bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Unusual Properties of Polytetrafluoroethylene Enable Massive‐Volume Vitrification of Stem Cells with Low‐Concentration Cryoprotectants
Authors: Cao Yuan , Zhao Gang , Panhwar Fazil , Zhang Xiaozhang , Chen Zhongrong , Cheng Lin , Zang Chuanbao , Liu Feng , Zhao Yuanjin , He Xiaoming 
Published: October 2018

AbstractInjectable stem cell‐hydrogel constructs hold great potential for regenerative medicine and cell‐based therapies. However, their clinical application is still challenging due to their short shelf‐life at ambient temperature and the time‐consuming fabrication procedure. Banking the constructs at cryogenic temperature may offer the possibility for their “off‐the‐shelf” availability to end‐users. However, ice formation during the cryopreservation process may compromise the construct quality and cell viability. Vitrification, cooling biological samples without apparent ice formation, has been explored to resolve the challenge. However, contemporary vitrification methods are limited to very small volume (up to ≈0.25 mL) and/or need highly toxic and high concentration (up to ≈8 m) of permeable cryoprotectants (pCPAs). Here, it is shown that polytetrafluoroethylene (PTFE, best known as Teflon for making nonstick cookware) capillary is flexible and unusually stable at cryogenic temperatures. By using the PTFE capillary as a flexible cryopreservation vessel together with alginate hydrogel microencapsulation and Fe3O4 nanoparticle‐mediated nanowarming to suppress ice formation, massive‐volume (e.g., 10 mL) vitrification of cell‐alginate hydrogel constructs with low concentrations (≈2.5 m) of pCPAs can be achieved. This may greatly facilitate the use of stem cell‐based constructs for tissue regeneration and cell based therapies in the clinic.
Facile Fabrication of Nitrogen‐Doped Porous Carbon as Superior Anode Material for Potassium‐Ion Batteries
Authors: Li Deping , Ren Xiaohua , Ai Qing , Sun Qing , Zhu Lin , Liu Yang , Liang Zhen , Peng Ruiqin , Si Pengchao , Lou Jun , Feng Jinkui , Ci Lijie 
Published: October 2018

AbstractPotassium‐ion batteries (PIBs), using carbon materials as the anode, are regarded as a promising alternative to lithium‐ion batteries owing to the feasible formation of stage‐1 potassium intercalation compounds (KC8). However, due to the large radius of the potassium ion, graphite‐based electrodes still suffer poor rate capability and insufficient cycling life. In this work, a hierarchically nitrogen‐doped porous carbon (NPC) is reported for the first time. The NPC electrode delivers a high reversible capacity of 384.2 mAh g−1 after 500 cycles at a current density of 0.1 A g−1 and an outstanding rate capability of 185 mAh g−1 at 10.0 A g−1, which surpasses most of the reported carbonaceous electrodes in PIBs. The excellent performance can be ascribed to the surface‐driven behavior dominated K‐storage mechanism, which is verified by quantitative kinetics analysis. Theoretical simulation results further illuminate the enhanced K affinity in N‐doped active sites, which accounts for the superior rate performance of the NPC electrode. In addition, galvanostatic intermittent titration technique measurements further quantify the diffusion coefficient of K ions. Considering the superior electrochemical performance of the electrode and comprehensive investigation of the K storage mechanism, this work can provide fundamental references for the subsequent research of potassium‐ion batteries.
A Water‐Splitting Carbon Nitride Photoelectrochemical Cell with Efficient Charge Separation and Remarkably Low Onset Potential
Authors: Peng Guiming , Albero Josep , Garcia Hermenegildo , Shalom Menny 
Published: October 2018

AbstractA simple method to grow a closely packed carbon nitride (CN) film by the crystallization of CN monomers on a conductive substrate followed by a thermal condensation is reported. The as‐synthesized CN exhibits excellent performance as photoanode material in a photoelectrochemical cell. Detailed (photo)electrochemical and transient absorption measurements indicate excellent charge separation properties, high hole‐extraction efficiency (up to 50 %), a long electron lifetime, and low amount of defect states below the CN conduction band. Consequently, the CN photoanode exhibits a markedly low overpotential of 0.25 V versus reversible hydrogen electrode (RHE), which is comparable with the state‐of‐the‐art metal‐based photoanodes, an impressive photocurrent density of 116 μA cm−2 at 1.23 V versus RHE in an alkaline solution without sacrificial agent, as well as excellent stability over a wide pH range (0–13).
Synthesis of Water‐Soluble Blue‐Emissive Tricyclic 2‐Aminopyridinium Salts by Three‐Component Coupling‐(3+3)‐Anellation
Authors: Bakulina Olga , Merkt Franziska K. , Knedel Tim‐Oliver , Janiak Christoph , Müller Thomas J. J. 
Published: October 2018

AbstractThe (3+3) anellation of alkynones and cyclic amidines is a novel and unexpected approach to generate intensively blue luminescent tricyclic 2‐aminopyridinium salts with quantum yields Φf up to 63 % in water. By implementation into a consecutive three‐component reaction, these title compounds are obtained rapidly and efficiently in a diversity‐oriented fashion. Most interestingly, these bi‐ and tricyclic 2‐aminopyridinium salts emit in dichloromethane and water solutions, thus making them interesting novel luminophore probes for bioanalytics, as well as in the solid state, thus making them blue emitters with tunable efficiency.
The Origin of the Reduced Reductive Stability of Ion–Solvent Complexes on Alkali and Alkaline Earth Metal Anodes
Authors: Chen Xiang , Li Hao‐Ran , Shen Xin , Zhang Qiang 
Published: October 2018

AbstractThe intrinsic instability of organic electrolytes seriously impedes practical applications of high‐capacity metal (Li, Na) anodes. Ion–solvent complexes can even promote the decomposition of electrolytes on metal anodes. Herein, first‐principles calculations were performed to investigate the origin of the reduced reductive stability of ion–solvent complexes. Both ester and ether electrolyte solvents are selected to interact with Li+, Na+, K+, Mg2+, and Ca2+. The LUMO energy levels of ion–ester complexes exhibit a linear relationship with the binding energy, regulated by the ratio of carbon atomic orbital in the LUMO, while LUMOs of ion–ether complexes are composed by the metal atomic orbitals. This work shows why ion–solvent complexes can reduce the reductive stability of electrolytes, reveals different mechanisms for ester and ether electrolytes, and provides a theoretical understanding of the electrolyte–anode interfacial reactions and guidance to electrolyte and metal anode design.
Synthesis of iron‐based metal organic framework and its visible light‐driven photocatalytic degradation of dye pollutants
Authors: Wang Chang‐Ji , Li Han‐Xu 
Published: October 2018

A novel metal–organic compound [Fe (ox)(phen)]n (phen = 1,10‐Phennannthroline, ox = oxalate acid) has been hydrothermally synthesized and structurally characterized by X‐ray single‐crystal diffraction, X‐ray diffraction, IR, UV–vis diffuse reflectance spectroscopy and X‐ray photoelectron spectroscopy. The compound crystallized in monoclinic,space group P21 with a = 0.92289 (3) nm, b = 1.35719 (3) nm, c = 1.02012 (4) nm,β = 94.372 (2)°,V = 1.27402(8)nm3,Z = 2,and exhibited a 2D layer structure. The photocatalytic activities of the compound were evaluated by decomposing Rhodamine B (RhB) and methyl orange (MO) under the visible light irradiation. In addition, the mechanism of the photocatalytic properties were proposed during this process.
Effect of pyrolysis temperature on pine sawdust chars and their gasification reactivity mechanism with CO2
Authors: Tong Wei , Liu Qingcai , Ren Shan , Zhou Jian , Zhang Tianshi , Yang Chen 
Published: October 2018

AbstractThe mechanism on CO2 gasification reactivity of pine sawdust chars (PS chars) obtained from the different pyrolysis temperatures (873, 973, and 1073 K) is studied on the basis of nonisothermal thermogravimetric method. The order of gasification reactivity is PS char‐873 > PS char‐973 > PS char‐1073. The effect of pyrolysis temperature is depicted by microstructure characterization, and the gasification reactivity is analyzed with nonisothermal kinetic models. The microstructure characterizations of chars are characterized by scanning electron micrograph, Brunauer–Emmett–Teller, Fourier transform infrared, and X‐ray diffraction. Results show that the microcrystalline structure of biomass char is the dominant factor for the effect of gasification reactivity with the pyrolysis temperature rising. The kinetic models of Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose are applied to describe the kinetics of gasification process. The average values of activation energy are in close agreement with the two methods. Both of the methods prove that F2 mechanism is applicable to the gasification of PS chars at lower pyrolysis temperature and F1 mechanism at higher pyrolysis temperature. Besides, there is a compensation effect between activation energy and preexponential factor in the CO2 gasification process.
Effects of the geometrical configuration of air–water mixer on the size and distribution of microbubbles in aeration systems
Authors: Basso Alessio , Hamad F. A. , Ganesan P. 
Published: October 2018

AbstractThe objective of this work is to present a novel geometrical configuration for microbubble generators (MBGs) to improve dissolved‐oxygen levels in water. Among various methodologies from the literature, Orifice and Venturi tubes have been considered as baseline cases. Experimental data from the literature are used to verify a computational fluid dynamics (CFD) case developed for a better understanding of the dynamics of MBGs. As a result, the validated CFD setup has been implemented on a modified Venturi‐type generator, where air is injected coaxially with respect to the tube axis, whereas a helicoid wall at variable pitch angle is used. Results show a reduction in the mean bubble diameter distribution from the baseline Venturi tubes, particularly, at low‐speed inlet velocities. This is of interest, especially to decrease the energy requirement for most common water aeration systems.
Computational fluid dynamics simulation of gas–liquid–solid polyethylene fluidized bed reactors incorporating with a dynamic polymerization kinetic model
Authors: Hui Pan , Yuan‐Xing Liu , Zheng‐Hong Luo 
Published: October 2018

AbstractA comprehensive polymerization kinetics model that includes site formation, chain initiation, chain propagation, chain transfer and chain deactivation elementary reactions was incorporated into the three‐fluid computational fluid dynamics (CFD) model to describe the polymer properties in the gas–liquid–solid three‐phase polyethylene fluidized bed reactor. The effect of operating conditions on polyethylene properties was firstly discussed. Furthermore, due to the importance and complexity of scaling up three‐phase reactors, the incorporated CFD model was then employed to investigate the scale‐up influence, which indicates that the difference of flow hydrodynamics in the reactor due to scale‐up effect will result in the difference of polymerization reaction rate.
Vascularization Strategies for Peripheral Nerve Tissue Engineering
Authors: Muangsanit Papon , Shipley Rebecca J. , Phillips James B. 
Published: October 2018

ABSTRACTVascularization plays a significant role in treating nerve injury, especially to avoid the central necrosis observed in nerve grafts for large and long nerve defects. It is known that sufficient vascularization can sustain cell survival and maintain cell integration within tissue‐engineered constructs. Several studies have also shown that vascularization affects nerve regeneration. Motivated by these studies, vascularized nerve grafts have been developed using various different techniques, although donor site morbidity and limited nerve supply remain significant drawbacks. Tissue engineering provides an exciting alternative approach to prefabricate vascularized nerve constructs which could overcome the limitations of grafts. In this review article, we focus on the role of vascularization in nerve regeneration, discussing various approaches to generate vascularized nerve constructs and the contribution of tissue engineering and mathematical modeling to aid in developing vascularized engineered nerve constructs, illustrating these aspects with examples from our research experience. Anat Rec, 301:1657–1667, 2018. © 2018 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
Redox‐Active Dynamic Self‐Supporting Thixotropic 3D‐Printable G‐Quadruplex Hydrogels
Authors: Biswas Ankan , Maiti Sayan , Kalaskar Deepak M. , Das Apurba K. 
Published: October 2018

AbstractRedox‐active G‐quadruplex hydrogels were prepared by dynamic boronate ester formation between ferroceneboronic acid and guanosine. Dynamic boronate esters imparted thixotropic and 3D‐printability to the hydrogel. Initially, the ferrocene moiety was oxidised to produce a weaker ferrocenium‐based green hydrogel. However, the less stable ferrocenium converted into more stable ferrocene to produce a hydrophobic, water‐stable and robust hydrogel.
Assessment of OATP transporter‐mediated drug–drug interaction using physiologically‐based pharmacokinetic (PBPK) modeling – a case example
Authors: Chen Yuan , Zhu Rui , Ma Fang , Mao Jialin , Chen Eugene C. , Choo Edna F. , Sahasranaman Srikumar , Liu Lichuan 
Published: October 2018

AbstractGDC‐0810 was under development as an oral anti‐cancer drug for the treatment of estrogen receptor‐positive breast cancer as a single agent or in combination. In vitro data indicated that GDC‐0810 is a potent inhibitor of OATP1B1/1B3. To assess clinical risk, a PBPK model was developed to predict the transporter drug–drug interaction (tDDI) between GDC‐0810 and pravastatin in human. The PBPK model was constructed in Simcyp® by integrating in vitro and in vivo data for GDC‐0810. The prediction of human pharmacokinetics (PK) was verified using GDC‐0810 phase I clinical PK data. The Simcyp transporter DDI model was verified using known OATP1B1/1B3 inhibitors (rifampicin, cyclosporine and gemfibrozil) and substrate (pravastatin), prior to using the model to predict GDC‐0810 tDDI. The effect of GDC‐0810 on pravastatin PK was then predicted based on the proposed clinical scenarios. Sensitivity analysis was conducted on the parameters with uncertainty. The developed PBPK model described the PK profile of GDC‐0810 reasonably well. In the tDDI verification, the model reasonably predicted pravastatin tDDI caused by rifampicin and gemfibrozil OATP1B1/3 inhibition but under‐predicted tDDI caused by cyclosporine. The effect of GDC‐0810 on pravastatin PK was predicted to be low to moderate (pravastatin Cmax ratios 1.01–2.05 and AUC ratio 1.04–2.23). The observed tDDI (Cmax ratio 1.20 and AUC ratio 1.41) was within the range of the predicted values. This work demonstrates an approach using a PBPK model to prospectively assess tDDI caused by a new chemical entity as an OATP1B1/3 uptake transporter inhibitor to assess clinical risk and to support development strategy.
The effect of emotional analysis on the improvement of experimental e‐learning systems
Authors: Khalfallah Jihen , Ben Hadj Slama Jaleleddine 
Published: October 2018

AbstractE‐learning, also known as online learning or technology enhanced learning, needs to provide more heterogeneous learning including not only Web‐based courses and virtual classrooms but also remote labs with an affective recognition system. These latter allow students to interact with real experiments conducted from a distance with real‐time facial expression recognition using a webcam. However, multiple systems do not include this kind of learning. Thus, students' motivation, interest, and learning might be negatively affected since there can be no emotional interaction without “on demand” learning. This work analyzes the impact of students' emotions to enhance the learning experience in two aspects: (i) filling the existing gaps of students and (ii) improving the usability and readability of the platform. The overall goal of our research is to build a novel intelligent tutoring system, called “LabTutor,” adapted to the profile of every student. It aims to serve as an experienced teacher for students who access and perform experiments on real laboratory equipment in the field of engineering education.
Rubipodanin B, a New Cytotoxic Cyclopeptide from Rubia podantha
Authors: Hu Yan‐Yun , Feng Li , Wang Jia , Zhang Xue‐Jia , Wang Zhe , Tan Ning‐Hua 
Published: October 2018

AbstractUsing the TLC cyclopeptide protosite detection method, a new cyclohexapeptide named rubipodanin B (1), together with 11 known Rubiaceae‐type cyclopeptides (RAs), RA‐X‐OMe (2), RA‐IV (3), RA‐XI (4), RA‐XIII‐OMe (5), rubiyunnanin C (6), RA‐I (7), RA‐III (8), RA‐V (9), RA‐VII (10), RA‐XII (11) and rubipodanin A (12), were obtained from the roots and rhizomes of Rubia podantha Diels. The structures were determined using various spectroscopic methods. Among them, 2 was firstly identified as a natural product, and 3–6 were firstly isolated from this species. Cytotoxicity and NF‐κB signaling pathway activity of 1, 2, 4, 6, 7 and 9 were evaluated. All these compounds showed cytotoxic activities against three human tumor cell lines, MDA‐MB‐231, SW620 and HepG2, with the IC50 values between 0.015 and 10.27 μm, and only 7 and 9 possessed NF‐κB inhibitory activities with the IC50 values of 2.42 and 0.046 μm, respectively, which demonstrated that 2‐alanine amino acid plays a key role to maintain the RAs bioactivity.
Producing Fatty Acid Methyl Esters from Free Fatty Acids with Ionic Liquids as Catalyst
Authors: Yang Fangxia , Zhang Junhua , Guo Yingjie , Feng Lele , Wei Shijun , Chen Shuai 
Published: October 2018

AbstractThree Brønsted acidic imidazole dicationic ionic liquids (ILs) with different length of alkyl chains, [Cn(Mim)2][HSO4]2 (n = 3, 6, 12), were prepared and used as catalyst for the esterification reaction of free fatty acids and methanol. Taking oleic acid as model acid, the catalytic performances of the synthesized ILs for the esterification were evaluated. The main physicochemical properties of the ILs, thermal stability, acidity, solubility in common solvents, and causticity on Austenitic stainless steel 316, were examined. [C3(Mim)2][HSO4]2 demonstrated the highest catalytic activity and enabled to assess the preliminary optimum esterification condition of oleic acid and methanol. Under optimized reaction conditions, the yield of oleic acid methyl ester was up to 95 %. The ILs have great potential as catalysts for producing fatty acid methyl esters from long‐chain free fatty acids.
Optimization and Exergy Analysis of Natural Gas Liquid Recovery Processes for the Maximization of Plant Profits
Authors: Hu Haili , Jiang Hong , Jing Jiaqiang , Pu Hongyu , Tan Jiatong , Leng Nanjiang 
Published: October 2018

AbstractMaximizing the profits of natural gas liquid recovery plants is a challenge. To improve the performance of an existing plant, three process schemes were compared and analyzed with Aspen HYSYS. A high‐pressure absorber (HPA) performed better owing to the added compressor and more reasonable cold energy utilization. The HPA was further optimized by establishing an objective function and identifying and adjusting the main variables on the basis of a new optimization algorithm. The propane recovery of the optimized HPA was 98.8 %, and the plant profitability increased by 3352 million $ a−1. Exergy analysis of the optimum process indicated that the column and air cooler contributed the most to the total exergy destruction. Suggestions for decreasing the exergy destruction of the process are also given.
Fault detection method based on principal component difference associated with DPCA
Authors: Zhang Cheng , Guo Qingxiu , Li Yuan 
Published: October 2018

AbstractAiming at the fault detection in a dynamic process with nonlinear or multimodal features, a new fault detection strategy based on principal component difference associated with dynamic PCA (Diff‐DPCA) is proposed in this paper. First, augment the training data set using the time lag, and then obtain an augmented training data set. Second, find the K‐nearest neighbor set of each sample in the augmented training set and calculate the mean of the K nearest neighbor set. Third, calculate the loading and score matrices of the augmented training data set using PCA, and then calculate the scores of the proposed mean above using the loading matrix. Next, calculate the difference between the scores of a sample and its corresponding mean. Finally, 2 new statistics are built in difference subspace and residual subspace respectively. Principal component difference associated with dynamic PCA, which inherit the ability of DPCA monitoring a dynamic process, can improve the fault detection rate in the process with multimodal or nonlinear characteristics; meanwhile, the new statistics present low autocorrelation levels. The proposed method in this paper and other traditional methods are applied to detect faults in 2 cases and the Tennessee Eastman process, such as PCA, DPCA, and FD‐KNN. The experimental results indicate that the proposed method outperforms the conventional PCA, DPCA, and FD‐KNN.
Synthesis and Characterization of Liquid‐Crystalline Tetraoxapentacene Derivatives Exhibiting Aggregation‐Induced Emission
Authors: Hiscock Lana K. , Raycraft Brooke M. , Wałęsa‐Chorab Monika , Cambe Coralie , Malinge Alexandre , Skene W. G. , Taing Hi , Eichhorn S. Holger , Dawe Louise N. , Maly Kenneth E. 
Published: October 2018

AbstractA series of new tetrakis(dialkoxyphenyl) dicyanotetraoxapentacene derivatives (1 a–c) were prepared by reaction of the appropriate terphenyl diols with tetrafluoroterephthalonitrile in good yields. Compounds 1 b and 1 c, which bear hexyloxy and decyloxy side chains, exhibited columnar hexagonal mesophases, as shown by polarized optical microscopy, variable‐temperature powder X‐ray diffraction, and differential scanning calorimetry. Single‐crystal X‐ray diffraction of methoxy‐substituted 1 a revealed that the dicyanotetraoxapentacene core is highly planar, consistent with the notion that these molecules are able to stack in columnar mesophases. A detailed photophysical characterization showed that these compounds exhibit aggregation‐induced emission in solution, emission in nonpolar solvents, weak emission in polar solvents, and strong emission in the solid state both as powder and in thin films. These observations are consistent with a weakly emissive charge‐transfer state in polar solvents and a more highly emissive locally excited state in nonpolar solvents.
Hydrothermal Dissolution of Low‐Quartz in Sodium Hydroxide Lyes: Kinetics and Equilibrium
Authors: Pfeiffer Thomas , Sander Stephan A. H. , Enke Dirk , Roggendorf Hans 
Published: October 2018

AbstractQuartz flours were dissolved at temperatures between 100 and 220 °C for up to 7 d in NaOH lyes. The starting materials were characterized by particle size analysis. Liquid and solid reaction products were characterized chemically and structurally. Sodium water glasses with silica concentrations of up to 20 wt % were obtained. Radius reduction of size distributed particle ensembles was calculated to evaluate the concentration control of the dissolution rate which is due to saturation effects. An equilibrium between low‐quartz and the resulting water glass explains the obtained results.