bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioresorbable Microspheres with Surface‐Loaded Nanosilver and Apatite as Dual‐Functional Injectable Cell Carriers for Bone Regeneration
Authors: Wei Pengfei , Yuan Zuoying , Cai Qing , Mao Jianping , Yang Xiaoping 
Published: May 2018

AbstractBone defect repair, especially in terms of infection, remains a big challenge in clinical therapy. To meet clinical requirements, the dual‐functional strategy including antibacterial activity and strong osteogenesis effect is a promising approach in bone tissue engineering. In the present study, bioresorbable porous‐structured microspheres are fabricated from amphiphilic block copolymer composed of poly(l‐lactide) and poly(ethyl glycol) blocks. After being surface coated with mussel‐inspired polydopamine, the microspheres are loaded with nanosilver via reduction of silver nitrate and apatite via biomineralization in sequence. The resulting composite microspheres are systematically characterized by in vitro coculturing with rat bone mesenchymal stromal cells and Staphylococcus aureus to evaluate cytotoxicity and antibacterial activity. In vivo evaluation is carried out by filling the composite microspheres into infected cranial defects in a rat model. The primary results indicate that the dual‐purpose microspheres have the capacity to defeat infection while promoting bone regeneration.
Redox‐Responsive Polymer with Self‐Immolative Linkers for the Release of Payloads
Authors: Iamsaard Supitchaya , Seidi Farzad , Dararatana Naruphorn , Crespy Daniel 
Published: May 2018

AbstractPrevious couplings of corrosion inhibitors to redox‐responsive polymers via covalent bonding suffer from several drawbacks. It is presented here novel redox‐responsive polymer‐corrosion inhibitor conjugates that contain self‐immolative linkers in their side chains. Very fast redox‐induced release of tryptamine, a drug and a corrosion inhibitor, is observed after applying a reductive trigger.
Probing the Viscoelastic Property of Pseudo Free‐Standing Conjugated Polymeric Thin Films
Authors: Zhang Song , Ocheje Michael U. , Luo Shaochuan , Ehlenberg Dakota , Appleby Benjamin , Weller Daniel , Zhou Dongshan , Rondeau‐Gagné Simon , Gu Xiaodan 
Published: May 2018

AbstractThe understanding of the structure‐mechanical property relationship for semiconducting polymers is essential for the application of flexible organic electronics. Herein pseudo free‐standing tensile testing, a technique that measures the mechanical property of thin films floating on the surface of water, is used to obtain the stress–strain behaviors of two semiconducting polymers, poly(3‐hexylthiophene) (P3HT) and poly(2,5‐bis(2‐decyltetradecyl)‐3,6‐di(thiophen‐2‐yl)diketopyrrolo[3,4‐c]pyrrole‐1,4‐dione‐alt‐thienovinylthiophene (DPP‐TVT) donor–acceptor (D–A) polymer. To our surprise, DPP‐TVT shows similar viscoelastic behavior to P3HT, despite DPP‐TVT possessing a larger conjugated backbone and much higher charge carrier mobility. The viscoelastic behavior of these polymers is due to sub room temperature glass transition temperatures (Tg), as shown by AC chip calorimetry. These results provide a comprehensive understanding of the viscoelastic properties of conjugated D–A polymers by thickness‐dependent, strain rate dependent, hysteresis tests, and stress‐relaxation tests, highlighting the importance of Tg for designing intrinsically stretchable conjugated polymers.
Softening and Shape Morphing of Stiff Tough Hydrogels by Localized Unlocking of the Trivalent Ionically Cross‐Linked Centers
Authors: Wang Jiahui , Li Tianzhen , Chen Fan , Zhou Dan , Li Baijia , Zhou Xiaohu , Gan Tiansheng , Handschuh‐Wang Stephan , Zhou Xuechang 
Published: May 2018

AbstractThe mechanical properties (e.g., stiffness, stretchability) of prefabricated hydrogels are of pivotal importance for diverse applications in tissue engineering, soft robotics, and medicine. This study reports a feasible method to fabricate ultrasoft and highly stretchable structures from stiff and tough hydrogels of low stretchability and the application of these switchable hydrogels in programmable shape‐morphing systems. Stiff and tough hydrogel structures are first fabricated by the mechanical strengthening of Ca2+‐alginate/polyacrylamide tough hydrogels by addition of Fe3+ ions, which introduces Fe3+ ionically cross‐linked centers into the Ca2+ divalent cross‐linked hydrogel, forming an additional and much less flexible trivalent ionically cross‐linked network. The resulting stiff and tough hydrogels are exposed to an L‐ascorbic acid (vitamin C, VC) solution to rapidly reduce Fe3+ to Fe2+. As a result, flexible divalent ionically cross‐linked networks are formed, leading to swift softening of the stiff and tough hydrogels. Moreover, localized stiffness variation of the tough hydrogels can be realized by precise patterning of the VC solution. To validate this concept, sequential steps of VC patterning are carried out for local tuning of the stiffness of the hydrogels. With this strategy, localized softening, unfolding, and sequential folding of the tough hydrogels into complex 3D structures is demonstrated.
Ion‐Conductive and Thermal Properties of a Synergistic Poly(ethylene carbonate)/Poly(trimethylene carbonate) Blend Electrolyte
Authors: Li Zhenguang , Mogensen Ronnie , Mindemark Jonas , Bowden Tim , Brandell Daniel , Tominaga Yoichi 
Published: May 2018

AbstractElectrolytes comprising poly(ethylene carbonate) (PEC)/poly(trimethylene carbonate) (PTM C) with lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) are prepared by a simple solvent casting method. Although PEC and PTMC have similar chemical structures, they are immiscible and two glass transitions are present in the differential scanning calorimetry (DSC) measurements. Interestingly, these two polymers change to miscible blends with the addition of LiTFSI, and the ionic conductivity increases with increasing lithium salt concentration. The optimum composition of the blend electrolyte is achieved at PEC6PTMC4, with a conductivity as high as 10−6 S cm−1 at 50 °C. This value is greater than that for single PEC‐ and PTMC‐based electrolytes. Moreover, the thermal stability of the blend‐based electrolytes is improved as compared to PEC‐based electrolytes. It is clear that the interaction between CO groups and Li+ gives rise to a compatible amorphous phase of PEC and PTMC.
Amine‐Triggered Dopamine Polymerization: From Aqueous Solution to Organic Solvents
Authors: Liu Xinghuan , Kang Junjie , Wang Yiqing , Li Wei , Guo Heling , Xu Liang , Guo Xuhong , Zhou Feng , Jia Xin 
Published: May 2018

AbstractDopamine (DA) polymerization has received significant attention in many fields, however, almost all of the works are limited to aqueous solution and hamper its wide application. This paper reports that amines can trigger DA polymerization by capturing the H+ from DA hydrochloride and intermediates to accelerate the generation of radical species in water or organic solvents. Increasing concentration and decreasing pKb of amines cause the reaction equilibrium to shift toward the product polydopamine (PDA). Water‐soluble and easily‐removable Na2SO4 nanowires and NaCl cubes can be used as templates to prepare different morphologies of hollow PDA structures by DA polymerization in ethanol solution. The carbonization production of PDA nanotubes at 900 °C (PDNC‐900) is obtained and demonstrates electrochemical activity in the oxygen reduction reaction that is comparable to that of Pt/C.
TEMPO Driven Mild and Modular Route to Functionalized Microparticles
Authors: Hafeez Sumbul , Barner Leonie , Nebhani Leena 
Published: May 2018

AbstractThe synthesis of crosslinked polymeric microspheres (3.8–15.0 µm) via (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) initiated thiol‐ene dispersion polymerization under ambient conditions is reported for the first time. The initiating ability of TEMPO for the thiol‐ene reaction is validated by electron paramagnetic resonance (EPR) and 1H nuclear magnetic resonance (NMR) spectroscopy on model reactions between 1‐octadecanethiol and two electron deficient enes, n‐butylacrylate and divinyl sulfone. Critically, the TEMPO resonance observed in the EPR spectra decreases with time when TEMPO is mixed with thiol and an electron deficient ene. The 1H NMR spectra demonstrate formation of up to 90% of thioether under ambient conditions. Based on these model reactions, a variety of crosslinked polymeric microspheres are synthesized with excellent morphological stability using poly(vinyl pyrrolidone) as surfactant. The ability of the microspheres for a second TEMPO initiated thiol‐ene reaction is demonstrated by the ligation of fluorescein‐5‐maleimide (an ene) to the microspheres' surface containing excess of thiol functionality and by ligation of cysteine (containing a thiol group) to the microspheres' surface containing an excess of ene functionality. The synthesized polymeric microspheres are characterized using scanning electron microscopy, differential scanning calorimetry, Fourier‐transform infrared spectroscopy, zeta potential, and X‐ray photoelectron spectroscopy.
Intramolecular Copper‐Containing Hyperbranched Polytriazole Assemblies for Label‐Free Cellular Bioimaging and Redox‐Triggered Copper Complex Delivery
Authors: Ban Qingfu , Du Junjie , Sun Wen , Chen Jianxin , Wu Si , Kong Jie 
Published: May 2018

AbstractIntramolecular Cu‐containing amphiphilic hyperbranched polytriazoles are purposefully designed and synthesized via a Cu(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction, and are self‐assembled into spherical assemblies. Based on the metal coordination ability of triazole groups, the copper catalyst can be intramolecularly coordinated with triazole groups in the CuAAC, producing the copper‐triazole coordination polyprodrugs. Unexpectedly, the amphiphilic hyperbranched polytriaozle assemblies can also be applied as fluorescent nanoprobes with aggregation‐induced emission enhancement. The cellular uptake verifies their functional application for cellular bioimaging. Furthermore, the results of cell viability indicate that the mPEG‐hb‐S‐S‐PTAs assemblies are effective copper delivery systems for cancer therapy by releasing the anticancer copper‐triazole coordination complexes. Therefore, the amphiphilic hyperbranched polytriazoles may have very promising applications in complex copper delivery and label‐free cellular bioimaging.
Tunable, Quantitative Fenton‐RAFT Polymerization via Metered Reagent Addition
Authors: Nothling Mitchell D. , McKenzie Thomas G. , Reyhani Amin , Qiao Greg G. 
Published: May 2018

AbstractA continuous supply of radical species is a key requirement for activating chain growth and accessing quantitative monomer conversions in reversible addition‐fragmentation chain transfer (RAFT) polymerization. In Fenton‐RAFT, activation is provided by hydroxyl radicals, whose indiscriminate reactivity and short‐lived nature poses a challenge to accessing extended polymerization times and quantitative monomer conversions. Here, an alternative Fenton‐RAFT procedure is presented, whereby radical generation can be finely controlled via metered dosing of a component of the Fenton redox reaction (H2O2) using an external pumping system. By limiting the instantaneous flux of radicals and ensuring sustained radical generation over tunable time periods, metered reagent addition reduces unwanted radical “wasting” reactions and provides access to consistent quantitative monomer conversions with high chain‐end fidelity. Fine tuning of radical concentration during polymerization is achieved simply via adjustment of reagent dose rate, offering significant potential for automation. This modular strategy holds promise for extending traditional RAFT initiation toward more tightly regulated radical concentration profiles and affords excellent prospects for the automation of Fenton‐RAFT polymerization.
Macroscopic Supramolecular Assembly through Electrostatic Interactions Based on a Flexible Spacing Coating
Authors: Zhang Qian , Liu Chongxian , Ju Guannan , Cheng Mengjiao , Shi Feng 
Published: May 2018

AbstractMacroscopic supramolecular assembly (MSA) is a recent advance in supramolecular chemistry that involves associating large building blocks with a size larger than 10 µm through noncovalent interactions. However, until now the applicable material system is rather limited to hydrogels, and MSA of rigid materials with supramolecular interactions widely used in molecular assembly has rarely been reported due to the difficulty in achieving multivalency between rigid surfaces. Herein, the concept of flexible spacing coating is applied with highly flowable properties, and the electrostatic‐interaction‐driven MSA of relatively rigid polydimethylsiloxane building blocks is demonstrated. With the flexible spacing coating of a polyelectrolyte multilayer, the oppositely charged rigid building blocks can realize MSA under shaking in water for 5 min. The major contribution of the electrostatic interaction is confirmed by both qualitative controlled MSA experiments in other solvents, disassembly in ionic solution and quantitative results with an in situ force measurement method.
Synergy between Electrochemical ATRP and RAFT for Polymerization at Low Copper Loading
Authors: Wang Yi , Fantin Marco , Matyjaszewski Krzysztof 
Published: May 2018

AbstractA dual‐concurrent atom transfer radical polymerization/reversible addition‐fragmentation chain‐transfer (ATRP/RAFT) system is used to control a radical polymerization by electrochemical reduction of small amount of copper complexes in the presence of a chain transfer agent (CTA). Electrochemical ATRP conditions provide a continuous supply of radicals, while the CTA aids the control over molecular weight and dispersity of poly(n‐butyl acrylate), even in the presence of low ppm amounts of catalyst. The polymerization could be turned “on” and “off” by shifting electrolysis potential. With as low as 10 ppm of Cu catalyst, addition of only 2% CTA (with respect to the ATRP initiator) improves control by decreasing dispersity from Ð = 1.41 to Ð = 1.25.
Effect of the Z‐ and Macro‐R‐Group on the Thermal Desulfurization of Polymers Synthesized with Acid/Base “Switchable” Dithiocarbamate RAFT Agents
Authors: Stace Sarah J. , Fellows Christopher M. , Moad Graeme , Keddie Daniel J. 
Published: May 2018

AbstractThermolysis is examined as a method for complete desulfurization of reversible addition‐fragmentation chain transfer (RAFT)‐synthesized polymers prepared with acid/base “switchable” N‐methyl‐N‐pyridyldithiocarbamates [RS2CZ or RS2CZH+]. Macro‐RAFT agents from more activated monomers (MAMs) (i.e., styrene (St), N‐isopropylacrylamide (NIPAm), and methyl methacrylate (MMA)) with RS2CZH+ and less activated monomers (LAMs) (i.e., vinyl acetate (VAc) and N‐vinylpyrolidone (NVP)) with RS2CZ are prepared by RAFT polymerization and analyzed by thermogravimetric analysis. In all cases, a mass loss consistent with loss of the end group (ZCS2H) is observed at temperatures lower than, and largely discrete from, that required for further degradation of the polymer. The temperatures for end group loss and the new end groups formed are strongly dependent on the identity of the R(P)n and the state of the pyridyl Z group; increasing in the series poly(MMA) < poly(St) ∼ poly(NIPAm) << poly(VAc) ∼ poly(NVP) for S2CZ and poly(MMA) < poly(St) ∼ poly(NIPAm) for S2CZH+. Clean end group removal is possible for poly(St) and poly(NVP). For poly(NIPAm), the thiocarbonyl chain end is removed, but the end group identity is less certain. For poly(MMA) and poly(VAc), some degradation of the polymer accompanies end group loss under the conditions used and further refinement of the process is required.
Green Tea Liquid Consumption Alters the Human Intestinal and Oral Microbiome
Authors: Yuan Xiaojie , Long Yong , Ji Zhaohua , Gao Jie , Fu Ting , Yan Min , Zhang Lei , Su Haixia , Zhang Weilu , Wen Xiaohui , Pu Zhongshu , Chen Hui , Wang Yufei , Gu Xu , Yan Binyuan , Kaliannan Kanakaraju , Shao Zhongjun 
Published: May 2018

ScopeGTPs (green tea polyphenols) exert anti‐CRC (colorectal cancer) activity. The intestinal microbiota and intestinal colonization by bacteria of oral origin has been implicated in colorectal carcinogenesis. GT modulates the composition of mouse gut microbiota harmonious with anticancer activity. Therefore, the effect of green tea liquid (GTL) consumption on the gut and oral microbiome is investigated in healthy volunteers (n = 12).Methods and results16S sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis of both fecal and saliva samples (collected before intervention, after 2 weeks of GTL (400 mL per day) and after a washout period of one week) in healthy volunteers show changes in microbial diversity and core microbiota and difference in clear classification (partial least squares‐discriminant analysis [PLS‐DA]). An irreversible, increased FIR:BAC (Firmicutes to Bacteroidetes ratio), elevated SCFA producing genera, and reduction of bacterial LPS synthesis in feces are discovered in response to GTL. GTL alters the salivary microbiota and reduces the functional pathways abundance relevance to carcinogenesis. Similar bacterial networks in fecal and salivary microbiota datasets comprising putative oral bacteria are found and GTL reduces the fecal levels of Fusobacterium. Interestingly, both Lachnospiraceae and B/E (Bifidobacterium to Enterobacteriacea ratio—markers of colonization resistance [CR]) are negatively associated with the presence of oral‐like bacterial networks in the feces.ConclusionThese results suggest that GTL consumption causes both oral and gut microbiome alterations.
The genome sequence of a SNP type 3K strain of Mycobacterium leprae isolated from a seventh‐century Hungarian case of lepromatous leprosy
Authors: Mendum T. A. , Taylor G. M. , Donoghue H. D. , Wu H. , Szalontai C. , Marcsik A. , Molnár E. , Pálfi G. , Stewart G. R. 
Published: May 2018

AbstractWe report on a Mycobacterium leprae genome isolated from the remains of an individual with lepromatous leprosy that were excavated from a seventh‐century Hungarian cemetery. We determined that the genome was from a single nucleotide polymorphism (SNP) type 3K0 M. leprae strain, a lineage that diverged early from other M. leprae lineages. This is one of the earliest 3K0 M. leprae genomes to be sequenced to date. A number of novel SNPs as well as SNPs characteristic of the 3K0 lineage were confirmed by conventional polymerase chain reaction and Sanger sequencing. Recovery of accompanying human DNA from the burial was poor, particularly when compared with that of the pathogen. Modern 3K0 M. leprae strains have only been isolated from East Asia and the Pacific, and so these findings require new scenarios to describe the origins and routes of dissemination of leprosy during antiquity that have resulted in the modern phylogeographical distribution of M. leprae.
Over 4,500 years of trepanation in Poland: From the unknown to therapeutic advisability
Authors: Lorkiewicz W. , Mietlińska J. , Karkus J. , Żądzińska E. , Jakubowski J. K. , Antoszewski B. 
Published: May 2018

AbstractThis paper discusses 6 trepanned skulls from central Poland, dating from the late Neolithic (3,000–2,800 BC) to early modern times (18th century AD). Four of them come from a small area in and around the town of Brześć Kujawski in Kujawy, a region of long‐lasting and intense human settlement in Poland. The analysed skulls provide striking evidence for the long history of trepanation in this part of Europe. Three surgical techniques were used: sawing, scraping, and drilling, either on their own or in combination with one another. Regardless of the method, all the trepanations were fully healed, which proves long‐term survival of the patients. All skulls belonged to adult males, who were generally at a higher risk of trauma in the populations from which 4 of the specimens derive. The studied skulls demonstrate a marked evolution in trepanation practices over time. Trepanations from the late medieval and early modern times tend to be smaller, less life threatening, and clearly made for therapeutic purposes to remedy cranial injuries. The remarkable skills of the surgeons who performed them could be linked to the influence of the renowned Danzig Anatomical School in Gdańsk, which was one of the leading centres of medical and anatomical research in northern and central Europe in the 17th and 18th centuries.
Dentin isotopic reconstruction of individual life histories reveals millet consumption during weaning and childhood at the Late Neolithic (4500 bp) Gaoshan site in southwestern China
Authors: Yi Bing , Liu Xiangyu , Yuan Haibing , Zhou Zhiqing , Chen Jian , Wang Tingting , Wang Yajuan , Hu Yaowu , Fuller Benjamin T. 
Published: May 2018

AbstractHere, we present results of a pilot project that measured δ13C and δ15N values in bone collagen (ribs and femora) as well as dentin serial sections to examine individual dietary life histories at a Late Neolithic (4500 bp) site known as Gaoshan Ancient City (高山古城) located on the Chengdu Plain in Sichuan Province, China. The isotopic data of the bones indicate that humans consumed C3‐based foods, which corresponds to the dominance of rice agriculture in this region. However, the isotopic data of the dentin serial sections of five individuals display much more positive δ13C values than those of the bones, strongly suggesting that millets (a C4 crop) contributed substantially to human diets during the weaning process and early childhood. Furthermore, the isotopic profiles of dentin sections of the first molars and canines demonstrate that the cession of weaning was individually variable and completed between ~2.5 and 4 years of age. Although limited in scope, this pilot study offers new evidence of millet consumption during human growth and development even though individuals relied on rice exclusively as adults. Moreover, our study provides another perspective with which to rethink the role that millets played during the development and spread of millet agriculture to the south of China in terms of cultural exchange and migration.
Optimal state estimation for equality‐constrained systems with complex noise
Authors: Yu Xingkai , Li Jianxun , Xu Jian , Zhang Zhe 
Published: May 2018

SummaryAccurate system description is important to obtain accurate state estimation for many application areas. Much a priori information and complex noise pollution exist in real systems and impact the accuracy of system descriptions. Thus, this paper focuses on the state estimation problem with prior information for systems with complex noise pollution. Considering the additional prior information about the state with constraint increase, the estimate quality is compared to classical state estimation methods, which cannot utilize the prior information. Therefore, linear systems with complex noise include additive noise and multiplicative noise, which are taken into account, and an optimal algorithm is deduced. For nonlinear systems and non‐Gaussian complex noise, an algorithm is proposed based on variational Bayesian inference to address this general problem. Furthermore, an algorithm comparison, a performance analysis, and a convergence analysis are presented. The estimation performance is illustrated in numerical target tracking examples.