bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical management of pediatric aggressive fibromatosis involving the mandible
Authors: Zhou Yong , Zhang Zhiyuan , Fu Honghai , Qiu Weiliu , Wang LiZhen , He Yue 
Published: May 2012

AbstractBackgroundPediatric aggressive fibromatosis (AF) is a rare, benign tumor with locally infiltrative growth. Therefore, how to prevent reoccurrence while maintaining the mandible contour and continuity as much as possible is very important when the mandible is involved.ProcedureWe selected 10 pediatric patients with AF involving the mandible in our department between January 2001 and December 2011. Patient clinical data, including patient characteristics, symptoms at presentation, management, and treatment outcome, were reviewed.ResultsPatients' ages ranged from 3 to 16 years with six males and four females. According to imaging, there were three cases where the tumor adhered to the mandible; the periosteum was resected with the tumor, followed by cryotherapy or cauterization. Another five cases involved the destruction of the periosteum and the cortical plate. Resection of the involved mandible with the tumor was performed, and the margin was trimmed. In the last two cases, the tumor had invaded the whole ramus, and the immediate iliac graft was operated on after resecting the lesions. Neither radiotherapy (RT) nor chemotherapy was used. There was no recurrence or contour defect of the face. The function of the mandible was not affected, and only one case showed a slight limitation when opening the mouth.ConclusionsFor the treatment of pediatric AF, we recommend complete tumor resection. As for the involved mandible, preserving the mandible contour and continuity as much as possible and providing adjunctive therapy, such as cryotherapy or cauterization, are vital. RT is not recommended. Pediatr Blood Cancer 2012;59:648–651. © 2012 Wiley Periodicals, Inc.
Magnetic‐clamping structures for the consolidation of composite laminates
Authors: Ziegenbein Jordan M. , Colton Jonathan S. 
Published: May 2012

AbstractVacuum bags are used in conjunction with autoclaves to generate the consolidation pressures and temperatures required to manufacture aerospace composites. As the scale of continuous fiber composite structures increases, autoclave processing becomes prohibitively expensive or infeasible. The objective of this study is to develop flexible magnetic clamping structures to increase the consolidation pressure during the conventional vacuum bagging of composite laminates, thereby obviating the need for an autoclave. The ferromagnetic rubber, which consists of rubber filled with iron particles, developed in this study provides a conformable and reusable vacuum bag that provides increased consolidation through attractive forces produced by electromagnets. Experiments and finite‐element modeling indicate that consolidation pressure in the range of 100 kPa can be generated by such a device with realistic power requirements. The effects of the magnetic clamping device process parameters on the consolidation pressure magnitude are modeled theoretically and are characterized experimentally. In addition, a method for the efficient design of the magnetic‐clamping device is developed. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Mineralization of hydroxyapatite crystallites on zein microspheres
Authors: Li Yueling , Yao Chen 
Published: May 2012

AbstractBioinspired mineralization process has been extended to the formation of bonelike hydroxyapatite (HAp) coatings on biodegradable polymer substrates. HAp‐coated zein microspheres were prepared through phase separation procedure, followed by incubation in modified simulated body fluids (mSBF). The morphologies of mineralized zein microspheres with different diameters and incubation time were investigated by scanning electron microscopy (SEM). The nature of the deposited mineral phase was characterized by energy‐dispersive spectroscopy (EDS) and wide‐angle X‐ray diffraction (XRD). The results showed that as the average diameter of zein microspheres increased to 1.13 μm, randomly oriented minerals were observed on the surface of microspheres. Two characteristic HAp diffraction reflections 002 and 211 centered at 2θ of 25.6° and 32.0° were ascertained on the XRD patterns of the mineralized microspheres. Incubation of zein microspheres with larger diameters in mSBF led to nucleation and growth of minerals on the surface. Even larger number of minerals were deposited and a porous structure of platelike HAp crystals was obtained after incubation for 21 days. The novel zein/HAp microspheres may have a wide variety of potential applications in bone regeneration and tissue engineering. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Using supercritical carbon dioxide in preparing carbon nanotube nanocomposite: Improved dispersion and mechanical properties
Authors: Chen Chen , Bortner Michael , Quigley John P. , Baird Donald G. 
Published: May 2012

AbstractImprovements in carbon nanotube (CNT) dispersion and subsequent mechanical properties of CNT/poly(phenylsulfone) (PPSF) composites were obtained by applying the supercritical CO2 (scCO2)‐aided melt‐blending technique that has been used in our laboratory for nanoclay/polymer composite preparation. The preparation process relied on rapid expansion of the CNTs followed by melt blending using a single‐screw extruder. Scanning electronic microscopy results revealed that the CNTs exposed to scCO2 at certain pressures, temperatures, exposure time, and depressurization rates have a more dispersed structure. Microscopy results showed improved CNT dispersion in the polymer matrix and more uniform networks formed with the use of scCO2, which indicated that CO2‐expanded CNTs are easier to disperse into the polymer matrix during the blending procedure. The CNT/PPSF composites prepared with scCO2‐aided melt blending and conventional melt blending showed similar tensile strength and elongation at break. The Young's modulus of the composite prepared by means of conventional direct melt blending failed to increase beyond the addition of 1 wt% CNT, but the scCO2‐aided melt‐blending method provided continuous improvements in Young's modulus up to the addition of 7 wt% CNT. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Influence of the epoxy functionalization of multiwall carbon nanotubes on the nonisothermal cure kinetics and thermal properties of epoxy/multiwall carbon nanotube nanocomposites
Authors: Barghamadi Mohamad , Behmadi Hossein 
Published: May 2012

AbstractMultiwall carbon nanotubes were functionalized with epoxy groups by chemical modification in four stages. At each stage, the compound was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Epoxy composite samples were prepared by mixing diglycidyl ether of bisphenol A‐based epoxy resin and synthetic epoxy‐functionalized multiwall carbon nanotube (E‐MWCNT) with different percentages (1, 3, 6, 9, 12, and 15%) in acetone. Ultrasonic dispersion was used to produce homogenous blends. The optimum ratio of the reacting components (9%) was investigated by total enthalpy of the curing reaction from differential scanning calorimetry (DSC) thermograms. The kinetics of the curing reaction for epoxy composites with 4,4′‐diaminodiphenylsolfon as a curing agent was studied by means of a DSC nonisothermal technique. The kinetic parameters such as activation energy, pre‐exponential factor, and rate constant were obtained from DSC data. The structure ofthe nanocomposites and dispersion of the E‐MWCNTs in the nanocomposites were observed using SEM, and the thermal properties were studied by thermogravimetric analysis. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Nanoclay‐encapsulated polystyrene microspheres by reverse atom transfer radical polymerization
Authors: Khezri Khezrollah , Haddadi‐Asl Vahid , Roghani‐Mamaqani Hossein , Salami‐Kalajahi Mehdi 
Published: May 2012

AbstractNanoclay‐encapsulated polystyrene microspheres were synthesized using reverse atom transfer radical polymerization in miniemulsion. Conversion and molecular weight were evaluated using gravimetry and gel permeation chromatography, respectively. Accordingly, conversion and molecular weight decrease by adding clay content. However, polydispersity index of the nanocomposites with higher clay content is higher. At high temperatures, thermal stability of the nanocomposites is relatively higher than the neat polystyrene, according to the thermogravimetric analysis results. Differential scanning calorimetry results show that glass transition temperature decreases by increasing clay content. Transmission electron microscopy result is in coincidence with X‐ray diffraction data and shows that clay layers are exfoliated in the matrix of PSNM 1. Scanning electron microscopy images display a homogeneous distribution of spherical particles with sizes in the range of ∼200 nm and also confirm dynamic light scattering (DLS) results. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Preparative Isolation and Purification of Indigo and Indirubin from Folium isatidis by High‐speed Counter‐current Chromatography
Authors: Lü Hai‐tao , Liu Jing , Deng Rui , Song Ji‐ying 
Published: May 2012

ABSTRACTIntroductionIndigo and indirubin are the main active ingredients found in traditional Chinese herbal medicine Folium isatidis. An effective method for the isolation and purification of indigo and indirubin from Folium isatidis is needed. Compared with the conventional column chromatographic techniques, high‐speed counter‐current chromatography (HSCCC) is a suitable alternative for the enrichment and purification of these target compounds, and eliminates the complications resulting from a solid support matrix.ObjectiveTo develop a reliable HSCCC method for isolation and identification of indigo and indirubin in a one‐step separation from Folium isatidis.MethodologyThe optimum extracting conditions of indigo and indirubin from Folium isatidis were investigated by orthogonal test L16 (45). The target compounds were isolated and purified with a solvent system of n‐hexane:ethyl acetate:ethanol:water (1:1:1:1, v/v) and the lower phase was used as the mobile phase in the head‐to‐tail elution mode. The purities of target compounds were tested by HPLC and their structures were identified by UV, IR, electrospray ion source (ESI)‐MS, 1H‐NMR and 13 C‐NMR analyses.ResultsFrom 165 mg of the crude extract, 5.65 mg of indigo and 1.00 mg of indirubin were obtained by HPLC analysis with purities of 98.4% and 99.0% respectively, and their mean recoveries were 91.0% and 90.7%, respectively.ConclusionThe HSCCC method is effective for the preparative separation and purification of indigo and indirubin in a one‐step separation from Folium isatidis. Copyright © 2012 John Wiley & Sons, Ltd.
Efficiency of first‐trimester growth restriction and low pregnancy‐associated plasma protein‐A in predicting small for gestational age at delivery
Authors: Carbone Jeanine F. , Tuuli Methodius G. , Bradshaw Rachael , Liebsch Julie , Odibo Anthony O. 
Published: May 2012

ABSTRACTObjectiveTo evaluate the efficiency of first‐trimester fetal growth restriction (FGR), low pregnancy‐associated plasma protein A (PAPP‐A), and their combination for predicting small for gestational age (SGA) at delivery.MethodsRetrospective cohort study of women undergoing first‐trimester aneuploidy screening. Fetal crown–rump lengths (CRLs) were at 10 to 14 weeks’ gestation and converted to gestational age adjusted Z‐scores. Low PAPP‐A was defined as levels < 5th percentile for GA. Receiver‐operating characteristic curves were used to assess screening efficiencies.ResultsAmong 3269 pregnancies meeting the inclusion criteria 185 (5.7%) infants were SGA. CRL Z‐score < −1.0 standard deviation was identified as the optimal definition of early FGR. Using either CRL Z‐score < −1.0 standard deviation or PAPP‐A < 5th percentile had the highest sensitivity (33%) with a specificity of 82.1% when screening for SGA. Using a combination resulted in an increased association (adjusted odds ratio 4.23[confidence interval 1.37–13.03]) at the expense of significantly reduced sensitivity (3.13%).ConclusionsFirst‐trimester FGR and PAPP‐A < 5th percentile are associated with delivery of an SGA infant. Neither of these parameters or the combination of the two are sufficient powerful predictors of SGA to be clinically useful screening tools. © 2012 John Wiley & Sons, Ltd.
Incorporating initial treatments improves performance of a mortality prediction model for patients with sepsis
Authors: Lagu Tara , Rothberg Michael B. , Nathanson Brian H. , Steingrub Jay S. , Lindenauer Peter K. 
Published: May 2012

ABSTRACTPurposeMortality prediction models can be used to adjust for presenting severity of illness in observational studies of treatment effectiveness. We aimed to determine the incremental benefit of adding information about critical care services to a sepsis mortality prediction model.MethodsIn a retrospective cohort of 166 931 eligible sepsis patients at 309 hospitals, we developed nested logistic regression models to predict mortality at the patient level. Our initial model included only demographic information. We then added progressively more detailed information such as comorbidities and initial treatments. We calculated each model's area under the receiver operating characteristic curve (AUROC) and also used a sheaf coefficient analysis to determine the relative effect of each additional group of variables.ResultsModel discrimination increased as more detailed patient information was added. With demographics alone, the AUROC was 0.59; adding comorbidities increased the AUROC to 0.67. The final model, which took into account mixed (hierarchical) effects at the hospital level as well as initial treatments administered within the first two hospital days, resulted in an AUROC of 0.78. The standardized sheaf coefficient for the initial treatments was approximately 30% greater than that for demographics or infection source.ConclusionsA sepsis disease risk score that incorporates information about the use of mechanical ventilation and vasopressors is superior to models that rely only on demographic information and comorbidities. Until administrative datasets include clinical information (such as vital signs and laboratory results), models such as this one could allow researchers to conduct observational studies of treatment effectiveness in sepsis patients. Copyright © 2012 John Wiley & Sons, Ltd.
Assessing the applicability of trial evidence to a target sample in the presence of heterogeneity of treatment effect
Authors: Weiss Carlos O. , Segal Jodi B. , Varadhan Ravi 
Published: May 2012

ABSTRACTPurposeTo propose methods for the quantitative assessment of the applicability of evidence from a trial to a target sample using individual data.MethodsDemonstration was with a trial of drug therapy to prevent mortality and an accompanying registry of people with heart failure. Principal components analysis with biplots did not identify measurement discrepancies. Multiple imputation with chained equations addressed missing predictor values. A proportional hazards model with interaction term, including graphical interpretation and a multivariate interaction test, identified heterogeneity of treatment effect. An interval of homogeneity of treatment effect was the interval of the baseline risk of outcome in which no two treatment effects were statistically significantly different. Absolute risk reduction for individuals was estimated for both benefit and harm outcomes and presented in a bivariate treatment effects scatterplot.ResultsOverall, the trial evidence applied to most of the registry according to overlapping distributions of estimated benefit and harm. However, 52% of trial and 33% of registry participants were estimated to have net benefit, and 14% of trial and 36% of registry participants were estimated to have strong net harmful treatment effect, that is, the individual estimate of harm was more than twice the estimate of benefit.ConclusionsThe proposed methods provide quantitative assessment of the applicability of trial evidence to a target sample. They combine the strengths of different study designs, namely, unbiased effects estimation from trials and representation in observational studies, while addressing the practical challenges of combining information, namely, measurement discrepancies and missing data. Copyright © 2012 John Wiley & Sons, Ltd.
Dynamic marginal structural modeling to evaluate the comparative effectiveness of more or less aggressive treatment intensification strategies in adults with type 2 diabetes
Authors: Neugebauer Romain , Fireman Bruce , Roy Jason A. , O'Connor Patrick J. , Selby Joe V. 
Published: May 2012

ABSTRACTPurposeChronic disease care typically involves treatment decisions that are frequently adjusted to the patient's evolving clinical course (e.g., hemoglobin A1c monitoring and treatment intensification in diabetes patients). Thus, in comparative effectiveness and safety research (CER), it often is less clinically relevant to contrast the health effects of static treatment decisions than to compare the effectiveness of competing medical guidelines, that is, adaptive treatment strategies that map the patient's unfolding clinical course to subsequent treatment decisions. With longitudinal observational studies, treatment decisions at any point in time may be influenced by clinical factors that also are risk factors for the outcome of interest. Such time‐dependent confounders cannot be properly handled with standard statistical approaches, because such confounders may be influenced by previous treatment decisions and may thus lie on causal pathways between the very outcomes and early treatment decisions whose effects are under study. Under explicit assumptions, we motivate the application of inverse probability weighting estimation to fit dynamic marginal structural models (MSMs) in observational studies to address pragmatic CER questions and properly adjust for time‐dependent confounding and informative loss to follow‐up.MethodsWe review the principles behind this modeling approach and describe its application in an observational study of type 2 diabetes patients to investigate the comparative effectiveness of four adaptive treatment intensification strategies for glucose control on subsequent development or progression of urinary albumin excretion.ResultsResults indicate a protective effect of more aggressive treatment intensification strategies in patients already on two or more oral agents or basal insulin. These conclusions are concordant with recent randomized trials.ConclusionsInverse probability weighting estimation to fit dynamic MSM is a viable and appealing alternative to inadequate standard modeling approaches in many CER problems where time‐dependent confounding and informative loss to follow‐up are expected. Copyright © 2012 John Wiley & Sons, Ltd.
Reweighted Mahalanobis distance matching for cluster‐randomized trials with missing data
Authors: Greevy Robert A. , Grijalva Carlos G. , Roumie Christianne L. , Beck Cole , Hung Adriana M. , Murff Harvey J. , Liu Xulei , Griffin Marie R. 
Published: May 2012

ABSTRACTPurposeThis paper introduces an improved tool for designing matched‐pairs randomized trials. The tool allows the incorporation of clinical and other knowledge regarding the relative importance of variables used in matching and allows for multiple types of missing data. The method is illustrated in the context of a cluster‐randomized trial. A Web application and an R package are introduced to implement the method and incorporate recent advances in the area.MethodsReweighted Mahalanobis distance (RMD) matching incorporates user‐specified weights and imputed values for missing data. Weight may be assigned to missingness indicators to match on missingness patterns. Three examples are presented, using real data from a cohort of 90 Veterans Health Administration sites that had at least 100 incident metformin users in 2007. Matching is utilized to balance seven factors aggregated at the site level. Covariate balance is assessed for 10 000 randomizations under each strategy: simple randomization, matched randomization using the Mahalanobis distance, and matched randomization using the RMD.ResultsThe RMD matching achieved better balance than simple randomization or MD randomization. In the first example, simple and MD randomization resulted in a 10% chance of seeing an absolute mean difference of greater than 26% in the percent of nonwhite patients per site; the RMD dramatically reduced that to 6%. The RMD achieved significant improvement over simple randomization even with as much as 20% of the data missing.ConclusionsReweighted Mahalanobis distance matching provides an easy‐to‐use tool that incorporates user knowledge and missing data. Copyright © 2012 John Wiley & Sons, Ltd.
Are antibiotics related to oral combination contraceptive failures in the Netherlands? A case‐crossover study
Authors: Koopmans Petra C. , Bos Jens H.J. , de Jong van den Berg Lolkje T.W. 
Published: May 2012

ABSTRACTPurposeTo investigate whether there is an association between use of antibiotics and breakthrough pregnancy.MethodsThe study was performed in a population‐based prescription database (IADB.nl). We computed case‐crossover odds ratios of 397 cases of defined breakthrough pregnancy comparing the use of antibiotics in the exposure window with the use of antibiotics in two control windows. We defined a control group consisting of 29 022 other pregnancies. We computed case–control odds ratios of the use of antibiotics in cases as compared with controls in the different time windows.ResultsThe case‐crossover odds ratios comparing the use of antibiotics in the exposure window with both control windows were 2.21 (95%CI = 1.03–4.75) and 1.65 (95%CI = 0.78–3.48), respectively. The traditional case–control odds ratios after adjustment for age were 1.71 (95%CI = 1.09–2.66) in the exposure window, 0.81 (95%CI = 0.44–1.47) 2 months before the exposure window, and 1.04 (95%CI = 0.61–1.78) 12 months before the exposure window.ConclusionsWe did find a relationship between the use of antibiotics and breakthrough pregnancy in a population‐based prescription database. The results did not hold for broad‐spectrum antibiotics or in a sensitivity analysis. The results are partly not the same as those found in a pharmacoepidemiological study with a similar design using two US pregnancy databases. Both studies can suffer from bias and confounding, but these will be different because of the use of different databases. Copyright © 2012 John Wiley & Sons, Ltd.