bluuebunny/crossref_metadata_2025 huggingface dataset:
Converting water absorbent polymer to alcohol absorbent polymer
Authors: Kabiri K. , Roshanfekr S.
Published: May 2012

In this paper, a commercial water absorbent polymer based on poly (sodium acrylate) (PAANa) was converted to an alcohol absorbent polymer. PAANa collapses in alcoholic swelling media such as ethanol and methanol. In the present paper, first, a full interpenetrating polymer network (IPN) gel was prepared through immersing PAANa hydrogel in a solution containing 2‐acrylamido2‐methyl propane sulfonic acid (AMPS), polyethylene glycol dimetahcrylate and ammonium persulfate. The second network was formed in hydrated PAANa through heating. It was synthesized in two conditions by chemical crosslinker and crosslinker‐free. The IPN was acid treated to investigate the effect of removing Na+ on alcohol absorbency. The synthesized IPN gels have the ability of absorbing up to 21 and 39 g/g ethanol and methanol, respectively. The samples which were synthesized using the chemical crosslinker in the second stage had more alcohol absorbency in comparison with the crosslinker‐free samples. Unexpectedly, acid treatment caused a decrease in alcohol absorbency. The IPN gels were characterized through thermogravimetric analyses (TGA) and dynamic mechanical thermal analysis (DMTA). The DMTA results confirmed the IPN structure of the gels, two distinctive peaks, which can be attributed to PAANa, and poly (AMPS) was observed in tan delta figures. TGA thermograms demonstrated that IPN had lower thermal stability in comparison with the initial PAANa, which can be attributed to higher vulnerability of SO3H group for degradation that reduced initial decomposition temperature. Copyright © 2012 John Wiley & Sons, Ltd.
Highly improved crystallization behavior of poly(L‐lactide) induced by a novel nucleating agent: substituted‐aryl phosphate salts
Authors: Shi Yunyun , Shao Lina , Yang Jinghui , Huang Ting , Wang Yonghong , Zhang Nan , Wang Yong
Published: May 2012

In this work, a novel nucleating agent (NA) based on substituted‐aryl phosphate salts was introduced into poly(L‐Lactide) (PLLA). The nonisothermal and isothermal crystallization behaviors of nucleated PLLA samples were investigated through differential scanning calorimetry (DSC), wide angle X‐ray diffraction, and polarized optical microscope (POM). Furthermore, the effect of annealing treatment on the cold crystallization behaviors of nucleated samples was also investigated. The results show that the crystallization of PLLA, whether for the melt crystallization (including nonisothermal and isothermal crystallization process) or for the cold crystallization (including the cold crystallization occurring during the DSC heating process and during the annealing process), is greatly dependent upon the content of NA. At relatively lower NA content (≤0.1 wt%), the nucleation effect of NA is inconspicuous, however, at higher NA content (≥0.2 wt%), it exhibits great nucleation effect for the crystallization of PLLA. Further results show that the double endothermic peak of PLLA depends on the temperature applied for the crystallization. Copyright © 2012 John Wiley & Sons, Ltd.
From sequence to molecular pathology, and a mechanism driving the neuroendocrine phenotype in prostate cancer
Authors: Lapuk Anna V , Wu Chunxiao , Wyatt Alexander W , McPherson Andrew , McConeghy Brian J , Brahmbhatt Sonal , Mo Fan , Zoubeidi Amina , Anderson Shawn , Bell Robert H , Haegert Anne , Shukin Robert , Wang Yuzhuo , Fazli Ladan , Hurtado‐Coll Antonio , Jones Edward C , Hach Faraz , Hormozdiari Fereydoun , Hajirasouliha Iman , Boutros Paul C , Bristow Robert G , Zhao Yongjun , Marra Marco A , Fanjul Andrea , Maher Christopher A , Chinnaiyan Arul M , Rubin Mark A , Beltran Himisha , Sahinalp S Cenk , Gleave Martin E , Volik Stanislav V , Collins Colin C
Published: May 2012

The current paradigm of cancer care relies on predictive nomograms which integrate detailed histopathology with clinical data. However, when predictions fail, the consequences for patients are often catastrophic, especially in prostate cancer where nomograms influence the decision to therapeutically intervene. We hypothesized that the high dimensional data afforded by massively parallel sequencing (MPS) is not only capable of providing biological insights, but may aid molecular pathology of prostate tumours. We assembled a cohort of six patients with high‐risk disease, and performed deep RNA and shallow DNA sequencing in primary tumours and matched metastases where available. Our analysis identified copy number abnormalities, accurately profiled gene expression levels, and detected both differential splicing and expressed fusion genes. We revealed occult and potentially dormant metastases, unambiguously supporting the patients' clinical history, and implicated the REST transcriptional complex in the development of neuroendocrine prostate cancer, validating this finding in a large independent cohort. We massively expand on the number of novel fusion genes described in prostate cancer; provide fresh evidence for the growing link between fusion gene aetiology and gene expression profiles; and show the utility of fusion genes for molecular pathology. Finally, we identified chromothripsis in a patient with chronic prostatitis. Our results provide a strong foundation for further development of MPS‐based molecular pathology. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Implementation of multi‐site neurocognitive assessments within a pediatric cooperative group: Can it be done?
Authors: Embry Leanne , Annett Robert D. , Kunin‐Batson Alicia , Patel Sunita K. , Sands Stephen , Reaman Gregory , Noll Robert B.
Published: May 2012

Background

Neurocognitive functioning is an important construct in childhood cancer survivorship, given the potential neurotoxicity of central nervous system (CNS) diseases and treatments and the relevance for important functional outcomes in adulthood. However, within pediatric oncology cooperative groups there have been significant barriers to neurocognitive data collection that have historically resulted in incomplete data (<30% compliance), thereby limiting progress in understanding the neurocognitive functioning of survivors. This paper describes the development, feasibility, and potential efficacy of a brief neurocognitive battery to maximize collection of psychometrically robust neurocognitive data within a pediatric cooperative group. We hypothesized that a novel set of procedures could result in collection of data from over 80% of eligible children.

Procedure

A novel assessment battery (ALTE07C1) that evaluates a child's cognitive, social, emotional, and behavioral functioning was developed. It included measures that were psychometrically sound, normed, widely available, and could be administered by any licensed psychologist. The battery required approximately 1 hour of administration time. A data monitoring team was developed to ensure prompt data collection.

Results

Approximately 75% (105 of 140) of institutions with eligible patients opened ALTE07C1; 159 participants have been enrolled. The overall compliance rate for submission of neurocognitive data exceeded 90%.

Discussion

Our study supports the feasibility and potential efficacy of a brief neurocognitive battery and a data monitoring team to evaluate children participating in multi‐site pediatric oncology trials. Future work will utilize ALTE07C1 as a primary or secondary endpoint for pediatric trials when there is risk for neurocognitive impairment. Pediatr Blood Cancer 2012;59:536–539. © 2012 Wiley Periodicals, Inc.
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

Background

Pediatric 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.

Procedure

We 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.

Results

Patients' 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.

Conclusions

For 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

Vacuum 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

Bioinspired 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

Improvements 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

Multiwall 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

Nanoclay‐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

Introduction

Indigo 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.

Objective

To develop a reliable HSCCC method for isolation and identification of indigo and indirubin in a one‐step separation from Folium isatidis.

Methodology

The 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.

Results

From 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.

Conclusion

The 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

Objective

To 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.

Methods

Retrospective 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.

Results

Among 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%).

Conclusions

First‐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

Purpose

Mortality 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.

Methods

In 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.

Results

Model 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.

Conclusions

A 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

Purpose

To propose methods for the quantitative assessment of the applicability of evidence from a trial to a target sample using individual data.

Methods

Demonstration 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.

Results

Overall, 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.

Conclusions

The 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

Purpose

Chronic 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.

Methods

We 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.

Results

Results 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.

Conclusions

Inverse 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

Purpose

This 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.

Methods

Reweighted 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.

Results

The 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.

Conclusions

Reweighted 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

Purpose

To investigate whether there is an association between use of antibiotics and breakthrough pregnancy.

Methods

The 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.

Results

The 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.

Conclusions

We 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.
Use of amiloride and multiple sclerosis: registry‐based cohort studies
Authors: Pasternak Björn , Svanström Henrik , Nielsen Nete M , Melbye Mads , Hviid Anders
Published: May 2012

Purpose

Amiloride reduces functional neurological deficits and neuronal damage in animal models of multiple sclerosis (MS). We investigated whether amiloride use was associated with reduced risk of incident MS and of MS hospitalization and death in humans.

Methods

We conducted two propensity score‐matched cohort studies, linking nationwide registry data on filled drug prescriptions, diagnostic information, and covariates. First, we compared rates of incident MS in new users of amiloride and new users of an active control treatment, thiazide diuretics. Second, rates of hospitalizations for MS and of death were compared between users of amiloride and thiazides in a cohort of MS patients. Treatment groups were matched 1 : 4 on propensity scores that included a wide range of covariates, and Cox regression was used to estimate hazard ratios (HRs).

Results

Comparing 36 659 users of amiloride and 177 031 users of thiazides, there were 19 cases of incident MS during 92 548 person‐years of follow‐up among amiloride users and 81 cases during 567 599 person‐years of follow‐up among thiazide users. There was no significantly decreased risk of MS associated with amiloride use (HR 1.34, 95%CI 0.81–2.20). In the cohort of MS patients, amiloride use was not associated with significantly decreased risk of MS hospitalization (HR 1.11, 95%CI 0.79–1.59) or death (HR 1.38, 95%CI 0.83–2.28).

Conclusion

Amiloride use was not associated with significantly decreased risk of incident MS or hospitalizations and death among patients with MS. Because amiloride users were represented by older patients, risks could not be evaluated in younger individuals. Copyright © 2012 John Wiley & Sons, Ltd.
Design and development of an integrated device consisting of an independent solar cell with electrical storage capacity
Authors: Mini Pothanad A. , Nair Shantikumar V. , Subramanian Kavasseri R. V.
Published: May 2012

A thin film‐integrated device was constructed consisting of photovoltaic layers combined with additional layers to store charge in real time within the same device. In our design, a dye‐sensitized solar cell and capacitor layers are integrated by a double‐anodized titanium plate, which consists of TiO2 nanotubes grown on either side by electrochemical anodization. The combination device can act either as an independent solar cell, a capacitor, or as a solar cell/capacitor device. The results presented here illustrate the capacitive behavior of high surface area nanotubular metal oxide films, with an achieved capacitance of 140 μF cm−2. Copyright © 2012 John Wiley & Sons, Ltd.
1,3,5‐tricorannulenylbenzene: stereochemistry, reduction and supramolecular dimerization of a branched oligocorannulene
Authors: Eisenberg David , Quimby Jennifer M. , Scott Lawrence T. , Shenhar Roy
Published: May 2012

Oligocorannulenes are polyarenes composed of several corannulene units that are covalently linked. Their behavior arises both from the diverse properties of each corannulenyl unit and from the interactions between them. In this paper, we present the synthesis, stereochemistry, reduction, and self‐assembly properties of a novel type of oligocorannulene: branched 1,3,5‐tricorannulenylbenzene. Several stereodynamical elements combine to give rich stereochemistry: bowl‐to‐bowl inversion, rotation about the aryl‐aryl single bonds, and residual stereoisomerism of molecular propellers. Reduction with lithium metal yields an intermediate hexaanion and ultimately produces a highly charged dodecaanion. Self‐diffusion NMR demonstrates that the dodecaanion undergoes supramolecular dimerization through charged polyarene stacking, wherein two molecules are linked at all three contact points. The preference for dimerization over dendrimerization is attributed to an entropic effect. The dimer is found to undergo complex structural dynamics, as well as ion‐pairing dynamics, as revealed by variable‐temperature 1H‐ and 7Li‐NMR. Copyright © 2012 John Wiley & Sons, Ltd.
Decomposition of GAP Single Droplets Used as Liquid Monopropellants
Authors: Tamura Goichi , Tanabe Mitsuaki , Kuwahara Takuo
Published: May 2012

Hydrazine monopropellant thrusters are used as propulsion system for trajectory corrections and other operations of satellites or unmanned spacecrafts. But hydrazine is difficult to handle, therefore the design and the synthesis of next generation monopropellants that could be able to supersede hydrazine is currently studied by scientists around the world. In this study, we focus on liquid glycidyl azide polymer (GAP) as next generation monopropellant. GAP is a liquid and stable substance at standard temperature and pressure. GAP is self‐reacting with exothermic decomposition, however, the decomposition of GAP single droplets when heated was not investigated. To clarify the decomposition of GAP single droplets, we examined their decomposition behavior. It was found that GAP single droplets changed their status at certain temperatures in a furnace. Bubbles were generated at temperatures over 493 K, and micro explosions occurred at temperatures above 603 K. The temperature in GAP single droplets rapidly rose when micro explosions occurred. Moreover, the activation energy was obtained from the results of micro explosion delay time and of DTA. It was found that GAP is able to easily generate micro explosions by a small amount of energy.
Dinitrophenyl Triazoles – “A Class of Energetic Azoles”: Synthesis, Characterisation, and Performance Evaluation Studies
Authors: Nimesh Sasidharan , Rajendran Arolickal G.
Published: May 2012

Energetic azoles have shown great potential as powerful energetic molecules, which find various applications in both military and civilian fields. This work describes the synthesis, characterization and performance evaluation of two energetic triazole derivatives, viz. N‐(2,4‐dinitrophenyl)‐3‐nitro‐1H‐1,2,4‐triazole (1a) and N‐(2,4‐dinitrophenyl)‐3‐azido‐1H‐1,2,4‐triazole (1b). The compounds were synthesized from 3‐nitro‐1,2,4‐triazole and 3‐azido‐1,2,4‐triazole, by a simple synthetic route and structurally characterized using FT‐IR and NMR (1H, 13C) spectroscopy as well as elemental analysis. Thermal analyses on the molecules were performed using simultaneous TG‐DTA. Both compounds (1a, 1b) showed good thermal stability with exothermic decomposition peaks at 348 °C and 217 °C, respectively, on DTA. The energetic and sensitivity properties of both compounds like friction sensitivities and heats of formation are reported. The heats of combustion at constant volume were determined using oxygen bomb calorimetry and the results were used to calculate the standard molar heats of formation (ΔfHm). The azido derivative (1b) showed a higher positive heat of formation. The thermo‐chemical properties of the compounds as well as the thermal decomposition products were predicted using the REAL thermodynamic code.
Thermal Decomposition Performance of Unsymmetrical Dimethylhydrazine (UDMH) Oxalate
Authors: Mu Xiaogang , Wang Xuanjun , Liu Xiangxuan , Zhang Youzhi
Published: May 2012

The thermal decomposition behavior of unsymmetrical dimethylhydrazine (UDMH) oxalate was studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TG/DTG), and thermogravimetric analysis combined with infrared spectroscopy (TG‐IR). The endothermic decomposition of UDMH oxalate occurred at temperatures between 180.4 °C and 217.6 °C, the maximum decomposition temperature is 199.2 °C. The kinetic parameters of the decomposition reaction were calculated based on the Kissinger equation. The TG‐IR spectra indicated that the thermal main decomposition products of UDMH oxalate are CO2,H2O and NH3.
Characterisation of the Major Synthetic Products of the Reactions Between Butanone and Hydrogen Peroxide
Authors: Smith Mark E , Wall Craig , Fitzgerald Mark
Published: May 2012

The reactions between butanone and hydrogen peroxide, both catalysed and un‐catalysed, were investigated and spectral and sensitiveness data reported. The major product of the un‐catalysed reaction, 2‐hydroxy,2‐hydroperoxybutane, displayed a Figure of Insensitiveness (F of I) of 10, Temperature of Ignition (T of I) of 132 °C, and initiated when 128 N of frictional force or an electrostatic discharge (ESD) of 4.5 J was applied. Differential scanning calorimetric analyses revealed an onset of decomposition at 128 °C, peak maximum of 140 °C, and decomposition energy of 203 J g−1. The major product of the cooled (5 °C) acid catalysed reaction between butanone and hydrogen peroxide, 2,2′‐dihydroperoxy‐2,2′‐dibutyl peroxide, displayed a F of I of<10, T of I of 110 °C and initiated upon application of 5 N of friction or a 0.45 J ESD. Calorimetry showed a melt at 38.3 °C, an onset of exothermic decomposition at 127 °C and the evolution of 1292 J g−1. The major product of the raised temperature (20 °C) acid catalysed synthesis, 1,4,7‐trimethyl‐1,4,7‐triethyl‐1,4,7‐cyclononatriperoxane, displayed F of I of<10 and initiated upon application of 5 N of friction or a 0.45 J ESD. Calorimetry revealed an onset to melting at 28.9 °C, an onset to thermal decomposition at 128 °C, and decomposition energy of 1438 J g−1.
Characterization of conduction band edge discontinuity for InAlAs/GaAsSb using InP/GaAsSb heterojunction bipolar transistors
Authors: Ng C. W. , Wang H.
Published: May 2012

In this work, the temperature‐dependent DC performance of InP/GaAsSb double heterojunction bipolar transistors (DHBTs) with an InP/InAlAs composite emitter was characterized. The current transport mechanisms in DHBTs with a type‐I InAlAs/GaAsSb emitter–base junction interface and a type‐II GaAsSb/InP base–collector were studied. The experimental results reveal that electron injection at emitter–base junction could be affected by conduction barrier limited carrier transport. A conduction band edge discontinuity of 9.5 meV for InAlAs/GaAsSb heterojunction was experimentally estimated.
Customer capabilities, switching costs, and bank performance
Authors: Brush Thomas H. , Dangol Ramesh , O'Brien Jonathan P.
Published: May 2012

Customers develop switching costs when they invest time and effort to develop capabilities required to optimally use a given product. Such capabilities are likely to be firm specific and cannot be transferred perfectly to competitors' product offerings. Customers who face switching costs are likely to remain with the same firm and consume complementary products that meet their needs. Thus, firms can achieve competitive advantage by exploiting customers' switching costs. In this paper, we hypothesize that the extent to which firms can benefit from customers' switching costs is contingent upon the firms' internal cross‐selling capabilities. We use online banking data to test our hypotheses and find that customers' switching costs contribute to banks' profitability only in the presence of high levels of internal cross‐selling capabilities. Copyright © 2012 John Wiley & Sons, Ltd.
Stem cells of the adult lung: their development and role in homeostasis, regeneration, and disease
Authors: Wansleeben Carolien , Barkauskas Christina E. , Rock Jason R. , Hogan Brigid L. M.
Published: May 2012

The lung has vital functions in gas exchange and immune defense. To fulfill these functions the cellular composition and complex three‐dimensional organization of the organ must be maintained for a lifetime. Cell turnover in the adult lung is normally low. However, in response to cellular injury by agents such as infection, toxic compounds, and irradiation there is rapid proliferation and differentiation of endogenous stem and progenitor cells to repair and regenerate the damaged tissue. In the mouse, different populations of epithelial progenitor cells have been identified in different regions of the respiratory system: basal cells in the proximal tracheobronchial region and submucosal glands, and secretory cells in the conducting airways and bronchioalveolar duct junction. The identification of the long‐term stem cells in the alveolar region is still under debate, and little is known about resident stem and progenitor cells for the many mesodermal populations. Within this framework information is provided about the origin of lung progenitor cells during development, the microenvironment in which they reside, the experimental injury and repair systems used to promote their regenerative response, and some of the mechanisms regulating their behavior. WIREs Dev Biol 2013, 2:131–148. doi: 10.1002/wdev.58

This article is categorized under:

Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches

Adult Stem Cells, Tissue Renewal, and Regeneration > Stem Cells and Disease
Computational approaches to discovering noncoding RNA
Authors: Krzyzanowski Paul M. , Muro Enrique M. , Andrade‐Navarro Miguel A.
Published: May 2012

New developments are being brought to the field of molecular biology with the mounting evidence that RNA transcripts not translated into protein (noncoding RNAs, ncRNAs) hold a variety of biological functions. Computational discovery of ncRNAs is one of these developments, fueled not only by the urge to characterize these sequences but also by necessity to prioritize ones with the most relevant functions for experimental verification. The heterogeneity in size and mode of activity of ncRNAs is reflected in the corresponding diversity of computational methods for their study. Sequence and structural analysis, conservation across species, and relative position to other genomic elements are being used for ncRNA detection. In addition, the recent development of techniques that allow deep sequencing of cell transcripts either globally or from isolated ncRNA‐related material is leading the field toward increased use of such high‐throughput data. We expect that imminent breakthroughs will include the classification of newer types of ncRNA and new insights into miRNA and piRNA biology, eventually leading toward the completion of a catalog of all human ncRNAs. WIREs RNA 2012, 3:567–579. doi: 10.1002/wrna.1121

This article is categorized under:

RNA Evolution and Genomics > Computational Analyses of RNA

Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs
Morphological distance and inter‐nest distance account for intra‐specific prey overlap in digger wasps (Hymenoptera: Crabronidae)
Authors: Polidori Carlo , Ballesteros Yolanda , Santoro Davide , Tormos José , Asís Josep D.
Published: May 2012

Although inter‐individual diet variation is common in predatory wasp populations, the factors accounting for such variation are still largely unknown. Here, we asked if paired diet dissimilarity in three species of digger wasps correlates with morphological distance and inter‐nest distance, two factors previously linked to diet partitioning in vertebrates. Results sharply differed among species and generations. All sampled populations showed significant inter‐individual diet variation for prey taxa, but only in half of the cases for prey size. In one generation of two species [Bembix zonata Klug and Stizus continuus (Klug)], similar‐sized wasps had similar prey taxonomic spectra (and for S. continuus also similar prey size spectra), a phenomenon which probably reduces intra‐specific competition. In addition, B. zonata females nesting closer to each other had more similar prey taxonomic spectra, suggesting that distant females probably hunt on different patches that harbour different prey species. For the females of a further species (Bembix merceti Parker), pairwise size difference and inter‐nest distance did not affect prey dissimilarity. Both morphological distance and inter‐nest distance are potentially important in shaping the overlap of individual resource use in wasps, though probably only in certain conditions such as a highly clumped distribution of nests and size‐related constraints on prey selection.
Muscle weakness in the elderly: role of sarcopenia, dynapenia, and possibilities for rehabilitation
Authors: Seene Teet , Kaasik Priit
Published: May 2012

Aging is a multifactorial process leading to changes in skeletal muscle quantity and quality, which cause muscle weakness and disability in the aging population. This paper discusses the reasons for muscle weakness—and its biological and physiological mechanisms—in the elderly and describes the role of sarcopenia and dynapenia, and the possibilities to modify the age-associated decline in muscle function and decelerate the development of muscle weakness and disability. Resistance and endurance training are effective measures of exercise therapy in the elderly, which improve muscle metabolism and thereby muscle function and life quality.
Determination of Sodium Dodecyl Sulfate (SDS) and Biosurfactants Sorption and Transport Parameters in Clayey Soil
Authors: Harendra S. , Vipulanandan C.
Published: May 2012

In this study, sorption and the transport mechanism of surfactants in clayey soil was examined. The adsorption and desorption isotherms for sodium dodecyl sulfate (SDS) and biosurfactant (UH‐biosurfactant) with sand and kaolinite were quantified. Kaolinite clay had the highest sorption capacity compared to blasting sand. Miscible displacement breakthrough experiments were done in order to determine the transport parameters. Transport parameters such as the dispersion coefficient (D) and the retardation factor (R) of the above‐mentioned surfactant solutions were determined in clayey soils [sand (82.5 %) and kaolinite (17.5 %) mixture] with and without ionic strength. In this study 0.1 g/L NaCl was used as the electrolyte solution. A two‐region transport convective–diffusive model was used to model the breakthrough curves of the surfactants. This model resulted in excellent descriptions of the data. Bromide ions were chosen as the tracer material in order to characterize the column. Perchloroethylene (PCE) is used in various kinds of industrial and commercial applications. SDS and UH‐biosurfactant were used to flush the PCE contaminated soil. UH‐biosurfactant solubilized more PCE compared to that of SDS in contaminated soils.