bluuebunny/crossref_metadata_2025_split huggingface dataset:
Convenient and useful synthesis of N‐carboxyanhydride monomers through selective cyclization of urethane derivatives of α‐amino acids
Authors: Koga Koichi , Sudo Atsushi , Nishida Haruo , Endo Takeshi 
Published: June 2009

AbstractA new convenient synthesis of N‐carboxyanhydrides (NCAs) of α‐amino acids was achieved by selective cyclization of urethane derivatives of α‐amino acids. The urethanes were readily synthesized via N‐carbamoylation of α‐amino acids by bis(4‐nitrophenyl)carbonate quantitatively. These urethanes having 4‐nitrophenoxy moiety were tolerant to air and moisture to allow their facile purification and storage. When the obtained urethanes were heated in 2‐butanone at 60 °C, they underwent the selective cyclization via intramolecular nucleophilic attack of the carboxyl moiety to the urethane moiety with releasing 4‐nitrophenol, leading to the successful formation of the corresponding NCAs. Addition of carboxylic acids remarkably stabilized the formed NCAs during the reaction, allowing their isolation in high yields. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3839–3844, 2009
End‐functionalized polystyrene by ATRP: A facile approach to primary amino and carboxylic acid terminal groups
Authors: Hegewald Jan , Pionteck Jürgen , Häußler Liane , Komber Hartmut , Voit Brigitte 
Published: June 2009

AbstractMonoamino‐terminated and monocarboxylic acid‐terminated polystyrenes containing active halogenated end groups were prepared by atom transfer radical polymerization (ATRP) using the so‐called initiator method and protective group chemistry. α‐Chloropropionates were synthesized and utilized as initiators containing the tert‐butoxycarbonyl (t‐BOC)‐protected amino and the tert‐butyl (t‐Bu)‐protected carboxylic acid function, respectively. Optimum polymerization conditions were attained using CuCl/N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDETA) as catalyst and 10 vol % n‐butanol as homogenizing agent at 110 °C. However, targeting larger quantities an alternative route was established employing 50 vol % N,N‐dimethylformamide (DMF). Subsequent hydrolysis of the ω‐tert‐butoxycarbonyl polystyrenes afforded well‐defined polymers with quantitative deprotection of the functional groups. Comparatively, thermolytic cleavage of the protective sites was studied. 1H NMR verified the quantitative removal of the t‐BOC‐protecting groups. Furthermore, the resulting α‐amino‐ω‐chloro polystyrenes were reacted with Sanger reagent to confirm the existence of the thereby converted primary amino groups. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3845–3859, 2009
Melt‐crystallization mechanism of poly(ethylene terephthalate)/multi‐walled carbon nanotubes prepared by in situ polymerization
Authors: Antoniadis G. , Paraskevopoulos K. M. , Bikiaris D. , Chrissafis K. 
Published: June 2009

AbstractA series of poly(ethylene terephthalate)/multi‐walled carbon nanotubes (PET/MWCNTs) nanocomposites were prepared by in situ polymerization using different amounts of multi‐walled carbon nanotubes (MWCNTs). The polymerization of poly(ethylene terephthalate) (PET) was carried out by the two‐stage melt polycondensation method. The intrinsic viscosity (IV) of the composites is ranged between 0.31 and 0.63 dL/g depending on the concentration of the MWCNTs. A decrease of IV was found by increasing MWCNTs content. This is due to the reactions taking place between the two components leading to branched and crosslinked macromolecules. These reactions are, mainly, responsible for thermal behavior of nanocomposites. The melting point of the nanocomposites was shifted to slightly higher temperatures by the addition till 0.55 wt % of MWCNTs while for higher concentration was reduced. The degree of crystallinity in all nanocomposites was, also, reduced by increasing MWCNTs amount. However, from crystallization temperature, it was found that MWCNTs till 1 wt % can enhance the crystallization rate of PET, whereas at higher content (2 wt %), the trend is the opposite due to the formation of crosslinked macromolecules. From the extended crystallization analysis, it was proved that MWCNTs act as nucleating agents for PET crystallization. Additionally, the crystallization mechanism due to the existence of MWCNT becomes more complicated because two mechanisms with different activation energies are taking place in the different degrees of crystallization, depending on the percentage of MWCNT. The effect of molecular weight also plays an important role. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1452–1466, 2009
Annealing behavior of the novel morphology of poly(butylene succinate) lath‐shaped single crystals
Authors: Duan Jiufang , Guo Baohua 
Published: June 2009

AbstractLamellar single crystals of poly(butylene succinate) (PBS) with novel morphologies were prepared from a chloroform/methanol solution by self‐seeding methods. Crystal structures and morphologies were investigated by means of atomic force microscopy (AFM). Lath‐shaped crystal and hexagonal‐shaped crystals coexist in one PBS single crystal and this has a lamellar thickness of around 5–6 nm as determined by AFM. The thickening of lamellae from 5–6 to 7–9 nm occurred during heating from 41 to 84 °C. In situ temperature‐controlled AFM observations demonstrated that the lath‐shaped crystal sections melted first and then the hexagonal sections while the edge of the single crystals remained regular during annealing. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1492–1496, 2009
CONOPS and autonomy recommendations for VTOL small unmanned aerial system based on Hurricane Katrina operations
Authors: Pratt Kevin S. , Murphy Robin , Stover Sam , Griffin Chandler 
Published: June 2009

AbstractThis field study examines vertical takeoff and landing (VTOL) small unmanned aerial system (SUAS) operations conducted as part of an 8‐day structural inspection task following Hurricane Katrina in 2005. From the observations of the 32 flights spread over 12 missions, four key findings are identified for concept of operations (CONOPS) and the next level of artificial intelligence for rotary‐wing SUASs operating in cluttered urban environments. These findings are (1) the minimum useful standoff distance from inspected structures is 2–5 m, (2) omnidirectional sensor capabilities are needed for obstacle avoidance, (3) global positioning system waypoint navigation is unnecessary, and (4) these operations require three operators for one SUAS. Based on the findings and other observations, a crewing organization and flight operations protocol for SUASs are proposed. Needed directions in research and development are also discussed. These recommendations are expected to contribute to the design of platforms, sensors, and artificial intelligence as well as facilitate the acceptance of SUASs in the workplace. © 2009 Wiley Periodicals, Inc.
Continuum limits for classical sequential growth models
Authors: Brightwell Graham , Georgiou Nicholas 
Published: June 2009

AbstractA random graph order, also known as a transitive percolation process, is defined by taking a random graph on the vertex set {0,…,n − 1} and putting i below j if there is a path i = i1…ik = j in the graph with i1 < … < ik.Rideout and Sorkin Phys. Rev. D 63 (2001) 104011 provide computational evidence that suitably normalized sequences of random graph orders have a “continuum limit.” We confirm that this is the case and show that the continuum limit is always a semiorder.Transitive percolation processes are a special case of a more general class called classical sequential growth models. We give a number of results describing the large‐scale structure of a general classical sequential growth model. We show that for any sufficiently large n, and any classical sequential growth model, there is a semiorder S on {0,…,n ‐ 1} such that the random partial order on {0,…,n ‐ 1} generated according to the model differs from S on an arbitrarily small proportion of pairs. We also show that, if any sequence of classical sequential growth models has a continuum limit, then this limit is (essentially) a semiorder. We give some examples of continuum limits that can occur.Classical sequential growth models were introduced as the only models satisfying certain properties making them suitable as discrete models for spacetime. Our results indicate that this class of models does not contain any that are good approximations to Minkowski space in any dimension ≥ 2. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2010
Space and sustainability. Potential for landscape as a spatial unit for assessing sustainability
Authors: Morse Stephen , Vogiatzakis Ioannis , Griffiths Geoff 
Published: June 2009

AbstractAssessment of sustainable development normally takes place within what can best be termed ‘administrative’ spaces (cities, regions, nation states etc.), where there is some managerial and policy control. Thus recommendations may be derived from an analysis of this space, for example the derivation of indicators and indices, which can feed more readily into decision‐making. They are alternatives to the use of defined ‘administrative’ spaces such as the ecosystem and landscape. The paper questions the viability of landscape as a viable spatial matrix for assessment of sustainability. Joint Character Areas (JCAs) in England were employed as the landscape space, and data were collected to assess environmental quality (via the creation of a Countryside Quality Index, CQI) and social deprivation (via the Townsend Index of Deprivation, TID) for each JCA, as these represent two dimensions of sustainability. Results suggest that when employing JCAs as the spatial matrix it is possible to derive a statistically significant regression between CQI as the independent variable as TDI as the dependent variable. Therefore landscape does have some viability as a space for assessing sustainability. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Sustainable development and cultural heritage management in Botswana: towards sustainable communities
Authors: Keitumetse Susan O. 
Published: June 2009

AbstractStrategies for the management of cultural heritage resources within a sustainable development concept framework are examined. In line with the 1992 Rio Declaration principles of sustainable development, the paper suggests sustainability principles relating to community participation as more relevant for the field of cultural heritage resource management in Botswana. The article illustrates this relevance by exploring and drawing out production and consumption indicators of cultural heritage resources in both their tangible and intangible composition. It concludes that participation principles of sustainable development are more applicable as a point of departure towards integration of sustainability into cultural heritage resource management as communities are carriers and immediate custodians of cultural resources in Africa. Conservation processes that set limits of acceptable change for resource use are suggested within a modified framework that links community interaction with cultural resources at both social and resource management levels. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Geostatistical analysis in clustering fMRI time series
Authors: Ye Jun , Lazar Nicole A. , Li Yehua 
Published: June 2009

AbstractClustering of functional magnetic resonance imaging (fMRI) time series—either directly or through characteristic features such as the cross‐correlation with the experimental protocol signal—has been extensively used for the identification of active regions in the brain. Both approaches have drawbacks; clustering of the time series themselves may identify voxels with similar temporal behavior that is unrelated to the stimulus, whereas cross‐correlation requires knowledge of the stimulus presentation protocol. In this paper we propose the use of autocorrelation structure instead—an idea borrowed from geostatistics; this approach does not suffer from the deficits associated with previous clustering methods. We first formalize the traditional classification methods as three steps: feature extraction, choice of classification metric and choice of classification algorithm. The use of different characteristics to effect the clustering (cross‐correlation, autocorrelation, and so forth) relates to the first of these three steps. We then demonstrate the efficacy of autocorrelation clustering on a simple visual task and on resting data. A byproduct of our analysis is the finding that masking prior to clustering, as is commonly done, may degrade the quality of the discovered clusters, and we offer an explanation for this phenomenon. Copyright © 2009 John Wiley & Sons, Ltd.
KLF4 and PBX1 Directly Regulate NANOG Expression in Human Embryonic Stem Cells
Authors: Chan Ken Kwok-Keung , Zhang Jingyao , Chia Na-Yu , Chan Yun-Shen , Sim Hui Shan , Tan Ker Sin , Oh Steve Kah-Weng , Ng Huck-Hui , Choo Andre Boon-Hwa 
Published: June 2009

Abstract
Insight into the regulation of core transcription factors is important for a better understanding of the molecular mechanisms that control self-renewal and pluripotency of human ESCs (hESCs). However, the transcriptional regulation of NANOG itself in hESCs has largely been elusive. We established a NANOG promoter luciferase reporter assay as a fast read-out for indicating the pluripotent status of hESCs. From the functional cDNA screens and NANOG promoter characterization, we successfully identified a zinc finger transcription factor KLF4 and a homeodomain transcription factor PBX1 as two novel transcriptional regulators that maintain the pluripotent and undifferentiated state of hESCs. We showed that both KLF4 and PBX1 mRNA and protein expression were downregulated during hESC differentiation. In addition, overexpression of KLF4 and PBX1 upregulated NANOG promoter activity and also the endogenous NANOG protein expression in hESCs. Direct binding of KLF4 on NANOG proximal promoter and PBX1 on a new upstream enhancer and proximal promoter were confirmed by chromatin immunoprecipitation and electrophoretic mobility shift assay. Knockdown of KLF4/PBX1 or mutation of KLF4/PBX1 binding motifs significantly downregulated NANOG promoter activity. We also showed that specific members of the SP/KLF and PBX family are functionally redundant at the NANOG promoter and that KLF4 and PBX1 cooperated with OCT4 and SOX2, and transactivated synergistically the NANOG promoter activity. Our results show two novel upstream transcription activators of NANOG that are functionally important for the self-renewal of hESC and provide new insights into the expanded regulatory circuitry that maintains hESC pluripotency.
Disclosure of potential conflicts of interest is found at the end of this article.
Adiponectin Stimulates Osteoblast Differentiation Through Induction of COX2 in Mesenchymal Progenitor Cells
Authors: Lee Hyun Woo , Kim Sang Yun , Kim A Young , Lee Eun Jig , Choi Je-Yong , Kim Jae Bum 
Published: June 2009

Abstract
In bone marrow, osteoblasts and adipocytes are differentiated from mesenchymal progenitor cells and their differentiation is reciprocally regulated by largely unknown mechanisms. In this study, we investigated downstream signaling cascades of adiponectin, a member of the adipocytokine family, in the regulation of osteoblast differentiation. Adiponectin augmented expression of several osteogenic marker genes and increased osteoblast differentiation in mesenchymal progenitor cells. The expression of cyclooxygenase-2 (COX2) was potently increased by adiponectin, whereas inhibition of COX2 activity abolished the effect of adiponectin on osteogenesis. In addition, adiponectin rapidly stimulated p38 mitogen-activated protein kinase via the adiponectin receptor, AdipoR1, which resulted in c-Jun activation for COX2 expression. Adiponectin also stimulated BMP2 expression in a COX2-dependent manner. Moreover, Runx2, a key osteogenic transcription factor, contributed to the acceleration of osteogenesis in the presence of adiponectin. Collectively, the finding that adiponectin could promote osteogenesis through an intracellular signaling cascade in mesenchymal progenitor cells suggests that adiponectin would be a potential therapeutic target for bone-related diseases.
Disclosure of potential conflicts of interest is found at the end of this article.
Adenoviral-Mediated Endothelial Precursor Cell Delivery of Soluble CD115 Suppresses Human Prostate Cancer Xenograft Growth in Mice
Authors: Lucas Trevor , Abraham Dietmar , Untergasser Gerold , Zins Karin , Hofer Erhard , Gunsilius Eberhard , Aharinejad Seyedhossein 
Published: June 2009

Abstract
Prostate cancer tumor growth and neovascularization is promoted by an interplay between migratory tumor stromal cells such as specialized tumor-associated macrophages (TAMs) and circulating endothelial precursor cells (CEPs). As vehicles for tumor therapy, human CEPs are relatively easy to isolate from peripheral blood, are able to proliferate long-term in vitro, are amenable to viral manipulation, and preferentially home to regions of ischemia found in growing tumors. We show here that human peripheral blood CEPs expanded ex vivo migrate to prostate cancer cells in vitro and efficiently home to human prostate tumor xenografts in vivo. Infection of precursors ex vivo with an adenovirus constructed to secrete a soluble form of the colony-stimulating factor-1 receptor CD115 that inhibits macrophage viability and migration in vitro significantly decreases the number of TAMs in xenografts (p &lt; .05), reduces proliferation (p &lt; .01) and vascular density (p &lt; .03), and suppresses the growth of xenografts (p &lt; .03). These data show for the first time that targeting stromal cell processes with cellular therapy has the potential to retard prostate tumor growth.
Disclosure of potential conflicts of interest is found at the end of this article.
Generation of Monoclonal Antibodies Specific for Cell Surface Molecules Expressed on Early Mouse Endoderm
Authors: Gadue Paul , Gouon-Evans Valerie , Cheng Xin , Wandzioch Ewa , Zaret Kenneth S , Grompe Markus , Streeter Philip R. , Keller Gordon M. 
Published: June 2009

Abstract
The development of functional cell populations such as hepatocytes and pancreatic β cells from embryonic stem cell (ESC) is dependent on the efficient induction of definitive endoderm early in the differentiation process. To monitor definitive endoderm formation in mouse ESC differentiation cultures in a quantitative fashion, we generated a reporter cell line that expresses human CD25 from the Foxa3 locus and human CD4 from the Foxa2 locus. Induction of these reporter ESCs with high concentrations of activin A led to the development of a CD25-Foxa3+CD4-Foxa2+ population within 4-5 days of culture. Isolation and characterization of this population showed that it consists predominantly of definitive endoderm that is able to undergo hepatic specification under the appropriate conditions. To develop reagents that can be used for studies on endoderm development from unmanipulated ESCs, from induced pluripotent stem cells, and from the mouse embryo, we generated monoclonal antibodies against the CD25-Foxa3+CD4-Foxa2+ population. With this approach, we identified two antibodies that react specifically with endoderm from ESC cultures and from the early embryo. The specificity of these antibodies enables one to quantitatively monitor endoderm development in ESC differentiation cultures, to study endoderm formation in the embryo, and to isolate pure populations of culture- or embryo-derived endodermal cells.
Disclosure of potential conflicts of interest is found at the end of this article.
Long-Term Safety and Function of RPE from Human Embryonic Stem Cells in Preclinical Models of Macular Degeneration
Authors: Lu Bin , Malcuit Christopher , Wang Shaomei , Girman Sergej , Francis Peter , Lemieux Linda , Lanza Robert , Lund Raymond 
Published: June 2009

Abstract
Assessments of safety and efficacy are crucial before human ESC (hESC) therapies can move into the clinic. Two important early potential hESC applications are the use of retinal pigment epithelium (RPE) for the treatment of age-related macular degeneration and Stargardt disease, an untreatable form of macular dystrophy that leads to early-onset blindness. Here we show long-term functional rescue using hESC-derived RPE in both the RCS rat and Elov14 mouse, which are animal models of retinal degeneration and Stargardt, respectively. Good Manufacturing Practice-compliant hESC-RPE survived subretinal transplantation in RCS rats for prolonged periods (&gt;220 days). The cells sustained visual function and photoreceptor integrity in a dose-dependent fashion without teratoma formation or untoward pathological reactions. Near-normal functional measurements were recorded at &gt;60 days survival in RCS rats. To further address safety concerns, a Good Laboratory Practice-compliant study was carried out in the NIH III immune-deficient mouse model. Long-term data (spanning the life of the animals) showed no gross or microscopic evidence of teratoma/tumor formation after subretinal hESC-RPE transplantation. These results suggest that hESCs could serve as a potentially safe and inexhaustible source of RPE for the efficacious treatment of a range of retinal degenerative diseases.
Disclosure of potential conflicts of interest is found at the end of this article.
Circulating Osteogenic Precursor Cells in Heterotopic Bone Formation
Authors: Suda Robin K. , Billings Paul C. , Egan Kevin P. , Kim Jung-Hoon , McCarrick-Walmsley Ruth , Glaser David L. , Porter David L. , Shore Eileen M. , Pignolo Robert J. 
Published: June 2009

AbstractCells with osteogenic potential can be found in a variety of tissues. Here we show that circulating osteogenic precursor (COP) cells, a bone marrow-derived type I collagen+/CD45+ subpopulation of mononuclear adherent cells, are present in early preosseous fibroproliferative lesions in patients with fibrodysplasia ossificans progressiva (FOP) and nucleate heterotopic ossification (HO) in a murine in vivo implantation assay. Blood samples from patients with FOP with active episodes of HO contain significantly higher numbers of clonally derived COP cell colonies than patients with stable disease or unaffected individuals. The highest level of COP cells was found in a patient just before the clinical onset of an HO exacerbation. Our studies show that even COP cells derived from an unaffected individual can contribute to HO in genetically susceptible host tissue. The possibility that circulating, hematopoietic-derived cells with osteogenic potential can seed inflammatory sites has tremendous implications and, to our knowledge, represents the first example of their involvement in clinical HO. Thus, bone formation is not limited to cells of the mesenchymal lineage, and circulating cells of hematopoietic origin can also serve as osteogenic precursors at remote sites of tissue inflammation.Disclosure of potential conflicts of interest is found at the end of this article.
Diagnosis in the first trimester of placenta accreta with previous Cesarean section
Authors: Yang J. I. , Kim H. Y. , Kim H. S. , Ryu H. S. 
Published: June 2009

AbstractThe prenatal diagnosis of adherent placenta is clinically very important, as this condition can seriously affect perinatal mortality and morbidity. The outcome is generally worse in cases with a history of Cesarean section. Here we report a case of placenta increta associated with previous Cesarean delivery, diagnosed by sonography during the first trimester, enabling earlier counseling of the parents and planning of appropriate treatment. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.