bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomaterials‐Based Approaches to Tumor Spheroid and Organoid Modeling
Authors: Thakuri Pradip Shahi , Liu Chun , Luker Gary D. , Tavana Hossein 
Published: December 2017

AbstractEvolving understanding of structural and biological complexity of tumors has stimulated development of physiologically relevant tumor models for cancer research and drug discovery. A major motivation for developing new tumor models is to recreate the 3D environment of tumors and context‐mediated functional regulation of cancer cells. Such models overcome many limitations of standard monolayer cancer cell cultures. Under defined culture conditions, cancer cells self‐assemble into 3D constructs known as spheroids. Additionally, cancer cells may recapitulate steps in embryonic development to self‐organize into 3D cultures known as organoids. Importantly, spheroids and organoids reproduce morphology and biologic properties of tumors, providing valuable new tools for research, drug discovery, and precision medicine in cancer. This Progress Report discusses uses of both natural and synthetic biomaterials to culture cancer cells as spheroids or organoids, specifically highlighting studies that demonstrate how these models recapitulate key properties of native tumors. The report concludes with the perspectives on the utility of these models and areas of need for future developments to more closely mimic pathologic events in tumors.
Multiorgan Microphysiological Systems for Drug Development: Strategies, Advances, and Challenges
Authors: Wang Ying I. , Carmona Carlos , Hickman James J. , Shuler Michael L. 
Published: December 2017

AbstractTraditional cell culture and animal models utilized for preclinical drug screening have led to high attrition rates of drug candidates in clinical trials due to their low predictive power for human response. Alternative models using human cells to build in vitro biomimetics of the human body with physiologically relevant organ–organ interactions hold great potential to act as “human surrogates” and provide more accurate prediction of drug effects in humans. This review is a comprehensive investigation into the development of tissue‐engineered human cell‐based microscale multiorgan models, or multiorgan microphysiological systems for drug testing. The evolution from traditional models to macro‐ and microscale multiorgan systems is discussed in regards to the rationale for recent global efforts in multiorgan microphysiological systems. Current advances in integrating cell culture and on‐chip analytical technologies, as well as proof‐of‐concept applications for these multiorgan microsystems are discussed. Major challenges for the field, such as reproducibility and physiological relevance, are discussed with comparisons of the strengths and weaknesses of various systems to solve these challenges. Conclusions focus on the current development stage of multiorgan microphysiological systems and new trends in the field.
Improving Defect‐Based Quantum Emitters in Silicon Carbide via Inorganic Passivation
Authors: Polking Mark J. , Dibos Alan M. , de Leon Nathalie P. , Park Hongkun 
Published: December 2017

AbstractDefect‐based color centers in wide‐bandgap crystalline solids are actively being explored for quantum information science, sensing, and imaging. Unfortunately, the luminescent properties of these emitters are frequently degraded by blinking and photobleaching that arise from poorly passivated host crystal surfaces. Here, a new method for stabilizing the photoluminescence and charge state of color centers based on epitaxial growth of an inorganic passivation layer is presented. Specifically, carbon antisite‐vacancy pairs (CAV centers) in 4H‐SiC, which serve as single‐photon emitters at visible wavelengths, are used as a model system to demonstrate the power of this inorganic passivation scheme. Analysis of CAV centers with scanning confocal microscopy indicates a dramatic improvement in photostability and an enhancement in emission after growth of an epitaxial AlN passivation layer. Permanent, spatially selective control of the defect charge state can also be achieved by exploiting the mismatch in spontaneous polarization at the AlN/SiC interface. These results demonstrate that epitaxial inorganic passivation of defect‐based quantum emitters provides a new method for enhancing photostability, emission, and charge state stability of these color centers.
Octahedral Distortions at High‐Temperature Superconducting La2CuO4 Interfaces: Visualizing Jahn–Teller Effects
Authors: Suyolcu Y. Eren , Wang Yi , Sigle Wilfried , Baiutti Federico , Cristiani Georg , Logvenov Gennady , Maier Joachim , van Aken Peter A. 
Published: December 2017

AbstractTuning the octahedral network represents a promising route for achieving new properties and functionalities in perovskite‐based oxide heterostructures. One of the interface‐mediated phenomena occurring in complex oxides is the Jahn—Teller (JT) effect. With the purpose of investigating octahedral distortions at interfaces showing high‐temperature interface superconductivity, atomic layer‐by‐layer oxide molecular‐beam epitaxy grown bilayers consisting of three unit cells, overdoped metallic La1.6M0.4CuO4, and three unit cells undoped insulating La2CuO4, where M represents a divalent dopant (namely, Ba2+, Sr2+, and Ca2+), are studied. The local crystal structure, chemistry, and dopant distribution are probed by analytical spherical‐aberration‐corrected scanning transmission electron microscopy. Here, the interrelation between the cationic size mismatch between dopant (M2+) and host La3+ ions and the local structure are reported, and the impact of the dopant distribution on the structural (CuO6 octahedra elongation) local properties is discussed. A clear correlation between dopant size and local lattice deformations is highlighted. Moreover, a relation between the nature of superconductivity (bulk vs interface) and JT distortions of the anionic sublattice is suggested.
Controlling Wrinkle Propagation in the Bilayer System with Thickness‐Gradient
Authors: Lim Jongcheon , Choi Se‐Jin , Kim Pilnam 
Published: December 2017

AbstractIn this paper, a novel strategy to control the orientation of nanowrinkles by applying a thickness‐gradient to a bilayer‐system is presented. Surface modification by plasma treatment on ultraviolet light‐curable polysiloxane‐based resin applies biaxial compressive strain, resulting in the formation of randomly oriented nanowrinkles over a large‐area. The thickness‐gradient of the resin, given by the meniscus formed between the groove made with patterned polydimethylsiloxane (PDMS) after spin‐coating of the resin, directed wrinkle propagation. Given the propagation orientation, nanowrinkles were well aligned over a large‐area using a simple and accessible method.
A Combined Electrochemical‐Microfluidic Strategy for the Microscale‐Sized Selective Modification of Transparent Conductive Oxides
Authors: Lamberti Francesco , Salmaso Stefano , Zambon Alessandro , Brigo Laura , Malfanti Alessio , Gatti Teresa , Agnoli Stefano , Granozzi Gaetano , Brusatin Giovanna , Elvassore Nicola , Giomo Monica 
Published: December 2017

AbstractSurface chemical functionalization of transparent conductive oxides (TCOs) is helpful for a wide range of technological applications, ranging from solar cells to biomedical devices, as it allows to tune the electrical, optical, and morphological properties of TCOs toward the desired goal. The electrochemical grafting technique is a surface modification methodology affording robust coatings with tuneable properties and has the potential to be exploited for modifying TCO surfaces. However, due to technical limitations, like the use of a 3‐electrode cell and the need for low pH‐solutions, this approach has not been recurrently applied. Here a novel electrochemical‐microfluidic combined methodology is used where the use of a microchannel drives the spatially controlled covalent grafting of reagents on a TCO surface. To corroborate the validity of this approach in producing more complex chemical structures localized on selected microscale‐sized areas, where a first electrochemical grafting step takes place, an electrochemical glucose biosensor is realized through a layer‐by‐layer approach that shows a remarkable limit of detection in the micromolar concentration range. The sensing mechanism is based on an efficient electron transfer from glucose to the functionalized TCO surface. Biosensor performance is conveniently tuned by acting on the number of enzymatic units loaded onto the biosensor‐tree.
A Novel Fold‐Based Design Approach toward Printable Soft Robotics Using Flexible 3D Printing Materials
Authors: Keong Benjamin Ang Wee , Hua Raye Yeow Chen 
Published: December 2017

AbstractSoft robotic technologies have been known to have various advantages over their rigid counterparts due to their compliant and deformable properties. They can carry out delicate object manipulation and perform complex maneuvers in confined spaces, which traditional robotics has difficulty with. The most widely adopted fabrication method for traditional soft elastomeric fluidic actuators is mold‐casting, which is cumbersome and involves several manual steps. Therefore, a substantial variability in performance and quality of these actuators arises directly from the manufacturing process. This paper presents on a novel fold‐based design of a 3D‐printed soft pneumatic bending actuator. In contrast to other works that rely on high‐end multimaterial 3D printers, a consumer‐grade open source 3D printer to fabricate soft pneumatic actuators in a fast and cheap way using fused deposition modeling technology has been adapted. This allows for consistency in both the quality of the actuators and their mechanical performance. The key findings in (1) a 3D‐printed fold‐based actuator fabrication process, (2) actuator characterization, and (3) a design‐centric approach toward different bending profiles for different applications are presented.
Print‐Light‐Synthesis of Platinum Nanostructured Indium‐Tin‐Oxide Electrodes for Energy Research
Authors: Lesch Andreas 
Published: December 2017

AbstractPrint‐light‐synthesis is a new concept for the large‐scale in situ fabrication of nanoparticles and structures on large substrates. Here, Pt nanoparticles are synthesized on indium tin oxide (ITO) coated glass slides by using combined inkjet printing and photonic curing operated under ambient conditions and with low material usage. A formulated chloroplatinic acid based ink provides stable and reproducible jetting, optimized ink–substrate interaction and fast ink drying to create well‐defined thin precursor films acting as nanoreactors. The precursor loading is precisely controlled by the printing parameters. Then, a short light pulse from a Xe flash lamp fully converts the printed Pt precursor containing film into pure Pt nanoparticles. The optimum precursor coverage is ≈1 µg mm−2 Pt consuming as less as ≈50 nL mm−2 of ink. Neither reducing nor capping agents are used resulting in pure Pt nanoparticles (30 nm average size) and micrometer‐size aggregates. The nanostructures are well‐adhered to the ITO substrate and show a stable electrochemical performance for the oxygen reduction reaction. The fast and cost‐effective process optimization in terms of ink formulation, substrate pre‐treatment, inkjet printing resolution, and post‐processing for the rapid fabrication of Pt nano‐ and microparticle‐coated ITO electrodes is presented and discussed.
In Vivo Photoacoustic Imaging of Brain Injury and Rehabilitation by High‐Efficient Near‐Infrared Dye Labeled Mesenchymal Stem Cells with Enhanced Brain Barrier Permeability
Authors: Li Weitao , Chen Ronghe , Lv Jing , Wang Hongke , Liu Yu , Peng Ya , Qian Zhiyu , Fu Guo , Nie Liming 
Published: December 2017

AbstractStem cell migration and interaction with pathology are critical to understand the complexity and status of disease recovery progress. However, the dynamic visualization still remains a great challenge due to imaging technical limitation, cell labeling difficulty, or blood–brain barrier (BBB). Herein, fast photoacoustic tomography (PAT) with optical molecular probes is applied to noninvasively monitor traumatic brain injury (TBI) and its rehabilitation. The vascular distribution and TBI hemorrhage are clearly imaged, longitudinally monitored, and quantified. Bone mesenchymal stem cells (BMSCs) labeled with modified Prussian blue particles (PBPs), excellent near‐infrared dyes and photoacoustic contrasts, are intravenously injected to the mice for improved observation and efficient therapy. BMSCs are demonstrated to be capable of overcoming BBB with enhanced delivery of PBPs to the brain parenchyma. Notably, the versatile BMSCs are observed by PAT to home to the damage region and repair the ruptured vasculature. Moreover, the wound treated by BMSCs exhibits much faster recovery speed than that without treatment. These findings can potentially provide a new noninvasive and high‐resolution approach to image TBI, monitor recovery process, and especially trace BMSCs. This study will stimulate extensive researches on brain diseases and provide promising strategies of dye labeled BMSCs in regenerative medicine.
Magnetic Sponge with Neutral–Ionic Phase Transitions
Authors: Kosaka Wataru , Takahashi Yusuke , Nishio Masaki , Narushima Keisuke , Fukunaga Hiroki , Miyasaka Hitoshi 
Published: December 2017

AbstractPhase transitions caused by the charge instability between the neutral and ionic phases of compounds, i.e., N–I phase transitions, provide avenues for switching the intrinsic properties of compounds related to electron/spin correlation and dipole generation as well as charge distribution. However, it is extremely difficult to control the transition temperature (Tc) for the N–I phase transition, and only chemical modification based on the original material have been investigated. Here, a design overview of the tuning of N–I phase transition by interstitial guest molecules is presented. This study reports a new chain coordination‐polymer [Ru2(3,4‐Cl2PhCO2)4TCNQ(EtO)2]∙DCE (1‐DCE; 3,4‐Cl2PhCO2− = 3,4‐dichlorobenzoate; TCNQ(EtO)2 2,5‐diethoxy‐7,7,8,8‐tetracyanoquinodimethane; and DCE = 1,2‐dichloroethane) that exhibits a one‐step N–I transition at 230 K (= Tc) with the N‐ and I‐states possessing a simple paramagnetic state and a ferrimagnetically correlated state for the high‐ and low‐temperature phases, respectively. The Tc continuously decreases depending on the content of DCE, which eventually disappears with the complete evacuation of DCE, affording solvent‐free compound 1 with the N‐state in the entire temperature range (this behavior is reversible). This is an example of tuning the in situ Tc for the N–I phase transition via the control of the interstitial guest molecules.
Unveiling the Influence of Surface Fermi Level Pinning on the Piezoelectric Response of Semiconducting Nanowires
Authors: Tao Ran , Mouis Mireille , Ardila Gustavo 
Published: December 2017

AbstractZnO nanowires (NWs) are excellent candidates for the integration of energy harvesters, mechanical sensors, piezotronic and piezophototronic devices. However, ZnO NWs are usually nonintentionally n‐doped during their growth. Thus, it can be expected theoretically that their piezoelectric response be degraded and mostly geometry‐independent as a result of strong screening effects by free carriers, while experimentally many NW‐based piezoelectric transducers demonstrate quite reasonable performance. In this paper, this apparent contradiction is explained by surface Fermi level pinning (SFLP). Simulations based on the finite element method are developed to investigate the influence of SFLP on the electrical response of ZnO piezogenerators based on arrays of vertical ZnO NWs (the so‐called VING) operated in compression or bending mode. The results show that the nonsymmetrical response with respect to loading direction, which has been observed experimentally when the VING is bent, can be explained when account is taken of the reverse piezoelectric effect associated with SFLP. Influence of geometry and comparison to thin film are also discussed. It is found that the performance improvement, which is observed experimentally at scales much larger than predicted by ab initio models when NWs are compared to thin films, can be partly related to SFLP effects rather than larger piezoelectric coefficients.
Epitaxial CuN Films with Highly Tunable Lattice Constant for Lattice‐Matched Magnetic Heterostructures with Enhanced Thermal Stability
Authors: Wen Zhenchao , Kubota Takahide , Takanashi Koki 
Published: December 2017

AbstractThe engineering of advanced materials for lattice‐matched magnetic heterostructures with remarkable magnetoelectric properties is of particular importance for future spintronic devices. Here, epitaxial CuN films with highly tunable lattice constant and resistivity are fabricated. The lattice constant of the CuN films is controlled from 0.362 to 0.388 nm, and the resistivity is varied over a range of more than two orders of magnitude. Lattice‐matched CuN/Co2Fe0.4Mn0.6Si (CFMS) heterostructures are achieved. A dramatic enhancement of the thermal stability of the heterostructure over that of Cu/CFMS is observed. Furthermore, magnetoresistance nanojunctions are fabricated using lattice‐matched CuN spacers, and an enhancement of the magnetoresistance effect at high annealing temperatures is observed. This work shows that the manipulation of the lattice constant and resistivity of CuN films in lattice‐matched heterostructures can be important for engineering future advanced electronic materials for the development of spintronic devices.
Aqueous‐Processed Polymer/Nanocrystal Hybrid Solar Cells with Double‐Side Bulk Heterojunction
Authors: Jin Gan , Chen Nannan , Zeng Qingsen , Liu Fangyuan , Yuan Wei , Xiang Siyuan , Feng Tanglue , Du Xiaohang , Ji Tianjiao , Wang Lijing , Wang Yaohua , Sun Henan , Sun Haizhu , Yang Bai 
Published: December 2017

AbstractAqueous‐solution‐processed solar cells (ASCs) are promising candidates of the next‐generation large‐area, low‐cost, and flexible photovoltaic conversion equipment because of their unique environmental friendly property. Aqueous‐solution‐processed polymer/nanocrystals (NCs) hybrid solar cells (AHSCs) can effectively integrate the advantages of the polymer (e.g., flexibility and lightweight) and the inorganic NCs (e.g., high mobility and broad absorption), and therefore be considered as an ideal system to further improve the performance of ASCs. In this work, double‐side bulk heterojunction (BHJ), in which one BHJ combines the active material with electron transport material and the other combines the active material with hole transport material, is developed in the AHSCs. Through comparing with the single‐side BHJ device, promoted carrier extraction, enhanced internal quantum efficiency, extended width of the depletion region, and prolonged carrier lifetime are achieved in double‐side BHJ devices. As a result, power conversion efficiency exceeding 6% is obtained, which breaks the bottleneck efficiency around ≈5.5%. This work demonstrates a device architecture which is more remarkable compared with the traditional only donor–acceptor blended BHJ. Under conservative estimation, it provides instructive architecture not only in the ASCs, but also in the organic solar cells (SCs), quantum dot SCs, and perovskite SCs.
Alkaline Benzoquinone Aqueous Flow Battery for Large‐Scale Storage of Electrical Energy
Authors: Yang Zhengjin , Tong Liuchuan , Tabor Daniel P. , Beh Eugene S. , Goulet Marc‐Antoni , De Porcellinis Diana , Aspuru‐Guzik Alán , Gordon Roy G. , Aziz Michael J. 
Published: December 2017

AbstractAn aqueous flow battery based on low‐cost, nonflammable, noncorrosive, and earth‐abundant elements is introduced. During charging, electrons are stored in a concentrated water solution of 2,5‐dihydroxy‐1,4‐benzoquinone, which rapidly receives electrons with inexpensive carbon electrodes without the assistance of any metal electrocatalyst. Electrons are withdrawn from a second water solution of a food additive, potassium ferrocyanide. When these two solutions flow along opposite sides of a cation‐conducting membrane, this flow battery delivers a cell potential of 1.21 V, a peak galvanic power density of 300 mW cm−2, and a coulombic efficiency exceeding 99%. Continuous cell cycling at 100 mA cm−2 shows a capacity retention rate of 99.76% cycle−1 over 150 cycles. Various molecular modifications involving substitution for hydrogens on the aryl ring are implemented to block decomposition by nucleophilic attack of hydroxide ions. These modifications result in increased capacity retention rates of up to 99.96% cycle−1 over 400 consecutive cycles, accompanied by changes in voltage, solubility, kinetics, and cell resistance. Quantum chemistry calculations of a large number of organic compounds predict a number of related structures that should have even higher performance and stability. Flow batteries based on alkaline‐soluble dihydroxybenzoquinones and derivatives are promising candidates for large‐scale, stationary storage of electrical energy.
Effect of Cation Composition on the Mechanical Stability of Perovskite Solar Cells
Authors: Rolston Nicholas , Printz Adam D. , Tracy Jared M. , Weerasinghe Hasitha C. , Vak Doojin , Haur Lew Jia , Priyadarshi Anish , Mathews Nripan , Slotcavage Daniel J. , McGehee Michael D. , Kalan Roghi E. , Zielinski Kenneth , Grimm Ronald L. , Tsai Hsinhan , Nie Wanyi , Mohite Aditya D. , Gholipour Somayeh , Saliba Michael , Grätzel Michael , Dauskardt Reinhold H. 
Published: December 2017

AbstractPhotoactive perovskite semiconductors are highly tunable, with numerous inorganic and organic cations readily incorporated to modify optoelectronic properties. However, despite the importance of device reliability and long service lifetimes, the effects of various cations on the mechanical properties of perovskites are largely overlooked. In this study, the cohesion energy of perovskites containing various cation combinations of methylammonium, formamidinium, cesium, butylammonium, and 5‐aminovaleric acid is reported. A trade‐off is observed between the mechanical integrity and the efficiency of perovskite devices. High efficiency devices exhibit decreased cohesion, which is attributed to reduced grain sizes with the inclusion of additional cations and PbI2 additives. Microindentation hardness testing is performed to estimate the fracture toughness of single‐crystal perovskite, and the results indicated perovskites are inherently fragile, even in the absence of grain boundaries and defects. The devices found to have the highest fracture energies are perovskites infiltrated into a porous TiO2/ZrO2/C triple layer, which provide extrinsic reinforcement and shielding for enhanced mechanical and chemical stability.