bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of composition and temperature on hydrated phase assemblages in magnesium oxychloride cements
Authors: Liu Zhuangzhuang , Balonis Magdalena , Huang Jian , Sha Aimin , Sant Gaurav 
Published: April 2017

AbstractDue to their nonhydraulic nature, magnesium oxychloride cements (MOCs) are susceptible to degradation following contact with water. Improving the water resistance of these materials requires better understanding of hydrated phase relations and the sensitivity of hydrated phases to water. Toward this end, a series of targeted experiments and complementary thermodynamic calculations were carried out to assess hydrated phase assemblages in the system MgO‐MgCl2‐H2O across a range of compositions. Focus is placed on appraising the effects of composition and reaction temperature. In broad agreement with literature data, under ambient conditions, hydrated MOCs are noted to contain Phase 3 (P3), Phase 5 (P5), and brucite, but the mass partitioning of these phases is highly dependent on H2O/MgCl2 and MgO/MgCl2 molar ratio as well as curing temperature and age. At room temperature, P3 is favored at lower water contents, however, P5 and/or brucite are favored to form as water availability increases. Thermodynamic calculations indicate that P3 is “more stable” than P5 at lower temperatures—an outcome which impacts the engineering properties, for example, strength and volume stability. The impacts of the accuracy and self‐consistency of currently available thermodynamic data and their implications on predicted phase assemblages are discussed.
Abnormal reoxidation effects in Ba‐excess La‐doped BaTiO3 ceramics prepared by the reduction‐reoxidation method
Authors: Zu Hao , Chen Tao , Gao Chao , Fu Qiuyun , Zhou Dongxiang , Hu Yunxiang , Zheng Zhiping , Luo Wei 
Published: April 2017

AbstractBa‐excess La‐doped BaTiO3 ceramics have been successfully applied to prepare laminated chip thermistor. Ceramics were firstly fired in a high‐purity N2 flow and then reoxidized in air to obtain positive temperature coefficient of resistivity effect. However, an abnormal reduction trend of room‐temperature (RT) resistivity was found to be always beginning at ~800°C during reoxidation. This anomaly was found closely correlated with the insulating second phase (Ba2TiO4) at grain boundary, which destroyed conducting pathways between semiconducting BaTiO3 grains. When reoxidation temperature was up to ~800°C, the insulating Ba2TiO4 could be gradually consumed and then conducting pathways reestablished leading to RT resistivity reduction. To further prove the proposed explanation, the reoxidation effects of TiO2‐added ceramics were also studied, in which no Ba2TiO4 existed and certainly the abnormal RT resistivity reduction disappeared.
Synthesis of TaB2 powders by borothermal reduction
Authors: Guo Wei‐Ming , Zeng Ling‐Yong , Su Guo‐Kang , Li Hao , Lin Hua‐Tay , Wu Shang‐Hua 
Published: April 2017

AbstractBorothermal reduction processes of Ta2O5 with boron under vacuum were investigated. Ta2O5 reacted with boron to form various borides (TaB2, Ta3B4, and TaB), depending on the boron/Ta2O5 molar ratio and temperature. In order to prepare pure TaB2 powders, two routes were developed. The first route was one‐step heat treatment at 1550°C. With boron/Ta2O5 molar ratio of 9.0, pure TaB2 powders with strong agglomeration were synthesized by the first route, and the particle size and oxygen content were 0.7 μm and 0.9 wt%, respectively. The second route consisted of two‐step heat treatment at 800°C and 1550°C plus intermediate water washing. With lower boron/Ta2O5 molar ratio of 8.2, pure TaB2 powders with less agglomeration and more uniform distribution were synthesized by the second route, and the particle size and oxygen content were 0.8 μm and 0.8 wt%, respectively. Moreover, the particle size similarity of TaB2 powders by the two routes suggested that byproduct boron oxides, which were previously reported as the most important factor in promoting the coarsening of ZrB2 powders by borothermal reduction, did not lead to the significant coarsening of TaB2 powders.
CuO‐added KNbO3‐BaZrO3 lead‐free piezoelectric ceramics with low loss and large electric field‐induced strain
Authors: Park Jongseong , Kim Dae‐Hyeon , Lee Tae‐Gon , Cho Sung‐Hoon , Park Su‐Jin , Ryu Jungho , Nahm Sahn 
Published: April 2017

AbstractCuO‐added (1‐x)KNbO3‐x mol%BaZrO3 ceramics with 0.0≤x≤7.0 were sintered at 960°C. Large double polarization vs electric field (P‐E) and sprout‐shaped strain vs electric field (S‐E) hysteresis curves were obtained from the specimens with x≤2.0. They exhibited large polarizing electric fields (EP) owing to the presence of a large number of defect dipoles (PDs) that formed between Cu2+ ions and oxygen vacancies. Small double P‐E hysteresis curves were observed for the specimens with x≥3.0 with reduced EP because of the decreased number of PDs and the presence of a polymorphic phase structure containing both orthorhombic and pseudocubic structures. In particular, the specimen with x=5.0 exhibited a large strain of 0.16% at 8.0 kV/mm with a small EP of 1.2 kV/mm and good fatigue property: this specimen maintained a strain of 0.13% at 6.0 kV/mm after 106 cycles of 3.0 kV/mm.
Oxygen permeation mechanism in polycrystalline mullite at high temperatures
Authors: Kitaoka Satoshi , Matsudaira Tsuneaki , Yokoe Daisuke , Kato Takeharu , Takata Masasuke 
Published: April 2017

AbstractThe oxygen permeability of polycrystalline mullite wafers, serving as a model environmental barrier coating layer on SiC fiber‐reinforced SiC matrix composites, was evaluated at temperatures above 1673 h with an oxygen tracer gas (18O2). Oxygen permeation occurred by grain‐boundary (GB) diffusion of oxygen from the high oxygen partial pressure (high‐Po2) surface to the low‐Po2 surface, with simultaneous GB diffusion of aluminum in the opposite direction. This GB interdiffusion of both oxygen and aluminum proceeded without acceleration or retardation, maintaining the Gibbs‐Duhem relationship. Oxygen permeation related to the GB diffusion of silicon was negligibly small compared to that generated by aluminum GB diffusion, resulting in decomposition of the mullite near the low‐Po2 surface. The GB diffusion coefficients for oxygen in the vicinity of the high‐Po2 surface were determined directly from the SIMS‐18O line profiles along individual GBs, as assessed from cross sections of the exposed wafer. The coefficients thus obtained were comparable to those determined in the absence of an oxygen potential gradient and those calculated from an oxygen permeation trial under the assumption of nearly ionic conductivity.
Low energy ion‐solid interactions and chemistry effects in a series of pyrochlores
Authors: Dong Liyuan , Li Yuhong , Devanathan Ram , Setyawan Wahyu , Gao Fei 
Published: April 2017

AbstractThe effect of chemistry on low energy recoil events was investigated at 10 K for each type of atom in pyrochlores, using molecular dynamics simulation. Contour plots of the threshold displacement energy (Ed) in Gd2Zr2O7 have been produced along more than 80 directions for each individual species. The Ed surface for each type of atom in Gd2Zr2O7 is highly anisotropic; Ed of Zr exhibits the largest degree of anisotropy, while that of O8b exhibits the smallest. The recommended values of Ed in Gd2Zr2O7 based on the observed minima are 56, 94 and 25 eV, respectively, for Gd, Zr, and O. The influence of cation radius on Ed in pyrochlores A2B2O7 (with A‐site ranging from Lu3+ to La3+ and B‐site ranging from Ti4+ to Ce4+) was also investigated along three directions [100], [110], and [111]. The Ed in pyrochlores strongly depended on the atom type, atom mass, knock‐on direction, and lattice position. The defects produced after low energy displacement events included cation antisite defects, cation Frenkel pairs, anion Frenkel pairs, various vacancies, and interstitials. Ce doping in pyrochlores may affect the radiation response, because it resulted in drastic changes in cation and anion displacement energies and formation of an unusual type of anti‐site defect. This work demonstrates links between Ed and amorphization resistance.
Preparation, luminescence properties and energy transfer of Ca9Y(PO4)7: Eu2+‐Tb3+ phosphors
Authors: Tang Miao , Fan Yanting , Qiu Zhongxian , Zhang Jilin , Yu Liping , Li Chengzhi , Lian Shixun , Zhou Wenli 
Published: April 2017

AbstractTb3+‐doped and Eu2+, Tb3+ co‐doped Ca9Y(PO4)7 phosphors were synthesized by conventional solid‐state method. Additionally, the luminescence properties, decay behavior and energy transfer mechanism have already been investigated in detail. The green emission intensity of Tb3+ ions under NUV excitation is weak due to its spin‐forbidden f‐f transition. While Eu2+ can efficiently absorb NUV light and yield broad blue emission, most of which can be absorbed by Tb3+ ions. Thus, the emission color can be easily tuned from cyan to green through the energy transfer of Eu2+→Tb3+ in Ca9Y(PO4)7:Eu2+,Tb3+ phosphor. In this work, the phenomenon of cross‐relaxation between 5D3 and 5D4 are also mentioned. The energy transfer is confirmed to be resulted from a quadrupole‐quadrupole mechanism.
First‐principles investigation of chemical stability and proton conductivity of M‐doped BaZrO3 (M=K, Rb, and Cs)
Authors: Kang Sung Gu , Sholl David S. 
Published: April 2017

AbstractFirst‐principles calculations were carried out to examine the chemical stability and proton conductivity of A‐site‐doped BaZrO3. In a previous study, we investigated these two properties of B‐site‐doped BaZrO3. [RSC Adv. 3 [10] 3333‐3341 (2013)] Here, we investigated BaZrO3 doped with K, Rb, and Cs at A‐sites. We found that K‐doped BaZrO3 showed the highest proton conductivity and chemical stability among the examined A‐site dopants with respect to the carbonate formation reaction. Remarkably, there is a lack of a trade‐off relationship between chemical stability and proton conductivity in A‐site‐doped BaZrO3.
Crystallization of calcium silicate hydrates on the surface of nanomaterials
Authors: Li Hui , Du Tao , Xiao Huigang , Zhang Qiangqiang 
Published: April 2017

AbstractThe poorly crystalline calcium silicate hydrate (C‐S‐H) is the primary binding phase in portland cement concrete. In this paper, the influence of adding anatase phase nano‐TiO2, nano‐SiO2, graphene oxide (GO), and multiwalled carbon nanotubes (CNT) on the crystallization and morphology of C‐S‐H are systematically investigated through tests. C‐S‐H gels were prepared using the double decomposition method, and the nanomaterial additions of nano‐TiO2, nano‐SiO2, GO, and CNT were 2 wt%, 2 wt%, 0.5 wt%, and 0.5 wt%, respectively. X‐ray diffraction (XRD) results show that a more crystalline nanostructure of C‐S‐H is induced by the addition of nano‐TiO2 or GO. This phenomenon is further confirmed by the transmission electron microscopy (TEM) observations. The TEM observations demonstrate that C‐S‐H would grow on the crystal face of TiO2 to form nanocrystalline regions with a lattice fringe spacing of 3.0 Å. When incorporated with GO, it will form a square lattice structure with a lattice constant of 3.1 Å on the surface of GO and later change to the lattice fringe structure with a spacing of 3.1 Å on the region bit away the GO surface. However, when adding nano‐SiO2 or CNT, these nanocrystalline regions are not observed. Further characterization through scanning electron microscopy (SEM) and atomic force microscopy (AFM) has been performed to investigate the effect of nanomaterials on C‐S‐H morphology. Different nanomaterials take a different morphology of C‐S‐H: sheet‐shape structures for pure C‐S‐H, rod‐shape with for C‐S‐H with nano‐TiO2, and granular agglomeration for C‐S‐H with nano‐SiO2. C‐S‐H with GO or CNT forms a structure of C‐S‐H growing on the templates.
Niobium and divalent‐modified titanium dioxide ceramics: Colossal permittivity and composition design
Authors: Li Zhenwei , Luo Xuan , Wu Wenjuan , Wu Jiagang 
Published: April 2017

AbstractColossal permittivity (CP) (εr=104~105) is attained in (A1/3Nb2/3)xTi1‐xO2 (A=Ba2+, Ca2+, Zn2+, Mg2+) ceramics. Here, (Ca1/3Nb2/3)xTi1‐xO2 material was studied as a typical example, and effects of Ca and Nb on their microstructure, dielectric properties and stability were studied. Both backscattering and elements mapping strongly confirmed the formation of secondary phases due to the addition of Ca and/or Nb. Secondary phases‐induced by Ca cannot affect dielectric properties of the ceramics when low Ca and Nb contents were doped, while secondary phases formed by Ca and Nb strongly affected their dielectric properties in a high doping level. In particular, their dielectric properties can be well modified by the optimization of sintering temperatures. In addition, the (Ca1/3Nb2/3)xTi1‐xO2 ceramics with x=0.01 exhibited the optimum dielectric properties (εr=130500 and tan δ=0.19). Electron‐pinned defect‐dipoles may be suitable to explain CP phenomenon of this work. We believed that this profound investigation can benefit the development of new TiO2 ceramics as a CP material.
Effects of phase transition on discharge properties of PLZST antiferroelectric ceramics
Authors: Xu Ran , Tian Jingjing , Zhu Qingshan , Zhao Tian , Feng Yujun , Wei Xiaoyong , Xu Zhuo 
Published: April 2017

AbstractThe effects of electric field‐induced phase transition on discharge properties of Pb0.94La0.04[(Zr0.52Sn0.48)0.84Ti0.16]O3 antiferroelectric (AFE) ceramics were investigated. Due to the forward phase transition, high polarization and energy density are achieved. The backward phase transition results in nonlinear increase of current in underdamped circuit. The stored charge (14.2 μC under 40 kV/cm at 22°C) can be released completely in very short duration due to the low remanent polarization. With increasing temperature, the polarization and releasable energy decline. However, the current amplitude reaches maximum at 40°C, which is attributed to the backward phase transition. The maximum current and power density are as high as 143.8 A/cm2 and 2.4 MW/cm3, which indicates the potential of the ceramics for pulsed capacitors.
Challenges in building interpersonal care in organized hospital stroke units: The perspectives of stroke survivors, family caregivers and the multidisciplinary team
Authors: Ryan Tony , Harrison Madeleine , Gardiner Clare , Jones Amanda 
Published: April 2017

AbstractAimsTo explore the organized stroke unit experience from the multiple perspectives of stroke survivor, family carer and the multi‐disciplinary team.BackgroundOrganized stroke unit care reduces morbidity, mortality and institutionalization and is promoted globally as the most effective form of acute and postacute provision. Little research has focused on how care is experienced in this setting from the perspectives of those who receive and provide care.DesignThis study used a qualitative approach, employing Framework Analysis. This methodology allows for a flexible approach to data collection and a comprehensive and systematic method of analysis.MethodSemi‐structured interviews were undertaken during 2011 and 2012 with former stroke unit stroke survivors, family carers and senior stroke physicians. In addition, eight focus groups were conducted with members of the multi‐disciplinary team.ResultsOne hundred and twenty‐five participants were recruited. Three key themes were identified across all data sets. First, two important processes are described: responses to the impact of stroke and seeking information and stroke‐specific knowledge. These are underpinned by a third theme: the challenge in building relationships in organized stroke unit care.ConclusionsStroke unit care provides satisfaction for stroke survivors, particularly in relation to highly specialized medical and nursing care and therapy. It is proposed that moves towards organized stroke unit care, particularly with the emphasis on reduction of length of stay and a focus on hyper‐acute models, have implications for interpersonal care practices and the sharing of stroke‐specific knowledge.
Physical and psychological health of family carers co‐residing with an adult relative with an intellectual disability
Authors: Grey Jillian M. , Totsika Vasiliki , Hastings Richard P. 
Published: April 2017

BackgroundProviding long‐term care to an adult relative with intellectual disability can impact negatively on caregivers’ health and well‐being.MethodsData were collected via online and postal questionnaires on 110 family carers’ physical and psychological health, family stress and perceived positive gains from caring. Psychological adaptation and carers’ satisfaction with available support were also examined.ResultsStudy participants reported more health problems than general populations. Higher support needs of care recipients were associated with increased family stress. Carers being female were associated with lower family stress. Older age and better socio‐economic position were associated with better psychological outcomes. Other associations were consistent with psychological adaption and perceived helpfulness of support buffering negative outcomes and facilitating positive gains from caring.ConclusionsFamily carers of adults with intellectual disability appear to experience poorer health outcome than population norms. Adaption to the caregiving role may buffer negative outcomes. Further large scale, population‐based, longitudinal research is needed.
Exploring fire adaptation in a land with little fire: serotiny in Leptospermum scoparium (Myrtaceae)
Authors: Battersby Paul F. , Wilmshurst Janet M. , Curran Timothy J. , McGlone Matthew S. , Perry George L. W. 
Published: April 2017

AbstractAimImmigrant floras often have distinctive traits, well suited to the host region but absent from the autochthonous flora. An example is serotiny in the New Zealand (NZ) small tree, Leptospermum scoparium (Myrtaceae) belonging to a strongly fire‐adapted Australian clade. Serotiny in L. scoparium has been attributed either to strong selection by fire since human settlement, or taken as evidence that pre‐human fire in NZ was more important than assumed. By integrating field data, experimental analyses and long‐term fire histories, we sought to explain the spatial pattern of serotiny in L. scoparium in NZ, and evaluate these two explanations.LocationNew Zealand.MethodsWe quantified the distribution of serotiny in L. scoparium by analysing 137 populations distributed across NZ (two previous studies and ours), including 31 with Holocene fire histories. We assessed the relationship of serotiny with a suite of fire and climate environmental predictors, and between serotiny and shoot‐level flammability.ResultsSerotiny was strongly positively associated with latitude (more in the north), lower rainfall and higher temperatures. Serotinous populations were rare at sites with no history of fire. Serotiny was most prevalent in northern wetlands, where fire was recurrent during the Holocene, but was nearly absent from the southwestern Southern Alps. Shoot‐level flammability and serotiny were not correlated.Main conclusionsThe distribution of serotiny in L. scoparium relates not only to current environments but also to the legacy of regional shifts in vegetation during Quaternary glacial–interglacial cycles. Serotiny was maintained where the landscape experienced sporadic fire, but it is absent from NZ's southern South Island because the sparse, open vegetation during the glacials did not support fire. Serotinous L. scoparium populations were therefore more common in the northern North Island. Human transformation of the fire regime over the last 750 years has likely favoured the spread of serotinous populations.
Relationship among LRP1 expression, Pyk2 phosphorylation and MMP‐9 activation in left ventricular remodelling after myocardial infarction
Authors: Revuelta‐López Elena , Soler‐Botija Carol , Nasarre Laura , Benitez‐Amaro Aleyda , de Gonzalo‐Calvo David , Bayes‐Genis Antoni , Llorente‐Cortés Vicenta 
Published: April 2017

AbstractLeft ventricular (LV) remodelling after myocardial infarction (MI) is a crucial determinant of the clinical course of heart failure. Matrix metalloproteinase (MMP) activation is strongly associated with LV remodelling after MI. Elucidation of plasma membrane receptors related to the activation of specific MMPs is fundamental for treating adverse cardiac remodelling after MI. The aim of current investigation was to explore the potential association between the low‐density lipoprotein receptor‐related protein 1 (LRP1) and MMP‐9 and MMP‐2 spatiotemporal expression after MI. Real‐time PCR and Western blot analyses showed that LRP1 mRNA and protein expression levels, respectively, were significantly increased in peri‐infarct and infarct zones at 10 and 21 days after MI. Confocal microscopy demonstrated high colocalization between LRP1 and the fibroblast marker vimentin, indicating that LRP1 is mostly expressed by cardiac fibroblasts in peri‐infarct and infarct areas. LRP1 also colocalized with proline‐rich tyrosine kinase 2 (pPyk2) and MMP‐9 in cardiac fibroblasts in ischaemic areas at 10 and 21 days after MI. Cell culture experiments revealed that hypoxia increases LRP1, pPyk2 protein levels and MMP‐9 activity in fibroblasts, without significant changes in MMP‐2 activity. MMP‐9 activation by hypoxia requires LRP1 and Pyk2 phosphorylation in fibroblasts. Collectively, our in vivo and in vitro data support a major role of cardiac fibroblast LRP1 levels on MMP‐9 up‐regulation associated with ventricular remodelling after MI.
A Novel CXCR4 antagonist enhances angiogenesis via modifying the ischaemic tissue environment
Authors: Yan Xiaoqing , Dai Xiaozhen , He Luqing , Ling Xiao , Shao Minglong , Zhang Chi , Wang Yuehui , Xiao Jian , Cai Lu , Li Xiaokun , Tan Yi 
Published: April 2017

AbstractEndothelial progenitor cells (EPCs) play a capital role in angiogenesis via directly participating in neo‐vessel formation and secreting pro‐angiogenic factors. Stromal cell‐derived factor 1 (SDF‐1) and its receptor CXCR4 play a critical role in the retention and quiescence of EPCs within its niche in the bone marrow. Disturbing the interaction between SDF‐1 and CXCR4 is an effective strategy for EPC mobilization. We developed a novel CXCR4 antagonist P2G, a mutant protein of SDF‐1β with high antagonistic activity against CXCR4 and high potency in enhancing ischaemic angiogenesis and blood perfusion. However, its direct effects on ischaemic tissue remain largely unknown. In this study, P2G was found to possess a robust capability to promote EPC infiltration and incorporation in neo‐vessels, enhance the expression and function of pro‐angiogenic factors, such as SDF‐1, vascular endothelial growth factor and matrix metalloprotein‐9, and activate cell signals involved in angiogenesis, such as proliferating cell nuclear antigen, protein kinase B (Akt), extracellular regulated protein kinases and mammalian target of rapamycin, in ischaemic tissue. Moreover, P2G can attenuate fibrotic remodelling to facilitate the recovery of ischaemic tissue. The capability of P2G in direct augmenting ischaemic environment for angiogenesis suggests that it is a potential candidate for the therapy of ischaemia diseases.