bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of particle number and brightness using a laser scanning confocal microscope operating in the analog mode
Authors: Dalal Rooshin B. , Digman Michelle A. , Horwitz Alan F. , Vetri Valeria , Gratton Enrico 
Published: October 2007

AbstractWe describe a method to obtain the brightness and number of molecules at each pixel of an image stack obtained with a laser scanning microscope. The method is based on intensity fluctuations due to the diffusion of molecules in a pixel. For a detector operating in the analog mode, the variance must be proportional to the intensity. Once this constant has been calibrated, we use the ratio between the variance and the intensity to derive the particle brightness. Then, from the ratio of the intensity to the brightness we obtain the average number of particles in the pixel. We show that the method works with molecules in solution and that the results are comparable to those obtained with fluctuation correlation spectroscopy. We compare the results obtained with the detector operating in the analog and photon counting mode. Although the dynamic range of the detector operating in the photon counting mode is superior, the performance of the analog detector is acceptable under common experimental conditions. Since most commercial laser scanning microscopes operate in the analog mode, the calculation of brightness and number of particles can be applied to data obtained with these instruments, provided that the variance is proportional to the intensity. We demonstrate that the recovered brightness of mEGFP, independent of concentration, is similar whether measured in solution or in two different cell types. Furthermore, we distinguish between mobile and immobile components, and introduce a method to correct for slow variations in intensity. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.
List‐coloring the square of a subcubic graph
Authors: Cranston Daniel W. , Kim Seog‐Jin 
Published: October 2007

AbstractThe square G2 of a graph G is the graph with the same vertex set G and with two vertices adjacent if their distance in G is at most 2. Thomassen showed that every planar graph G with maximum degree Δ(G) = 3 satisfies χ(G2) ≤ 7. Kostochka and Woodall conjectured that for every graph, the list‐chromatic number of G2 equals the chromatic number of G2, that is, χl(G2) = χ(G2) for all G. If true, this conjecture (together with Thomassen's result) implies that every planar graph G with Δ(G) = 3 satisfies χl(G2) ≤ 7. We prove that every connected graph (not necessarily planar) with Δ(G) = 3 other than the Petersen graph satisfies χl(G2) ≤8 (and this is best possible). In addition, we show that if G is a planar graph with Δ(G) = 3 and girth g(G) ≥ 7, then χl(G2) ≤ 7. Dvořák, Škrekovski, and Tancer showed that if G is a planar graph with Δ(G) = 3 and girth g(G) ≥ 10, then χl(G2) ≤6. We improve the girth bound to show that if G is a planar graph with Δ(G) = 3 and g(G) ≥ 9, then χl(G2) ≤ 6. All of our proofs can be easily translated into linear‐time coloring algorithms. © 2007 Wiley Periodicals, Inc. J Graph Theory 57: 65–87, 2008
Scaled Gromov hyperbolic graphs
Authors: Jonckheere Edmond , Lohsoonthorn Poonsuk , Bonahon Francis 
Published: October 2007

AbstractIn this article, the δ‐hyperbolic concept, originally developed for infinite graphs, is adapted to very large but finite graphs. Such graphs can indeed exhibit properties typical of negatively curved spaces, yet the traditional δ‐hyperbolic concept, which requires existence of an upper bound on the fatness δ of the geodesic triangles, is unable to capture those properties, as any finite graph has finite δ. Here the idea is to scale δ relative to the diameter of the geodesic triangles and use the Cartan–Alexandrov–Toponogov (CAT) theory to derive the thresholding value of δdiam below which the geometry has negative curvature properties. © 2007 Wiley Periodicals, Inc. J Graph Theory 57: 157–180, 2008
Understanding rehospitalization risk: Can hospital discharge be modified to reduce recurrent hospitalization?
Authors: Strunin Lee , Stone Meg , Jack Brian 
Published: October 2007

AbstractBACKGROUNDA high rate of unnecessary rehospitalization has been shown to be related to a poorly managed discharge processes.OBJECTIVEA qualitative study was conducted in order to understand the phenomenon of frequent rehospitalization from the perspective of discharged patients and to determine if activities at the time of discharge could be designed to reduce the number of adverse events and rehospitalization.DESIGNSemistructured, open‐ended interviews were conducted with 21 patients during their hospital stay at Boston Medical Center. Interviews assessed continuity of care after discharge, need for and availability of social support, and ability to obtain follow‐up medical care.RESULTSDifficult life circumstances posed a greater barrier to recuperation than lack of medical knowledge. All participants were able to describe their medical condition, the reasons they were admitted to the hospital, and the discharge instructions they received. All reported the types of medications being taken or the conditions for which the medications were prescribed. Recuperation was compromised by factors that contribute to undermining the ability of patients to follow their doctors' recommendations including support for medical and basic needs, substance use, and limitations in the availability of transportation to medical appointments. Distress, particularly depression, further contributed to poor health and undermined the ability to follow doctors' recommendations and the discharge plans.CONCLUSIONSDischarge interventions that assess the need for social support and provide access and services have the potential to reduce chronic rehospitalization. Journal of Hospital Medicine 2007;2:297–304. © 2007 Society of Hospital Medicine.
Current research and future challenges in urban mesoscale modelling
Authors: Martilli Alberto 
Published: October 2007

AbstractIncreases in environmental problems linked to urbanization and increases in computational power are proposed as the main mechanisms behind positive feedbacks between experimental investigation and numerical modelling in mesoscale urban studies. The focus here is on the modelling, with a description of state‐of‐the‐art techniques used to parameterize urban‐induced dynamical and thermal effects in mesoscale models. An analysis of possible future developments in urban mesoscale modelling is presented. Emphasis is laid on the link between mesoscale and microscale models, increases in numerical resolution, and improvement in anthropogenic heat flux estimation. Copyright © 2007 Royal Meteorological Society
Cirque infills in the Khibiny Mountains, Kola Peninsula, Russia — palaeoglaciological interpretations and modern analogues in East Antarctica
Authors: Hättestrand Clas , Kolka Vasili , Johansen Nina 
Published: October 2007

AbstractWe report here on cirque infills mapped in the Khibiny Mountains, Kola Peninsula, Russia. Cirque infills are morainic deposits located near the headwalls of valleys and cirques. Their location and shape, often with concave margins towards the valley side, indicate that they were deposited by ice flowing up‐valley, into the mountains, rather than by local glaciers. We suggest that they formed during the last deglaciation, when Khibiny was a nunatak and Fennoscandian ice sheet lobes extended into valleys and cirques of the massif. The formation of cirque infills is probably more related to ice sheet dynamic factors, occurring when the ice margin retreated from the cirques, than to climate‐driven interruption in the ice‐marginal retreat. Glacial conditions similar to those prevalent when the Khibiny cirque infills were formed, occur today in Antarctica where the ice sheets engulf nunatak ranges. In Heimefrontfjella, Antarctica, the formation of supraglacial moraines at the head of cirques are linked to blue‐ice conditions, indicating locally low accumulation rates, a dry continental climate and sublimation dominated ablation. We suggest that these Antarctic moraines are modern analogues of cirque infills on the Kola Peninsula, and possibly, that the cirque infills may be used as palaeoenvironmental indicators. Copyright © 2007 John Wiley & Sons, Ltd.
The role of the Iceland Ice Sheet in the North Atlantic during the late Quaternary: a review and evidence from Denmark Strait
Authors: Andrews John T. 
Published: October 2007

AbstractInvestigations indicate that the Iceland Ice Sheet was reduced in size during MIS 3 but readvanced to the shelf break at the LGM. Retreat occurred very rapidly around 15 k–16 k cal. yr BP. By contrast, the margin of the ice sheet on the East Greenland shelf, north of the Denmark Strait, was at or close to the shelf break during MIS 3 and 2 and retreat starting ∼17 k cal. yr BP. Quantitative X‐ray diffraction analysis of the <2 mm sediment fraction was undertaken on 161 samples from Iceland and East Greenland diamictons, and from cores on the slopes and margins of the Denmark Strait. Weight% mineralogical data are used in a principal component analysis to differentiate sediments derived from the two margins. The first two PC axes explain 52% of the variance. These associations are used to characterise sediments as being affiliated with (a) Iceland, (b) East Greenland or (c) mixed. The contribution from Iceland becomes prominent during MIS 2. The extensive outcrop of early Tertiary basalts on East Greenland between 68° and 71° N is an alternative source for basaltic clasts and North Atlantic sediments with εNd(0) values close to ±0. Copyright © 2007 John Wiley & Sons, Ltd.
Positively negative: the impact of negativity upon the political consumer
Authors: Lloyd Jenny 
Published: October 2007

Abstract

For years there has been an ongoing debate as to the role and impact that ‘marketing’ has had on politics. Yet, it is the case that many of the concepts associated with the field of marketing have real relevance and have, in fact, been employed within the field of political campaigning for many decades. This is an empirical paper that focuses upon the concept of political brands and the impact that current trends in campaign strategy, and in particular the growth and continued use of negative campaigning, have upon them. Using a constructivist grounded theory approach, the implications associated with such activity are examined and, in particular, its effect upon the consumer/brand relationship.
Within the consideration of the results, it becomes clear that political brands' use of negative campaigning is somewhat shortsighted; offering short‐term gains but at the cost of long‐term damage not only to their brand image but also to the wider democratic system as it stands. In a search for political ‘brands’ that more effectively meet their needs, there appears a tendency for political consumers to now look outside of the conventional political sector. The emergent concept of the ‘negative brand’ is explored together with the implications for political consumers, political brands and the wider field of conventional party politics.
Copyright © 2007 John Wiley & Sons, Ltd.
Stable nitrogen isotope values in arid‐land kangaroos correlated with mean annual rainfall: potential as a palaeoclimatic indicator
Authors: Pate F. D. , Anson T. J. 
Published: October 2007

AbstractBone collagen stable nitrogen isotope values are reported for modern kangaroos (Macropus spp.) from eight field sites along a 1160 km south–north transect from temperate coastal to arid interior South Australia, in order to investigate δ15N tissue variability in relation to rainfall and relative humidity. Mean annual rainfall along the transect ranges from 775 mm at Mount Gambier in the southeastern coast to 176 mm at Innamincka in the arid northern interior, while 3pm relative humidity ranges from 73% at coastal Flinders Chase to 36% at Innamincka. In arid habitats (176–238 mm rainfall), the δ15N values of kangaroo bone collagen become more positive in relation to decreasing mean annual rainfall (r2 = 0.98), while there is only a weak correlation with relative humidity (r2 = 0.67). In contrast, in temperate and semi‐arid coastal habitats (350–775 mm), there is no correlation between kangaroo bone collagen δ15N values and rainfall (r2 = 0.0011) or between δ15N values and relative humidity (r2 = 0.0035). Thus, in South Australia, kangaroo bone collagen δ15N values do not show a simple linear correlation with either rainfall or relative humidity across all habitats. These results suggest that stable nitrogen isotope analyses of herbivore bones obtained from archaeological and palaeontological sites may provide a reliable proxy for past rainfall values in arid‐land ecosystems. Copyright © 2007 John Wiley & Sons, Ltd.
The depsipeptide technique applied to peptide segment condensation: Scope and limitations
Authors: Coin Irene , Schmieder Peter , Bienert Michael , Beyermann Michael 
Published: October 2007

AbstractA promising application of the depsipeptide technique has recently been proposed to provide ideal conditions for segment condensation, in that coupling of peptides bearing a C‐terminal depsipeptide unit occurs without giving rise to epimerization at the activated amino acid. This is due to the low tendency of the activated depsipeptide units, in contrast to the corresponding peptide segments, to form optically labile oxazolones. In this work we demonstrate that coupling of depsipeptides via base‐assisted activation using HBTU occurs not only without loss of configuration, but even much faster than the coupling of the corresponding all‐amide segments. Nevertheless, when the coupling of long depsipeptide segments proceeds slowly, we uncovered the occurrence of β‐elimination at the activated depsipeptide unit, in an extent dependent on the presence of base in the system and on the type of the solvent. Beta‐elimination was completely suppressed by using carbodiimide/HOBt activation in a non‐polar solvent (DCM), and in more polar media it was limited by substituting TMP for DIEA during HBTU activation, or using particular solvent mixtures (such as DMSO/toluene) for activation via carbodiimide. Finally, we show the application of C‐terminal pseudoprolines, in comparison with that of depsipeptide units, to segment coupling. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Electrospray ionization ion‐trap time‐of‐flight tandem mass spectrometry of two furofurans: sesamin and gmelinol
Authors: Yan Guoquan , Li Qianrong , Tan Huarong , Ge Tiefei 
Published: October 2007

AbstractHigh‐resolution electrospray ionization multistage tandem mass spectrometry (MS1–7) in positive ion mode was used to determine the accurate masses and the fragmentation pathways of two furofurans, sesamin and gmelinol. The protonated molecules [M+H]+ were absent in the conventional mass spectra of both compounds, but two characteristic ions, [M+H−H2O]+ and [M+H−H2]+, were always observed. Successive losses of CH2O and CO are the common characteristic fragmentations. Based on the exact masses acquired from 21 different tandem mass spectra, two or three fragmentation pathways for each compound are proposed. The consecutive losses of two H2O molecules and one H2 molecule readily take place from the furan rings for both sesamin and gmelinol, resulting in the absence of the protonated molecules in the single‐stage experiments. HCHO loss is observed at least three times in the tandem mass spectra, mainly from methylenedioxy groups (OCH2O) for sesamin but only from tetrahydrofuran rings for gmelinol. Moreover, CO loss is found at least three times in the tandem mass spectra of both sesamin and gmelinol from the 3,4‐methylenedioxyphenyl (ArOCH2O) moieties for sesamin and from both the dimethoxyphenyl and the tetrahydrofuran ring moieties for gmelinol. In addition, the disubstituted benzyl cation ArCH at m/z 135 for sesamin and at m/z 151 for gmelinol was found in the MS3 spectra of both sesamin and gmelinol, which is very helpful in the identification of the compositions of 3,4‐disubstituted groups on the benzene rings of the furofurans. Copyright © 2007 John Wiley & Sons, Ltd.
Study of interactions between arsenicals and thioredoxins (human and E. coli) using mass spectrometry
Authors: Wang Zhongwen , Zhang Hongquan , Li Xing‐Fang , Le X. Chris 
Published: October 2007

AbstractThioredoxin (Trx) plays an important role in achieving redox balances in cells and protecting the cells from oxidative damage. However, little is known about how arsenic affects Trx chemically. It is conceivable that trivalent arsenicals may bind to Trx, which has a highly conserved ‐CysGlyProCys‐ sequence. The objective of this study is to characterize the binding of seven arsenic species with Trx from E. coli and humans, using two mass spectrometry techniques. The arsenic‐Trx complexes and the free arsenicals were well separated by size‐exclusion liquid chromatography (LC) and detected with inductively coupled plasma mass spectrometry (ICPMS). The LC/ICPMS analyses showed that the trivalent arsenic species were able to form complexes with both human and E. coli Trx. Determination of binding constants indicated that affinity to Trx was higher for monomethylarsonous acid (MMAIII) and phenylarsine oxide (PhAsIII) than inorganic arsenite (iAsIII) and dimethylarsinous acid (DMAIII), probably because MMAIII and PhAsIII were able to form stable complexes by binding to two vicinal cysteines in the ‐CysGlyProCys‐ region of the Trx. The complexes of arsenicals with both human and E. coli Trx were further characterized by nano‐electrospray tandem mass spectrometry. Binding stoichiometries for different arsenic species were consistent with the available cysteine residues in the Trx. Mass spectral evidence also suggests that the pentavalent arsenicals could be reduced by Trx. This study provides the first detailed chemical characterization of the interactions between Trx and arsenic species. Copyright © 2007 John Wiley & Sons, Ltd.
Tightening McDonald cerclage suture under sonographic guidance
Authors: Hershkovitz R. , Burstein E. , Pinku A. 
Published: October 2007

AbstractObjectiveThe technical factors contributing to failure of cerclage are not fully understood. The aims of this study were to assess the possibility of tightening the McDonald cerclage under ultrasound guidance and to examine the width and shape of the cervical canal before and after tightening the suture.MethodsA prospective study was performed. The sole indication for cerclage placement was clinical history of cervical insufficiency. Cervical length and canal width were measured by transvaginal ultrasound, at 12–14 weeks' gestation, with the patient's bladder empty, after which the cerclage was performed. Tightening of the suture was performed under sonographic guidance (transabdominal or transrectal) until the cervical canal disappeared from view. After tying the suture, cervical length and the canal width were assessed sonographically.ResultsFifty‐eight patients were enrolled in the study; 50 patients had singleton pregnancies and eight patients carried twins. The mean cervical length at the beginning of the procedure was 31 ± 13 mm (median 30 mm, range 15–48 mm). The mean cervical canal width was 2.1 ± 0.9 mm (median 2.0 mm, range 0.9–4.5 mm). The mean addition to the length of the cervical canal after the procedure was 11 ± 0.8 mm (median 1.0, range 8–19 mm). No complications were noted during the procedures. An interesting sonographic finding was an hourglass shape of the cervical canal after the procedure in 16 patients. Of 58 patients, 47 delivered at term, 10 delivered preterm and one miscarried at 18 weeks. Nine of 10 patients with preterm delivery had an hourglass‐shaped sonographic appearance of the cervical canal after the procedure.ConclusionsMcDonald cerclage can be tightened under ultrasound guidance. The sonographic appearance of an hourglass shape of the cervical canal following suture tightening may be a risk factor for preterm delivery. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Sexual reproductive biology of the endangered Japanese red maple (Acer pycnanthum)
Authors: Saeki Ikuyo 
Published: October 2007

AbstractJapanese red maple, Acer pycnanthum, is an endangered wetland species having dioecious sex expression. Prior studies conclude that land development has caused severe loss of habitat, and seedling regeneration is rare. However, information is lacking on sexual reproduction, which is the first critical stage of regeneration. My research objective was to describe flowering and fruiting characteristics of Japanese red maple, focusing on tree sizes at the onset of flowering, factors affecting flowering regularity and fruit abundance, periodicity of fruit production, and sex ratio. In a study of a young population, Japanese red maple initiated flowering at a small size under 100% light intensity. Initiation of flowering occurred at relatively lower height in males than females, and males flowered more regularly than females. A survey of 1,106 clones from 46 natural populations revealed that male clones were significantly more abundant than female clones. In a 4‐year study of mature populations, nearly all clones flowered regularly, and fruit abundance of dominant females was typically high. Fruit abundance at the population level also remained high, although fruit abundance of individual female clones varied year by year. Therefore, sexual reproductive ability is highly vigorous. Sex ratio exhibited a major deviation from a 1:1 ratio in populations with a small number of clones. In conservation planning, we should prioritize avoidance of an unbalanced sex ratio by increasing population sizes. In addition, populations having many clones >40 cm dbh with large, well‐lighted crowns have a high potential of regular and abundant seed production.
Surfactant‐Mediated Catalytic Determination of Fe(II) in Herbal and Pharmaceutical Products
Authors: Khan Muhammad Nasiruddin , Siddiqui Zaheeruddin , Uddin Fahim 
Published: October 2007

AbstractIn the present work, the catalyzed oxidation of neutral red (NR) by bromate was used to work out a kinetic‐based analytical method as an alternative technique for the determination of Fe(II) in real and synthetic samples. A use of a surfactant, N‐dodecylpyridinium chloride enhanced the sensitivity of the reaction by becoming involved in the reaction mechanism and providing a more suitable reaction environment. The iron‐catalyzed oxidation of NR with potassium bromate was studied kinetically by using a fixed time method. The reaction was followed by measuring the decrease in absorbance at 535 nm. The use of a surfactant in the analytical run showed a five times increase in the sensitivity of the method. It served as a ready reservoir of NR by increasing its solubilization. The salt effect, pH, and reagent concentration were also investigated to achieve a more selective and sensitive analytical procedure. Under optimized conditions (4.2 × 10−5 mol L−1 NR, 1.4 × 10−3 mol L−1 KBrO3, 1.5 × 10−2 mol L−1 cationic surfactant, 0.5 mol L−1 LiCl and pH 2.60 at 30 °C), iron(II) was determined in the range 0.1–0.5 μg mL−1 with a detection limit of 0.019 μg mL−1 and a relative standard deviation (n = 6) 1.02% for 0.2 μg mL−1 Fe(II). The influence of foreign ions on the accuracy of the results was investigated. The developed method is extremely sensitive, selective and simple. The method was applied successfully to the determination of iron in the herbal pharmaceutical and synthetic samples. The results showed good agreement with those obtained by atomic absorption spectrophotometry.