bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kriging metamodeling in seismic risk assessment based on stochastic ground motion models
Authors: Gidaris Ioannis , Taflanidis Alexandros A. , Mavroeidis George P. 
Published: May 2015

SummaryAn efficient computational framework is presented for seismic risk assessment within a modeling approach that utilizes stochastic ground motion models to describe the seismic hazard. The framework is based on the use of a kriging surrogate model (metamodel) to provide an approximate relationship between the structural response and the structural and ground motion parameters that are considered as uncertain. The stochastic character of the excitation is addressed by assuming that under the influence of the white noise (used within the ground motion model) the response follows a lognormal distribution. Once the surrogate model is established, a task that involves the formulation of an initial database to inform the metamodel development, it is then directly used for all response evaluations required to estimate seismic risk. The model prediction error stemming from the metamodel is directly incorporated within the seismic risk quantification and assessment, whereas an adaptive approach is developed to refine the database that informs the metamodel development. The ability to efficiently obtain derivative information through the kriging metamodel and its utility for various tasks within the probabilistic seismic risk assessment is also discussed. As an illustrative example, the assessment of seismic risk for a benchmark four‐story concrete office building is presented. The potential that ground motions include near‐fault characteristics is explicitly addressed within the context of this example. The implementation of the framework for the same structure equipped with fluid viscous dampers is also demonstrated. Copyright © 2015 John Wiley & Sons, Ltd.
Effective use of seismic response envelopes for reinforced concrete structures
Authors: Sessa Salvatore , Marmo Francesco , Rosati Luciano 
Published: May 2015

SummaryBy exploiting the theory of the response envelopes formulated by Menun and Der Kiureghian [Envelopes for seismic response vectors. I–Theory, J. Str. Engrg. 2000; 126(3); 467–473], an algorithmic approach for seismic analysis of reinforced concrete frames is presented. It aims to fill a gap between research on spectral analysis of structures and current design practice in which the use of seismic response envelopes, available since early 2000s, is hampered by the lack of efficient and robust implementations. The proposed strategy is based on customary features (such as modal shapes and response spectra) currently adopted in professional practice, and it takes advantage of recently published formulations for the evaluation of stress resultants in arbitrarily shaped reinforced concrete cross‐sections subjected to axial force and biaxial bending. Numerical applications are illustrated in order to show the procedure's efficiency and effectiveness. Copyright © 2015 John Wiley & Sons, Ltd.
Determinants of Regional Variation in Health Expenditures in Germany
Authors: Göpffarth Dirk , Kopetsch Thomas , Schmitz Hendrik 
Published: May 2015

SummaryHealth care expenditure in Germany shows clear regional differences. Such geographic variations are often seen as an indicator for inefficiency. With its homogeneous health care system, low co‐payments and uniform prices, Germany is a particularly suited example to analyse regional variations. We use data for the year 2011 on expenditure, utilization of health services and state of health in Germany's statutory health insurance system. This data, which originate from a variety of administrative sources and cover about 90% of the population, are enriched with a wealth of socio‐economic variables, data on pollutants, prices and individual preferences. State of health and demography explains 55% of the differences as measured by the standard deviation while all control variables account for a total of 72% of the differences at county level. With other measures of variation, we can account for an even greater proportion. A higher proportion of variation than usually supposed can thus be explained. Whilst this study cannot quantify inefficiencies, our results contradict the thesis that regional variations reflect inefficiency. Copyright © 2015 John Wiley & Sons, Ltd.
Head and neck second primary cancer rates in the human papillomavirus era: A population‐based analysis
Authors: Diaz Dayssy Alexandra , Reis Isildinha M. , Weed Donald T. , Elsayyad Nagy , Samuels Michael , Abramowitz Matthew C. 
Published: May 2015

AbstractBackgroundPatients with head and neck cancer are at high risk for second primary malignancies. Human papillomavirus (HPV)‐driven tumors are generally high‐grade oropharyngeal cancers. We analyzed the incidence of second primary malignancy of the head and neck in patients with primary squamous cell carcinoma (SCC) of the head and neck and temporal trends in the HPV era.MethodsThe Surveillance, Epidemiology, and End Results (SEER) database was queried for patients with SCC of the head and neck (range, 1973–2008). Cumulative incidence rates of second primary malignancy of the head and neck were compared based on competing risk analysis.ResultsA total of 104,639 cases were included in this study, of which 4616 patients had second primary malignancy of the head and neck. Oropharyngeal cancer incidence increased over time. Estimated incidence rate/10,000 person‐years (105.5, 80.6, and 50.2 for 1973–1989, 1990–1999, and 2000–2008, respectively) and cumulative incidence rates (10‐year rates of 6.68%, 5.72%, and 4.59% for 1973–1989, 1990–1999, and 2000–2008, respectively) of second primary malignancies of the head and neck for patients with oropharyngeal cancer decreased over time (p < .001). The second primary malignancy of the head and neck incidence rate was significantly lower in patients with high‐grade oropharyngeal cancer from 2000 to 2008 (30.3 vs 65.5 and 54.6 from 1973–1989 and 1990–1999, respectively; p < .001).ConclusionThe incidence of second primary malignancy of the head and neck in patients with head and neck cancer has decreased over time. This is driven by lower rates in patients with high‐grade oropharyngeal cancer, is temporally related with increases in HPV‐associated oropharyngeal cancer, and suggests that incidence rates of second primary malignancy of the head and neck may be lower for HPV‐associated cancer. © 2015 Wiley Periodicals, Inc. Head Neck 38: E873–E883, 2016
Effect of a second primary thyroid carcinoma on patients with head and neck squamous cell carcinoma
Authors: Tolisano Anthony M. , Klem Christopher , Lustik Michael B. , Sniezek Joseph C. , Golden J. Blake 
Published: May 2015

ABSTRACTBackgroundThe purpose of this study was to characterize the timing, histology, and behavior of second primary thyroid carcinoma (SPTC) developing after a diagnosis of head and neck squamous cell carcinoma (HNSCC).MethodsWe conducted a retrospective review of the Surveillance, Epidemiology, and End Results (SEER) 9 database.ResultsPatients with HNSCC who develop SPTC die 1.6 times sooner than those without SPTC. This effect is only seen if SPTC presents >6 months after diagnosis of HNSCC. Models were adjusted for age, sex, year of diagnosis, and location of HNSCC. There was no effect of prior radiation therapy on either mortality rates or time to development of thyroid cancer in patients with SPTC. The type of thyroid carcinoma that developed was similar between cohorts.ConclusionThe development of SPTC in patients with HNSCC results in decreased overall length of survival. © 2015 Wiley Periodicals, Inc. Head Neck 38: E890–E894, 2016
Lipid droplets formation in human endothelial cells in response to polyunsaturated fatty acids and 1‐methyl‐nicotinamide (MNA); confocal Raman imaging and fluorescence microscopy studies
Authors: Majzner Katarzyna , Chlopicki Stefan , Baranska Malgorzata 
Published: May 2015

In this work the formation of lipid droplets (LDs) in human endothelial cells culture in response to the uptake of polyunsaturated fatty acids (PUFAs) was studied. Additionally, an effect of 1‐methylnicotinamide (MNA) on the process of LDs formation was investigated. LDs have been previously described structurally and to some degree biochemically, however neither the precise function of LDs nor the factors responsible for LD induction have been clarified. Lipid droplets, sometimes referred in the literature as lipid bodies are organelles known to regulate neutrophil, eosinophil, or tumor cell functions but their presence and function in the endothelium is largely unexplored. 3D linear Raman spectroscopy was used to study LDs formation in vitro in a single endothelial cell. The method provides information about distribution and size of LDs as well as their composition. The incubation of endothelial cells with various PUFAs resulted in formation of LDs. As a complementary method for LDs identification a fluorescence microscopy was applied. Fluorescence measurements confirmed the Raman results suggesting endothelial cells uptake of PUFAs and subsequent LDs formation in the cytoplasm of the endothelium. Furthermore, MNA seem to potentiate intracellular uptake of PUFAs to the endothelium that may bear physiological and pharmacological significance.
Confocal Raman imaging of HAoEC cell with LDs.magnified imageConfocal Raman imaging of HAoEC cell with LDs.
Controlled release of simvastatin‐loaded thermo‐sensitive PLGA‐PEG‐PLGA hydrogel for bone tissue regeneration: in vitro and in vivo characteristics
Authors: Yan Qi , Xiao Li‐Qun , Tan Lei , Sun Wei , Wu Tao , Chen Liang‐Wen , Mei Yan , Shi Bin 
Published: May 2015

AbstractReports on the local delivery of drug loaded injectable hydrogels for bone regeneration are currently limited. This study assessed the effect of controlled simvastatin (SIM) release from a thermo‐sensitive hydrogel in vitro and in vivo. We successfully manufactured and evaluated thermo‐sensitive poly(d,l‐lactide‐co‐glycolide)‐poly(ethylene glycol)‐poly(d,l‐lactide‐co‐glycolide) triblock copolymers (PLGA‐PEG‐PLGA) loaded with SIM. The osteogenic effect of this hydrogel was tested in vitro and in vivo. MC‐3T3 E1 cells proliferation and osteoblastic differentiation was analyzed after cultivation with the hydrogel extracts. Cells co‐cultured with SIM/PLGA‐PEG‐PLGA extracts showed an increase in mineralization and osteogenic gene expression compared to the other two groups. Additionally, the characteristics of this composite in vivo were demonstrated using a rat bone defect model. The bone defects injected with SIM/PLGA‐PEG‐PLGA hydrogel showed increased new bone formation compared to samples treated with PLGA‐PEG‐PLGA and control samples. The results of this study suggest that SIM/PLGA‐PEG‐PLGA might provide potential therapeutic value for bone healing. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3580–3589, 2015.
Scaffolds with shape memory behavior for the treatment of large bone defects
Authors: Rychter Piotr , Pamula Elzbieta , Orchel Arkadiusz , Posadowska Urszula , Krok‐Borkowicz Małgorzata , Kaps Anna , Smigiel‐Gac Natalia , Smola Anna , Kasperczyk Janusz , Prochwicz Wojciech , Dobrzynski Piotr 
Published: May 2015

AbstractThe aim of the presented study was preparation, analysis of properties, and in vitro characterization of porous shape‐memory scaffolds, designed for large bone defects treatment using minimally invasive surgery approach. Biodegradable terpolymers of l‐lactide/glycolide/trimethylene carbonate (LA/GL/TMC) and l‐lactide/glycolide/ε‐caprolactone (LA/GL/Cap) were selected for formulation of these scaffolds. Basic parameters of shape memory behavior (i.e. recovery ratio, recovery time) and changes in morphology (SEM, average porosity) and properties (surface topography, water contact angle, compressive strength) during shape memory cycle were characterized. The scaffolds preserved good mechanical properties (compressive strength about 0.7 to 0.9 MPa) and high porosity (more than 80%) both in initial shape as well as after return from compressed shape. Then the scaffolds in temporary shape were inserted into the model defect of bone tissue at 37°C. After 12 min the defect was filled completely as a result of shape recovery process induced by body temperature. The scaffold obtained from LA/GL/TMC terpolymer was found the most prospective for the planned application thanks to its appropriate recovery time, high recovery ratio (more than 90%), and cytocompatibility in contact with human osteoblasts and chondrocytes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3503–3515, 2015.
Biological responses of preosteoblasts to particulate and ion forms ofCo‐Cr alloy
Authors: Yang Shuye , Zhang Kai , Li Fangfang , Jiang Jianhao , Jia Tanghong , Yang Shang‐You 
Published: May 2015

AbstractThis study compared the particulate and ion forms of a cobalt‐chrome (Co‐Cr) alloy on the differentiation/activation of preosteoblasts. Mouse preosteoblasts (MC3T3‐E1) were cultured in an osteoblast‐induction medium in the presence of particulate and ion forms of a Co‐Cr alloy, followed by cell proliferation and cytotoxicity evaluations. The maturation and function of osteoblasts were assessed by alkaline phosphatase (ALP) assay and related gene expressions. Both particulate and ion forms of the metals significantly reduced the proliferation of MC3T3‐E1 cells in a dose‐dependent manner. Similarly, cells challenged with high concentrations of particles and ions exhibited a marked cytotoxic effect and diminished expression of ALP. Real‐time (RT) polymerase chain reaction (PCR) data have suggested that cells with Co‐Cr particles dramatically promoted over‐expression of monocyte chemo‐attractant protein‐1 (MCP‐1), tumor necrosis factor‐α (TNF‐α), and interleukin‐6 (IL‐6), whereas Co2+ions treatment predominately up‐regulated expressions of receptor activator of nuclear factor kappa‐B ligand (RANKL), nuclear factor of activated T‐cells cytoplasmic 1 (NFATc1), and down‐regulated expression of osteoprotegerin (OPG) and Osterix (Osx). Overall, this study provides evidence that both Co‐Cr alloy particles and metal ions interfered with the MC3T3‐E1 cells for their growth, maturation, and functions. Further, Co‐Cr particles exhibited stronger effects on inflammatory mediators, while metal ions showed more influence on inhibition of osteoblast differentiation and promotion of osteoclastogenesis. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3564–3571, 2015.
BMP2 Regulation of CXCL12 Cellular, Temporal, and Spatial Expression Is Essential During Fracture Repair
Authors: Myers Timothy J , Longobardi Lara , Willcockson Helen , Temple Joseph D , Tagliafierro Lidia , Ye Ping , Li Tieshi , Esposito Alessandra , Moats-Staats Billie M , Spagnoli Anna 
Published: May 2015

ABSTRACT

The cellular and humoral responses that orchestrate fracture healing are still elusive. Here we report that bone morphogenic protein 2 (BMP2)-dependent fracture healing occurs through a tight control of chemokine C-X-C motif-ligand-12 (CXCL12) cellular, spatial, and temporal expression. We found that the fracture repair process elicited an early site-specific response of CXCL12+-BMP2+ endosteal cells and osteocytes that was not present in unfractured bones and gradually decreased as healing progressed. Absence of a full complement of BMP2 in mesenchyme osteoprogenitors (BMP2cKO/+) prevented healing and led to a dysregulated temporal and cellular upregulation of CXCL12 expression associated with a deranged angiogenic response. Healing was rescued when BMP2cKO/+ mice were systemically treated with AMD3100, an antagonist of CXCR4 and agonist for CXCR7 both receptors for CXCL12. We further found that mesenchymal stromal cells (MSCs), capable of delivering BMP2 at the endosteal site, restored fracture healing when transplanted into BMP2cKO/+ mice by rectifying the CXCL12 expression pattern. Our in vitro studies showed that in isolated endosteal cells, BMP2, while inducing osteoblastic differentiation, stimulated expression of pericyte markers that was coupled with a decrease in CXCL12. Furthermore, in isolated BMP2cKO/cKO endosteal cells, high expression levels of CXCL12 inhibited osteoblastic differentiation that was restored by AMD3100 treatment or coculture with BMP2-expressing MSCs that led to an upregulation of pericyte markers while decreasing platelet endothelial cell adhesion molecule (PECAM). Taken together, our studies show that following fracture, a CXCL12+-BMP2+ perivascular cell population is recruited along the endosteum, then a timely increase of BMP2 leads to downregulation of CXCL12 that is essential to determine the fate of the CXCL12+-BMP2+ to osteogenesis while departing their supportive role to angiogenesis. Our findings have far-reaching implications for understanding mechanisms regulating the selective recruitment of distinct cells into the repairing niches and the development of novel pharmacological (by targeting BMP2/CXCL12) and cellular (MSCs, endosteal cells) interventions to promote fracture healing. © 2015 American Society for Bone and Mineral Research.
Aberrant Activation of TGF-β in Subchondral Bone at the Onset of Rheumatoid Arthritis Joint Destruction
Authors: Xu Xin , Zheng Liwei , Bian Qin , Xie Liang , Liu Wenlong , Zhen Gehua , Crane Janet L , Zhou Xuedong , Cao Xu 
Published: May 2015

ABSTRACT

Rheumatoid arthritis (RA) is an autoimmune disease that often leads to joint destruction. A myriad of drugs targeting the immune abnormalities and downstream inflammatory cascades have been developed, but the joint destruction is not effectively halted. Here we report that aberrant activation of TGF-β in the subchondral bone marrow by immune response increases osteoprogenitors and uncoupled bone resorption and formation in RA mouse/rat models. Importantly, either systemic or local blockade of TGF-β activity in the subchondral bone attenuated articular cartilage degeneration in RA. Moreover, conditional deletion of TGF-β receptor II (Tgfbr2) in nestin-positive cells also effectively halted progression of RA joint destruction. Our data demonstrate that aberrant activation of TGF-β in the subchondral bone is involved at the onset of RA joint cartilage degeneration. Thus, modulation of subchondral bone TGF-β activity could be a potential therapy for RA joint destruction. © 2015 American Society for Bone and Mineral Research
Age‐dependency of glycosaminoglycan content in lumbar discs: A 3t gagcEST study
Authors: Müller‐Lutz Anja , Schleich Christoph , Pentang Gael , Schmitt Benjamin , Lanzman Rotem S. , Matuschke Felix , Wittsack Hans‐Jörg , Miese Falk 
Published: May 2015

PurposeTo analyze age‐dependency of glycosaminoglycan content using gagCEST (glycosaminoglycan chemical exchange saturation transfer) imaging in lumbar intervertebral discs of healthy volunteers.Materials and MethodsIn all, 70 volunteers without low back pain (mean age 44 ± 14 years, range: 21–69 years) were examined with T2‐weighted and gagCEST imaging with a 3T MR scanner, with approval of the local Ethics Committee after written informed consent was obtained. Pfirrmann grading and classification into discs without bulging and herniation, discs with bulging, and discs with herniation were performed. Only intervertebral discs without bulging and herniation were analyzed. A region‐of‐interest‐based gagCEST analysis of nucleus pulposus (NP) and annulus fibrosus (AF) was performed. Correlation between age and gagCEST was tested within groups of equal Pfirrmann score.ResultsGagCEST effects decreased significantly from 3.09 ± 1.12% in 20–29 years old volunteers to −0.24 ± 1.36% in 50–59 years old volunteers (P < 0.001). In the case of Pfirrmann scores 2 and 3, a significant correlation was observed between gagCEST effect and age (Pfirrmann score 2, NP: ρ = –0.558, P < 0.001; Pfirrmann score 3, NP: ρ = –0.337, P = 0.048). For Pfirrmann scores 1 and 4, no significant correlation was obtained (Pfirrmann score 1, NP: ρ = –0.046, P = 0.824; Pfirrmann score 4, NP: ρ = –0.316, P = 0.188).ConclusionWe show a decreased gagCEST effect likely corresponding to decreasing glycosaminoglycans with aging. Hence, age‐matched analysis of gagCEST imaging may be necessary in future studies. J. MAGN. RESON. IMAGING 2015;42:1517–1523.
Exploring the Implications of Virtual Reality Technology in Tourism Marketing: An Integrated Research Framework
Authors: Huang Yu Chih , Backman Kenneth Frank , Backman Sheila J. , Chang Lan Lan 
Published: May 2015

AbstractThe proliferation of the Internet and other technological innovations has transformed the structure of the tourism industry as well as affected how tourism destinations are perceived and consumed. The 3D virtual world provides opportunities for destination marketing organizations to communicate with targeted markets by offering a rich environment for potential visitors to explore tourism destinations. However, as of yet, there is little understanding about how to effectively market tourism destinations to virtual world participants who are technology users as well as potential consumers. The purpose of the present study is to develop a research framework that integrates the technology acceptance model (TAM) and self‐determination theory to understand how tourists use a 3D virtual world. Primary data were obtained for this study through self‐administered Web questionnaires. The data were conducted in a laboratory setting with 186 participants. This study contributes to the empirical TAM literature by applying the model to a 3D virtual tourism site. Additionally, this study provides a research framework to capture the entertainment nature of a 3D virtual world by extending the TAM to incorporate psychological elements of self‐determination theory to understand consumer experience. From the perspective of tourism professionals, this study contributes to an understanding of how best to construct informative and interactive tourist destinations in 3D virtual worlds to attract potential online and real‐world tourists. Copyright © 2015 John Wiley & Sons, Ltd.
Supplemental Activator and Reducing Agent Atom Transfer Radical Polymerization of 2‐Hydroxyethyl Acrylate from High Molar Mass Poly(ethylene oxide) Macroinitiator in Dilute Solution
Authors: Nicol Erwan , Nzé René‐Ponce 
Published: May 2015

Triple hydrophilic asymmetric poly(2‐hydroxyethyl acrylate)‐b‐poly(ethylene oxide)‐b‐poly(2‐hydroxyethyl acrylate) (PHEA‐b‐PEO‐b‐PHEA) triblock copolymers are obtained by copper(0) catalyzed reversible deactivation radical polymerization (RDRP). Copper wire catalyzed polymerization of HEA from large PEO (Mn = 35 000 g mol−1) macroinitiator in dimethylsulfoxide or in water fails to reach high monomer conversion in a controlled manner contrary to what is previously published with a shorter PEO macroinitiator. Catalysis by nascent Cu(0) particles generated by disproportionating CuBr in water allows rapid polymerization and high monomer conversion with a rather good control of both dispersity and HEA block length. Model disproportionation experiment shows that HEA influences the disproportionation/comproportionation equilibrium. Larger quantities of HEA lead to higher apparent rate constants and less disproportionation of CuBr which is in agreement with the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) mechanism and not with the single electron transfer–living radical polymerization (SET‐LRP) mechanism.
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