bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrically Switchable, Hyper‐Reflective Blue Phase Liquid Crystals Films
Authors: Xu Xiaowan , Liu Zhen , Liu Yanjun , Zhang Xinhai , Zheng Zhigang , Luo Dan , Sun Xiaowei 
Published: December 2017

AbstractBlue phase liquid crystals (BPLCs) with three‐dimensional periodicity have attracted significant attention due to their fast response time in the submillisecond region, which is critical in sequential liquid crystal displays and fast switchable photonic devices. However, the reflectivity of single‐layer BPLC films in the visible range, which is generally used for reflective display, is still low and limited to 50%, which hinders its use in a wide range of applications. Herein, hyper‐reflective, electrically switchable, fast responsive, and colorful reflective displays are demonstrated, which are based on multi‐layer BPLC films consisting of two single‐layer BPLC templates with opposite handedness. Hyper‐reflectivities of 89%, 82%, and 68% in the red, green, and blue color regions are achieved by refilling multi‐layer BPLC templates with achiral nematic liquid crystals. A reflectance switching of the film is achieved by unwinding the helical structure of the blue phase in an electric field, where the highest reflectance achieved in the red, green, and blue color regions is 94%, 86%, and 72%, respectively, in the presence of an electric field of 1 V µm−1. Compared to previously demonstrated BPLC films, this newly developed multi‐layer BPLC film substantially improves the overall reflection efficiency by up to 3.6 times. Our study on hyper‐reflective BPLC film provides an attractive platform for future development including sequential colorful reflective displays and switchable optoelectronic devices.
Imaging Inelastic Fracture Processes in Biomimetic Nanocomposites and Nacre by Laser Speckle for Better Toughness
Authors: Verho Tuukka , Karppinen Pasi , Gröschel André H. , Ikkala Olli 
Published: December 2017

AbstractMollusk nacre is a prototypical biological inorganic–organic composite that combines high toughness, stiffness, and strength by its brick‐and‐mortar microstructure, which has inspired several synthetic mimics. Its remarkable fracture toughness relies on inelastic deformations at the process zone at the crack tip that dissolve stress concentrations and stop cracks. The micrometer‐scale structure allows resolving the size and shape of the process zone to understand the fracture processes. However, for better scalability, nacre‐mimetic nanocomposites with aligned inorganic or graphene nanosheets are extensively pursued, to avoid the packing problems of mesoscale sheets like in nacre or slow in situ biomineralization. This calls for novel methods to explore the process zone of biomimetic nanocomposites. Here the fracture of nacre and nacre‐inspired clay/polymer nanocomposite is explored using laser speckle imaging that reveals the process zone even in absence of changes in optical scattering. To demonstrate the diagnostic value, compared to nacre, the nacre‐inspired nanocomposite develops a process zone more abruptly with macroscopic crack deflection shown by a flattened process zone. In situ scanning electron microscopy suggests similar toughening mechanisms in nanocomposite and nacre. These new insights guide the design of nacre‐inspired nanocomposites toward better mechanical properties to reach the level of synergy of their biological model.
Enabling Photon Upconversion and Precise Control of Donor–Acceptor Interaction through Interfacial Energy Transfer
Authors: Zhou Bo , Yan Long , Tao Lili , Song Nan , Wu Ming , Wang Ting , Zhang Qinyuan 
Published: December 2017

AbstractUpconverting materials have achieved great progress in recent years, however, it remains challenging for the mechanistic research on new upconversion strategy of lanthanides. Here, a novel and efficient strategy to realize photon upconversion from more lanthanides and fine control of lanthanide donor–acceptor interactions through using the interfacial energy transfer (IET) is reported. Unlike conventional energy‐transfer upconversion and recently reported energy‐migration upconversion, the IET approach is capable of enabling upconversions from Er3+, Tm3+, Ho3+, Tb3+, Eu3+, Dy3+ to Sm3+ in NaYF4‐ and NaYbF4‐based core–shell nanostructures simultaneously. Applying the IET in a Nd–Yb coupled sensitizing system can also enable the 808/980 nm dual‐wavelength excited upconversion from a single particle. More importantly, the construction of IET concept allows for a fine control and manipulation of lanthanide donor–acceptor interactions and dynamics at the nanometer‐length scale by establishing a physical model upon an interlayer‐mediated nanostructure. These findings open a door for the fundamental understanding of the luminescence dynamics involving lanthanides at nanoscale, which would further help conceive new scientific concepts and control photon upconversion at a single lanthanide ion level.
Valence State Manipulation of Cerium Oxide Nanoparticles on a Titanium Surface for Modulating Cell Fate and Bone Formation
Authors: Li Jinhua , Wen Jin , Li Bin , Li Wan , Qiao Wei , Shen Jie , Jin Weihong , Jiang Xinquan , Yeung Kelvin W. K. , Chu Paul K. 
Published: December 2017

AbstractUnderstanding cell–biomaterial interactions is critical for the control of cell fate for tissue engineering and regenerative medicine. Here, cerium oxide nanoparticles (CeONPs) are applied at different Ce4+/Ce3+ ratios (i.e., 0.46, 1.23, and 3.23) to titanium substrate surfaces by magnetron sputtering and vacuum annealing. Evaluation of the cytotoxicity of the modified surface to cultured rat bone marrow mesenchymal stem cells (BMSCs) reveals that the cytocompatibility and cell proliferation are proportional to the increases in Ce4+/Ce3+ ratio on titanium surface. The bone formation capability induced by these surface modified titanium alloys is evaluated by implanting various CeONP samples into the intramedullary cavity of rat femur for 8 weeks. New bone formation adjacent to the implant shows a close relationship to the surface Ce4+/Ce3+ ratio; higher Ce4+/Ce3+ ratio achieves better osseointegration. The mechanism of this in vivo outcome is explored by culturing rat BMSCs and RAW264.7 murine macrophages on CeONP samples for different durations. The improvement in osteogenic differentiation capability of BMSCs is directly proportional to the increased Ce4+/Ce3+ ratio on the titanium surface. Increases in the Ce4+/Ce3+ ratio also elevate the polarization of the M2 phenotype of RAW264.7 murine macrophages, particularly with respect to the healing‐associated M2 percentage and anti‐inflammatory cytokine secretion. The manipulation of valence states of CeONPs appears to provide an effective modulation of the osteogenic capability of stem cells and the M2 polarization of macrophages, resulting in favorable outcomes of new bone formation and osseointegration.
The Dawn of Lead‐Free Perovskite Solar Cell: Highly Stable Double Perovskite Cs2AgBiBr6 Film
Authors: Wu Cuncun , Zhang Qiaohui , Liu Yang , Luo Wei , Guo Xuan , Huang Ziru , Ting Hungkit , Sun Weihai , Zhong Xinrui , Wei Shiyuan , Wang Shufeng , Chen Zhijian , Xiao Lixin 
Published: December 2017

AbstractRecently, lead‐free double perovskites have emerged as a promising environmentally friendly photovoltaic material for their intrinsic thermodynamic stability, appropriate bandgaps, small carrier effective masses, and low exciton binding energies. However, currently no solar cell based on these double perovskites has been reported, due to the challenge in film processing. Herein, a first lead‐free double perovskite planar heterojunction solar cell with a high quality Cs2AgBiBr6 film, fabricated by low‐pressure assisted solution processing under ambient conditions, is reported. The device presents a best power conversion efficiency of 1.44%. The preliminary efficiency and the high stability under ambient condition without encapsulation, together with the high film quality with simple processing, demonstrate promise for lead‐free perovskite solar cells.
Rational Design of Nickel Hydroxide‐Based Nanocrystals on Graphene for Ultrafast Energy Storage
Authors: Zhao Bote , Zhang Lei , Zhang Qiaobao , Chen Dongchang , Cheng Yong , Deng Xiang , Chen Yu , Murphy Ryan , Xiong Xunhui , Song Bo , Wong Ching‐Ping , Wang Ming‐Sheng , Liu Meilin 
Published: December 2017

AbstractCompact, light, and powerful energy storage devices are urgently needed for many emerging applications; however, the development of advanced power sources relies heavily on advances in materials innovation. Here, the findings in rational design, one‐pot synthesis, and characterization of a series of Ni hydroxide‐based electrode materials in alkaline media for fast energy storage are reported. Under the guidance of density functional theory calculations and experimental investigations, a composite electrode composed of Co‐/Mn‐substituted Ni hydroxides grown on reduced graphene oxide (rGO) is designed and prepared, demonstrating capacities of 665 and 427 C g−1 at current densities of 2 and 20 A g−1, respectively. The superior performance is attributed mainly to the low deprotonation energy and the facile electron transport, as elaborated by theoretical calculations. When coupled with an electrode based on organic molecular‐modified rGO, the resulting hybrid device demonstrates an energy density of 74.7 W h kg−1 at a power density of 1.68 kW kg−1 while maintaining capacity retention of 91% after 10,000 cycles (20 A g−1). The findings not only provide a promising electrode material for high‐performance hybrid capacitors but also open a new avenue toward knowledge‐based design of efficient electrode materials for other energy storage applications.
Evaluating Food Policy Councils Using Structural Equation Modeling
Authors: Calancie Larissa , Allen Nicole E. , Ng Shu Wen , Weiner Bryan J. , Ward Dianne S. , Ware William B. , Ammerman Alice S. 
Published: December 2017

AbstractAt least 282 Food Policy Councils (FPCs) are currently working to improve access to healthy foods in their communities by connecting food system sectors, gathering community input, and advising food policy. Empirical research on FPCs is limited. This study empirically evaluates FPCs to better understand the relationships between Organizational Capacity, Social Capital, and Council Effectiveness by testing a FPC Framework adapted from Allen and colleagues (2012). Members of all FPCs in the U.S., Canada, and Native American Tribes and First Nations were invited to complete the Food Policy Council Self‐Assessment Tool (FPC‐SAT). Structural equation modeling was used to test the FPC Framework. Three hundred and fifty‐four FPC members from 95 councils completed the FPC‐SAT. After slight modification, a revised FPC Framework was a good fit with the data (χ2 = 40.085, df = 24, p‐value = .021, comparative fit index = 0.988, Tucker Lewis index = 0.982, root mean squared error of approximation = 0.044, p‐close = .650). A moderation analysis revealed that community context influences the relationship between Social Capital and Council Effectiveness within the FPC Framework. The FPC Framework can guide capacity building interventions and FPC evaluations. The empirically tested framework can help FPCs efficiently work toward achieving their missions and improving their local food system.
Highlighting the Way Forward: A Review of Community Mental Health Research and Practice Published in AJCP and JCP
Authors: Townley Greg , Terry Rachel 
Published: December 2017

AbstractArticles published in the two most prominent journals of community psychology in North America, the American Journal of Community Psychology (AJCP) and Journal of Community Psychology (JCP), provide a clear indicator of trends in community research and practice. An examination of community psychology's history and scholarship suggests that the field has reduced its emphasis on promoting mental health, well‐being, and liberation of individuals with serious mental illnesses over the past several decades. To further investigate this claim, the current review presents an analysis of articles relevant to community mental health (N = 307) published in the American Journal of Community Psychology (AJCP) and Journal of Community Psychology (JCP) from 1973 to 2015. The review focuses on article characteristics (e.g., type of article and methods employed), author characteristics, topic areas, and theoretical frameworks. Results document a downward trend in published articles from the mid‐1980s to mid‐2000s, with a substantial increase in published work between 2006 and 2015. A majority of articles were empirical and employed quantitative methods. The most frequent topic area was community mental health centers and services (n = 49), but the past three decades demonstrate a clear shift away from mental health service provision to address pressing social issues that impact community mental health, particularly homelessness (n = 42) and community integration of adults with serious mental illnesses (n = 40). Findings reflect both the past and present state of community psychology and suggest promising directions for re‐engaging with community mental health and fostering well‐being, inclusion, and liberation of adults experiencing serious mental health challenges.
A Zeolite Family Nonjointly Built from the 1,3‐Stellated Cubic Building Unit
Authors: Jo Donghui , Park Gi Tae , Shin Jiho , Hong Suk Bong 
Published: December 2017

AbstractFrom a technological point of view, the synthesis of new high‐silica zeolites is of prime importance owing to their high potential as industrial catalysts and catalyst supports. Two such materials have been synthesized which are made up of the 1,3‐stellated cubic unit (hexahedral ([4254]) bre unit) as a secondary building unit, with the aid of existing imidazolium‐based structure‐directing agents under “excess fluoride” conditions. One of them, denoted PST‐21, is the first aluminosilicate zeolite consisting of 9‐ring apertures solely; it displays exceptional activity towards steering the skeletal isomerization of 1‐butene to isobutene and bridges the gap between small‐ and medium‐pore structures. A series of hypothetical structures are also described that are nonjointly built from the bre unit; all of these structures are chemically feasible and will thus be helpful in designing the synthesis of novel zeolites containing 9‐ring and/or 10‐ring channels.
Synthesis and Structure Revision of Dichrocephones A and B
Authors: Schmiedel Volker M. , Hong Young J. , Lentz Dieter , Tantillo Dean J. , Christmann Mathias 
Published: December 2017

AbstractHerein, we report the first enantioselective synthesis of dichrocephones A and B, which are cytotoxic triquinane sesquiterpenes with a dense array of stereogenic centers within a strained polycyclic environment. Key features include the application of a catalytic asymmetric Wittig reaction, followed by stereoselective functionalization of the propellane core into a pentacyclic intermediate. Double reductive ring cleavage yielded the proposed structure of dichrocephone A. Mismatched spectroscopic data for our synthetic material compared to the natural isolate led us to revise the previously proposed configuration based on biosynthetic considerations and NMR calculations. Implementation of these findings culminated in the synthesis of dichrocephones A and B.
Modeling the viscoelasticity of polyetherimide
Authors: Wu Qi , Ogasawara Tomotaka , Yoshikawa Nobuhiro , Zhai Hongzhou 
Published: December 2017

ABSTRACTViscoelasticity is a mechanical phenomenon where the material modulus varies with time and temperature. Modern experimental methods can determine material properties within certain time and temperature ranges, but modeling the viscoelastic behavior remains challenging, mainly because the data processing is complex and different materials have distinct properties. Using polyetherimide as an example and based on the change in the secondary bonds of polyetherimide in different viscoelastic stages, we proposed a new shift factor model in Arrhenius format with alterable activation energy. We also used two methods based on nonlinear least squares to obtain the Maxwell model of the polyetherimide, and we then used a novel method integrated with Laplace transforms and partial fraction decomposition to convert the Maxwell model into the Voigt model. The results of our model are reliable and self‐consistent, showing its potential for modeling the viscoelasticity of other materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46102.
Tetraacylgermanes as highly efficient photoinitiators for visible light cured dimethacrylate resins and dental composites
Authors: Moszner Norbert , Fischer Urs Karl , Lamparth Iris , Fässler Pascal , Radebner Judith , Eibel Anna , Haas Michael , Gescheidt Georg , Stueger Harald 
Published: December 2017

ABSTRACTTetrabenzoylgermane1and various substituted tetrabenzoylgermanes2–7were investigated as visible light (VL) photoinitiators (PIs) for dental dimethacrylate resins and dimethacrylate‐based composites. The tetrabenzoylgermanes1–7show a very strong VL absorption between 400 and 450 nm. Substituents on the benzoyl chromophore strongly influence their properties such as melting point, solubility, absorption behavior, or PI reactivity. A good photobleaching behavior and a very high reactivity as VL PI was found in photo‐differential scanning calorimeter experiments for selected tetrabenzoylgermanes. Composite pastes containing only ∼0.1 wt % of Ge‐PI exhibited a sufficient photocuring due to the high PI‐reactivity of the tetraacylgermanes. Among the investigated germane PIs, tetrakis(2‐methylbenzoyl)germane2shows the best performance as VL PI for restorative composites and enables the composites to be photocured using an LED with an emission maximum of 500 nm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46115.
Comparative study of gamma and ion beam irradiation of polymeric nanocomposite on electrical conductivity
Authors: Lotfy S. , Atta A. , Abdeltwab E. 
Published: December 2017

ABSTRACTPoly(vinyl alcohol) (PVA) was used to prepare nanocomposites of multi‐wall carbon nanotubes (MWCNT) and functionalized carbon nanotubes (MWCNT‐NH2) in existence of 2‐carboxyethyl acrylate oligomers (CEA). Radiation‐induced crosslinking of the prepared matrix was carried out via gamma and ion beam irradiation. A comparative study of gamma and ion beam irradiation effect on the electrical conductivity of nanocomposite was conducted. The gelation of the gamma irradiated matrix outperforms the ion beam irradiated matrix. The order of gelation is PVA > (PVA/CEA) > (PVA/CEA)‐MWCNT > (PVA/CEA)‐MWCNT‐NH2. There is a significant reduction in the swelling of the nanocomposite. The formation of nanocomposites was confirmed by scanning electron microscopy, energy‐dispersive X‐ray (EDX) and FTIR examinations. The direct current electrical properties of PVA/nanocomposites are examined at room temperature by applying electric voltage from 1 to 20 V. The results revealed that the electrical conductivity is increased by adding the carbon nanotubes and irradiation by gamma and ion beam. At an applied electric voltage 20 V, in the electrical conductivity of the unirradiated PVA was from 9.20 × 10−8 S cm−1. After adding MWCNT an increase up to 4.70 × 10−5 S cm−1 was observed. While after ion beam irradiation, a further increase up to 9.30 × 10−5 S cm−1 was noticed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46146.
Exploration of interaction of canthaxanthin with human serum albumin by spectroscopic and molecular simulation methods
Authors: Jia Jie , Wang Yuxian , Liu Yueying , Xiang Yuhong 
Published: December 2017

AbstractThe interaction between the food colorant canthaxanthin (CA) and human serum albumin (HSA) in aqueous solution was explored by using fluorescence spectroscopy, three‐dimensional fluorescence spectra, synchronous fluorescence spectra, UV–vis absorbance spectroscopy, circular dichroism (CD) spectra and molecular docking methods. The thermodynamic parameters calculated from fluorescence spectra data showed that CA could result in the HSA fluorescence quenching. From the KSV change with the temperature dependence, it was concluded that HSA fluorescence quenching triggered by CA is the static quenching and the number of binding sites is one. Furthermore, the secondary structure of HSA was changed with the addition of CA based on the results of synchronous fluorescence, three‐dimensional fluorescence and CD spectra. Hydrogen bonds and van der Waals forces played key roles in the binding process of CA with HSA, which can be obtained from negative standard enthalpy (ΔH) and negative standard entropy (ΔS). Furthermore, the conclusions were certified by molecular docking studies and the binding mode was further analyzed with Discovery Studio. These conclusions can highlight the potential of the interaction mechanism of food additives and HSA.
Engineered cell migration to lesions linked to autoimmune disease
Authors: Mosabbir Abdullah Al , Qudrat Anam , Truong Kevin 
Published: December 2017

AbstractThe damaging and degenerative effects in autoimmune diseases such as rheumatoid arthritis, multiple sclerosis and Crohn's disease often manifests as the formation of lesions that feature a high local concentration of granulocyte–macrophage colony‐stimulating factor (GM‐CSF). GM‐CSF along with other pro‐inflammatory factors form a positive feedback loop that ultimately perpetuate the lesions. Hence, to engineer chemotaxis to GM‐CSF, we created a new chimeric GM‐CSF receptor alpha subunit (GMRchi) that was coupled with a previously engineered Ca2+‐activated RhoA. When these proteins were expressed in mammalian cells, it allowed migration to chemical and cellular sources of GM‐CSF. As a possible therapeutic intervention, we further implemented the mechanism of cell–cell membrane fusion and subsequent death. Since the microenvironment of lesions is more than just GM‐CSF secretion, the further ability to recognize a combination of other features such as tissue markers will be needed for greater specificity. Nonetheless, this work represents a first step to enable cell‐based therapy of autoimmune lesions.
Feedback from human posterior parietal cortex enables visuospatial category representations as early as primary visual cortex
Authors: Li Yanyan , Hu Xiaopeng , Yu Yongqiang , Zhao Ke , Saalmann Yuri B. , Wang Liang 
Published: December 2017

AbstractIntroductionCategorization is a fundamental cognitive process, whereby the brain assigns meaning to sensory stimuli. Previous studies have found category representations in prefrontal cortex and posterior parietal cortex (PPC). However, these higher‐order areas lack the fine‐scale spatial representations of early sensory areas, and it remains unclear what mechanisms enable flexible categorization based on fine‐scale features.MethodsIn this study, we decoded functional MRI signals and measured causal influences, across visual, parietal, and prefrontal cortex from participants performing categorization based on coarse‐ or fine‐scale spatial information in thirteen healthy adults.ResultsWe show that category information based on coarse discriminations was represented in the PPC, in the intraparietal sulcus region, IPS1/2, at an early stage of categorization trials, whereas representations of category information based on fine‐scale discriminations formed later during interactions between IPS1/2 and primary visual cortex (V1). Specifically, when fine‐scale discriminations were necessary, we decoded significant category information from V1 at an intermediate stage of trials and again from IPS1/2 at a late stage. IPS1/2 feedback was critical, because categorization performance improved as causal influence from IPS1/2 to V1 increased. Further, these mechanisms were plastic, as the selectivity of IPS1/2 and V1 responses shifted markedly with retraining to categorize the same stimuli into two new groups.ConclusionsOur findings suggest that reentrant processing between the PPC and visual cortex enables flexible abstraction of category information.