bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tuning the properties of segmented polyhydroxyurethanes via chain extender structure
Authors: Beniah Goliath , Heath William H. , Jeon Junho , Torkelson John M. 
Published: February 2017

ABSTRACTThe influence of chain extender structure on the properties of segmented polyhydroxyurethane (PHU) was investigated with four diamine molecules: 1,4‐diaminobutane, isophorone diamine, methylene bis(cyclohexyl amine), and bis(aminomethyl) norbornane. These nonisocyanate polyurethanes were synthesized with polytetramethylene oxide‐based soft segment and divinyl benzene dicyclocarbonate (DVBDCC) as hard segment. They were characterized with small‐angle X‐ray scattering (SAXS), dynamic mechanical analysis (DMA), and tensile testing. All PHUs possess nanophase‐separated morphology with interdomain spacings of 12 to 16 nm via SAXS. DMA shows that the nanophase separation is accompanied with broad interphases having a wide range of local compositions. These PHUs exhibit tan δ ≥ 0.30 over broad temperature ranges, indicating their potential as effective damping materials. The flow temperature (Tflow), the temperature range with tan δ ≥ 0.30, and the tensile properties of these PHUs are strongly affected by the molecular structure of the chain extender used in synthesis. At 50 wt % hard‐segment content, values of Tflow, tensile strength, and elongation‐at‐break can be tuned via chain extender from 57 to 105 °C, 1.6 to 22.4 MPa, and 70 to 500%, respectively. Notably, PHU at 50 wt % hard‐segment content, synthesized with norbornane‐based chain extender exhibits the best thermal and mechanical properties with Tflow of 105 °C, tensile strength of 22.4 MPa, elongation‐at‐break of 500%, and tan δ ≥ 0.30 over 74 °C in breadth. By varying hard‐segment content between 30 and 50 wt %, norbornane‐based PHUs afford broad tunability in tensile strength from 0.5 to 22.4 MPa with tan δ ≥ 0.30 spanning temperature range as large as 85 °C. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44942.
Networked Iterative Learning Control Design for Nonlinear Systems with Stochastic Output Packet Dropouts
Authors: Liu Jian , Ruan Xiaoe 
Published: February 2017

AbstractThis paper develops two proportional‐type (P‐type) networked iterative learning control (NILC) schemes for a class of discrete‐time nonlinear systems whose stochastic output packet dropouts are modeled as 0‐1 Bernoulli stochastic sequences. In constructing the NILC schemes, two kinds of compensation algorithm of the dropped outputs are given. One is to replace the instant‐wise dropped output data with the synchronous desired output data; the other is to substitute the dropped data with the consensus‐instant output data used at the previous iteration. By adopting the lifting technique, it is derived that under certain conditions the expectations of the tracking errors incurred by the proposed NILC schemes converge to zero along the iteration axis. Numerical experiments are carried out for validity and effectiveness.
Finite‐Time Consensus Problem for Second‐Order Multi‐Agent Systems Under Switching Topologies
Authors: Wang Fang , Chen Xin , He Yong , Wu Min 
Published: February 2017

AbstractThis paper investigates the finite‐time consensus problem for multi‐agent systems with second‐order individual dynamics under switching topologies. A distributed continuous‐time protocol is designed to guarantee finite‐time consensus for homogeneous agents without predetermined leaders, i.e., it ensures agents asymptotically converge to an average consensus within finite time, even if the interaction topology among them is time‐varying but stepwise jointly‐connected. In particular, it introduces a distributed continuous‐time protocol to reach consensus in finite time and reduce the chattering together. Finally, the simulation results are also given to validate the proposed approach.
Analysis of water distribution networks using MATLAB and Excel spreadsheet: Q‐based methods
Authors: Niazkar Majid , Afzali Seied Hosein 
Published: February 2017

ABSTRACTWith the emergence of computers, literatures of water distribution network (WDN), and application of computer‐aided programs for modeling WDNs have been significantly improved. Although MATLAB and Excel spreadsheet provide suitable facilities for both academic and practical purposes, the comprehensive application of these programs in WDN analysis has not been addressed. In this paper, the step‐by‐step implementation of three Q‐based methods is presented for solving WDNs using these programs. In order to focus more on the educational aspects of computer application, a simple pipe network is analyzed using these Q‐based methods. However, as basics of the implementation are sufficiently covered, the provided codes can be improved to analyze more complicated pipe networks. © 2017 Wiley Periodicals, Inc. Comput Appl Eng Educ 25:277–289, 2017; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21796
Structural Defect‐Induced Bandgap Narrowing in Dopant‐Free Anodic TiO2 Nanotubes
Authors: Nasirpouri Farzad , Peighambardoust PhD student (Ms) Naeimeh‐Sadat , Samardak Alexander , Ognev Alexey , Korochentsev Vladimir , Osmushko Ivan , Binions Russell 
Published: February 2017

AbstractThe application of TiO2 in energy‐harvesting materials has been restricted, owing to its relatively large bandgap. In accordance with theoretical predictions of lower bandgap and higher absorbance of visible light in TiO2 nanotube arrays, we demonstrate experimentally that large‐area TiO2 nanotube arrays produced either by low‐temperature anodization or by two‐step anodization on electropolished Ti exhibit a narrowed bandgap; reducing the bandgap from 3.2 to 2.92 eV in an amorphous (as‐anodized) state and to 2.84 eV in the anatase (annealed) phase. The bandgap energy of oxide nanotubes was measured by calculating Tauc plots, according to the diffuse reflectance spectra. Furthermore, the band structure of the TiO2 nanotube arrays measured by using X‐ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy revealed similar bandgap narrowing evidence. This bandgap narrowing behavior can be attributed to either surface edge states, owing to the incorporation of oxygen atoms on the high surface area of the nanotubes, or the formation of Ti3+ defect states form nonbonding states within the bandgap below the Fermi‐level edge. Annealing the tubes further reduced the energy bandgap, owing to the formation of anatase crystalline phase.
Different Gelation and Self‐Sorting Properties of Two Isomeric Polyamides Owing to the Parallel versus Anti‐Parallel Alignment of Backbone Dipoles
Authors: Leung Chui‐Fan , Chow Hak‐Fun 
Published: February 2017

AbstractTwo isomeric bottlebrush polyamides P‐1 and A‐1, with the same repeating monomer dipole units aligned along the polymer backbone in pseudo‐parallel and pseudo‐antiparallel fashion, respectively, were synthesized and characterized. Both polymers can form thermoreversible gels with aromatic solvents but P‐1 was found to show inferior gelation strength compared with that of A‐1. Furthermore, despite their close structural resemblance, a 1:1 mixture of the P‐1 and A‐1 polymers was shown to exhibit self‐sorting in the gel state. Gel formation was found to be a kinetically trapped process through hydrogen bonding, π–π stacking interactions, and side chain interdigitation. The different gelation and self‐sorting properties can be explained by the local dipole–dipole interactions originating from the different modes of backbone dipole alignment. In single gel systems, the antiparallel‐aligned dipoles in A‐1 facilitated a more compact molecular packing owing to the enthalpically more favorable polymer chain association. On the other hand, the parallel‐aligned dipoles in P‐1 gave rise to a less stable head‐to‐head packing, which had difficulties to convert to the more stable head‐to‐tail packing in a kinetically trapped environment. In the mixed gel system, it is the unfavorable hetero‐polymer mismatch dipole–dipole interaction that inhibited the mixing of the A‐1 and P‐1 polymers and led to self‐sorting.
Vom Laborkuriosum zum kontinuierlichen Prozess: Die Entwicklung thermomorpher Lösungsmittelsysteme
Authors: Dreimann Jens Martin , Faßbach Thiemo Alexander , Fuchs Sarah , Fürst Marc Robert Laurent , Gaide Tom , Kuhlmann René , Ostrowski Karoline Anna , Stadler Andreas , Seidensticker Thomas , Vogelsang Dennis , Warmeling Helge Werner Franz , Vorholt Andreas Johannes 
Published: February 2017

AbstractDie homogene Katalyse zeichnet sich gegenüber der heterogenen Katalyse durch höhere Selektivität und Aktivität bei gleichzeitig milderen Reaktionsbedingungen aus; die Abtrennung der teuren Übergangsmetallkatalysatoren von den Reaktionsprodukten ist jedoch schwierig. Temperaturgesteuerte Lösungsmittelsysteme, die bei geringer Temperatur in zwei Phasen vorliegen und bei Temperaturerhöhung ein homogenes, einphasiges Lösungsmittelsystem ausbilden, ermöglichen eine Reaktionsführung ohne Stofftransportlimitierungen. Durch Abkühlung bildet sich erneut ein Zweiphasensystem aus, bei dem im Idealfall eine Phase das Produkt und die andere den Katalysator enthält.
Structure Engineered g‐C3N4 Nano‐Sheets by Switching the Pyrolysis Gas Atmosphere for Enhanced Photo‐Catalytic Degradation
Authors: Chai Yuanyuan , Liu Qianqian , Zhang Lu , Ren Jia , Dai Wei‐Lin 
Published: February 2017

AbstractWe developed a new one step approach to synthesize g‐C3N4 nano‐sheets by direct thermal pyrolysis process of urea in NH3 atmosphere. For the first time, the influence of the preparation gas atmosphere on the composition, crystalline and polymerization degree, and the activity of the g‐C3N4 synthesized from thermal condensation of urea was investigated. Impressively, the g‐C3N4 nano‐sheets obtained under NH3 gas atmosphere exhibited much superior photo‐catalytic activities to the prepared g‐C3N4 in air or N2, and the rate of the g‐C3N4‐NH3 was about 5 times higher than that on g‐C3N4‐N2 sample. The detailed characterization analysis revealed that NH3 thermal pyrolysis atmosphere contributed to the polymerization degree and the formation of the layer with a more regular structure due to the efficiently extending of the conjugated π‐conjugative system, which was favorable to the transfer of the photo‐induced charge carriers. Furthermore, we studied in depth the structure‐performance relationship in the system, and it was found that the synergistic effect of the larger surface area, the adjusted band energy structure and the well crystallization may be conductive to the higher separation of the electron–hole pair, thus leading to the wonderful performance for the g‐C3N4‐NH3. Notably, the method has the merits of low cost, scalable production and environmental friendliness.
Further Studies on the Direct Synthesis of α,β‐Unsaturated Ketimines and α,β‐Enones by Chemoselective Dehydrative Addition of Functionalized Alkenes to Secondary Amides
Authors: Huang Pei‐Qiang , Huang Ying‐Hong 
Published: February 2017

AbstractDescribed in this paper are the results of an investigation on the extension of the C‐H alkyliminylation and acylation of alkenes with secondary amides. The nucleophilic partner has been extended to cover a series of functionalized alkenes bearing functional groups including ester, α,β‐unsaturated ester, uncongested ketone groups, as well as enol derivatives of acetaldehyde such as enol ether and enamides. The electrophilic partner has been extended from N‐(2,6‐dimethylphenyl) and N‐methyl amides to N‐n‐butyl, and N‐cyclohexyl amides. The results demonstrated that the method can be used to synthesize a number of functionalized α,β‐unsaturated ketimines and α,β‐enones in an efficient, high yielding, and one‐pot manner. The method was applied to a concise synthesis of (E)‐6‐styryltetrahydro‐2H‐pyran‐2‐one (5), an immediate intermediate in the syntheses of a series of styryllactone natural products including (±)‐goniothalamine (6), (±)‐goniothalamine oxide (7), (±)‐goniodiol (8), (±)‐leiocarpin A (9), (±)‐9‐deoxygoniopypyrone (10), and (±)‐7‐epi‐goniodiol (11).
Significant changes in sexual behavior after a diagnosis of human papillomavirus‐positive and human papillomavirus‐negative oral cancer
Authors: Taberna Miren , Inglehart Ronald C. , Pickard Robert K. L. , Fakhry Carole , Agrawal Amit , Katz Mira L. , Gillison Maura L. 
Published: February 2017

BACKGROUNDSexual behavior and oral human papillomavirus (HPV) infection are risk factors for oral squamous cell carcinoma (OSCC). The effects of OSCC diagnosis and treatment on subsequent relationship stress and sexual behavior are unknown.METHODSIncident cases of HPV‐positive or HPV‐negative OSCC in patients who had a partnered relationship and partners of patients with oropharyngeal cancer were eligible for a study in which surveys were administered at diagnosis and at the 6‐month follow‐up time point to assess relationship distress, HPV transmission and concerns about health consequences, and sexual behavior. The frequency distributions of responses, stratified by tumor HPV status, were compared at baseline and follow‐up.RESULTSIn total, 262 patients with OSCC and 81 partners were enrolled. Among the patients, 142 (54.2%) had HPV‐positive OSCC, and 120 (45.8%) had HPV‐negative OSCC. Relationship distress was infrequently reported, and 69% of patients felt that their relationship had strengthened since the cancer diagnosis. Both HPV‐positive patients (25%) and their partners (14%) reported feelings of guilt or responsibility for the diagnosis of an HPV‐caused cancer. Concern over sexual, but not nonsexual, HPV transmission to partners was reported by 50%. Significant declines in the frequency of vaginal and oral sexual behaviors were reported at follow‐up, regardless of tumor HPV status. From baseline to 6 months, significant increases in abstinence from vaginal sex (from 10% to 34%; P < .01) and oral sex (from 25% to 80%; P < .01) were reported.CONCLUSIONSDiagnosis and treatment of OSCC are associated with significant declines in the frequency of vaginal and oral sex, regardless of tumor HPV status. Sexual behavior is an important quality‐of‐life outcome to assess within clinical trials. [See related editorial on pages 000‐000, this issue.] Cancer 2017. © 2017 American Cancer Society. Cancer 2017;123:1156–1165. © 2016 American Cancer Society.
A prospective evaluation of clinical and genetic predictors of weight changes in breast cancer survivors
Authors: Sadim Maureen , Xu Yanfei , Selig Katharina , Paulus Julie , Uthe Regina , Agarwl Surbhi , Dubin Iram , Oikonomopoulou Panagiota , Zaichenko Lesya , McCandlish Silvia Aki , Van Horn Linda , Mantzoros Christos , Ankerst Donna Pauler , Kaklamani Virginia G. 
Published: February 2017

BACKGROUNDPostdiagnosis weight gain in patients with breast cancer has been associated with increased cancer recurrence and mortality. This study was designed to identify risk factors for weight gain and create a predictive model to identify a high‐risk population for targeted interventions.METHODSThe weight of 393 patients with breast cancer from the Northwestern Robert H. Lurie Cancer Center was measured over a 2‐year period from diagnosis, with body mass index (BMI) change over 18 months as the primary endpoint. Demographics, clinical factors, treatment methods, as well as tumor characteristics were also recorded; and a lifestyle questionnaire was conducted. Blood samples were genotyped for 16 single nucleotide polymorphisms in FTO, adiponectin pathway genes (ADIPOQ, ADIPOR1), and FNDC5. Serum leptin, adiponectin, and irisin levels also were measured.RESULTSMean ± standard deviation 18‐month BMI changes were 0.68 ± 1.42, 0.98 ± 1.62, 0.79 ± 1.74, and −0.44 ± 1.58 kg/m2 for patients ages <40, 40 to 49, 50 to 59, and ≥60 years, respectively. The optimal multivariable model for 18‐month BMI change contained the predictors age, height, and endocrine therapy, but only age was statistically significant, with a 0.04 kg/m2 increase in 18‐month BMI change per younger year of age. Single nucleotide polymorphisms in ADIPOR1, FTO, and FNDC5 were associated with 18‐month BMI change, and the first 2 remained significant after adjusting for the optimal clinical model (all P < .05).CONCLUSIONSWomen age 60 years and younger at the time of breast cancer diagnosis who have an obesity genetic risk model are at increased risk for weight gain after treatment and should be targeted for weight‐maintenance interventions. Cancer 2017;123:2413–21. © 2017 American Cancer Society.
Impact of the elimination of cost sharing for mammographic breast cancer screening among rural US women: A natural experiment
Authors: Peppercorn Jeffrey , Horick Nora , Houck Kevin , Rabin Julia , Villagra Victor , Lyman Gary H. , Wheeler Stephanie B. 
Published: February 2017

BACKGROUNDRural US women experience disparities in breast cancer screening and outcomes. In 2006, a national rural health insurance provider, the National Rural Electric Cooperative Association (NRECA), eliminated out‐of‐pocket costs for screening mammography.METHODSThis study evaluated the elimination of cost sharing as a natural experiment: it compared trends in screening before and after the policy change. NRECA insurance claims data were used to identify all women aged 40 to 64 years who were eligible for breast cancer screening, and mammography utilization from 1998 through 2011 was evaluated. Repeated measures regression models were used to evaluate changes in utilization over time and the association between screening and sociodemographic factors.RESULTSThe analysis was based on 45,738 women enrolled in the NRECA membership database for an average of 6.1 years and included 279,940 person‐years of enrollment. Between 1998 and 2011, the annual screening rate increased from 35% to a peak of 50% among women aged 40 to 49 years and from 49% to 58% among women aged 50 to 64 years. The biennial screening rate increased from 56% to 66% for women aged 40 to 49 years and from 68% to 73% for women aged 50 to 64 years. Screening rates increased significantly (P < .0001) after the elimination of cost sharing and then declined slightly after changes to government screening guidelines in 2009. Younger women experienced greater increases in both annual screening (6.2%) and biennial screening (5.6%) after the elimination of cost sharing in comparison with older women (3.0% and 2.6%, respectively). In a multivariate analysis, rural residence, lower population income, and lower population education were associated with modestly lower screening.CONCLUSIONSIn a national sample of predominantly rural working‐age women, the elimination of cost sharing correlated with increased breast cancer screening. Cancer 2017;123:2506–15. © 2017 American Cancer Society.
Upconversion Nanoparticles Synthesized by Ultrashort Pulsed Laser Ablation in Liquid: Effect of the Stabilizing Environment
Authors: Gemini Laura , Schmitz Tim , Kling Rainer , Barcikowski Stephan , Gökce Bilal 
Published: February 2017

AbstractThe distinctive feature of upconverting compounds to absorb and emit light in the near‐infrared region has made upconverting nanoparticles of great interest in various application fields. Nevertheless, these colloids show a highly hydrophobic behavior, and therefore, the use of a proper stabilizing agent is necessary in most cases. Although few chemical techniques for colloid stabilization are available, it is still difficult to achieve a fully reproducible synthesis method for stable upconverting nanoparticle colloids. In this work, upconversion 18 %Yb:1 %Er:NaYF4 nanoparticles were produced by ultrafast pulsed laser ablation in a water and 2‐[2‐(2‐methoxyethoxy)‐ ethoxy]acetic acid (MEEAA) environment to assess the stabilization effect of the surfactant on the nanoparticle colloid properties. The effects of the laser fluence and MEEAA concentration on the nanoparticles′ properties were investigated by TEM, EDS, and emission spectra analyses. The results show that ultrashort pulsed laser ablation in liquid allows generating highly spherical nanoparticles with conserved stoichiometry and optical properties. Moreover, it is possible to obtain colloids with significantly higher stability and preserved optical properties by one‐step PLAL processes directly in the MEEAA environment.
Preparation and Fluorescence Properties of Perylenediimide Nanodispersions Having a One‐Dimensional π‐Stacked Structure
Authors: Sasaki Shino , Higuchi Shohei , Asahi Tsuyoshi 
Published: February 2017

AbstractWe prepared stable nanodispersions of a fluorescent perylenediimide (PDI) derivative having long alkyl chains by nanosecond laser fragmentation of its microcrystalline powder in acetonitrile (ACN). The nanoparticles had cube‐like or rod shapes with a mean size of 100 nm, and they dispersed stably for longer than 1 month. The prepared nanobricks exhibited absorption and fluorescence spectra characteristic of one‐dimensional aggregates with cofacial stacking of PDI planes. Single‐particle fluorescence measurements demonstrated that nanobricks had a well‐aligned structure of one‐dimensional columns of PDI. The aqueous dispersions were also fabricated by redispersing the prepared nanobricks, utilizing lipophilic interactions of surfactants having long alkyl chains. We examined the fluorescence properties of nanoparticles dispersed in ACN and in water, and observed amplified fluorescence quenching by the surface‐adsorbed dye.
Solvent‐ and Halogen‐Free Modification of Biobased Polyphenols to Introduce Vinyl Groups: Versatile Aromatic Building Blocks for Polymer Synthesis
Authors: Duval Antoine , Avérous Luc 
Published: February 2017

AbstractVarious biobased polyphenols (lignins and condensed tannins) were derivatized with vinyl ethylene carbonate, a functional cyclic carbonate, to obtain multifunctional aromatic polymers bearing vinyl groups. The reaction was optimized on a condensed tannin and soda lignin. In both cases, full conversion of the phenol groups was achieved in only 1 h at 150 °C without solvent and with K2CO3 as a cheap and safe catalyst. This reaction was later applied to other condensed tannins and technical lignins (Kraft and organosolv), showing only little dependence on the chemical structure of the polyphenols. The obtained derivatives were thoroughly characterized by 1H and 31P NMR spectroscopy, FTIR spectroscopy, and size‐exclusion chromatography. The developed method was compared with previously published protocols for the introduction of vinyl groups on lignin, and shows promising advances toward the modification of biobased polyphenols according to green chemistry principles. The obtained macromolecules show great potential as highly versatile biobased aromatic building blocks for the synthesis of polymers through, for example, radical, metathesis, or thiol–ene reactions.
Flexible Asymmetric Threadlike Supercapacitors Based on NiCo2Se4 Nanosheet and NiCo2O4/Polypyrrole Electrodes
Authors: Wang Qiufan , Ma Yun , Wu Yunlong , Zhang Daohong , Miao Menghe 
Published: February 2017

AbstractFlexible threadlike supercapacitors with improved performance are needed for many wearable electronics applications. Here, we report a high performance flexible asymmetric all‐solid‐state threadlike supercapacitor with a NiCo2Se4 positive electrode and a NiCo2O4@PPy (PPy: polypyrrole) negative electrode. The as‐prepared electrodes display outstanding volume specific capacitance (14.2 F cm−3) and excellent cycling performance (94 % retention after 5000 cycles at 0.6 mA) owing to their nanosheet and nanosphere structures. The asymmetric all‐solid‐state threadlike supercapacitor expanded the stability voltage window from 0–1.0 V to 0–1.7 V and exhibits high volume energy density (5.18 mWh cm−3) and superior flexibility under different bending conditions. This study provides a scalable method for fabricating high performance flexible supercapacitors from easily available materials for use in wearable and portable electronics.