bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement error in two‐stage analyses, with application to air pollution epidemiology
Authors: Szpiro Adam A. , Paciorek Christopher J. 
Published: January 2014

AbstractPublic health researchers often estimate health effects of exposures (e.g., pollution, diet, and lifestyle) that cannot be directly measured for study subjects. A common strategy in environmental epidemiology is to use a first‐stage (exposure) model to estimate the exposure on the basis of covariates and/or spatiotemporal proximity and to use predictions from the exposure model as the covariate of interest in the second‐stage (health) model. This induces a complex form of measurement error. We propose an analytical framework and methodology that is robust to misspecification of the first‐stage model and provides valid inference for the second‐stage model parameter of interest.We decompose the measurement error into components analogous to classical and Berkson errors and characterize properties of the estimator in the second‐stage model if the first‐stage model predictions are plugged in without correction. Specifically, we derive conditions for compatibility between the first‐stage and second‐stage models that guarantee consistency (and have direct and important real‐world design implications), and we derive an asymptotic estimate of finite‐sample bias when the compatibility conditions are satisfied. We propose a methodology that does the following: (i) corrects for finite‐sample bias; and (ii) correctly estimates standard errors. We demonstrate the utility of our methodology in simulations and an example from air pollution epidemiology. Copyright © 2013 John Wiley & Sons, Ltd.
Detailed analysis of a smouldering fire scenario at the murder scene experimental and numerical investigations
Authors: Hofmann Anja , Knaust Christian , Krüger Simone , Raspe Tina , Deubel Jan H. 
Published: January 2014

SUMMARYBased on forensic evidence, a smouldering fire was observed to have occurred at a murder scene. Identification of a reasonable timeline – specifically the fire dynamics of the ignition and fire growth that occurred coincident with the death that took place – became an important focus of the criminal investigation that followed. The fire service was called when a neighbour saw a grey smoke escaping through the ventilation system of the bathrooms on the roof of the house. One flat door with elevated temperatures was found. The fire fighter who entered the flat first reported later that the flat was completely filled with smoke and all windows were closed. When the fire fighter opened the balcony door, he saw flames on the sofa that he extinguished. Then he found a body on the floor. The autopsy showed later that the victim was dead before the fire started. The police suspected that the murderer probably had deliberately set the fire to destroy evidence. One suspect had been witnessed to be in the flat approximately 2 h before the fire was detected by the neighbour. The aim of this project was to investigate how the fire most likely started and developed. Copyright © 2014 John Wiley & Sons, Ltd.
Biembedding Steiner Triple Systems in Surfaces Using the Bose Construction
Authors: Griggs T. S. , Psomas C. , Širáň J. 
Published: January 2014

AbstractA uniform framework is presented for biembedding Steiner triple systems obtained from the Bose construction using a cyclic group of odd order, in both orientable and nonorientable surfaces. Within this framework, in the nonorientable case, a formula is given for the number of isomorphism classes and the particular biembedding of Ducrocq and Sterboul (preprint 18pp., 1978) is identified. In the orientable case, it is shown that the biembedding of Grannell et al. (J Combin Des6(), 325–336) is, up to isomorphism, the unique biembedding of its type. Automorphism groups of the biembeddings are also given.
Smad6 Suppresses the Growth and Self‐Renewal of Hepatic Progenitor Cells
Authors: Ding Ze‐Yang , Liang Hui‐Fang , Jin Guan‐Nan , Chen Wei‐Xun , Wang Wei , Datta Pran K. , Zhang Ming‐Zhi , Zhang Bixiang , Chen Xiao‐Ping 
Published: January 2014

AbstractActivation of hepatic progenitor cells (HPCs) is commonly observed in chronic liver disease and Wnt/β‐catenin signaling plays a crucial role in the expansion of HPCs. However, the molecular mechanisms that regulate the activation of Wnt/β‐catenin signaling in the liver, especially in HPCs, remain largely elusive. Here, we reported that ectopic expression of Smad6 suppressed the proliferation and self‐renewal of WB‐F344 cells, a HPC cell line. Mechanistically, we found that Smad6 inhibited Wnt/β‐catenin signaling through promoting the interaction of C‐terminal binding protein (CtBP) with β‐catenin/T‐cell factor (TCF) complex to inhibit β‐catenin mediated transcriptional activation in WB‐F344 cells. We used siRNA targeting β‐catenin to demonstrate that Wnt/β‐catenin signaling was required for the proliferation and self‐renewal of HPCs. Taken together, these results suggest that Smad6 is a regulatory molecule which regulates the proliferation, self‐renewal and Wnt/β‐catenin signaling in HPCs. J. Cell. Physiol. 229: 651–660, 2014. © 2013 Wiley Periodicals, Inc.
Modeling of 24‐hour glucose and insulin profiles in patients with type 2 diabetes mellitus treated with biphasic insulin aspart
Authors: Røge Rikke M. , Klim Søren , Kristensen Niels R. , Ingwersen Steen H. , Kjellsson Maria C. 
Published: January 2014

AbstractInsulin therapy for diabetes patients is designed to mimic the endogenous insulin response of healthy subjects and thereby generate normal blood glucose levels. In order to control the blood glucose in insulin‐treated diabetes patients, it is important to be able to predict the effect of exogenous insulin on blood glucose. A pharmacokinetic/pharmacodynamic model for glucose homoeostasis describing the effect of exogenous insulin would facilitate such prediction. Thus the aim of this work was to extend the previously developed integrated glucose–insulin (IGI) model to predict 24‐hour glucose profiles for patients with Type 2 diabetes following exogenous insulin administration. Clinical data from two trials were included in the analysis. In both trials, 24‐hour meal tolerance tests were used as the experimental setup, where exogenous insulin (biphasic insulin aspart) was administered in relation to meals. The IGI model was successfully extended to include the effect of exogenous insulin. Circadian variations in glucose homeostasis were assessed on relevant parameters, and a significant improvement was achieved by including a circadian rhythm on the endogenous glucose production in the model. The extended model is a useful tool for clinical trial simulation and for elucidating the effect profile of new insulin products.
Orientable Hamilton Cycle Embeddings of Complete Tripartite Graphs II: Voltage Graph Constructions and Applications
Authors: Ellingham M. N. , Schroeder Justin Z. 
Published: January 2014

AbstractIn an earlier article the authors constructed a hamilton cycle embedding of in a nonorientable surface for all and then used these embeddings to determine the genus of some large families of graphs. In this two‐part series, we extend those results to orientable surfaces for all . In part II, a voltage graph construction is presented for building embeddings of the complete tripartite graph on an orientable surface such that the boundary of every face is a hamilton cycle. This construction works for all such that p is prime, completing the proof started by part I (which covers the case ) that there exists an orientable hamilton cycle embedding of for all , . These embeddings are then used to determine the genus of several families of graphs, notably for and, in some cases, for .
Analysis of new biomarkers for cholangiocarcinoma
Authors: Miwa Masanao , You Gyokukou , Tanaka Hideaki , Taniguchi Seigo , Fujii Takahiro , Kamemura Kazuo , Suzaki Masafumi , Isono Takahiro , Tooyama Ikuo , Tanaka Masakazu , Srivatanakul Petcharin , Viwatthanasittiphong Chutiwan , Sangrajrang Suleeporn , Khuhaprema Thiravud 
Published: January 2014

Abstract Cholangiocarcinoma is one of the most serious diseases in northeast Thailand, where its incidence is reported to be the highest in the world. We tried to develop a new method to detect cholangiocarcinoma in the early stages using serum proteins. We found that after fluorescent labeling of the sugar moiety of serum proteins, a new peak was identified, which might be a promising marker for cholangiocarcinoma.
Three‐dimensional through‐time radial GRAPPA for renal MR angiography
Authors: Wright Katherine L. , Lee Gregory R. , Ehses Philipp , Griswold Mark A. , Gulani Vikas , Seiberlich Nicole 
Published: January 2014

PurposeTo achieve high temporal and spatial resolution for contrast‐enhanced time‐resolved MR angiography exams (trMRAs), fast imaging techniques such as non‐Cartesian parallel imaging must be used. In this study, the three‐dimensional (3D) through‐time radial generalized autocalibrating partially parallel acquisition (GRAPPA) method is used to reconstruct highly accelerated stack‐of‐stars data for time‐resolved renal MRAs.Materials and MethodsThrough‐time radial GRAPPA has been recently introduced as a method for non‐Cartesian GRAPPA weight calibration, and a similar concept can also be used in 3D acquisitions. By combining different sources of calibration information, acquisition time can be reduced. Here, different GRAPPA weight calibration schemes are explored in simulation, and the results are applied to reconstruct undersampled stack‐of‐stars data.ResultsSimulations demonstrate that an accurate and efficient approach to 3D calibration is to combine a small number of central partitions with as many temporal repetitions as exam time permits. These findings were used to reconstruct renal trMRA data with an in‐plane acceleration factor as high as 12.6 with respect to the Nyquist sampling criterion, where the lowest root mean squared error value of 16.4% was achieved when using a calibration scheme with 8 partitions, 16 repetitions, and a 4 projection × 8 read point segment size.Conclusion3D through‐time radial GRAPPA can be used to successfully reconstruct highly accelerated non‐Cartesian data. By using in‐plane radial undersampling, a trMRA can be acquired with a temporal footprint less than 4s/frame with a spatial resolution of approximately 1.5 mm × 1.5 mm × 3 mm. J. Magn. Reson. Imaging 2014;40:864–874. © 2014 Wiley Periodicals, Inc.
Antimicrobial potentials of active component isolated from Citrullus colocynthis fruits and structure–activity relationships of its analogues against foodborne bacteria
Authors: Kim Min‐Gi , Lee Sung‐Eun , Yang Ji‐Yeon , Lee Hoi‐Seon 
Published: January 2014

AbstractBACKGROUNDSynthetic preservatives have been consistently used to maintain the quality of food products. However, the degree of danger to human health cannot be ignored. In this study, the antimicrobial activities of Citrullus colocynthis fruits and 4‐methylquinoline analogues were investigated to develop natural preservatives against foodborne bacteria.RESULTSAntimicrobial activities of the methanol extract and five fractions derived from C. colocynthis fruits were evaluated against five foodborne bacteria. The chloroform fraction possessed strong activities against five foodborne bacteria. 4‐Methylquinoline was isolated by chromatographic analyses. To establish the structure–activity relationships, the antimicrobial activities of 4‐methylquinoline analogues (2‐hydroxyquinoline, 4‐hydroxyquinoline, 6‐hydroxyquinoline, 2‐methylquinoline, 6‐methyquinoline, 8‐methylquinoline and 2‐methyl‐8‐hydroxyquinoline) were tested against food‐borne bacteria. When employing the agar diffusion method, 2‐methyl‐8‐hydroxyquinoline was found to have potent activities against the five foodborne bacteria. In terms of minimum bactericidal concentration or minimum inhibitory concentration, 2‐methyl‐8‐hydroxyquinoline had significantly higher antimicrobial activity against the five foodborne bacteria.CONCLUSIONCitrullus colocynthis fruits and 4‐methylquinoline analogues could be useful for the development of eco‐friendly food supplemental agents and pharmaceuticals. © 2014 Society of Chemical Industry
Prognostic significance of lymph node status in patients with metastatic colorectal carcinoma treated with lymphadenectomy
Authors: Liu Yan‐Long , Xu Hai‐tao , Jiang Shi‐Xiong , Yang Yan‐Mei , Cui Bin‐Bin 
Published: January 2014

Background and ObjectivesTo test prognostic significance of lymph node status in patients with metastatic colorectal carcinoma (mCRC).MethodsFour hundred ninety six patients diagnosed with synchronous mCRC and treated with lymphadenectomy between 1995 and 2008 were identified and divided into groups pN0, pN1, and pN2 (140 (28.2%) in pN0, 223 (45.0%) in pN1, and 133 (26.8%) in pN2 group) according to their lymph node status. The Kaplan–Meier and Cox regression analyses were used to test associations and independent predictor status of lymph node involvement.ResultsThe Cox proportional hazards regression showed pN as significantly associated with disease‐specific survival (DSS) both in univariate (HR = 1.609, 95% CI 1.411 to 1.835, P < 0.001) and multivariate (HR = 1.630, 95% CI 1.422 to 1.868, P < 0.001) analyses. The Kaplan–Meier analysis demonstrated that patients with pN2 and pN1 had a significantly worse DSS compared with patients with pN0 tumors (respectively, 17.273 ± 1.020 and 27.145 ± 1.715 vs. 34.992 ± 2.143 months; P < 0.001). In accuracy analyses based on AUC values, nodal status demonstrated the highest accuracy (65.1%) out of all the variables.ConclusionsOur findings indicate that optimal TNM staging for mCRC should incorporate lymph node status to provide a more effective and predictive model. J. Surg. Oncol. © 2014 Wiley Periodicals, Inc.
Shape‐Memory Effect by Specific Biodegradable Polymer Blending for Biomedical Applications
Authors: Cha Kook Jin , Lih Eugene , Choi Jiyeon , Joung Yoon Ki , Ahn Dong Jun , Han Dong Keun 
Published: January 2014

AbstractSpecific biodegradable polymers having shape‐memory properties through “polymer‐blend” method are investigated and their shape‐switching in body temperature (37 °C) is characterized. Poly(L‐lactide‐co‐caprolactone) (PLCL) and poly(L‐lactide‐co‐glycolide) (PLGA) are dissolved in chloroform and the films of several blending ratios of PLCL/PLGA are prepared by solvent casting. The shape‐memory properties of films are also examined using dynamic mechanical analysis (DMA). Among the blending ratios, the PLCL50/PLGA50 film shows good performance of shape‐fixity and shape‐recovery based on glass transition temperature. It displays that the degree of shape recovery is 100% at 37 °C and the shape recovery proceeds within only 15 s. In vitro biocompatibility studies are shown to have good blood compatibility and cytocompatibility for the PLCL50/PLGA50 films. It is expected that this blended biodegradable polymer can be potentially used as a material for blood‐contacting medical devices such as a self‐expended vascular polymer stents and vascular closure devices in biomedical applications.
Reduced cortical plasticity and GABAergic modulation in essential tremor
Authors: Chuang Wen‐Li , Huang Ying‐Zu , Lu Chin‐Song , Chen Rou‐Shayn 
Published: January 2014

ABSTRACTEssential tremor (ET) is the most common movement disorder among adults. Cerebellar dysfunction is thought to be involved in the pathogenesis of ET; however, imaging, electrophysiological studies, and clinical observations have suggested that the cerebral cortex also may participate. We sought to investigate the possible motor cortical contribution to ET by assessing response to continuous theta‐burst stimulation (cTBS), a recognized tool that can produce transient plastic changes, in the primary motor and premotor cortex of patients with ET. We compared parameters, including motor‐evoked potential amplitude, cortical silent period, and short‐interval intracortical inhibition, before and after applying cTBS in healthy controls and patients with ET. We found that, although cTBS applied to either the motor or premotor cortex was capable of producing a suppressive effect on motor cortical excitability in ET patients, the effects lasted for a significantly shorter time compared with the effect produced in healthy individuals. The change seen in measures of intracortical inhibition after motor cortical or premotor cTBS in healthy controls was reduced or absent in the ET patients. Tremor amplitude was decreased significantly after applying cTBS over either the motor or premotor cortex, but the tremor frequency remained unchanged. These findings suggest that inhibitory circuits within the motor cortex are aberrant and less modifiable in ET patients. The reduced plasticity in response to motor and premotor TBS supports the theory of abnormal gamma‐aminobutyric acid (GABA) modulation in ET. © 2014 International Parkinson and Movement Disorder Society
Multilevel ordinal factor analysis of the Positive and Negative Syndrome Scale (PANSS)
Authors: Stochl Jan , Jones Peter B. , Plaistow James , Reininghaus Ulrich , Priebe Stefan , Perez Jesus , Croudace Tim J. 
Published: January 2014

AbstractClinical assessments of the presence and severity of psychopathology are often collected by health care professionals in mental health services or clinical researchers trained to use semi‐structured interviews. Clustering by interviewer or rater needs to be considered when performing psychometric analyses such as factor analysis or item response modelling as non‐independence of observations arises in these situations. We apply more suitable multilevel methods to analyse ordinally scored Positive and Negative Syndrome Scale (PANSS) items. Our aim is to highlight the differences in results that occur when the data are analysed using a hierarchically sensitive approach rather than using a traditional (aggregated) analysis. Our sample (n = 507) consisted of patients diagnosed with schizophrenia who participated in a multi‐centre randomized control clinical trial, the DIALOG study. Analyses reported and compared include an exploratory factor analysis as well as several recently published multifactor models re‐estimated within a confirmatory analysis framework. Our results show that the fit of the model and the parsimony of the exploratory factor analysis (EFA) models indicated by the number of factors necessary to explain the inter‐correlation among PANSS items improved significantly when data clustering is taken into account through multilevel analysis. Our modeling results support the pentagonal PANSS model first proposed by White et al. (1997). Copyright © 2014 John Wiley & Sons, Ltd.
Thermal behavior of poly(vinylbenzyl chloride)‐grafted poly(ethylene‐co‐tetrafluoroethylene) films
Authors: Song Ju‐Myung , Lee Sun‐Young , Woo Hyun‐Su , Sohn Joon‐Yong , Shin Junhwa 
Published: January 2014

ABSTRACTThe effect of the degree of grafting (DOG) on the thermal behavior of poly(vinylbenzyl chloride)‐grafted poly(ethylene‐co‐tetrafluoroethylene) (ETFE‐g‐PVBC) films was investigated by differential scanning calorimetry (DSC), X‐ray diffraction (XRD), dynamic mechanical analysis (DMA), FT‐IR, and thermogravimetric analysis (TGA) instruments. Several ETFE‐g‐PVBC films with various degrees of grafting, including 10, 24, 41, 60, and 94%, were prepared using a radiation grafting technique. The DSC and XRD results of the ETFE‐g‐PVBC films revealed that the crystallinity of the films decreased as the DOG increased. The DMA and FT‐IR results of the films indicated that a crosslinking reaction occurred at temperatures above 250 °C. In the thermal properties of the grafted films, an increase in the DOG led to an increase in the decomposition temperature. The activation energy (Ea) of the thermal decomposition was calculated using Kissinger's equation from TGA results. The Ea value of the PVBC graft chain was found to increase as the DOG increased, indicating that the crosslinking reaction of ETFE‐g‐PVBC films increased with an increase in the DOG during the thermal degradation process. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 517–525
Mapping Permafrost Features that Influence the Hydrological Processes of a Thermokarst Lake on the Qinghai‐Tibet Plateau, China
Authors: Pan Xicai , You Yanhui , Roth Kurt , Guo Lei , Wang Xinbing , Yu Qihao 
Published: January 2014

ABSTRACTClimate warming has been observed for some time in the permafrost regions on the Qinghai‐Tibet Plateau (QTP), China, resulting in active layer thickening, shrinkage or expansion of thermokarst lakes, and reduced permafrost extent. Little is known, however, about the hydrological processes near thermokarst lakes and their influences on lake development. We employed ground‐penetrating radar (GPR) profiling, topographic mapping and drilling to explore the interaction between hydrological processes and thermokarst lake development at a site on the QTP. The GPR data and borehole water‐level measurements revealed spatio‐temporal variation of the frost table and soil water storage, and indicated the main direction of subsurface flow through soil on hillslopes near the lake. The measurements hinted at the self‐organised formation of lateral flow channels at the thawing frost table near the lake. The ensuing recharge of the lake is balanced by drainage from the deepest end of the lake, down the topographic gradient, as ascertained by coring and lake bed mapping. Such a process‐based qualitative understanding is crucial for assessing the impact of climate change, in conjunction with the local topography and hydrogeology, on the evolution of thermokarst lakes on the QTP. Copyright © 2014 John Wiley & Sons, Ltd.
Performance of small‐scale straw‐to‐heat supply chains in Norway
Authors: Belbo Helmer , Talbot Bruce 
Published: January 2014

Straw can become an important contributor to the biomass feedstocks of Europe and North America. In Norway, between 12 and 17% of a national target to increase the renewable energy share by 14 TWh can be sustainably met by mobilizing straw feedstocks. However, straw must compete in an energy market with a vast availability of forest‐based woody biomass, and a clean electrical energy pool, 95% of which is derived from hydropower. The performance of seven local straw supply chains was monitored over a period of 3 years to estimate straw yields, supply costs, operating costs of the heating plants, and to synthesiz experiences on supply solutions. Storage facilities for bales constituted the largest single cost in the supply chain. Square bales were both more economical to use and required considerably less plant management time, making them more preferable than round bales for small‐scale utilization. The total cost of straw firing averaged out in the range of 36–42 € MWh−1, which is 40–46% of the current cost of electric heating (∼90 € MWh−1). The positive economic outcome provides a good incentive to roll out many more similar plants although heat pumps could be expected to reduce the margin in some applications. WIREs Energy Environ 2014, 3:400–407. doi: 10.1002/wene.107This article is categorized under:

Bioenergy > Systems and Infrastructure