bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bipolar Charge Transport in PCPDTBT‐PCBM Bulk‐Heterojunctions for Photovoltaic Applications
Authors: Morana Mauro , Wegscheider Matthias , Bonanni Alberta , Kopidakis Nikos , Shaheen Sean , Scharber Markus , Zhu Zhengguo , Waller David , Gaudiana Russell , Brabec Christoph 
Published: June 2008

AbstractAn experimental study of the transport properties of a low‐bandgap conjugated polymer giving high photovoltaic quantum efficiencies in the near infrared spectral region (Eg‐opt ∼ 1.35 eV) is presented. Using a organic thin film transistor geometry, we demonstrate a relatively high in‐plane hole mobility, up to 1.5 · × 10−2 cm2 V−1 s−1 and quantify the electron mobility at 3 × · 10−5 cm2 V−1 s−1 on a SiO2 dielectric. In addition, singular contact behavior results in bipolar quasi‐Ohmic injection both from low and high workfunction metals like LiF/Al and Au. X‐ray investigations revealed a degree of interchain π‐stacking that is probably embedded in a disordered matrix. Disorder also manifests itself in a strong positive field dependence of the hole mobility from the electric field. In blends made with the electron acceptor methanofullerene [6,6]‐phenyl C61 butyric acid methyl ester (PCBM), the transistor characteristics suggest a relatively unfavorable intermixing of the two components for the application to photovoltaic devices. We attribute this to a too fine dispersion of [C60]‐PCBM in the polymer matrix, that is also confirmed by the quenching of the photoluminescence signal measured in PCPDTBT [C60]‐PCBM films with various composition. We show that a higher degree of phase separation can be induced during the film formation by using 1,8‐octanedithiol (ODT), which leads to a more efficient electron percolation in the [C60]‐PCBM. In addition, the experimental results, in combination with those of solar cells seem to support the correlation between the blend morphology and charge recombination. We tentatively propose that the drift length, and similarly the electrical fill factor, can be limited by the recombination of holes with electrons trapped on isolated [C60]‐PCBM clusters. Ionized and isolated [C60]‐PCBM molecules can modify the local electric field in the solar cell by build‐up of a space‐charge. The results also suggest that further improvements of the fill factor may also be limited by a strong electrical‐field dependence of the hole transport.
Autosomal STR genetic variability in the Gran Chaco native population: Homogeneity or heterogeneity?
Authors: Crossetti Shaiane Goulart , Demarchi Dario A. , Raimann Paulo Eduardo , Salzano Francisco Mauro , Hutz Mara Helena , Callegari‐Jacques Sidia Maria 
Published: June 2008

AbstractTo investigate the population structure and variation in Gran Chaco's Amerindian population, data from 15 short tandem repeats (STRs) were determined in 128 individuals from three tribes of the Argentinean part of this region. STR genotypic differences, structure analysis, and multidimensional plot for the DA distances indicated that (1) Wichí from the Chaco Province are genetically distinct from the other populations, but still preserve a fair amount of genetic similarity with Wichí from Formosa; (2) the Toba populations studied are genetically indistinguishable; and (3) Toba subjects from Formosa are similar to the Pilagá of the same linguistic group (Guaykurú) and to the Wichí from Formosa who speak a Mataco language. This similarity could be due to their past mobility and the custom of absorbing females taken as prisoners from groups raided by them. Language, geography, and genetics seem to play similar roles in determining the population structure of these groups. Analyses of molecular variance and GST′ values calculated considering three South American regions indicated that the Argentinean Chaco is genetically homogeneous; addition of the Ayoreo Amerindians of the Paraguayan Chaco, however, led to diversity values that are not much different from those of South Amerindians in general. The present data contribute to efforts that try to understand in what way groups with diverse sociocultural settings (tribal, agricultural, and industrial) differ in genetic structure. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Occupational exposure to solvents and gasoline and risk of cancers in the urinary tract among Finnish workers
Authors: Lohi Jouni , Kyyrönen Pentti , Kauppinen Timo , Kujala Veikko , Pukkala Eero 
Published: June 2008

AbstractBackgroundBladder cancer (BC) is generally considered as an occupational disease, and some chemical exposures may also be associated with renal cell cancer (RCC). The aim of this study was to estimate the risk of cancers of the urinary tract in relation to occupational exposure to solvents and gasoline.MethodsA cross‐sectional cohort of all economically active Finns from the 1970 population census was followed up for BC (10,277 cases) and RCC (9,954 cases). Census occupations were assigned estimates of exposure to hydrocarbon (HC) solvents and gasoline with a job exposure matrix. Relative risk (RR) estimates were defined using Poisson regression models, adjusted for smoking and obesity.ResultsExposure to solvents was positively associated with the incidence of BC in women but not in men. The RR estimates were above 1.2 in nearly all exposure categories of all exposures studied but a statistically significant excess was only seen for middle levels of chlorinated HC solvents (1.7; 95% CI = 1.2–2.5) and a low level of aromatic HC solvents (1.6; 95% CI = 1.3–2.1). The RR estimates for RCC were close to unity in all categories of exposure.ConclusionsOur findings suggest that occupational exposure to certain solvents may have an impact on BC risk. The risk of RCC does not appear to be altered by exposure to HC solvents or gasoline. Am. J. Ind. Med. 51:668–672, 2008. Published 2008 Wiley‐Liss, Inc.
Ornamental lakes — an overlooked conservation resource?
Authors: Sayer C. D. , Davidson T. A. , Kelly A. 
Published: June 2008

Abstract
Shallow lakes excavated for ornamental purposes during the 18th and 19th centuries are abundant in lowland Europe. However, relative to older man‐made and/or natural lakes, these lakes may have been undervalued from the perspective of nature conservation.
To evaluate this idea a comparison was made between the aquatic macrophyte communities (submerged and floating‐leaved vegetation) of 66 shallow, English lakes including 34 ornamental lakes and 32 flooded medieval peat workings (the Norfolk and Suffolk Broads system), the latter being widely protected by conservation legislation.
Some 47%, 38% and 15% of the lakes studied were phytoplankton‐dominated, macrophyte‐dominated or deemed too shallow (<50 cm water depth), respectively, to support a macrophyte vegetation. A higher proportion of the ornamental lakes were macrophyte‐dominated (51%) by comparison with the broads (34%). In addition, many of the ornamental lakes contained diverse plant communities including abundant populations of Characeae, a common feature of lakes in the region before the major onset of eutrophication.
From the perspectives of macrophyte species richness, charophyte communities and indeed ‘reference condition macrophyte assemblages’, many of the studied ornamental lakes can be considered to be of high conservation value. Yet, in contrast to the broads, the vast majority of ornamental lakes have little conservation protection and are rarely subject to biological monitoring and/or surveying, thus leaving them vulnerable to eutrophication and inappropriate management. This study suggests that ornamental lakes are worthy of much greater attention from conservation organizations.
Copyright © 2008 John Wiley & Sons, Ltd.
Lymphangiogenesis and Its Relationship With Lymphatic Metastasis and Prognosis in Malignant Melanoma
Authors: Liu Baoquan , Ma Jing , Wang Xiaolei , Su Fei , Li Xuemei , Yang Shucai , Ma Wenping , Zhang Yafang 
Published: June 2008

AbstractRegional lymph node metastasis is one of the important indicators of cutaneous malignant melanoma. Newly formed lymphatic vessels are considered to provide a route whereby tumor cells can migrate to the lymph nodes. Both vascular endothelial growth factors (VEGF) ‐C and ‐D have been confirmed to participate in tumor lymphangiogenesis, but the prognostic significance of VEGF‐C, VEGF‐D, and lymphangiogenesis in cutaneous malignant melanoma remains controversial. To clarify the effects of these factors and to evaluate the relationships between lymphangiogenesis, lymph node metastasis, and prognosis in patients with malignant melanoma, the expressions of VEGF‐C, VEGF‐D, and their receptor (VEGFR) ‐3 were detected by immunohistochemistry and reverse transcriptase‐polymerase chain reaction. The expressions of both VEGF‐C and VEGF‐D proteins were concomitantly detected in the cytoplasm of the malignant cells. VEGF‐C and VEGF‐D expressions were associated with VEGFR‐3 expression and were significantly correlated with both peritumoral lymphangiogenesis and lymph node metastasis. The incidence of peritumoral lymphatic vessels was significantly higher in lymph node metastatic melanomas than that in nonmetastatic melanomas. Univariate and multivariate analyses indicated that VEGF‐C and VEGF‐D were independent prognostic factors for overall survival and disease‐free survival in patients with malignant melanoma. This study suggests that both VEGF‐C and VEGF‐D are involved in peritumoral lymphangiogenesis and lymphatic metastasis. VEGF‐C and VEGF‐D expression may be clinically useful indicators for prognostic evaluation in patients with cutaneous malignant melanoma. Anat Rec, 2008. © 2008 Wiley‐Liss, Inc.
Vertically combined shaved cell method in a z‐coordinate nonhydrostatic atmospheric model
Authors: Yamazaki Hiroe , Satomura Takehiko 
Published: June 2008

AbstractThe vertically combined shaved cell method is implemented into a z‐coordinate nonhydrostatic two‐dimensional atmospheric model based on the finite‐volume method. Quasi‐flux form fully compressible equations are employed as governing equations. The results of flow over a bell‐shaped mountain and a semicircular mountain are compared to those from a model using terrain‐following coordinates. These results indicate that the proposed method does not suffer from vertical velocity errors at the edge of the cells, and reproduces smooth and accurate mountain waves over not only gentle but also steep slopes where significant errors are observed in the terrain‐following model. Copyright © 2008 Royal Meteorological Society
Summer air temperature distribution and thermal environment in urban areas of Japan
Authors: Aikawa Masahide , Hiraki Takatoshi , Eiho Jiro 
Published: June 2008

AbstractThe air temperature distribution was measured, and the thermal environment was studied in August (summer season) in an urban area of approximately 10 km × 15 km in Hyogo Prefecture, Japan. We introduced a new index to evaluate the thermal condition. Combining the newly introduced index with other indices enabled us to show the thermal conditions in more detail. The inland thermal conditions were milder than those in the coastal areas when the air temperature was lower than 30 °C. In contrast, the inland thermal conditions were more severe than those in the coastal areas when the air temperature was higher than 30 °C. Copyright © 2008 Royal Meteorological Society
Infrared microscopy for the study of biological cell monolayers. I. Spectral effects of acetone and formalin fixation
Authors: Hastings Gary , Wang Ruili , Krug Peter , Katz David , Hilliard Julia 
Published: June 2008

AbstractInfrared spectroscopy of biological cell monolayers grown on surfaces is a poorly developed field. This is unfortunate because these monolayers have potential as biological sensors. Here we have used infrared microscopy, in both transmission and transflection geometries, to study air‐dried Vero cell monolayers. Using both methods allows one to distinguish sampling artefactual features from real sample spectral features. In transflection experiments, amide I/II absorption bands down‐shift 9/4 cm−1, respectively, relative to the corresponding bands in transmission experiments. In all other spectral regions no pronounced frequency differences in spectral bands in transmission and transflection experiments were observed. Transmission and transflection infrared microscopy were used to obtain infrared spectra for unfixed and acetone‐ or formalin‐fixed Vero cell monolayers. Formalin‐fixed monolayers display spectra that are very similar to that obtained using unfixed cells. However, acetone fixation leads to considerable spectral modifications. For unfixed and formalin‐fixed monolayers, a distinct band is observed at 1740 cm−1. This band is absent in spectra obtained using acetone‐fixed monolayers. The 1740 cm−1 band is associated with cellular ester lipids. In support of this hypothesis, two bands at 2925 and 2854 cm−1 are also found to disappear upon acetone fixation. These bands are associated with CH modes of the cellular lipids. Acetone fixation also leads to modification of protein amide I and II absorption bands. This may be expected as acetone causes coagulation of soluble cellular proteins. Other spectral changes associated with acetone or formalin fixation in the 1400–800 cm−1 region are discussed. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 921–930, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
The molecular structure and physical properties of elastin fibers as revealed by Raman microspectroscopy
Authors: Green Ellen , Ellis Richard , Winlove Peter 
Published: June 2008

AbstractRaman microspectroscopy has been used to investigate the structure of α‐elastin and fibrous elastin from ligament and aorta, and to explore changes associated with mechanical strain and temperature. Although no vibrational modes associated with cross‐linking of the fibers could be identified, the secondary structure of dehydrated fibrous elastin was significantly different from α‐elastin. The former differed from previous experimental measurements, but was close to the theoretical predictions with 36% β‐structures, 46% unordered, and 18% α‐helix. α‐Elastin contained 29% β‐structures, 53% unordered, and 18% α‐helix. In nuchal fibers the amide I mode was polarized, consistent with the peptide bond. Strains of up to 60% in ligament fiber bundles resulted in no significant shifts in peak position or in secondary structure. Polarization measurements revealed that the peptide bonds and several side chains re‐orientated closer to the fiber axis. Heating nuchal fibers to 60°C to increase the energetic component of the elasticity was associated with a 30% increase in the proportion of β‐structures in the amide I band, a 50% increase in the amide III band, and a 50% reduction in the signal from bound water. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 931–940, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Enantioselective cyanosilylation of ketones catalyzed by recyclable polymeric and dimeric MN(III) salen complexes at room temperature
Authors: Khan Noor‐Ul H. , Agrawal Santosh , Kureshy Rukhsana I. , Abdi Sayed H.R. , Prathap K. Jeya , Jasra Raksh V. 
Published: June 2008

AbstractRecyclable polymeric 1 and dimeric 2 chiral Mn(III) salen complexes catalyzed enantioselective cyanosilylation of various ketones in the presence of triphenylphosphine oxide as an additive proceeded smoothly at room temperature, providing excellent yields (up to 98%) and enantiomeric excess (up to 86%) of respective cyanohydrin trimethylsilyl ether. For most of the substrates, the Catalyst 1 showed slightly better reactivity and enantioselecitivity than the Catalyst 2 nevertheless both the catalysts were easily recovered and reused four times with the retention of their efficiency. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Sarcomere alignment is regulated by myocyte shape
Authors: Bray Mark‐Anthony , Sheehy Sean P. , Parker Kevin Kit 
Published: June 2008

AbstractCardiac organogenesis and pathogenesis are both characterized by changes in myocyte shape, cytoskeletal architecture, and the extracellular matrix (ECM). However, the mechanisms by which the ECM influences myocyte shape and myofibrillar patterning are unknown. We hypothesized that geometric cues in the ECM align sarcomeres by directing the actin network orientation. To test our hypothesis, we cultured neonatal rat ventricular myocytes on islands of micro‐patterned ECM to measure how they remodeled their cytoskeleton in response to extracellular cues. Myocytes spread and assumed the shape of circular and rectangular islands and reorganized their cytoskeletons and myofibrillar arrays with respect to the ECM boundary conditions. Circular myocytes did not assemble predictable actin networks nor organized sarcomere arrays. In contrast, myocytes cultured on rectangular ECM patterns with aspect ratios ranging from 1:1 to 7:1 aligned their sarcomeres in predictable and repeatable patterns based on highly localized focal adhesion complexes. Examination of averaged α‐actinin images revealed invariant sarcomeric registration irrespective of myocyte aspect ratio. Since the sarcomere sub‐units possess a fixed length, this observation indicates that cytoskeleton configuration is length‐limited by the extracellular boundary conditions. These results indicate that modification of the extracellular microenvironment induces dynamic reconfiguring of the myocyte shape and intracellular architecture. Furthermore, geometric boundaries such as corners induce localized myofibrillar anisotropy that becomes global as the myocyte aspect ratio increases. Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.
Heterogeneous modes of uptake for latex beads revealed through live cell imaging of phagocytes expressing a probe for phosphatidylinositol‐(3,4,5)‐trisphosphate and phosphatidylinositol‐(3,4)‐bisphosphate
Authors: Giorgione Jennifer , Clarke Margaret 
Published: June 2008

AbstractLatex beads are the preferred phagocytic substrate in biochemical studies of phagosome composition and maturation. Using living Dictyostelium cells and fluorescent probes, we compared the properties of phagosomes formed to ingest latex beads or digestible prey. Significant differences were found during the initial steps of phagocytosis. During uptake of bacteria or yeast, PHcrac‐GFP, a probe that binds to membranes enriched in PI(3,4,5)P3 and PI(3,4)P2, always labeled the nascent phagosome and faded shortly after it sealed. However, labeling of bead‐containing phagosomes was highly variable. Beads were engulfed by phagosomes either lacking or displaying the PHcrac‐GFP label, and that label, if present, often persisted for many minutes, revealing that early trafficking steps for bead‐containing phagosomes are quite heterogeneous. Later stages of the endocytic pathway appeared more similar for phagosomes containing prey and latex beads. Both types of phagosomes fused with acidic endosomes while undergoing transport along microtubules, both acquired the V‐ATPase and lost it prior to exocytosis, and both bound the late endosome marker vacuolin B, which was transferred to the plasma membrane upon exocytosis. We conclude that caution is needed in extrapolating results from latex bead phagosomes to phagosomes containing physiological substances, especially in early stages of the endocytic pathway. Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.
Quadratic form: A robust metric for quantitative comparison of flow cytometric histograms
Authors: Bernas Tytus , Asem Elikplimi K. , Robinson J. Paul , Rajwa Bartek 
Published: June 2008

AbstractComparison of fluorescence distributions is a fundamental part of the analysis of flow cytometric data. This approach is applied to detect differences between control and test sample and thus analyze a biological response. Comparison of standard test samples over time provides an estimate of instrument stability for quality control. However, application of statistical methods of distribution comparison in flow cytometry is difficult owing to instrument noise and the complex shape of intensity distributions. We applied quadratic form (QF) as a mathematical metric for comparison of flow cytometry histograms. QF operates on histograms as vectors and calculates the total distance in an interbin manner using a matrix of distances between single histogram bins. Euclidean interbin distance and histograms normalized to unity were used. Critical values corresponding to 95% significance level were calculated using Monte‐Carlo simulation and single‐maximum Gaussian distributions populated with several numbers of events. The QF statistic was then validated for non‐Gaussian single‐maximum distributions and multiple‐maxima distributions. We determined that the critical values for Gaussian distributions depended on standard deviations and number of events in the compared histograms. A simple empirical function was constructed to characterize this dependence. Furthermore, it was verified that critical values (corresponding to 95% significance) for non‐Gaussian histograms were similar to values for the Gaussian histograms characterized by the same standard deviation. We applied the QF statistic to estimate the differences between histograms of DNA content (ploidy) in cells of old and young leaf tissue of Brassica campestris. Furthermore, we quantified differences in fluorescence intensity in immunostaining of human lymphocytes. Quadratic form (QF) provides a true (mathematical) metric for estimation of distance between flow cytometry histograms of arbitrary shape. QF can be applied as a statistical test for estimation of significance of the distance measure. The respective critical values depend only on the number of events and standard deviations of compared histograms and are not affected by distribution shape. Therefore, applications of QF do not require assumptions concerning distribution shape and can be easily implemented in practice. This notion was confirmed using empirical distributions of DNA content in plant tissue and distributions of immunofluorescence in human cells. © 2008 International Society for Advancement of Cytometry
Chromatic aberration correction and deconvolution for UV sensitive imaging of fluorescent sterols in cytoplasmic lipid droplets
Authors: Wüstner Daniel , Færgeman Nils J. 
Published: June 2008

AbstractIntrinsically fluorescent sterols, like dehydroergosterol (DHE), mimic cholesterol closely and are therefore suitable to determine cholesterol transport by fluorescence microscopy. Disadvantages of DHE are its low quantum yield, rapid bleaching, and the fact that its excitation and emission is in the UV region of the spectrum. Thus, one has to deal with chromatic aberration and low signal‐to‐noise ratio. We developed a method to correct for chromatic aberration between the UV channel and the red/green channel in multicolor imaging of DHE compared with the lipid droplet marker Nile Red in living macrophage foam cells and in adipocytes. We used deconvolution microscopy and developed image segmentation techniques to assess the DHE content of lipid droplets in both cell types in an automated manner. Pulse‐chase studies and colocalization analysis were performed to monitor the redistribution of DHE upon adipocyte differentiation. DHE is targeted to transferrin‐positive recycling endosomes in preadipocytes but associates with droplets in mature adipocytes. Only in adipocytes but not in foam cells fluorescent sterol was confined to the droplet‐limiting membrane. We developed an approach to visualize and quantify sterol content of lipid droplets in living cells with potential for automated high content screening of cellular sterol transport. © 2008 International Society for Advancement of Cytometry