiveness of the method. Copyright © 2007 John Wiley & Sons, Ltd.
On the solution of generalized non‐linear complex‐symmetric eigenvalue problems
Authors: Dumont N. A.
Published: February 2007

This paper brings an attempt toward the systematic solution of the generalized non‐linear, complex‐symmetric eigenproblem (K0−iωC1−ω2M1−iω3C2−ω4M2−···)ϕ=0, with real, symmetric matrices K0, Cj, Mj ε Rn×n, which are associated with the dynamic governing equations of a structure submitted to viscous damping, as laid out in the frame of an advanced mode superposition technique. The problem can be restated as (K(ω)−ωM(ω))ϕ=0, where K(ω)=K and M(ω)=M are complex‐symmetric matrices given as power series of the complex eigenfrequencies ω, such that, if (ω, ϕ) is a solution eigenpair, ϕTM(ω)ϕ=1 and ϕTK(ω)ϕ=ω. The traditional Rayleigh quotient iteration and the more recent Jacobi–Davidson method are outlined for complex‐symmetric linear problems and shown to be mathematically equivalent, both with asymptotically cubic convergence. The Jacobi–Davidson method is more robust and adequate for the solution of a set of eigenpairs. The non‐linear eigenproblem subject of this paper can be dealt with in the exact frame of the linear analysis, thus also presenting cubic convergence. Two examples help us to visualize some of the basic concepts developed. Three more examples illustrate the applicability of the proposed algorithm to solve non‐linear problems, in the general case of underdamping, but also for overdamping combined with multiple and close eigenvalues. Copyright © 2007 John Wiley & Sons, Ltd.
Local government reform in Jamaica and Trinidad: a policy dilemma
Authors: Schoburgh Eris D.
Published: February 2007

Issues of local governance have dominated Caribbean policy agenda for the past two decades, prompting considerable thought and action on local government reform by scholars, local government practitioners and policy makers, alike. No reforms have been as ubiquitous as those of local government. Permitted by an international reformist agenda, local government reform policy is linked positively to efforts to redress incapacities of public management and administration. This article examines conceptual and empirical issues relating to implementation of local government reform in two Caribbean countries, Jamaica and Trinidad. It analyses how the vision for local governance is articulated through specific reform taxonomies and argues that, although local government reform is normatively a policy aimed at fundamental changes in intergovernmental relations, in Jamaica and Trinidad reform has led merely to adjustments in the internal administration of local government. Copyright © 2007 John Wiley & Sons, Ltd.
An epidemiological study of holoprosencephaly from a regional congenital anomaly register: 1995–2004
Authors: Ong S. , Tonks A. , Woodward E. R. , Wyldes M. P. , Kilby M. D.
Published: February 2007

Background

Adequate contemporary information to counsel patients with a prenatal diagnosis of holoprosencephaly is lacking. We addressed this using data from the West Midlands Congenital Anomaly Register (WMCAR), a population‐based malformation register, during a time where technological improvements have been stable and anomaly screening is well established.

Methods

Cases were defined using the ICD 10 code for holoprosencephaly. Cases of livebirths, stillbirths and termination at all gestations were included in the study. The diagnosis was verified by a pathology or definitive radiological report with cross validation from the regional pathology, clinical genetics, cytogenetics and fetal medicine databases.

Results

There were 113 cases reported of holoprosencephaly for the years 1995–2004. This represents a prevalence of 1.7 per 10 000 births and terminations, with no change in prevalence over time. There was a decreased risk of holoprosencephaly in the white population [white vs. nonwhite; RR 0.53(0.36–0.79)]. Karyotypical abnormality was noted in 46% of cases where the karyotype was known. Trisomy 13 was the most common chromosomal abnormality. Correct allocation of a diagnosis of holoprosencephaly by ultrasound occurred in 77% of cases, with another 12% having a severe intracranial abnormality but was not reported as holoprosencephaly. In 4%, a prenatal diagnosis of holoprosencephaly was not made. Termination of pregnancy was performed in 80% of all cases.

Conclusion

Holoprosencephaly is a morbid condition associated with significant secondary etiologies. Copyright © 2007 John Wiley & Sons, Ltd.
Secondary infertility as a late complication of vesico‐amniotic shunt therapy
Authors: Kamphuis M. M. , Lim F. , Klumper F. J. , Oepkes D.
Published: February 2007

Objective

Vesico‐amniotic shunting can be used for the treatment of fetal obstructive uropathy. However, the procedure is associated with a significant risk of complications. We report a case of a complicated vesico‐amniotic placement, where a vesico‐amniotic shunt ultimately resulted in, fortunately reversible, infertility.

Case

A 36‐year‐old multigravida was referred to our center at 13 weeks' gestation for the evaluation of fetal lower urinary obstruction. A vesico‐amniotic shunt placement requiring several attempts was performed. A few weeks later premature rupture of the membranes occurred. At the request of the parents, the pregnancy was terminated at 22 weeks'gestation. The patient visited us again for secondary infertility, which turned out to be caused by a shunt left behind in the uterus, acting as an IUD. After hysteroscopic removal, she soon became pregnant again.

Conclusion

This case illustrates the importance of careful documentation relating to each and every operation, of all materials used and what was retained in the patient. At delivery, obstetric staff should be completely aware of the prenatal treatment procedures performed, to ensure that no foreign objects are left by oversight, inside the patient's body. Copyright © 2007 John Wiley & Sons, Ltd.
Trends in psychotropic medication use among U.S. adults
Authors: Paulose‐Ram Ryne , Safran Marc A. , Jonas Bruce S. , Gu Qiuping , Orwig Denise
Published: February 2007

Purpose

To examine trends and prevalence of prescription psychotropic medication use among noninstitutionalized US adults.

Methods

Prescription medication data from the third National Health and Nutrition Examination Survey (NHANES; 1988–1994; n = 20 050) and the 1999–2002 NHANES (n = 12 060), two nationally representative cross‐sectional health examination surveys, were examined for persons aged ≥17 years.

Results

The age‐adjusted prevalence of psychotropic medication use increased from 6.1% in 1988–1994 to 11.1% in 1999–2002 (p < 0.001). This was due to more than a three‐fold increase in antidepressant use (2.5%, 1988–1994 vs. 8.1%, 1999–2002 (p < 0.001)). Significant increases between time periods for antidepressant use were seen for all age, gender, and race‐ethnic groups although increases were less pronounced for males than females and non‐Hispanic blacks and Mexican Americans than non‐Hispanic whites. Prevalence of use remained relatively constant from 1988–1994 to 1999–2002 for anxiolytic/sedative/hypnotic (ASH) medications (3.5–3.8%), antipsychotics (0.8–1.0%), and antimanic agents (0.3–0.4%). The age‐adjusted prevalence of multiple psychotropic medication use increased from 1.2% in 1988–1994 to 3.1% in 1999–2002 (p < 0.001).

Conclusions

Psychotropic medication use among US adults increased since 1988–1994, specifically of antidepressants. Increases varied by gender and race‐ethnicity indicating under‐utilization for non‐Hispanic blacks and Mexican Americans compared to non‐Hispanic whites for both males and females. Published in 2007 by John Wiley & Sons, Ltd.
Microstructure‐properties correlations in dynamically vulcanized nanocomposite thermoplastic elastomers based on PP/EPDM
Authors: Naderi Ghasem , Lafleur Pierre G. , Dubois Charles
Published: February 2007

Thermoplastic vulcanized (TPV) nanocomposites were prepared in a laboratory mixer using EPDM, polypropylene of different viscosities, maleic anhydride modified polypropylene, an organo‐clay, and a sulfur‐based curing system. Based on the obtained results from X‐ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimeter, and mechanical properties, the microstructure of the prepared nanocomposites was found to be sensitive to the viscosity difference between the two phases and the clay content. X‐ray diffraction and TEM images of the TPV nanocomposites showed that clay was nearly exfoliated and randomly distributed into the polypropylene phase. The SEM photomicrographs of the dynamically vulcanized thermoplastic elastomer samples showed that the rubber particles were dispersed through the polypropylene in form of aggregates and their size increased with the introduction of clay. The nanoscale dimensions of the dispersed clay resulted in a significant improvement of the tensile modulus of the TPV nanocomposite samples, from 20 to 90% depending on clay content and the viscosity ratio of PP/EPDM. In the PP nanocomposites, the clay layers act as nucleating agents, resulting in higher crystallization temperature and reduced degree of crystallinity. Moreover, the oxygen permeability in the TPV nanocomposites was found to be lower than in unfilled but otherwise similar materials. POLYM. ENG. SCI., 47:207–217, 2007. © 2007 Society of Plastics Engineers.
Synthesis, thermal properties, and flame retardance of the epoxy‐silsesquioxane hybrid resins
Authors: Lu Tingli , Chen Tao , Liang Guozheng
Published: February 2007

Epoxy/silsesquioxane‐OH (EP‐SDOH, ED) hybrid resins were prepared from cyclohexyl‐disilanol silsesquioxane (SDOH) and diglycidyl ether of bisphenol A via the reaction between silanol and the oxirane group, with the cobalt naphthanate as a catalyst. It was found that incorporation of SDOH allows the reaction between oxirane ring and SiOH, and the silsesquioxane cage structure can be the main chain or as the side chain of the hybrid resin. The EP‐SDOH hybrid resins with various SDOH contents were cured by 4,4′‐diaminodiphenylsulphone, and the curing reaction was investigated by differential scanning calorimetry. The curing characteristics of EP‐SDOH hybrids had been observed to be influenced by the content of SDOH in the hybrid. The differential scanning calorimetry thermograms indicated that the EP‐SDOH hybrid exhibited a higher initial temperature, peak temperature, as well as final temperature than those of the pure epoxy resin when cured by the same curing agent 4,4′‐diaminodiphenylsulphone. The curing kinetic parameters were calculated by using the Ozawa method and the results indicated that EP‐SDOH hybrids possess the same curing mechanism as the pure epoxy resin. The properties of the cured EP‐SDOH hybrid resins such as the glass transition temperature (Tg), dynamic mechanical analysis, thermal stability, as well as the flame retardance were also investigated, and the results showed that introducing silsesquioxane‐OH unit into epoxy resin successfully modified the local structure, made the chain stiffness, restrict the chain mobility, and eventually improved thermal stability and flame retardance of epoxy resin. POLYM. ENG. SCI., 47:225–234, 2007. © 2007 Society of Plastics Engineers.
Reactive modification of PBT with applications in low density extrusion foaming
Authors: Jeong Byeong Joon , Xanthos Marino
Published: February 2007

By contrast to polyethylene terephthalate (PET), extrusion foaming of polybutylene terephthalate (PBT) to medium–low densities has been seldom reported in the literature. In this study, a commercial linear PBT resin was reactively modified in a batch mixer to a branched structure with a higher molecular weight (MW) and a broader molecular weight distribution (MWD) as evidenced by rheological analysis. Chain branching was also accomplished by single screw extrusion, where the competing degradation reaction needed to be taken into account. Optimization of the extrusion operational conditions, which also involved the use of suitable consititutive equations, led to the production of a branched resin with viscoelastic characteristics suitable for low density extrusion foaming by injection of physical blowing agents (PBA). The branched product made under the optimized conditions showed good foamability. The effect of pressure drop rate on cell nucleation rate and the effect of the crystallization rate on cell density and cell morphology are examined. POLYM. ENG. SCI., 47:244–253, 2007. © 2007 Society of Plastics Engineers.