bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of miR‐182 on hepatic fibrosis induced by Schistosomiasis japonica by targeting FOXO1 through PI3K/AKT signaling pathway
Authors: Huang Yu , Fan Xiangxue , Tao Ran , Song Qiqin , Wang Likui , Zhang Hongyue , Kong Hongyan , Huang Jiaquan
Published: January 2018

The study aimed to investigate the impact of miR‐182 and FOXO1 on S. japonica‐induced hepatic fibrosis. Microarray analysis was performed to screen out differential expressed miRNAs and mRNAs. Rat hepatic fibrosis model and human hepatocellular cell line LX‐2 were used to study the effect of miR‐182 and FOXO1. qRT‐PCR and Western blot were used to detect the expression of miR‐182, FOXO1 or other fibrosis markers. The targeting relationship between FOXO1 and miR‐182 was verified by luciferase reporter assay. Immunohistochemistry or immunofluorescence staining was conducted to detect FOXO1 or α‐SMA in rat hepatic tissues. Cell viability and apoptosis were detected by MTT assay and flow cytometry. The expression of PI3K/AKT pathway‐related proteins was detected by Western blot. miR‐182 was highly expressed in liver fibrosis samples, and FOXO1 expression was negatively correlated with miR‐182 expression. After transfection of miR‐182, FOXO1 expression was down‐regulated, with the results of LX‐2 cells proliferation inhibition and apoptosis induction, as well as the aggravation of rat hepatic fibrosis. The expression of p‐AKT/AKT and p‐S6/S6 was increased, meaning that the PI3K/AKT signal pathway was activated. The results were reversed when treated with Wortmannin (PI3K inhibitor). After transfection of miR‐182 inhibitor, FOXO1 expression was up‐regulated, LX‐2 cell proliferation was inhibited, and apoptosis rate was increased. High‐expressed miR‐182 and low‐expressed FOXO1 promoted proliferation and inhibiting apoptosis on liver fibrosis cells, stimulating the development of S. japonica‐induced hepatic fibrosis through feeding back to PI3K/AKT signaling pathway.
MicroRNA501‐5p induces p53 proteasome degradation through the activation of the mTOR/MDM2 pathway in ADPKD cells
Authors: de Stephanis Lucia , Mangolini Alessandra , Servello Miriam , Harris Peter C. , Dell'Atti Lucio , Pinton Paolo , Aguiari Gianluca
Published: January 2018

Cell proliferation and apoptosis are typical hallmarks of autosomal dominant polycystic kidney disease (ADPKD) and cause the development of kidney cysts that lead to end‐stage renal disease (ESRD). Many factors, impaired by polycystin complex loss of function, may promote these biological processes, including cAMP, mTOR, and EGFR signaling pathways. In addition, microRNAs (miRs) may also regulate the ADPKD related signaling network and their dysregulation contributes to disease progression. However, the role of miRs in ADPKD pathogenesis has not been fully understood, but also the function of p53 is quite obscure, especially its regulatory contribution on cell proliferation and apoptosis. Here, we describe for the first time that miR501‐5p, upregulated in ADPKD cells and tissues, induces the activation of mTOR kinase by PTEN and TSC1 gene repression. The increased activity of mTOR kinase enhances the expression of E3 ubiquitin ligase MDM2 that in turn promotes p53 ubiquitination, leading to its degradation by proteasome machinery in a network involving p70S6K. Moreover, the overexpression of miR501‐5p stimulates cell proliferation in kidney cells by the inhibition of p53 function in a mechanism driven by mTOR signaling. In fact, the downregulation of this miR as well as the pharmacological treatment with proteasome and mTOR inhibitors in ADPKD cells reduces cell growth by the activation of apoptosis. Consequently, the stimulation of cell death in ADPKD cells may occur through the inhibition of mTOR/MDM2 signaling and the restoring of p53 function. The data presented here confirm that the impaired mTOR signaling plays an important role in ADPKD.
Chondrogenic differentiation of human scalp adipose‐derived stem cells in Polycaprolactone scaffold and using Freeze Thaw Freeze method
Authors: Moradian Tehrani Rana , Mirzaei Hamed , Verdi Javad , Sahebkar Amirhossein , Noureddini Mahdi , Salehi Rasoul , Alani Behrang , Kianmehr Mojtaba
Published: January 2018

Human adipose tissue has been identified as a viable alternative source for mesenchymal stem cells. SADSCs were isolated from human scalp biopsy and then were characterized by Flow cytometry. SADSCS expressed CD90, CD44, and CD105 but did not express CD45 surface marker. Growth factors were used for chondrogenesis induction. Histology and immunohistology methods and gene expression by real‐time PCR 14 days after induced cells have shown the feature of chondrocytes in their morphology and extracellular matrix in both inducing patterns of combination and cycling induction. Moreover, the expression of gene markers of chondrogenesis for example collagen type II aggrecan and SOX9 has shown by real‐time PCR assay. Then, SADSCs were seeded alone on polycaprolatone (PCL) and with Freeze thaw Freeze (PCL+FTF) scaffolds and SADSCs differentiated toward the chondrogenic lineage and chondrogenesis induction were evaluated using scanning electron microcopy (SEM) and MTT assay. Our results showed that SADSCs were also similar to the other adipose‐derived stem cells. Using TGF‐beta3 and BMP‐6 were effective for chondrogenesis induction. Therefore using of TGF‐beta3 and BMP‐6 growth factors may be the important key for in vitro chondrogenesis induction. The bio‐composite of PCL+FTF nanofibrous scaffolds enhance the chondroblast differentiation and proliferation compared to PCL scaffolds .Therefore, our model will make it possible to study the mechanism of transition from chondroblast to chondrocyte.
Exosomal miRNAs as novel cancer biomarkers: Challenges and opportunities
Authors: Salehi Mahsa , Sharifi Mohammadreza
Published: January 2018

A biomarker with high specificity and sensitivity, is a basic requirement for non‐invasive cancer diagnosis. Exosomes are a type of lipid bilayer extracellular vesicles (EVs), containing different components, including proteins, lipids, DNA, messenger RNA (mRNA), and non‐coding RNAs. Increasing evidence indicates that nucleic acids are protected by exosome lipid membrane. These vesicles are almost released from all cell types, into biological fluids. In cancer, the expression of microRNAs (miRNAs), located in the tumor cell‐derived exosomes, is deregulated and it could be led to metastasis and therapy resistance. Due to the presence of exosomes in various body fluids and the stability of miRNAs in exosomes, exosomal miRNAs can provide a new class of biomarkers for early and minimally invasive cancer diagnosis. In this article, we review the miRNAs and their roles in cancer. Furthermore, we explain the different types of EVs, especially exosomes, and their functional roles in cancer. At the end, we discuss about the importance of exosomal miRNAs for cancer diagnosis. As well as, we briefly summarize the exosome isolation techniques and obstacles, limiting the clinical applications of exosomal miRNAs.
Association of IGFN1 variant with polypoidal choroidal vasculopathy
Authors: Wen Xiaofeng , Liu Yu , Yan Qi , Liang Minling , Tang Miao , Liu Ran , Pan Jianying , Liu Qiuhui , Chen Tingting , Guo Shixin , Liang Juanran , Lu Lin , Ding Xiaoyan , Chen Wei , Wei Lai
Published: January 2018

Background

Polypoidal choroidal vasculopathy (PCV) and neovascular age‐related macular degeneration (nAMD) share a similar phenotype but are different in their clinical manifestations, responses to treatment and prognosis. Whether PCV is a subtype of AMD or a distinct entity from nAMD remains unknown. Therefore, we performed a whole‐exome sequencing based association analysis to compare the genetic architecture of PCV and nAMD in Han Chinese.

Methods

Whole‐exome sequencing analysis was performed on 21 nAMD cases, 20 PCV cases and 20 healthy controls. As a follow‐up validation, 145 nAMD cases, 160 PCV cases and 193 controls were genotyped using the Sequenom MassARRAY platform (Sequenom, San Diego, CA, USA).

Results

A novel variant, c.6196A>G in the IGFN1 gene, was significantly associated with only PCV (combined p = 7.1 × 10–11, odds ratio = 9.44), but not with nAMD (combined p = 0.683, odds ratio = 1.30). The minor allele G conferred an increased risk of PCV.

Conclusions

The findings of the present study indicate that, although some of the susceptibility loci are shared between PCV and nAMD, a unique genetic signature may decide the pathogenesis of PCV.
[Emim][BF4]: An Efficient Green Protocol for the Synthesis of Bioactive 2‐(5‐(substituted)‐2,6‐dioxo‐1,2,5,6‐tetrahydropyrimidin‐4‐yl)‐2,3‐dihydrophthalazine‐1,4‐dione Derivatives
Authors: Sumalatha Jorepalli , Radha Rani Chinthaparthi , Sreedevi Adikay
Published: January 2018

The present study is designed to synthesize the 2‐(5‐(substituted)‐2,6‐dioxo‐1,2,5,6‐tetrahydropyrimidin‐4‐yl)‐2,3‐dihydrophthalazine‐1,4‐diones and investigate their anticancer activity. This is the first example of the condensation reaction of a series of phthalhydrazide derivatives in ionic liquid. In this investigation, the titled compounds syntheses were carried out by simple and efficient three component coupling of phthalhydrazide, aldehydes, and barbituric acid in the presence of [Emim][BF4] ionic liquid. This methodology was provided and promotes the higher product yields in shorter reaction times and mild reaction conditions. The title compounds were tested for their anticancer activity. Some of them were shown the significant cytotoxic activity against the selected cancer cell lines.
Political Economy and Quality of Primary Health Service in Rural Bangladesh and the United States of America: A Comparative Analysis
Authors: Osman Ferdous Arfina , Bennett Sara
Published: January 2018

We examined the quality of publicly provided primary healthcare service in two different rural settings: USA and Bangladesh. Using both primary and secondary data, the quality of primary healthcare services was examined across four dimensions: access, equity, responsiveness and citizen's influence over services. Findings demonstrate that apart from responsiveness, the US underperforms across all other dimensions of quality. Compared with the US, Bangladesh fared worse in almost all indicators other than physically accessibility. Wider political economy factors that shaped the quality of service were the colonial legacy, political competition, the economic system and social inequality. Copyright © 2018 John Wiley & Sons, Ltd.
Projected changes in future climate over the Midwest and Great Lakes region using downscaled CMIP5 ensembles
Authors: Byun Kyuhyun , Hamlet Alan F.
Published: January 2018

Despite an increasing body of evidence from observed data that climate change is having a significant impact on different types of biogeophysical systems in the Midwest and Great Lakes region, there still remain critical questions of how quickly and how much climate will be altered over this region in the future. For this evaluation, we make use of 31 global climate model (GCM) projections from the Coupled Model Intercomparison Project, Phase 5 (CMIP5). Based on changes in temperature (T) and precipitation (P) over the Midwest, we selected ten GCM scenarios which (1) simulate historical climate well and (2) successfully capture the range of future climate from the entire CMIP5 ensemble. We then downscaled T and P projections to 1/16° gridded data sets for two different emission scenarios (RCP4.5 and RCP8.5) for three 30‐year future periods using the Hybrid Delta (HD) statistical downscaling approach which was proven to be applicable for daily‐scale application by a validation work using historical data. T is projected to increase across all seasons, with ensemble mean changes up to 6.5 °C by 2100 for the RCP8.5 scenarios. P increases up to 30% in spring and winter with decreasing snowfall to precipitation ratio, while summer P decreases moderately (−15%) by the 2080s. Changes in daily extreme events show similar seasonal patterns including increasing daily extreme P events in winter and decreasing P in summer. Growing season P may actually increase, however, despite projected P reductions in the warmest summer months. Regional warming results in decreased heating degree days (−1639 °C days, −32%) and increasing cooling degree days (+318 °C days, +957%) by 2080s, with overall net reductions in energy demand.
Polarized Raman, FTIR, and DFT study of Na2Ti3O7 microcrystals
Authors: Silva Fábio Lacerda Resende e , Filho Adailton Azevedo Araújo , da Silva Mauricélio Bezerra , Balzuweit Karla , Bantignies Jean‐Louis , Caetano Ewerton Wagner Santos , Moreira Roberto Luiz , Freire Valder Nogueira , Righi Ariete
Published: January 2018

Sodium trititanate Na2Ti3O7 microcrystals were carefully prepared by sodium carbonate and titanium dioxide solid‐state reaction and characterized by scanning and transmission electron microscopies, selected area electron diffraction, X‐ray powder diffraction, and Raman and Fourier transform infrared spectroscopies. Electron microscopic techniques revealed that the samples were formed by elongated particles several microns long with broad size distributions. The zone axis and crystal growth direction of the elongated particles were determined by selected area electron diffraction. These results were useful for identifying the symmetries of the optical vibrational modes obtained by infrared absorption and polarized Raman scattering of oriented crystals. For a complete assignment of the depicted phonon modes, Fourier transform infrared spectroscopy and Raman data were compared with theoretical data obtained from first‐principles calculations within the framework of the density functional theory. A very nice agreement was established between the characteristic features of measured and calculated vibrational modes. In particular, all optical phonon modes of Na2Ti3O7 could be experimentally observed and assigned to their correct symmetries. These results must be useful for describing the physical behavior of the system and designing new technological applications.
Chiral ligand exchange countercurrent chromatography: Enantioseparation of amino acids
Authors: Xiong Qing , Jin Jing , Lv Liqiong , Bu Zhisi , Tong Shengqiang
Published: January 2018

This work deals with the enantioseparation of α‐amino acids by chiral ligand exchange high‐speed countercurrent chromatography using N‐n‐dodecyl‐l‐hydroxyproline as a chiral ligand and copper(II) as a transition metal ion. A biphasic solvent system composed of n‐hexane/n‐butanol/aqueous phase with different volume ratios was selected for each α‐amino acid. The enantioseparation conditions were optimized by enantioselective liquid–liquid extractions, in which the main influence factors, including type of chiral ligand, concentration of chiral ligand and transition metal ion, separation temperature, and pH of the aqueous phase, were investigated for racemic phenylalanine. Altogether, we tried to enantioseparate 15 racemic α‐amino acids by the analytical countercurrent chromatography, of which only five of them could be successfully enantioseparated. Different elution sequence for phenylalanine enantiomer was observed compared with traditional liquid chromatography and the proposed interactions between chiral ligand, transition metal ion (Cu2+), and enantiomer are discussed.
A New Colorimetric Platform for Protein Detection Based on Recognition‐Induced Cascade of Polymeric Nanoparticles Disassembly
Authors: Fang Fang , Liu Jin , Li Yushu , Yang Junjiao , Yang Jing
Published: January 2018

Despite great progress, it is still of high interest to explore new homogeneous assays for simple, visual, and selective protein detection. Herein, one new colorimetric sensor has been developed for visual detection of protein by using polymeric micelles as a sensing scaffold and the molecular recognition between protein and the ligand on the surface of the polymeric micelles as the driving force to trigger the readout of the detection signal. The polymeric micelles formed via the self‐assembly of the amphiphilic block polymer biotin‐labeled poly(ethylene glycol)‐block‐poly(3‐acryl aminophenylboronic acid) are endowed with colorful feature by incorporation of alizarin red S (ARS) into the hydrophobic core. Based on the response to streptavidin recognition, these micelles are further disintegrated through the competitive binding of α‐cyclodextrin with boronic acid for disassociation of ARS, which achieves orange–yellow to pink–purple transition in 2 h. This work will open the way to develop one new mix‐and‐measure, visual, and homogeneous assay.
Design, Synthesis, and Photophysical Property of Strongly Fluorescent Benzofuran–Ethynylene Copolymer
Authors: Chen Chih‐Hsien , Luo Zi‐Huan , Tan Kaiting
Published: January 2018

A novel alternating benzofuran–ethynylene copolymer is designed and synthesized through a series of palladium‐catalyzed reactions, and extremely strong fluorescence is observed. The electronic levels of frontier orbitals are estimated by electrochemical and photophysical measurements for copolymer and corresponding monomers. The extension of π‐electron conjugation is shown after polymerization reaction, in which the energy of highest occupied molecular orbital (HOMO) is increased and that of the lowest unoccupied molecular orbital (LUMO) is decreased, simultaneously. The fluorescence quantum yield of this copolymer is as high as 75%, and time‐resolved fluorescence measurement confirms this intrinsic property. A preliminary optoelectronic device is fabricated to test the potential application of this copolymer as an emitting layer. In comparison with other known dibenzofuran‐based materials, moderate performance is obtained. The incorporation of a benzofuran group combining acetylene moiety in a polymeric skeleton provides a novel choice of highly fluorescent materials.
Core/Shell Polystyrene/Magnetite Hybrid Nanoparticles Fabricated by Pickering Emulsion Polymerization and Their Magnetorheological Response
Authors: Chae Hyun Sik , Piao Shang Hao , Han Wen Jiao , Choi Hyoung Jin
Published: January 2018

Soft‐magnetic polystyrene (PS)/Fe3O4 core/shell composite nanoparticles are fabricated by surfactant‐free Pickering emulsion polymerization using Fe3O4 nanoparticles as a solid stabilizer. The morphology of the synthesized PS/Fe3O4 particles consisting of a PS surface coated with Fe3O4 nanoparticles is examined by scanning electron microscopy and transmission electron microscopy. The thermal properties of Fe3O4 and PS/Fe3O4 are examined by thermogravimetric analysis, while the chemical bonding and composition of the nanocomposite are characterized by Fourier transform infrared spectroscopy and X‐ray diffraction. The magnetorheological (MR) properties of the PS/Fe3O4 composite nanoparticles dispersed in silicone oil are analyzed using a rotational rheometer under an external magnetic field. The PS/Fe3O4‐based MR fluids exhibit typical MR properties and a lower density compared to Fe3O4 nanoparticles, indicating the improved dispersion stability of the MR fluid compared to that of the Fe3O4 nanoparticle‐based MR fluid.
Differentiation‐associated urothelial cytochrome P450 oxidoreductase predicates the xenobiotic‐metabolizing activity of “luminal” muscle‐invasive bladder cancers
Authors: Baker Simon C. , Arlt Volker M. , Indra Radek , Joel Madeleine , Stiborová Marie , Eardley Ian , Ahmad Niaz , Otto Wolfgang , Burger Maximilian , Rubenwolf Peter , Phillips David H. , Southgate Jennifer
Published: January 2018

Extra‐hepatic metabolism of xenobiotics by epithelial tissues has evolved as a self‐defence mechanism but has potential to contribute to the local activation of carcinogens. Bladder epithelium (urothelium) is bathed in excreted urinary toxicants and pro‐carcinogens. This study reveals how differentiation affects cytochrome P450 (CYP) activity and the role of NADPH:P450 oxidoreductase (POR). CYP1A1 and CYP1B1 transcripts were inducible in normal human urothelial (NHU) cells maintained in both undifferentiated and functional barrier‐forming differentiated states in vitro. However, ethoxyresorufin O‐deethylation (EROD) activity, the generation of reactive BaP metabolites and BaP‐DNA adducts, were predominantly detected in differentiated NHU cell cultures. This gain‐of‐function was attributable to the expression of POR, an essential electron donor for all CYPs, which was significantly upregulated as part of urothelial differentiation. Immunohistology of muscle‐invasive bladder cancer (MIBC) revealed significant overall suppression of POR expression. Stratification of MIBC biopsies into “luminal” and “basal” groups, based on GATA3 and cytokeratin 5/6 labeling, showed POR over‐expression by a subgroup of the differentiated luminal tumors. In bladder cancer cell lines, CYP1‐activity was undetectable/low in basal PORlo T24 and SCaBER cells and higher in the luminal POR over‐expressing RT4 and RT112 cells than in differentiated NHU cells, indicating that CYP‐function is related to differentiation status in bladder cancers. This study establishes POR as a predictive biomarker of metabolic potential. This has implications in bladder carcinogenesis for the hepatic versus local activation of carcinogens and as a functional predictor of the potential for MIBC to respond to prodrug therapies.
Improving parallel imaging by jointly reconstructing multi‐contrast data
Authors: Bilgic Berkin , Kim Tae Hyung , Liao Congyu , Manhard Mary Kate , Wald Lawrence L. , Haldar Justin P. , Setsompop Kawin
Published: January 2018

Purpose

To develop parallel imaging techniques that simultaneously exploit coil sensitivity encoding, image phase prior information, similarities across multiple images, and complementary k‐space sampling for highly accelerated data acquisition.

Methods

We introduce joint virtual coil (JVC)‐generalized autocalibrating partially parallel acquisitions (GRAPPA) to jointly reconstruct data acquired with different contrast preparations, and show its application in 2D, 3D, and simultaneous multi‐slice (SMS) acquisitions. We extend the joint parallel imaging concept to exploit limited support and smooth phase constraints through Joint (J‐) LORAKS formulation. J‐LORAKS allows joint parallel imaging from limited autocalibration signal region, as well as permitting partial Fourier sampling and calibrationless reconstruction.

Results

We demonstrate highly accelerated 2D balanced steady‐state free precession with phase cycling, SMS multi‐echo spin echo, 3D multi‐echo magnetization‐prepared rapid gradient echo, and multi‐echo gradient recalled echo acquisitions in vivo. Compared to conventional GRAPPA, proposed joint acquisition/reconstruction techniques provide more than 2‐fold reduction in reconstruction error.

Conclusion

JVC‐GRAPPA takes advantage of additional spatial encoding from phase information and image similarity, and employs different sampling patterns across acquisitions. J‐LORAKS achieves a more parsimonious low‐rank representation of local k‐space by considering multiple images as additional coils. Both approaches provide dramatic improvement in artifact and noise mitigation over conventional single‐contrast parallel imaging reconstruction. Magn Reson Med 80:619–632, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
On the analysis of independent sets via multilevel splitting
Authors: Vaisman Radislav , Kroese Dirk P.
Published: January 2018

Counting the number of independent sets is an important problem in graph theory, combinatorics, optimization, and social sciences. However, a polynomial‐time exact calculation, or even a reasonably close approximation, is widely believed to be impossible, since their existence implies an efficient solution to various problems in the non‐deterministic polynomial‐time complexity class. To cope with the approximation challenge, we express the independent set counting problem as a rare‐event estimation problem. We develop a multilevel splitting algorithm which is generally capable of delivering accurate results, while using a manageable computational effort, even when applied to large graphs. We apply the algorithm to both counting and optimization (finding a maximum independent set) problems, and show that it compares favorably with the existing state of the art.
Synthesis and characterization of hyperbranched poly(ether sulfone)imides and MWCNTs‐COOH/NH2 Nanocomposites
Authors: Fathima Rigana M. , Balasubramanian R. , Balaji S. , Sarojadevi M.
Published: January 2018

A new triamine 1,3,5‐tris{4′‐[4″‐(4″′‐aminophenoxy) phenylsulfonyl]phenoxy} benzene (TAPPSPB) was synthesized and successfully polymerized into hyperbranched polyimides (HBPIs) with commercially available dianhydrides BTDA and PMDA by A2+B3 method. HBPI‐PMDA‐AMT2/MWCNT nanocomposites were prepared by the reaction of TAPPSPB with PMDA and amino functionalized MWCNT by the conventional two step method by varying the percentage of MWCNT (1, 3, 5, and 7 wt%).The structure of the amine and the resulting hyperbranched polyimides were characterized by FT‐IR, 1H, and 13C‐NMR analysis. The Tg and T5% temperature of the HBPIs and nanocomposites were in the range of 229‐266°C and 430‐493°C, respectively. The results from DSC and TGA show that the Tg and the thermal stability of the HBPI‐PMDA‐AMT2/MWCNT nanocomposites are higher than that of pristine HBPIs. The dielectric constant (in the range of 3.05–8.54 at 1 MHz) and dielectric loss (in the range of and 0.64–0.87 at 1 MHz) increased with an increase of MWCNTs‐COOH/NH2. SEM studies revealed that the MWCNT are evenly dispersed throughout the polymer matrix in the nanocomposites. X‐ray diffraction studies shows that the synthesized HBPIs and nanocomposites are amorphous in nature. POLYM. COMPOS., 40:600–614, 2019. © 2018 Society of Plastics Engineers
Current controversies in prenatal diagnosis 1: All prenatally detected lower urinary tract obstructions should be shunted
Authors: Devlieger Roland , Douglas Wilson R. , Ruano Rodrigo
Published: January 2018

What's already known about this topic?

LUTO is a rare but life‐threatening condition affecting the fetus and child in which prenatal therapy is currently being offered but remains controversial. A recent RCT comparing this treatment to post‐natal treatment in selected cases failed to come to robust conclusions due to under‐recruitment. So, the controversy persists.

What does this study add?

In this debate, 2 renown experts in the field develop their arguments pro and against shunting for all LUTO cases based on the current literature and a long‐standing clinical experience in the field of fetal therapy.
Modeling diffusion mass transport in multiphase polymer systems for gas barrier applications: A review
Authors: Zid Sarra , Zinet Matthieu , Espuche Eliane
Published: January 2018

Polymer nanocomposites offer a great interest as gas barrier materials because of their much‐enhanced properties arising from the nanoparticles shape, size, and spatial arrangement within the matrix. However, optimization and further development of such materials requires fundamental understanding of the influence of the nanocomposite structure on permeating gas diffusion. This step can be greatly facilitated through modeling/simulation strategies able to establish relationships between the material microstructure and the achieved enhancement of barrier properties. This review first presents the analytical models developed to estimate the effective diffusivity in polymer nanocomposites. The predictions of the models are analyzed with respect to experimental data reported in the literature and their ability to describe accurately the nanocomposite transport properties when the microstructure complexity increases is discussed. Then, modeling approaches based on numerical simulation techniques (e.g., the finite element method) that allow simulating the diffusion processes and assessing the effect of filler shape, orientation, dispersion, and spatial arrangement are reviewed and discussed. Finally, the importance of 3D simulation strategies for the understanding and prediction of transport properties in the most complex nanocomposite microstructures is addressed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 621–638
Reflecting on the use and abuse of scientific data facilitates students’ ethical and epistemological development
Authors: Howitt Susan M. , Wilson Anna N.
Published: January 2018

Scientists use judgment in deciding what and how much data to present in publications but science degrees rarely address this issue. Instead, scientific knowledge is presented as certain and students have limited opportunities to use their own judgment in the laboratory. A consequence of this may be that students approach science with a moral absolutist mindset, believing that science is about learning facts and scientists have little need to exercise ethical judgments in relation to data. Students may also hold different ethical standards for themselves and professional scientists. We draw on data from a first‐year science module to show that these views can be challenged by encouraging students to reflect on their own behavior and that of famous scientists in situations with varying degrees of professional ethical ambiguity. We provide evidence of significant transitions in students’ thinking, suggesting that reflection on these issues may lead to substantial epistemological and ethical development. By the end of the module, many students had moved from an initial position of certainty to the acceptance of multiple viewpoints or to a more mature understanding of the evidence‐based nature of science, as well as gaining the ability to critique decisions and make ethical judgments.
Two‐step estimation in ratio‐of‐mediator‐probability weighted causal mediation analysis
Authors: Bein Edward , Deutsch Jonah , Hong Guanglei , Porter Kristin E. , Qin Xu , Yang Cheng
Published: January 2018

This study investigates appropriate estimation of estimator variability in the context of causal mediation analysis that employs propensity score‐based weighting. Such an analysis decomposes the total effect of a treatment on the outcome into an indirect effect transmitted through a focal mediator and a direct effect bypassing the mediator. Ratio‐of‐mediator‐probability weighting estimates these causal effects by adjusting for the confounding impact of a large number of pretreatment covariates through propensity score‐based weighting. In step 1, a propensity score model is estimated. In step 2, the causal effects of interest are estimated using weights derived from the prior step's regression coefficient estimates. Statistical inferences obtained from this 2‐step estimation procedure are potentially problematic if the estimated standard errors of the causal effect estimates do not reflect the sampling uncertainty in the estimation of the weights. This study extends to ratio‐of‐mediator‐probability weighting analysis a solution to the 2‐step estimation problem by stacking the score functions from both steps. We derive the asymptotic variance‐covariance matrix for the indirect effect and direct effect 2‐step estimators, provide simulation results, and illustrate with an application study. Our simulation results indicate that the sampling uncertainty in the estimated weights should not be ignored. The standard error estimation using the stacking procedure offers a viable alternative to bootstrap standard error estimation. We discuss broad implications of this approach for causal analysis involving propensity score‐based weighting.
A nonparametric method to detect increased frequencies of adverse drug reactions over time
Authors: Heimann Günter , Belleli Rossella , Kerman Jouni , Fisch Roland , Kahn Joseph , Behr Sigrid , Berlin Conny
Published: January 2018

Signal detection is routinely applied to spontaneous report safety databases in the pharmaceutical industry and by regulators. As an example, methods that search for increases in the frequencies of known adverse drug reactions for a given drug are routinely applied, and the results are reported to the health authorities on a regular basis. Such methods need to be sensitive to detect true signals even when some of the adverse drug reactions are rare. The methods need to be specific and account for multiplicity to avoid false positive signals when the list of known adverse drug reactions is long. To apply them as part of a routine process, the methods also have to cope with very diverse drugs (increasing or decreasing number of cases over time, seasonal patterns, very safe drugs versus drugs for life‐threatening diseases). In this paper, we develop new nonparametric signal detection methods, directed at detecting differences between a reporting and a reference period, or trends within a reporting period. These methods are based on bootstrap and permutation distributions, and they combine statistical significance with clinical relevance. We conducted a large simulation study to understand the operating characteristics of the methods. Our simulations show that the new methods have good power and control the family‐wise error rate at the specified level. Overall, in all scenarios that we explored, the method performs much better than our current standard in terms of power, and it generates considerably less false positive signals as compared to the current standard.
Distinction and quantification of inorganic sulfur species including thiosulfate by X‐ray fluorescence (WD‐XRF)
Authors: Hennings Stephanie , Pleßow Alexander
Published: January 2018

Sulfur occurs in a variety of inorganic and organic compounds with oxidation states from −II up to +VI. Differentiation of these species in solid geochemical samples can be challenging because of oxidation processes during sample preparation by acidic digestion. Applying pressed powder pellets and an analysis by wavelength‐dispersive X‐ray fluorescence minimises reactions with oxidants and water.

Main subjects of this work were five inorganic sulfur species, sulfide −II, elemental sulfur 0, thiosulfate +II, sulfite +IV, and sulfate +VI, and the determination of their fluorescence energies in the sulfur X‐ray spectra. S Kα1,2 and S Kβ1 can be observed for all species, S Kβ′ satellites only for species with coordinated oxygen. The results are in good agreement with previously published data. Yet none of the 38 investigated papers from the past 90 years reported S Kα1,2 of thiosulfate, which was determined as E = 2,309.12 eV in this work apparently for the first time.

Binary mixtures of sulfur species are strongly differing in their ability of being quantitatively differentiated, as a reliable quantification requires a sufficient difference of the respective fluorescence energies. Regression equations for each mixture can be used to calculate the ratio of mass fractions of the investigated species from the evaluated fluorescence energy.

If boundary conditions are considered, the presented approaches can be applied for analyses of geochemical samples or quality control of technical products. The main advantage of the described methods is the option of implementation to everyday X‐ray fluorescence lab routine without substantial additional effort.
Solar Light Photocatalytic Degradation of Malachite Green by Hydrothermally Synthesized Strontium Arsenate Nanomaterial through Response Surface Methodology
Authors: Khademinia Shahin , Behzad Mahdi , Kafi‐Ahmadi Leila , Hadilou Samira
Published: January 2018

Nanostructured Sr2As2O7 samples were synthesized by hydrothermal crystal growth reactions between Sr(NO3)2 and As2O3 with different stoichiometric Sr:As molar ratios as 1:1 (S1), 1:2 (S2), and 2:1 (S3). The synthesized nanomaterials were characterized by powder X‐ray diffraction (PXRD) technique and fourier‐transform infrared (FT‐IR) spectroscopy. Rietveld analysis showed that the obtained materials were crystallized well in the monoclinic crystal structure with the space group P21. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. TEM images verified formation of the particles with nanometer size. Ultraviolet‐visible spectra analysis showed that the synthesized Sr2As2O7 nanomaterials had strong light absorption in the ultraviolet light region. Photocatalytic performance of the synthesized nanomaterials was also investigated for the degradation of pollutant Malachite Green (4‐{[4‐(dimethylamino)phenyl](phenyl)methylidene}‐N′N‐dimethylcyclohexa‐25‐dien‐1‐iminium chloride) (MG) in aqueous solution under solar light condition. The optimal conditions were obtained by design expert software for S1. It was found that the optimum condition was 0.14 mL H2O2, 20 mg catalyst, and 33 min time. The volume and concentration of the as prepared MG solution were 70 mL and 100 ppm, respectively, for obtaining the optimum conditions. The degradation yield in the optimized conditions was 97 % for S1.
Contribution to the free vibration problem of a free‐free beam with large end masses
Authors: Šalinić Slaviša , Obradović Aleksandar , Dunjić Momčilo , Sekulić Dragan , Lazarević Željko
Published: January 2018

Free vibration of an Euler‐Bernoulli beam with rigid bodies connected to the beam ends by both revolute joints and torsional springs is considered. The mass centers of rigid bodies have both the transverse and the axial eccentricity relative to the neutral axis of the undeformed beam. The coupling of the partial differential equations of axial and bending vibrations of the beam due to boundary conditions is considered. The frequency equation and the mode shape orthogonality condition of the system are derived. In order to illustrate the effect of the transverse and the axial eccentricity on the vibration behavior of the beam, a numerical example is provided.
Direct simulation of thermo‐coupled fatigue failure for metals
Authors: Zhan Lin , Wang Si‐Yu , Xi Hui‐Feng , Xiao Heng
Published: January 2018

A new finite strain elastoplastic flow model with thermo‐coupled effects is proposed for the purpose of simulating cyclic and non‐cyclic thermo‐coupled fatigue failure behavior of metals. Novelties in four respects are incorporated in the proposed model: (i) the usual notion of yielding is rendered irrelevant with a smooth transition from the elastic to the plastic state; (ii) the thermodynamic consistency stipulated by the second law is identically ensured; (iii) asymptotic loss of the strength in cyclic and non‐cyclic thermomechanical processes is incorporated as inherent constitutive features; and, accordingly, (iv) the fatigue failure behavior may be derived as direct consequences of the proposed model, without involving any additional failure criteria and any additional variables. Thermo‐coupled responses of a metal bar with two fixed ends under cyclic heating and cooling over various temperature ranges are studied based on a simple case of the proposed model. Results are obtained for the maximum tensile and compressive stresses changing with the cycle number and, in particular, for the thermal fatigue life versus the temperature amplitude. Model predictions compare well with test data.
Do Wages Lead Inflation? Swiss Evidence
Authors: Zanetti Attilio
Published: January 2018

We construct a quarterly time series for nominal hourly wages and unit labour costs from 1975 onwards and investigate the empirical link between wages and CPI inflation in Switzerland in order to identify causality effects and assess the relevance of wages as an indicator for short-run price changes. We find evidence that prices systematically influence wages whereas the influence of wages on prices is much more sensitive to the choice of the sample period. In particular, the explanatory power of wages disappears in a low inflation environment. These findings move in the same direction as most evidence obtained with US data.
Sustainability of Swiss Fiscal Policy
Authors: Kirchgässner Gebhard , Prohl Silika
Published: January 2018

We examine whether Swiss federal fiscal policy was sustainable over the period from 1900 to 2002. We perform unit root and cointegration tests for federal revenues and expenditures, taking into account a structural shift in the budgetary process related to World War II. We find sustainability considering the entire period. However, splitting the sample into two sub-samples before and after World War II, the results do much less support sustainability.
Personality, Job Satisfaction and Health — The Mediating Influence of Affectivity
Authors: Fischer Justina A. V. , Sousa-Poza Alfonso
Published: January 2018

This paper evaluates the relationship between job satisfaction and subjective and objective measures of health of workers over 50 using the Swiss Household Panel (SHP) and cross-sectional data from the Survey on Health, Ageing and Retirement in Europe (SHARE). Methodologically, we address problems of (a) cross-sectional causality and (b) absence of objective measures of physical health and intellectual ability. We find a positive link between job satisfaction and various self-report health measures and intellectual ability, but not for physical health. Further analysis with the SHP indicates that job satisfaction serves as transmission channel of working conditions, prior health state and affective mental state for most self-report measures, while for specific health problems such as depressive states and problems with the back a direct beneficial effect of job satisfaction remains.
Constant-Quality House Price Indexes for Switzerland
Authors: Bourassa Steven C. , Hoesli Martin , Scognamiglio Donato , Sormani Philippe
Published: January 2018

The measurement of house price movements is a vital topic from both academic and practical perspectives and hence has been the focus of much research. There is almost unanimous consensus in the literature that house price indexes should control for the quality of properties; the most widely used methods to attain this aim are the hedonic and repeat sales approaches. The objective of this paper is to compare the Swiss house prices indexes published by the Swiss National Bank (SNB), which are constructed using medians of list prices as published in newspapers and on the internet, to hedonic indexes based on sale prices for the period 1985 to 2006. We find that the list price indexes exhibit quite a different price path than the hedonic indexes during the period. In particular, they appear to overstate price changes in housing markets. We attribute this, at least in part, to changes over time in the composition of the sample of properties on the market.
Spatial Estimation of the Impact of Airport Noise on Residential Housing Prices
Authors: Salvi Marco
Published: January 2018

The paper applies spatial econometric techniques to measure the impact of airport noise on the price of single-family homes in the Zurich Airport area. We exploit a large database of geo-referenced noise measurements to investigate the reaction of prices to different noise metrics. The particular institutional setting of Zurich Airport, with changing patterns of runways configurations allows to distinguish the impact of noise at different times of the day. The use of neighborhood fixed-effects is compared to the results given by a costlier modelling strategy involving a rich set of location descriptors. The paper documents the impact of airport noise on housing prices. In the base model specification the Noise Discount Index is 0.97% with typical discounts in the range of −2% to −8%. Accounting for the spatiality of the data has little effect on the results.
Do Foreigners Pay Higher Rents for the Same Quality of Housing in Geneva and Zurich?
Authors: Baranzini Andrea , Schaerer Caroline , Ramirez José V. , Thalmann Philippe
Published: January 2018

The Geneva and Zurich housing markets are characterised by high proportions of foreigners and a large share of rental housing. This provides ideal conditions for testing whether foreigners pay more for the same quality of housing than Swiss households and whether flats in neighbourhoods with higher proportions of foreigners rent at a discount. Hedonic price equations using a rich dataset on dwellings and their occupants yield evidence of such discrimination and prejudice. They also suggest more complex relationships between tenant nationality, housing and neighbourhood quality, and rents.
Interest rate setting on the Swiss Franc repo market
Authors: Kraenzlin Sébastien
Published: January 2018

Repurchase agreements (repos) are secured money market transactions. The cash taker provides collateral in the form of securities and in return receives money from the cash provider. To ensure the continuous covering of the cash amount, the definition of eligible collateral, its handling and valuation play an important role. This is mainly because the collateral nearly eliminates credit risk. In Switzerland, Swiss franc repos are almost exclusively conducted via the highly standardized repo platform, with four different pre-defined collateral baskets. Each basket comprises different security categories, such as government bonds or covered bonds. This paper analyzes the interest rate setting on the repo market with data from June 1999 to June 2005. It evaluates if the securities provided as collateral influenced the repo rate or not. A price differentiation with respect to the collateral provided is found.
Indeterminacy, causality, and the foundations of monetary policy analysis
Authors: McCallum Bennett T.
Published: January 2018

To be useful as a guide to behavior, a model that includes a relationship between x

t
and z

t+1 must specify whether x

t
is influenced by the expectation at t of z

t+1 or, that z

t+1 is inertially influenced by x

t
. We show that, for a broad class of linear RE models, distinct causal specifications will be uniquely associated with distinct solutions. Alternatively, a solution refinement requiring continuity of solution coefficients with respect to basic parameters implies this same solution. For a given structure there is only one RE solution that is fully consistent with the model’s specification.
International price differences in ski lift tickets
Authors: Falk Martin
Published: January 2018

This paper provides empirical evidence on international price differences in ski lift tickets based on 214 ski areas in Austria, France, and Switzerland for the winter season 2010/2011. We find that French and Austrian one-day lift tickets (net of VAT) are an average of 17 and 7 per cent lower, respectively, than Swiss ticket prices after controlling for ski areas’ characteristics. The results of quantile regressions show that the magnitude of the international price differences is quite similar for low- and high-priced ski areas. Furthermore, price differences across countries do not increase with distance to the nearest border ski area.
Household money demand: The euro area case
Authors: Seitz Franz , von Landesberger Julian
Published: January 2018

In this paper we analyse household holdings of the broad monetary aggregate M3 in the euro area from 1991 until 2010. We develop a nominal model with satisfactory economic and statistical properties. The main determinants are a transactions variable, wealth considerations, opportunity costs and uncertainty. The model is robust to different samples considered and a multitude of mis-specification tests. The exercise also provides insights that go beyond the portfolio allocation decision of households. According to our analysis, it is quite apparent that in equilibrium, households jointly determine consumption and broad money holdings both influenced by wealth as well as interest rates.