julilili42/papers huggingface dataset:
Gold nanoparticle-based biosensors
2010-03-01

The unique properties of gold nanoparticles have stimulated the increasing interest in the application of GNPs in interfacing biological recognition events with signal transduction and in designing biosensing devices exhibiting novel functions. The optical properties of GNPs provide wide range opportunities for construction optical biosensors. The excellent biocompatibility, conductivity, catalytic properties and high surface-to-volume ratio and high density of GNPs facilitate extensive application of GNPs in construction of electrochemical and piezoelectric biosensors with enhanced analytical performance with respect to other biosensor designs. In this article, the recent advances in construction of GNP-based optical, electrochemical and piezoelectric biosensors are reviewed, and some illustrative examples given, with a focus on the roles GNPs play in the biosensing process and the mechanism of GNPs for improving the analytical performances. Finally, the review concludes with an outline of present and future research for the real-world applications.
Pancreatic fat is negatively associated with insulin secretion in individuals with impaired fasting glucose and/or impaired glucose tolerance: a nuclear magnetic resonance study
2010-03-01

Abstract Background The pathogenesis of type 2 diabetes is characterized by insulin resistance and β‐cell dysfunction. Pancreatic fat load may add to the development of β‐cell dysfunction. The aim was to thoroughly quantify the fat content of pancreas sections (caput, corpus, and cauda) and to compare the impact of pancreatic, intrahepatic, and visceral fat on insulin secretion in humans. Methods Fifty‐one subjects were subjected to an oral glucose tolerance test (OGTT) with glucose, insulin, and C‐peptide measurements [28 subjects displayed normal glucose tolerance, 23 impaired fasting glycemia (IFG)] and/or impaired glucose tolerance (IGT)], and also to whole‐body magnetic resonance imaging (MRI), pancreas MRI, and liver magnetic resonance spectroscopy (MRS). Results After adjustment for gender and age, the mean pancreatic fat content was positively associated with body mass index (BMI), visceral adipose tissue (VAT), and waist circumference (all p ≤ 0.0013). The mean pancreatic fat content was negatively associated with OGTT‐based measures of insulin secretion (all p ≤ 0.03). Analysis of the subgroups of glucose tolerance showed that this was restricted to subjects with IGT and/or IFG. Visceral fat also represented a determinant of β‐cell function in individuals with IGT and/or IFG (all p ≤ 0.02), whereas intrahepatic fat did not. In a stepwise multivariate regression analysis, pancreatic fat turned out to be a stronger determinant of impaired insulin secretion than visceral fat. Conclusions Pancreatic fat is negatively associated with insulin secretion in subjects with IGT/IFG and, therefore, might represent an additional pathogenetic factor leading to β‐cell dysfunction. Copyright © 2010 John Wiley &amp; Sons, Ltd.
Direct and Indirect Effects in a Logit Model
2010-03-01

In this article, I discuss a method by Erikson et al. (2005, Proceedings of the National Academy of Science 102: 9730–9733) for decomposing a total effect in a logit model into direct and indirect effects. Moreover, I extend this method in three ways. First, in the original method the variable through which the indirect effect occurs is assumed to be normally distributed. In this article, the method is generalized by allowing this variable to have any distribution. Second, the original method did not provide standard errors for the estimates. In this article, the bootstrap is proposed as a method of providing those. Third, I show how to include control variables in this decomposition, which was not allowed in the original method. The original method and these extensions are implemented in the ldecomp command.
Embryogenesis – the humble beginnings of plant life
2010-03-01

Summary Each plant starts life from the zygote formed by the fusion of an egg and a sperm cell. The zygote gives rise to a multicellular embryo that displays a basic plant body organization and is surrounded by nutritive endosperm and maternal tissue. How the body organization is generated had already been studied before the genome sequence of Arabidopsis thaliana was completed 10 years ago, but several regulatory mechanisms of embryo development have since been discovered or analysed in more detail. Although this progress did not strictly depend on the availability of the genome sequence itself, several advances were considerably facilitated. In this review, we mainly address early embryo development, highlighting general mechanisms and crucial regulators, including phytohormones, that are involved in patterning the embryo and were mainly analysed in the post‐genome decade. We also highlight some unsolved problems, provide a brief outlook on the future of Arabidopsis embryo research, and discuss how the knowledge gained from Arabidopsis could be translated to crop species.
Promoting democracy – promoting autocracy? International politics and national political regimes
2010-03-01

Has the last tide of democratization been replaced by a new wave of democratic reversal? Do two decades of international democracy promotion now have to compete with the promotion of authoritarian rule by powers that have resisted democratization internally? Are there more pressing grounds than ever to investigate international political influences on the prospects not just for transition to and consolidation of democracy but the persistence, resurgence and spread of more authoritarian regimes? These are among the big issues raised in this introduction to the special issue. It does not pretend to provide definitive responses, but rather makes a start on how to look for some answers. The introduction spells out an agenda that should take a central place in future research into the influence of international politics on national political regimes. It gives a window onto how the multinational contributions in this issue add to our knowledge and take that agenda further forwards.
The Costs and Benefits of Occasional Sex: Theoretical Predictions and a Case Study
2010-03-01

Theory predicts that occasional sexual reproduction in predominantly parthenogenetic organisms offers all the advantages of obligate sexuality without paying its full costs. However, empirical examples identifying and evaluating the costs and benefits of rare sex are scarce. After reviewing the theoretical perspective on rare sex, we present our findings of potential costs and benefits of occasional sex in polyploid, sperm-dependent parthenogens of the planarian flatworm Schmidtea polychroa. Despite costs associated with the production of less fertile tetraploids as sexual intermediates, the benefits of rare sex prevail in S. polychroa and may be sufficiently strong to prevent extinction of parthenogenetic populations. This offers an explanation for the dominance of parthenogenesis in S. polychroa. We discuss the enigmatic question why not all organisms show a mixed reproduction mode.
Cross‐Border Diversification in Bank Asset Portfolios*
2010-03-01

Abstract We compute optimally diversified international asset portfolios for banks located in France, Germany, Italy, the United Kingdom and the United States using the mean–variance portfolio model with currency hedging. We compare these benchmark portfolios with the actual cross‐border asset positions of banks from 1995 to 2003 and ask whether the differences are best explained by regulations, institutions, cultural conditions or other financial frictions. Our results suggest that both culture and regulations affect the probability of a country's being overweighted in banks' portfolios: countries whose residents score higher on a survey measure of trust are more likely to be overweighted, while countries that have tighter capital controls are less likely to be overweighted. From a policy standpoint, the importance of culture suggests a limit to the degree of financial integration that may be achievable by the removal of formal economic barriers.
Platelets in Regeneration
2010-03-01

Platelets, as the first cellular response after disruption of vascular and/or tissue integrity, cover any existing injury within our body. But is the regenerative potential of platelets limited to providing a cellular patch for wounds? This review highlights the recent advance in our understanding of platelets being distinctly regulated and regulating cells that contribute immensely to the healing process from the very initial stage to the late events of tissue regeneration. For instance, the intrinsic actions of platelets as a regenerative cell, the participation of platelets in angiogenic processes, and the interplay of platelets and circulating stem and progenitor cells, as well as potential therapeutic implications, are addressed. Although we are starting to understand the underlying mechanisms connecting platelets to the components of tissue regeneration just mentioned, many aspects remain to be elucidated. The demand to invest research in this area is underscored by the fact that platelets or platelet-derived molecules are already applied in clinical contexts such as connective tissue regeneration, whereas other research fields have largely neglected platelet effects going beyond their participation in the coagulation cascade. Understanding the mechanisms connecting platelets to tissue regeneration, however, will inevitably open novel options in regenerative medicine.
Oxidized LDL-Activated Platelets Induce Vascular Inflammation
2010-03-01

Platelets are involved in the initiation of atherosclerosis by adherence to inflamed endothelium. Monocytes bind to these platelets and transmigrate into the vessel wall, transforming into macrophages and foam cells. We have previously shown that lipid-laden platelets are phagocytosed by macrophages. In this study we investigated the functional consequences of oxidized low-density lipoprotein (oxLDL) uptake on platelet function and interaction with the endothelium. Human platelets were isolated from healthy donors and activated by adenosine diphosphate. Immunofluorescence microscopy and flow cytometry revealed that oxLDL is located intracellularly in vesicles. With mepacrine costaining and confocal microtomography, we were able to identify dense granules as the vesicles that contain oxLDL. OxLDL-laden platelets induced intercellular adhesion molecule 1 expression in endothelial cells more than exogenous native LDL, oxLDL, and oxLDL-negative platelets. Furthermore, oxLDL-laden platelets induced foam cell development from CD34(+) progenitor cells. On endothelial regeneration, oxLDL-laden platelets had the opposite effect: The number of CD34(+) progenitor cells (colony-forming units) able to transform into endothelial cells was significantly reduced in the presence of oxLDL-platelets, whereas native LDL had no effect. Our results demonstrate that activated platelets internalize oxLDL and that oxLDL-laden platelets activate endothelium, inhibit endothelial regeneration, and promote foam cell development. Platelet oxLDL contributes significantly to vascular inflammation and is able to promote atherosclerosis.
Evaluation of the representative elementary volume (REV) of a fractured geothermal sandstone reservoir
2010-03-01

The objective of this study is to evaluate a representative elementary volume (REV) in a fractured geothermal sandstone reservoir in Germany using the discrete fracture network (DFN) model approach. Due to the lack of in situ data from the deep geothermal reservoir, field measurements of outcrop reservoir analogues were conducted to get a quantitative description of the DFN. Field measurements reveal that the geometry of the DFN is largely influenced by the lithological layering (e.g. relationship between joint spacing and bed thickness). Thus, DFN models have to be completed individually for each layer since each bed is distinct compared to its neighbouring beds. Various DFNs were generated using statistical-derived fracture input data. The two-dimensional universal distinct element code UDEC was used for fracture flow simulations. In order to determine the minimum REV, the equivalent average conductivity tensors were obtained with increasing block size. Plots of conductivity tensor coefficients versus block size exhibit only minor variation of the hydraulic properties with increasing block size. Hence, an REV size of 10 m × 10 m could be determined for all studied stochastically derived discrete fracture networks.
Platelet Aggregates-Induced Human CD34+Progenitor Cell Proliferation and Differentiation to Macrophages and Foam Cells Is Mediated by Stromal Cell Derived Factor 1 in Vitro
2010-03-01

The chemokine stromal cell derived factor 1 (SDF-1) regulates chemotactic recruitment (homing) and differentiation of CD34 (+) stem cells. Platelets express substantial amounts of SDF-1 upon activation. The aim of the present study was to evaluate the role of SDF-1 in platelet-induced proliferation and differentiation of human CD34 (+) cells to macrophages and foam cells, as well as in regulation of matrix metalloproteinase (MMP)-9 secretion. Co-culture experiments of platelet thrombi (2 x 10(8)/mL) with human CD34 (+) progenitor cells resulted in platelet phagocytosis by the latter, causing their differentiation into CD68-positive macrophages and subsequent Sudan red III-positive foam cells. Platelet aggregates-induced foam cell generation and MMP-9 secretion were attenuated by a neutralizing monoclonal antibody against platelet-derived SDF-1, as evaluated by immunofluorescence microscopy and gelatin zymography. Co-culture experiments of human arterial endothelial cells and human CD34 (+) progenitor cells resulted in a fourfold increased proliferation of CD34 (+) cells in the presence of platelets being mainly regulated by platelet-derived SDF-1 in vitro. These findings imply that in the presence of platelet thrombi, CD34 (+) progenitor cells phagocytize platelets in an SDF-1 dependent manner, causing their differentiation into macrophages and then foam cells, a mechanism most likely contributing to atherogenesis and atheroprogression.
Interaction of C-type lectin-like receptors NKp65 and KACL facilitates dedicated immune recognition of human keratinocytes
2010-03-01

Many well-known immune-related C-type lectin-like receptors (CTLRs) such as NKG2D, CD69, and the Ly49 receptors are encoded in the natural killer gene complex (NKC). Recently, we characterized the orphan NKC gene CLEC2A encoding for KACL, a further member of the human CLEC2 family of CTLRs. In contrast to the other CLEC2 family members AICL, CD69, and LLT1, KACL expression is mostly restricted to skin. Here we show that KACL is a non–disulfide-linked homodimeric surface receptor and stimulates cytotoxicity by human NK92MI cells. We identified the corresponding activating receptor on NK92MI cells that is encoded adjacently to the CLEC2A locus and binds KACL with high affinity. This CTLR, termed NKp65, stimulates NK cytotoxicity and release of proinflammatory cytokines upon engagement of cell-bound KACL. NKp65, a distant relative of the human activating NK receptor NKp80, possesses an amino-terminal hemITAM that is required for NKp65-mediated cytotoxicity. Finally, we show that KACL expression is mainly restricted to keratinocytes. Freshly isolated keratinocytes express KACL and are capable of stimulating NKp65-expressing cells in a KACL-dependent manner. Thus, we report a unique NKC-encoded receptor-ligand system that may fulfill a dedicated function in the immunobiology of human skin.
A new baenid turtle from the Upper Cretaceous (Maastrichtian) Hell Creek Formation of North Dakota and a preliminary taxonomic review of Cretaceous Baenidae
2010-03-01

ABSTRACT ABSTRACT A fragmentary skull from the Hell Creek Formation (Maastrichtian) of southwestern North Dakota represents a new taxon of baenid turtle named herein Gamerabaena sonsalla. The length of the frontals, jugal contribution to the labial ridge, and convex contact between the vomer and the pterygoids indicate its affinities with the clade Palatobaena, but the new taxon clearly lacks the great posterior expansion of the triturating surface, complete absence of a lingual ridge, subrectangular skull, and wide angle between the maxillae that diagnose Palatobaena spp. A maximum parsimony analysis provides strong support for G. sonsalla as sister taxon to Palatobaena spp. Gamerabaena sonsalla has several morphological features that are intermediate between Plesiobaena antiqua and the morphologically disparate Palatobaena spp., including orbits that are oriented slightly dorsally and moderately expanded posterior triturating surfaces. Our phylogenetic analysis, combined with stratigraphic arguments, indicates that our skull-based taxon G. sonsalla could belong to the shell-based taxon "Baena" hayi. Similarly, the skull taxa Hayemys latifrons and Eubaena cephalica may be synonymous with the shell taxa Thescelus insiliens and "Baena" hatcheri, respectively. ACKNOWLEDGMENTS We wish to thank the landowners, D. and M. Sonsalla, for donating the specimen to the North Dakota Heritage Center. Jim Parham, S. Modesto, and an anonymous reviewer made suggestions that significantly improved the manuscript. William Pinder assisted in the preparation of the specimens and J. Lyson and E. Schachner drew the figures. Funds for the preparation and illustrations of the specimen were provided by NSF grant IBN-0316025 to S. Gilbert. Additional funding for this project was provided by a National Science Foundation Graduate Research Fellowship to T.R.L. Much of the work for this paper was completed while T.R.L. was working with S. Gilbert at Swarthmore College.
BEES AND MELITTOPHILOUS PLANTS OF SECONDARY ATLANTIC FOREST HABITATS AT SANTA CATARINA ISLAND, SOUTHERN BRAZIL
2010-03-01

The present study contributes to the knowledge of the apifauna and its food sources on the Santa Catarina Island, SC, southern Brazil. Bees and their food sources were recorded through non-systematic collections, between November 1999 and April 2008, in several environments on the island. A total of 169 species of bees were captured on 126 species of melittophilous plants. The majority of plants recorded are subshrub and shrub species, with only nine species of trees. 91% of the bee species were collected on native plants, which represent 64% of plant species, while only seven species of bees (4%) were captured exclusively on exotic plants (27% of the plant species). In our study, we show the importance of non-arboreal native plants in maintaining a rich diversity of bees and we indicate plant species that can be used as target species in rapid surveys of the subtropical apifauna in Brazil. The spectrum of species with oligolectic habits and their pollen sources as well as the recording of new food sources for rare species in surveys of bees on flowers are discussed.
Interaction of Platelets and Inflammatory Endothelium in the Development and Progression of Coronary Artery Disease
2010-03-01

An expanding body of evidence emphasizes the role of platelets as initial actors in inflammatory diseases such as atherosclerosis. Platelets interact with leukocytes and endothelial cells and enforce monocyte transformation into macrophages. Platelets not only mediate the recruitment of leukocytes. They also bind oxidized phospholipids and may promote foam cell formation. Platelets furthermore recruit progenitor cells to the scene, which are able to differentiate into foam cells or endothelial cells, presumably depending on the local microenvironment. Furthermore, platelets are capable of promoting the recruitment of circulating dendritic cells and influencing their functions, thereby presumably modulating immune reactions in atherogenesis. Taken together, platelets may participate in the initiation, development, and total extent of atherosclerotic lesions.
Design of an automotive traffic sign recognition system targeting a multi-core SoC implementation
2010-03-01

This paper describes the design of an automotive traffic sign recognition application. All stages of the design process, starting on system-level with an abstract, pure functional model down to final hardware/software implementations on an FPGA, are shown. The proposed design flow tackles existing bottlenecks of today's system-level design processes, following an early model-based performance evaluation and analysis strategy, which takes into account hardware, software and real-time operating system aspects. The experiments with the traffic sign recognition application show, that the developed mechanisms are able to identify appropriate system configurations and to provide a seamless link into the underlying implementation flows.
Diagnostic and Therapeutic Potentials of Platelet Glycoprotein VI
2010-03-01

Platelets respond immediately to vascular injury by adhesion, aggregation, and thrombus formation. Disruption of the endothelial cell layer exposes extracellular matrix to the bloodstream. Collagen binding to platelet glycoprotein VI (GPVI) mediates the initial adhesion of the rolling platelet to the vascular wound. Signaling by GPVI leads to the onset of the platelet activation cascade that is finally crowned by a firm and shear-resistant integrin-based adhesive clot. Blockade of collagen binding to GPVI would prevent initial adhesion and further activation of the platelet and would have an enormous impact in antithrombotic therapy. Besides the therapeutical implication, radiolabeled GPVI gives us a valuable diagnostic means that may be used clinically for plaque imaging in the near future.
CD36 and Macrophage Scavenger Receptor A Modulate Foam Cell Formation via Inhibition of Lipid-Laden Platelet Phagocytosis
2010-03-01

CD34 (+) progenitor cells are a promising source of regeneration in atherosclerosis or ischemic heart disease. However, as recently published, CD34(+) progenitor cells have the potential to differentiate not only into endothelial cells but also into foam cells upon interaction with platelets. The mechanism of platelet-induced differentiation of progenitor cells into foam cells is as yet unclear. In the present study we investigated the role of scavenger receptor (SR)-A and CD36 in platelet-induced foam cell formation. Human CD34(+) progenitor cells were freshly derived from human umbilical veins and were co-incubated with platelets (2 x 10(8)/mL) up to 14 days resulting in large lipid-laden foam cells. Developing macrophages expressed SR-A, CD36, and Lox-1 as measured by fluorescent-activated cell sorting analysis. The presence of a blocking anti-CD36 or anti-SR-A antibody nearly abrogated foam cell formation, whereas anti-Lox-1 did not affect foam cell formation. Consistently blocking either anti-CD36 or anti-SR-A antibody significantly reduced the phagocytosis of lipid-laden platelets by macrophages. We conclude that CD36 and SR-A play an important role in platelet-induced foam cell formation from CD34(+) progenitor cells and thus represent a promising target to inhibit platelet-induced foam cell formation.
The Political Thinking of the Mainland Taishang: Some Preliminary Observations from the Field
2010-03-01

This article explores the political thinking of Taiwanese business people ( taishang) and factory managers ( taigan) on the Chinese mainland by drawing on qualitative data gathered between 2006 and 2008 in the Pearl River Delta and the Shanghai/ Kunshan metropolitan area. An ideal type of taishang is constructed to explain the major features of their identification with Taiwan, their perspectives on cross-Strait relations, their integration in Chinese society and their self-assessment as political actors in the shaping of cross-Strait relations. An important finding of this study is that the taishang is a rather apolitical figure who does not see much leeway to develop autonomous political leverage. However, this may change gradually as cross-Strait relations have eased significantly since the Kuomintang (KMT) (Guomindang) came to power in mid-2008 and the governments in Beijing and Taibei have experienced a rapprochement.