bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effective solvation of alkaline earth ions by proline‐rich proteolytic peptides of galectin‐3 upon electrospray ionisation
Authors: Lehmann Wolf D. , Wei Junhua , Hung Chien‐Wen , Gabius Hans‐Joachim , Kirsch Dieter , Spengler Bernhard , Kübler Dieter 
Published: July 2006

AbstractIn an analysis of a combined chymotrypsin/AspN digest of galectin‐3 by positive ion nano‐electrospray ionisation mass spectrometry (nanoESI‐MS) several peptides were observed which showed metal adduct ions as their most abundant ion signals. The most prominent adduct ions were observed at m/z values corresponding to [M+40]2+, [M+41]3+, and [M+42]4+ ions. Detailed investigation of the [M+40]2+ ion of the peptide GAPAGPLIVPY showed that it was not, as originally expected, a [M+H+39K]2+ adduct ion but had the composition [M+40Ca]2+. This was verified by several approaches: (i) nanoESI‐MS/MS of the [M+Ca]2+ adduct ions resulted in the virtually exclusive formation of doubly charged fragment ions; (ii) mass determination by quadrupole time‐of‐flight (QTOF)‐MS provided a preliminary identification; and (iii) accurate mass measurement using nanoESI Fourier transform ion cyclotron resonance (FTICR)‐MS at a mass resolving power of 500 000 allowed the specific detection and identification of the isobaric ion pairs [M+40Ca]2+/[M+H+39K]2+ and [M+24Mg]2+/[M+H+23Na]2+. All peptides in the chymotryptic galectin‐3 digest without a basic residue (K or R) showed addition of calcium as the most prominent ionisation principle. A further common feature of these nonbasic peptides was the presence of several proline residues, which is assumed to be a factor promoting the intense addition of calcium. It was observed that the common trace levels of sodium and calcium in analytical grade solvents (about 1–10 µM) are sufficient to generate the [M+H+23Na]2+ and [M+40Ca]2+ ions as the most prominent species of the peptide GAPAGPLIVPY. We conclude that the sequence motifs P‐XX‐P and P‐XXX‐P favour the solvation of alkaline earth ions in ESI‐MS. In view of the successful detection of physiological Ca/protein interactions by ESI‐MS, this finding may point to a solvation of Ca2+ by galectin in solution. The findings open new routes of research in the study of metal/protein and metal/peptide interactions. Copyright © 2006 John Wiley & Sons, Ltd.
Quantitative analyses of β‐carotene and retinol in serum and feces in support of clinical bioavailability studies
Authors: Zhu Dongwei , Wang Yan , Pang Yan , Liu Ang , Guo Jian , Bouwman Carolien A. , West Clive E. , van Breemen Richard B. 
Published: July 2006

AbstractAmong more than 50 provitamin carotenoids, β‐carotene is the most metabolically active source of retinol. Despite diets rich in fruits and vegetables containing β‐carotene, vitamin A deficiency is the leading cause of blindness and childhood mortality in developing countries. In addition, the uncertainty of β‐carotene bioconversion into vitamin A suggests that new data are needed to update the nutritional guidelines in developed countries. Previously, we reported the development of a carotene/retinol plateau isotopic enrichment method (CarRet PIE) for the determination of β‐carotene bioavailability and bioconversion into retinol, which utilizes positive ion atmospheric pressure chemical ionization (APCI) liquid chromatography/mass spectrometry (LC/MS). While seeking to validate the CarRet PIE using a mass balance approach requiring fecal measurements of β‐carotene and retinol, interference was encountered that required substantial modifications of the LC/MS assay. Here we report a new LC/MS assay that is based on the detection of molecular anions of β‐carotene using negative ion APCI with a reversed‐phase C30 column for HPLC separation. Sample preparation required saponification to eliminate interfering triglycerides. The limit of detection (LOD) of β‐carotene was 0.25 pmol calculated on the basis of an injection of 20 µL of 0.0125 µM β‐carotene, and the limit of quantitation (LOQ) was 1.0 pmol based on the injection of 20 µL of 0.050 µM β‐carotene. The linear range was 1.1 to 2179 pmol on‐column. The wide linear range and low LOD and LOQ of this assay facilitated the sensitive and selective quantitative analysis of β‐carotene in both serum and fecal samples in support of an on‐going clinical investigation of β‐carotene bioavailability and bioconversion into vitamin A. Copyright © 2006 John Wiley & Sons, Ltd.
Simultaneous determination of isoflavones and lignans at trace levels in natural waters and wastewater samples using liquid chromatography/electrospray ionization ion trap mass spectrometry
Authors: Kang Jinguo , Price William E. , Hick Larry A. 
Published: July 2006

AbstractA high‐performance liquid chromatography/electrospray ionization ion trap mass spectrometry (HPLC/ESI‐MSn) method has been developed for the trace determination of phytoestrogens in aquatic environmental samples. The method includes solid‐phase extraction (SPE) and analysis using liquid chromatography/electrospray ionization ion trap mass spectrometry. The aquatic environmental samples, influent of a wastewater treatment plant (WWTP) and creek water, were adjusted to pH ∼5 before extraction. The analyzed phytoestrogens were identified by an MSn method and quantified against a deuterated internal standard (genistein‐3′,5′,6,8‐D4). In negative ion mode, 0.1% formic acid was employed in acetonitrile/water mobile phase. The method detection limits ranged from 0.5 to 10 ng/L in WWTP influent and from 0.1 to 5 ng/L in creek water. Average SPE recoveries for the analyzed phytoestrogens ranged from 85 to 95%, with a relative standard deviation (RSD) (%) ranging from 3.9 to 6.5. The concentrations of the six analyzed phytoestrogens varied from 0.2 to 600 ng/L with high levels of enterolignans (enterolactone and enterodiol) found in the collected wastewater. The method is shown to be suitable for the determination of phytoestrogens in aquatic environmental samples at nano‐ and sub‐nanogram per liter levels. Copyright © 2006 John Wiley & Sons, Ltd.
Covering the Percutaneous Endoscopic Gastrostomy (PEG) Tube Prevents Peristomal Infection
Authors: Suzuki Yutaka , Urashima Mitsuyoshi , Ishibashi Yoshio , Abo Masahiro , Mashiko Hiroshi , Eda Yukimoto , Kusakabe Toshiro , Kawasaki Naruo , Yanaga Katsuhiko 
Published: July 2006

AbstractBackgroundBecause oropharyngeal bacteria can be brought through the abdominal wall during percutaneous endoscopic gastrostomy (PEG), peristomal infection is one of the most frequent complications in patients who undergo the procedure. This study aimed to determine whether covering the PEG tube with a sheath that could be detached in the stomach could help prevent peristomal infection.MethodsIn three community hospitals in Japan, data from 449 patients with swallowing dysfunction were prospectively collected between March 2000 and February 2002 for non‐covered PEG (n = 206) and between March 2002 and February 2004 for covered PEG (n = 243).ResultsAfter adjusting for hospital, age, gender, and underlying diseases, covering the PEG significantly reduced peristomal purulent infection compared with non‐covered PEG (odds ratio: 0.05; 95% confidence interval: 0.02–0.13). Body temperature, white blood cell count, and C‐reactive protein at day 3 after PEG placement, as well as duration of antibiotics usage, were significantly lower or shorter in patients treated with covered PEG than non‐covered PEG. In spite of the same frequencies in the two groups of methicillin‐resistant Staphylococcus aureus and Pseudomonas aeruginosa in oropharyngeal cultures before PEG placement, these organisms were detected significantly less frequently in peristomal lesions of patients who underwent covered PEG. Moreover, 28 patients treated with covered PEG received no antibiotic therapy, and 27 of them had no signs of peristomal infection.ConclusionsThese results suggest that covering the PEG tube, with or without providing antibiotic therapy, may prevent peristomal infection in spite of the presence of oropharyngeal bacterial flora after percutaneous endoscopic gastrostomy.
Exact Interval Estimation, Power Calculation, and Sample Size Determination in Normal Correlation Analysis
Authors: Shieh Gwowen 
Published: July 2006

AbstractThis paper considers the problem of analysis of correlation coefficients from a multivariate normal population. A unified theorem is derived for the regression model with normally distributed explanatory variables and the general results are employed to provide useful expressions for the distributions of simple, multiple, and partial-multiple correlation coefficients. The inversion principle and monotonicity property of the proposed formulations are used to describe alternative approaches to the exact interval estimation, power calculation, and sample size determination for correlation coefficients.
Continental Ice Sheets and the Planetary Radiation Budget
Authors: Oerlemans J. 
Published: July 2006

AbstractThe interaction between continential ice sheets and the planetary radiation budget is potentially important in climate-sensitivity studies. A simple ice-sheet model incorporated in an energybalance climate model provides a tool for studying this interaction in a quantitative way. Experiments in which the ice-sheet model is coupled step by step to the climate model show that ice sheets hardly affect the zonal mean radiation balance because the albedo feedback due to sea ice and snow cover is dominating. The model requires a 5% drop in the solar constant to create ice sheets of ice-age size.If the feedback between surface elevation and ice-mass balance is included (in a very crude way), the ice-sheet size (L, measured southward from 70°N) becomes much more sensitive to in insolation. For a range of normalized solar constants, roughly from 0.98 to 1.02, two stable solutions exist: L ⋍ 0 and L ⋍ 2000 km. This result demonstrates that the response of ice sheets to insolation variations is far from linear. It also stresses the need for explicit modeling of the ice-mass balance of ice sheets, particularly its dependence on surface elevation.
A Paleoclimate Model of Northern Hemisphere Ice Sheets
Authors: Birchfield G.E. , Weertman Johannes , Lunde Albert T. 
Published: July 2006

AbstractA model for predicting the growth and decay of ice sheets based on the astronomical theory of climate change is presented. The purpose of the study in part is to isolate the role of the ice-sheet physics and earth response under varying ice load by simplifying to the extreme the role of the hydrosphere-atmosphere. Ice sheet physics and the response of the lithosphere-asthenosphere under the ice load are modeled explicitly. Insolation anomalies (taken at a fixed latitude) directly force latitudinal displacement of the snow line. Accumulation rate a, and ablation rate a′ evaluated at mean sea level are specificed as external constants; a,a′ decrease linearly with ice sheet elevation. Rough tuning of the model to the general shape of the ice-volume record of the last two major glacials determines the external constants. Model predictions of the ages of several events in the last major glaciation compare well with the radiological ages. The six glacial terminatios (I–VI) over the last 600,000 yr are identified and the predicted ages compare reasonably well with the δ18O record for two deep-sea cores. A direct comparison of model power spectra of ice volume as a function of period with spectra of the δ18O record shows apparent underprediction of power near 100,000 yr. When a quantitative but heuristic method for taking into account the “red noise” spectrum evident in the geological records is used, a much more favorable comparison is possible. The model prediction lends support to the hypothesis that the nonlinearity of the ice-sheet physics is responsible for the 100,000-yr periodicity in the geological record of the late Pleistocene.
Correlation Between Long-Term Pedogenic CaCO3 Formation Rate and Modern Precipitation in Deserts of the American Southwest
Authors: Marion Giles M. 
Published: July 2006

AbstractThe rates of CaCO3 formation in desert soils of the American Southwest are highly variable and potentially useful in estimating the age of soil profiles. The objective of this study was to examine the correlation between the long-term rate of CaCO3 formation (LTR) and modern mean annual precipitation (MAP) and temperature (MAT). LTR is not significantly related to temperature but is linearly related to MAP [LTR = 0.0150(MAP − 37), r2 = 0.924]. The slope of the regression is significantly different from 0.0 and is equivalent to a calcium concentration of 6.0 mg liter−1 in rainfall. However, the intercept term, which suggests a lower limit of precipitation for CaCO3 formation of 37 mm, is not significantly different from 0.0. The LTR-MAP relationship may be useful in estimating the age of soil profiles by the CaCO3 method in the desert Southwest.
Stratigraphy and Paleoecology of Pleistocene Interstadial Sediments, Central British Columbia
Authors: Clague John J. , Hebda Richard J. , Mathewes Rolf W. 
Published: July 2006

AbstractTwo exposures of organic-rich interstadial sediments in central British Columbia provide information on middle Wisconsinan environments and climates near the center of the region subsequently covered by the late Wisconsinan Cordilleran Ice Sheet. Interstadial sediments at Bullion Pit overlie drift of early Wisconsinan or older age and underlie thick drift of late Wisconsinan age. Alluvium (or colluvium) and peat were deposited on the floor of the ancestral Quesnel River valley 46,000–40,000 14C yr ago when the vegetation consisted of spruce forest with dry openings and local fens and the climate was colder and perhaps drier than today. This is broadly consistent with paleoclimatic reconstructions for the same time interval for Babine Lake, 400 km to the northwest, and for Meadow Creek, 400 km to the southeast. Plant-rich pond sediments containing tephra layers and vertebrate remains are exposed between two drifts in a ravine at Mexican Hill, 30 km east of Quesnel. Although they may be contemporaneous with the Bullion Pit beds, the nonglacial sediments at Mexican Hill more likely were deposited sometime after the warmest part of the last interglaciation, but prior to 50,000 yr B.P. At that time, the vegetation at Mexican Hill probably was parkland. The present vegetation at Mexican Hill is boreal forest; thus, a drier and possibly cooler climate is indicated.
Lake evolution during the past 30,000 years in China, and its implications for environmental change
Authors: Fang Jin-qi 
Published: July 2006

AbstractThroughout China over the last 30,000 years high lake levels were reached during 30,000–24,000, 22,500-20,000, and 9500-3500 yr B.P. Lake recovery after the last glacial maximum (LGM) apparently was much slower, and involved stronger regional differences, than was lake regression during the onset of the last glaciation. According to the character of lake development during the last 18,000 years, three regions and six subregions have been distinguished. In the Tibetan Plateau and alpine regions of western China the plentiful supply of meltwater may have caused lakes to recover and reach their highest levels fust after the LGM. Lake hydrology in central and northern China was directly controlled by rainfall and evaporation, and most lakes reached their highest levels between 9500 and 3500 yr B.P. In the lowlands of eastern China lake recovery was closely tied with channel aggradation and water level rise of rivers, which are associated with Holocene sea level rise and human agricultural activities. Most lakes recovered and were most extensive in the middle and late Holocene.
Thermoluminescence and Excess 226Ra Decay Dating of Late Quaternary Fluvial Sands, East Alligator River, Australia
Authors: Murray Andrew , Wohl Ellen , East Jon 
Published: July 2006

AbstractThermoluminescence (TL) dating was applied to seven samples of siliceous fluvial sands from the East Alligator River of Northern Australia, giving ages ranging from modern to 6000 yr B.P. Two methods of estimating the equivalent dose (ED), total bleach and regenerative, were applied to the 90- to 125-μm quartz fraction of the samples in order to determine the reliability and internal consistency of the technique. High-resolution γ and α spectroscopy were used to measure radionuclide contents; these measurements revealed an excess 226Ra activity compared with 230Th. This excess decreased with depth, and was used directly to derive mean sedimentation rates, and thus sediment ages. Both this method and one 14C date confirmed the validity of the TL values, which increased systematically with depth and were consistent with site stratigraphy. TL was of limited use in the dating of these late Holocene deposits because of age uncertainties of 500 to 1600 yr, resulting from a significant residual ED. This residual probably resulted from incomplete bleaching during reworking upstream of the sampling site. For Pleistocene deposits, the residual ED will be less significant because of higher total EDs, and TL dates will be correspondingly more accurate.
The Last Glacial Maximum on Spitsbergen, Svalbard
Authors: Mangerud Jan , Bolstad Magne , Elgersma Anne , Helliksen Dag , Landvik Jon Y. , Lønne Ida , Lycke Anne Katrine , Salvigsen Otto , Sandahl Tom , Svendsen John Inge 
Published: July 2006

AbstractMost scientists have concluded previously that the west coast of Spitsbergen, Svalbard, remained ice-free during the late Weichselian, between 25,000 and 10,000 yr B.P. We conclude that the glaciation was more extensive. Terraces that were postulated to have been ice-free are covered by a thin, late Weichselian till. Sudden drop in the marine limit and basal radiocarbon dates of raised glaciomarine sediments demonstrates that the glaciers in the main fjords, Isfjorden and Van Mijenfjorden, terminated west (outside) of the fjord mouths. Basal radiocarbon dates from glaciomarine clay above till in cores from the continental shelf west of Spitsbergen yielded ages of about 12,500 yr B.P., from which we conclude that the ice extended to the shelf edge. Based on the extent of amino acid diagenesis in radiocarbon-dated molluscs, the duration of the maximum extension of the late Weichselian glaciation was short, certainly less than 10,000 years. During the ice-free period preceding that glaciation, at least back to 40,000 yr B.P., the glaciers on Svalbard were not significantly larger than at present, as shown by marine deposits close to the glacier snouts. Many radiocarbon dates place deglaciation of the outer coast at about 12,500 yr B.P. At about 10,000 yr B.P., the rest of the archipelago rapidly became ice-free.
Patterns of Holocene Climatic Change in the Midwestern United States
Authors: Wright H. E. 
Published: July 2006

AbstractThe Holocene pollen sequence in the Minnesota area is “asymmetric” around the so-called prairie period: the early Holocene is dominated by elm (with pine in the north) and the late Holocene by oak. The elm zone is interpreted as a manifestation of summer monsoonal rains enhanced by the Milankovitch insolation maximum, and the pine in the north is interpreted as a result of summer cooling near the retreating ice sheet. As the summer insolation waned during the Holocene, its associated monsoonal rains from the Caribbean moisture source lasted longer in the south (northeastern Iowa and southern Wisconsin), where the inferred mesic elm forest changed to prairie as late as 5000 yr B.P., compared to 8000 yr. B.P. in Minnesota (and 9000 yr B.P. in the Dakotas).
African Urban Spaces in Historical Perspective. Edited by STEVENJ.SALM and TOYINFALOLA. Rochester NY: University of Rochester Press, 2005. Pp. xl+395. £50/$75 (ISBN 1-58046-163-8). Urbanization and African Cultures. Edited by TOYINFALOLA and STEVENJ.SALM. Durham NC: Carolina Academic Press, 2005. Pp. xv+464. $45, paperback (ISBN 0-89089-558-9).
Authors: BURTON ANDREW 
Published: July 2006

The profile of African urban history has risen considerably of late, with the appearance of a number of important monographs and edited collections. What is more, with the plethora of younger scholars as well as more established historians now exploring Africa's urban pasts, its profile is set to rise further. African Urban Spaces in Historical Perspective represents the latest contribution to this emerging sub-field. A companion volume, Urbanization and African Cultures, is of a more interdisciplinary character. Both are drawn from contributions to a 2003 University of Texas conference.African Urban Spaces will be of more interest to readers of this journal, not only because of its historical focus but also its higher quality and greater cohesion. It covers an impressive geographical and temporal range, with chapters on primary and secondary cities throughout Africa, spanning the precolonial past to the present. It is introduced by one of the pioneers of Africa's urban history, Catherine Coquery-Vidrovitch, who teases themes from the collection and signals promising avenues for future research. However, poor referencing mars the introduction, a symptom of the apparently loose editorial role exercised over the book as a whole. Greater intervention could have strengthened the collection considerably: not only to ensure consistent referencing (authors variously adopt endnotes and social science/intratext systems) and to minimize typographical errors, but more seriously to tighten the sloppier passages and chapters. The quality of the chapters varies considerably, some representing useful scholarly contributions, others being pedestrian accounts offering little or nothing new.