bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallisation and spherulite morphology of polylactide stereocomplex
Authors: Shyr Tien‐Wei , Ko Huan‐Chieh , Wu Tzu‐Ming , Wu Tzong‐Ming 
Published: September 2018

AbstractIn this study we investigated the crystallisation behaviours of stereocomplex crystals in poly(l‐lactic acid)/poly(d‐lactic acid) (PLLA/PDLA) blends (LD blends) of various weight ratios. The crystallisation and melting behaviours were studied using DSC, and the crystal structure was analysed through wide‐angle X‐ray diffraction. The morphology of homocrystals and stereocomplex crystals in the blends was examined using a hot‐stage polarising microscope and a scanning electron microscope. The DSC results showed that homocrystals and stereocomplex crystals were present in all LD blends except that with 50 wt% PLLA/50 wt% PDLA; in this blend, only stereocomplex crystals were present. The regime II → III transition temperature of stereocomplex crystals in a Lauritzen–Hoffman plot of the LD blends was determined to be 165 °C. A concentric spherulite consisting of stereocomplex crystals and homocrystals formed under two‐step isothermal crystallisation conditions with three growth stages was observed. The confined spherulitic growth rate in the concentric spherulite and the unrestricted spherulitic growth rate in individual spherulites were also analysed. © 2018 Society of Chemical Industry
Dynamic supramolecular polymers built from cucurbit[n]urils and viologens
Authors: Correia Henrique Dias , Chowdhury Shagor , Ramos Ana Paula , Guy Laure , Demets Grégoire Jean‐François , Bucher Christophe 
Published: September 2018

AbstractThis review article focuses on supramolecular assemblies involving cucurbit[n]uril‐based containers and viologen guests as key building elements. Cucurbit[n]urils (CB[n], n = 5–8,10) are fascinating hosts forming a wide range of inclusion complexes (caviplexes) with 4,4′‐bipyridinium salts, known as viologens, either as discrete 1:1 inclusion compounds with CB[7] or as ternary inclusion compounds involving two hosts or two guests (2:1 with CB[7] and 1:2 or 1:1:1 with CB[8]). This property is currently being actively exploited to design and prepare self‐assembled dynamic stimuli‐responsive supramolecular polymers including gels, vesicles, films and organized arrays of polymeric microspheres or nanoparticles. This review highlights the main benefits of such polymers and gives an overview of the achievements and progress made in this field over the past decades. © 2018 Society of Chemical Industry
Employing (half‐)titanocene complexes as initiators for the synthesis of end‐functionalized polylactides by coordination polymerization
Authors: Patias Georgios , Choinopoulos Ioannis , Koinis Spyros , Pitsikalis Marinos 
Published: September 2018

ABSTRACTSeven (half‐)titanocene alkoxide complexes, [Cp2TiCl(OEt)], [Cp2TiCl(O‐2‐Bu)], [Cp2TiCl(OCH2CF2CF2H)], [CpTiCl2(OEt)], [CpTiCl2(O‐(S)‐2‐Bu)], [CpTiCl2(OCH2CF3)], and [Cp2TiCl(OCH2CF3)], were synthesized and employed in lactide coordination polymerization. These organotitanium (IV) compounds proved to be very efficient initiators for the ring‐opening polymerization of enantiomeric l‐lactide and racemic mixture of rac‐lactide, leading to end‐functionalized polymers. Kinetic studies illustrated that these compounds produce well‐defined polymers in a controlled manner. This was further demonstrated by synthesizing poly(l‐lactide‐b‐hexyl isocyanate) diblock copolymer. The effect of the alkoxy end groups on the thermal behavior of the polymers was also studied by thermogravimetric analysis and differential scanning calorimetry. The polymers were characterized using size exclusion chromatography and proton nuclear magnetic resonance spectroscopy. The optical properties of the diblock copolymer were also investigated. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2192–2202
Ligand effect in the synthesis of hyperbranched polymers via copper‐catalyzed azide‐alkyne cycloaddition polymerization (CuAACP)
Authors: Gan Weiping , Cao Xiaosong , Shi Yi , Zou Lei , Gao Haifeng 
Published: September 2018

ABSTRACTCopper‐catalyzed azide‐alkyne cycloaddition polymerization (CuAACP) of AB2 monomers demonstrated a chain‐growth mechanism without any external ligand because of the complexation of in situ formed triazole groups with Cu catalysts. In this study, we explored the use of various ligands that affected the polymerization kinetics to tune the polymers’ molecular weights and the degree of branching (DB). Eight ligands were studied, including polyethylene glycol monomethyl ether (PEG350, Mn = 350), tris(benzyltriazolylmethyl)amine (TBTA), 2,6‐bis(1‐undecyl‐1H‐benzo[d]imidazol‐2‐yl)pyridine (Py(DBim)2), 2,2′‐bipyridyl (bpy), 4,4′‐di‐n‐nonyl‐2,2′‐bipyridine (dNbpy), N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA), N,N,N′,N″,N″‐penta(n‐butyl)diethylenetriamine (PBuDETA), and N,N,N′,N″,N″‐pentabenzyldiethylenetriamine (PBnDETA). All ligands except PEG350 exhibited stronger coordination with Cu(I) than the polytriazole polymer, which freed the Cu catalyst from polymers and resulted in dominant step‐growth polymerization with simultaneous chain‐growth feature. Meanwhile, the use of PEG350 ligand retained the confined Cu in the polymer, demonstrating a chain‐growth mechanism, but lower polymer molecular weights as compared with the no‐external‐ligand polymerization. Results indicated that aliphatic substituent groups on ligands had little effect on the molecular weights and DB of the polymers, but rigid aromatic substituent groups decreased both values. By varying the ligand species and amounts, hyperbranched polymers with DB value ranging from 0.53 ([TBTA]0/[Cu]0 = 5) to 0.98 ([PMDETA]0/[Cu]0 = 2) have been achieved. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2238–2244
Synthesis of polydithiourethanes and their thermal, optical, and mechanical properties originated from monomers structure
Authors: Yoshida Yoshiaki , Endo Takeshi 
Published: September 2018

ABSTRACTPolyaddition of various diisothiocyanates and dithiols was achieved with triethylamine in dimethylformamide at 25 °C for 12 h under nitrogen, and then the corresponding polydithiourethanes (PDTUs) were obtained with high yield and molecular weight without depending on the monomer structures, although the dithiol monomer of the low nucleophilicity was unsuitable for polyaddition in this system. The chemical and physical properties of the obtained PDTUs such as solvent solubility, glass transition temperature, thermal stability, transparency, refractive index, and tensile strength, were analyzed in detail by gel permeation chromatography, nuclear magnetic resonance, Fourier transform infrared–attenuated total reflection, ultraviolet–visible, differential scanning calorimetry, thermogravimetric analysis, and tensile testing measurements. These results proved that PDTUs and their cast films having the aliphatic diisothiocyanate and dithiol moieties exhibited excellent chemical and physical properties compared to that of the aromatic PDTUs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2255–2262
Double network hydrogels with controlled shape deformation: A mini review
Authors: Yang Jia , Li Yu , Zhu Lin , Qin Gang , Chen Qiang 
Published: September 2018

ABSTRACTDouble network hydrogels (DN gels), consisting of two networks with strongly asymmetric network structures and properties, are one of most investigated high strength hydrogels. In most cases, the first network of DN gels is rigid, brittle and tightly crosslinked, while the second network is soft, ductile and loosely crosslinked. Because of the tunable and diverse network structures, DN gels with controlled shape deformation have attracted great attention in recent years. The shape deformation of DN gels can be controlled by first network, second network, or both networks. In this mini review, the shape deformation of DN gels via different networks will be summarized, and the application and future perspectives also are discussed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1351–1362
Environmental risk factors for asthma in 13‐14 year old African children
Authors: Ayuk Adaeze C. , Ramjith Jordache , Zar Heather J. 
Published: September 2018

AbstractBackground Asthma prevalence in African children is high. Factors driving the prevalence or disease severity are poorly understood. This study aims to investigate environmental factors associated with asthma and severity in African children.Methods Population based cross‐sectional study of children aged 13–14 years from 10 African centers who participated in ISAAC III. Self‐reported environmental exposures included engaging in physical exercise, television watching, various biomass and ETS exposure, consumption of paracetamol, large family sizes and having pets in the home. Univariable and multivariable analyses were done adjusting for center variations. Prevalences, odds ratio and 95% confidence intervals (CI) were calculated.Results There were 258 267 children recruited among the 13‐14‐year‐old participants. Of these, 28,391 respondents from 232 schools completed both the written questionnaire (WQ) and environmental questionnaire (EQ). The prevalence of asthma and severe asthma were 12.8% (CI 12.4‐13.2), and 8.7% (CI 8.4‐8.0) respectively. Factors strongly associated with asthma were maternal smoking (OR = 1.41; 95%CI: 1.23‐1.64), open fire heating (OR = 1.28; 95%CI: 1.08‐1.51) electric heating (OR = 1.13; 95%CI: 1.01‐1.28), physical exercise (OR = 1.29; 95%CI: 1.11‐1.50), monthly paracetamol use (OR 1.23; 95%CI 1.13‐1.33), having an elder sibling (OR = 0.87; 95%CI 0.77‐0.98). Factors associated with severe asthma were maternal smoking (OR = 1.61; 95%CI: 1.38‐1.89), cat pet (OR = 1.14; 95%CI: 1.04‐1.25), frequent physical exercise (OR = 1.42; 95%CI: 1.23‐1.64) and monthly paracetamol use (OR = 1.20; 95%CI 1.07, 1.34).Conclusion Several environmental exposures were associated with asthma and severe disease.
Towards developing a valid scoring tool for bronchitis during flexible bronchoscopy
Authors: Thomas Rahul J. , Eg Kah P. , Masters Ian B. , McElrea Margaret , Chang Anne B. 
Published: September 2018

AbstractBackgroundA valid bronchoscopic scoring tool for bronchitis would be useful for clinical and research purposes as currently there are none in children. From 100 digitally recorded flexible bronchoscopies (FB), we related the various macroscopic features to airway neutrophil % to develop a FB‐derived bronchitis score (BScoreexp). We aimed to develop a FB‐derived bronchitis tool.MethodsFB recordings for six visualised features: secretions (amount and color) and mucosal appearance (erythema, pallor, ridging, oedema) based on pre‐determined criteria on a pictorial chart were assessed by two physicians independently, blinded to the clinical history. These features were used to obtain various models of BScoreexp that were plotted against bronchoalveolar lavage (BAL) neutrophil % using a receiver operating characteristic (ROC) curve. Inter‐ and intra‐rater agreement (weighted‐kappa, K) were assessed from 30 FBs.ResultsUsing BAL neutrophilia of 20% to define inflammation, the highest area under ROC (aROC) of 0.71, 95%CI 0.61‐0.82 was obtained by the giving three times weightage to secretion amount and color and adding it to erythema and oedema. Inter‐rater K values for secretion amount (K = 0.87, 95%CI 0.73‐1.0) and color (K = 0.86, 95%CI 0.69‐1.0) were excellent. Respective intra‐rater K were 0.95 (0.87‐1.0) and 0.68 (0.47‐0.89). Other inter‐rater K ranged from 0.4 (erythema) to 0.64 (pallor).ConclusionA repeatable FB‐defined bronchitis scoring tool can be derived. However, a prospective study needs to be performed with larger numbers to further evaluate and validate these results.
On densities for solutions to stochastic fixed point equations
Authors: Leckey Kevin 
Published: September 2018

AbstractWe consider systems of stochastic fixed point equations that arise in the asymptotic analysis of random recursive structures and algorithms such as Quicksort, large Pólya urn processes, and path lengths of random recursive trees and split trees. The main result states sufficient conditions on the fixed point equations that imply the existence of bounded, smooth, rapidly decreasing Lebesgue densities.
Knowledge sourcing by multidivisional firms
Authors: Garg Pranav , Zhao Minyuan 
Published: September 2018

Research Summary: Research on knowledge sourcing has generally treated firms as monolithic entities, even though firms most active in knowledge sourcing often comprise heterogeneous divisions, each possessing specialized knowledge and facing unique market prospects. This study examines how heterogeneity across divisions affects knowledge sourcing by multidivisional firms. We argue that firms source more early‐stage knowledge, whose market prospects are highly uncertain, for low‐performing divisions; by remaining active in the relevant markets, firms keep the flexibility to tap favorable market opportunities should they arise in the future. In contrast, firms source more late‐stage knowledge, whose market prospects are largely revealed, for high‐performing divisions so as to maximize current returns. The intra‐firm heterogeneity, in turn, explains inter‐firm differences in knowledge sourcing. Data from the pharmaceutical industry support these arguments.Managerial Summary: Firms that source external knowledge often span multiple technological areas and markets, and hence it is not immediately clear what to source and how much to source. This study examines how multidivisional firms tailor their knowledge‐sourcing strategies to differences in performance across their divisions. We find that firms source more early‐stage knowledge, whose market prospects are uncertain, for divisions with low innovation performance. This helps firms prop up those divisions and remain active in the related markets. In contrast, firms source more late‐stage knowledge, whose market prospects are more certain, for divisions with high sales performance. This helps firms leverage the strengths of those divisions and realize immediate gains. Performance differences across divisions inside firms, therefore, can explain differences in knowledge‐sourcing strategies across firms.
Scalable Multiplexed Drug‐Combination Screening Platforms Using 3D Microtumor Model for Precision Medicine
Authors: Zhang Zhixiong , Chen Yu‐Chih , Urs Sumithra , Chen Lili , Simeone Diane M. , Yoon Euisik 
Published: September 2018

AbstractCancer heterogeneity is a notorious hallmark of this disease, and it is desirable to tailor effective treatments for each individual patient. Drug combinations have been widely accepted in cancer treatment for better therapeutic efficacy as compared to a single compound. However, experimental complexity and cost grow exponentially with more target compounds under investigation. The primary challenge remains to efficiently perform a large‐scale drug combination screening using a small number of patient primary samples for testing. Here, a scalable, easy‐to‐use, high‐throughput drug combination screening scheme is reported, which has the potential of screening all possible pairwise drug combinations for arbitrary number of drugs with multiple logarithmic mixing ratios. A “Christmas tree mixer” structure is introduced to generate a logarithmic concentration mixing ratio between drug pairs, providing a large drug concentration range for screening. A three‐layer structure design and special inlets arrangement facilitate simple drug loading process. As a proof of concept, an 8‐drug combination chip is implemented, which is capable of screening 172 different treatment conditions over 1032 3D cancer spheroids on a single chip. Using both cancer cell lines and patient‐derived cancer cells, effective drug combination screening is demonstrated for precision medicine.
Single‐Molecule Co‐Immunoprecipitation Reveals Functional Inheritance of EGFRs in Extracellular Vesicles
Authors: Sung Mi Sook , Jung Jik‐Han , Jeong Cherlhyun , Yoon Tae‐Young , Park Ji‐Ho 
Published: September 2018

AbstractCancer cells actively release extracellular vesicles (EVs) as important carriers of cellular information to tumor microenvironments. Although the composition and quantity of the proteins contained in EVs are characterized, it remains unknown how these proteins in EVs are related to those in the original cells at the functional level. With epidermal growth factor receptor (EGFR) in lung adenocarcinoma cells as a model oncoprotein, it is studied how distinct types of EVs, microvesicles and exosomes, represent their original cells at the protein and protein–protein interaction (PPI) level. Using the recently developed single‐molecule immunolabeling and co‐immunoprecipitation schemes, the quantity and PPI strengths of EGFRs derived from EVs and the original lung adenocarcinoma cells are determined. It is found that the microvesicles exhibit higher correlations with the original cells than the exosomes in terms of the EGFR levels and their PPI patterns. In spite of these detailed differences between the microvesicles and exosomes, the EGFR PPI strengths measured for EVs generally show a tight correlation with those determined for the original cells. The results suggest that EGFRs contained in EVs closely reflect the cellular EGFR in terms of their downstream signaling capacity.
Fluorinated Acid‐Labile Branched Hydroxyl‐Rich Nanosystems for Flexible and Robust Delivery of Plasmids
Authors: Qi Yu , Song Haiqing , Xiao Haihua , Cheng Gang , Yu Bingran , Xu Fu‐Jian 
Published: September 2018

AbstractNucleic acid‐based therapy specially needs a safe and robust delivery vector. Herein, a novel fluorinated acid‐labile branched hydroxyl‐rich polycation (ARP‐F) is proposed for the flexible and effective delivery nanovector of different plasmids including reporter genes and the Cas9 plasmid. Acid‐responsive polycation (ARP) with plentiful ortho ester linkages and hydroxyl groups is first synthesized via a facile one‐pot ring‐opening polymerization, followed by decoration of fluorinated alkyl chains onto ARP to achieve ARP‐F. ARP‐F possesses good pH‐responsive degradability, biocompatibility, and its preliminary transfection ability evaluated by reporter plasmids pRL‐CMV (encoding Renilla luciferase) and pEGFP‐N1 (encoding enhanced green fluorescent protein) is also excellent. CRISPR‐Cas9 (clustered regularly interspaced short palindromic repeat/CRISPR‐associated nuclease 9) technology is a potent genome‐editing tool. The subsequent delivery of pCas9‐surv (one typical all‐in‐one Cas9 plasmid) mediated by ARP‐F exhibits impressive in vitro and in vivo tumor inhibition performances. In addition, the combination of ARP‐F/pCas9‐surv with temozolomide could further enhance tumor inhibition activities by increasing the sensitivity of cancer cells to anticancer drugs. Such high‐performance polycation would provide a very promising means to produce efficient delivery nanovectors of versatile plasmids.
Ultrahigh‐Capacity and Long‐Life Lithium–Metal Batteries Enabled by Engineering Carbon Nanofiber–Stabilized Graphene Aerogel Film Host
Authors: Zhao Changtai , Yu Chang , Li Shaofeng , Guo Wei , Zhao Yang , Dong Qiang , Lin Xiaoting , Song Zhongxin , Tan Xinyi , Wang Changhong , Zheng Matthew , Sun Xueliang , Qiu Jieshan 
Published: September 2018

AbstractA safe, high‐capacity, and long‐life Li metal anode is highly desired due to recent developments in high‐energy‐density Li–metal batteries. However, there are still rigorous challenges associated with the undesirable formation of Li dendrites, lack of suitable host materials, and unstable chemical interfaces. Herein, a carbon nanofiber‐stabilized graphene aerogel film (G‐CNF film), inspired by constructional engineering, is constructed. As the host material for Li deposition, the G‐CNF film features a large surface area, porous structure, and a robust skeleton that can render low local current density. This allows for dendrite‐free Li deposition and mitigation of problems associated with large volume change. Importantly, the G‐CNF film can keep high Li plating/stripping efficiency at nearly 99% for over 700 h with an areal capacity of 10 mA h cm−2 (the specific capacity up to 2588 mA h g−1 based on the total mass of carbon host and Li metal). The symmetric cells can stably run for more than 1000 h with low voltage hysteresis. The full cell with the LiFePO4 cathode also delivers enhanced capacity and lowered overpotential. As two‐in‐one host materials for both cathodes and anodes in Li–O2 batteries, the battery exhibits a capacity of 1.2 mA h cm−2.
EU Climate and Energy Policy: New Challenges for Old Energy Suppliers
Authors: Overland Indra 
Published: September 2018

AbstractClimate policy will transform the EU energy demand mix. This has implications for the main suppliers of fossil fuels to the EU, foremost among which are Algeria, Colombia, Kazakhstan, Nigeria, Norway, Russia, Saudi Arabia and the USA. Norway has a better starting point for adapting to changing EU energy demand than the other energy suppliers and therefore represents a best-case scenario. Whatever Norway fails to do, the other countries are even less likely to achieve. The question is whether Norway has been quick enough to exploit the opportunities to play a proactive role in the EU’s energy transition. This chapter argues that it has not, dragging its feet on natural gas vehicles, Norwegian wind power, electricity interconnectors, green battery development and mixing of hydrogen into natural gas. Some possible reasons for the tardiness are Norway’s dual resource course of oil and hydropower, carbon lock-in, energy populism, resource nationalism and blind spots in the perception of Norway’s place in international climate and energy policy.
Racial and Ethnic Disparities in the Lifetime Prevalence of Homelessness in the United States
Authors: Fusaro Vincent A. , Levy Helen G. , Shaefer H. Luke 
Published: September 2018

Abstract
Homelessness in the United States is often examined using cross-sectional, point-in-time samples. Any experience of homelessness is a risk factor for adverse outcomes, so it is also useful to understand the incidence of homelessness over longer periods. We estimate the lifetime prevalence of homelessness among members of the Baby Boom cohort (n = 6,545) using the 2012 and 2014 waves of the Health and Retirement Study (HRS), a nationally representative survey of older Americans. Our analysis indicates that 6.2 % of respondents had a period of homelessness at some point in their lives. We also identify dramatic disparities in lifetime incidence of homelessness by racial and ethnic subgroups. Rates of homelessness were higher for non-Hispanic blacks (16.8 %) or Hispanics of any race (8.1 %) than for non-Hispanic whites (4.8 %; all differences significant with p &lt; .05). The black-white gap, but not the Hispanic-white gap, remained significant after adjustment for covariates such as education, veteran status, and geographic region.