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121.
Daniel M. Marincel Huairuo Zhang Stephen Jesse Alex Belianinov Mahmut B. Okatan Sergei V. Kalinin W. Mark Rainforth Ian M. Reaney Clive A. Randall Susan Trolier‐McKinstry 《Journal of the American Ceramic Society》2015,98(6):1848-1857
Domain wall movement at and near engineered 10°, 15°, and 24° tilt and 10° and 30° twist grain boundaries was measured by band excitation piezoresponse force microscopy for Pb(Zr,Ti)O3 films with Zr/Ti ratio of 45/55 and 52/48. A minimum in nonlinear response was observed at the grain boundary for the highest angle twist and tilt grain boundaries, while a maximum in nonlinear response was observed at the 10° tilt grain boundaries. The observed nonlinear response was correlated with the domain configurations imaged in cross section by transmission electron microscopy. 相似文献
122.
123.
Susan M. Bogus Keith R. Molenaar James E. Diekmann 《Construction Management & Economics》2013,31(8):829-837
Overlapping activities that are traditionally performed in a sequential manner can significantly reduce project delivery times. Overlapping, however, should be approached in a systematic manner to reduce the costs and risks. Information gathered from sector‐based case studies and from the manufacturing domain suggest a formalised framework for identifying overlapping opportunities and strategies can be successfully implemented for infrastructure projects. This framework considers activity characteristics, such as evolution of upstream information and sensitivity of downstream activities to changes in upstream information, to identify appropriate overlapping strategies. Overlapping strategies, such as early freezing of design criteria, overdesign, and early release of preliminary information, are selected based on activity characteristics. These strategies operate either by speeding up the evolution of upstream information or by reducing the sensitivity of downstream activities. By aligning overlapping strategies with activity characteristics, project managers can make better decisions on when and how much to overlap sequential activities to reduce overall project delivery time. 相似文献
124.
Susan S. Fainstein Norman I. Fainstein 《Journal of the American Planning Association. American Planning Association》2013,79(3):275-285
Decentralization of planning can provide disadvantaged groups with greater access to bureaucratic decision making, incentives to community development, and enhanced democratic participation. In recent years community control has become less of a racial issue and therefore more acceptable to white community leaders. Surveys of community leaders in New York City indicate a high level of support among all racial groups for increased local control, although minority leaders still favor a higher level of community input than do whites. Support for community control is highly correlated with negative evaluations of city services. Decentralization of administrative programs is also favored by many city officials, although with limitations on community input. The New York Office of Neighborhood Government experiment received highly laudatory endorsements from the bureaucrats who served in district service cabinets. The Housing and Development Administration has relied on local groups to implement the Neighborhood Preservation Program for housing rehabilitation. In both cases, however, community participation was eventually stymied. Implementation of decentralization is made difficult because of contradictions between class and locational interests. Meaningful local participation is often either co-opted or suppressed. Nevertheless, urban decentralization continues as one path of moderate but viable reform. 相似文献
125.
Susan S. Fainstein 《Journal of the American Planning Association. American Planning Association》2013,79(3):268-275
In this essay, the author traces her development from a political scientist to an urban planner. Looking back on more than 40 years as a scholar and professor of planning, Fainstein deems issues of inequality derived from class, ethnicity, and gender to have been the focus of her teaching and scholarship. At first, she approached these questions through empirical investigations of citizen participation and theoretical exploration of the neo-Marxist literature and her early research focused on the politics of planning in American cities, the contributions of community groups, and the roles played by business interests. Later, she examined redevelopment and housing programs in London and Amsterdam to contrast these more welfare-oriented European cities to the American model and examined the relationship between gender and planning. Eventually, she brought together her empirical and theoretical research to develop a theory of urban justice and to suggest policies at the local level that were in line with these principles. 相似文献
126.
127.
Michelle L. Baack Susan E. Puumala Stephen E. Messier Deborah K. Pritchett William S. Harris 《Lipids》2016,51(4):423-433
Docosahexaenoic acid (DHA) is an essential fatty acid (FA) important for health and neurodevelopment. Premature infants are at risk of DHA deficiency and circulating levels directly correlate with health outcomes. Most supplementation strategies have focused on increasing DHA content in mother's milk or infant formula. However, extremely premature infants may not reach full feedings for weeks and commercially available parenteral lipid emulsions do not contain preformed DHA, so blood levels decline rapidly after birth. Our objective was to develop a DHA supplementation strategy to overcome these barriers. This double‐blind, randomized, controlled trial determined feasibility, tolerability and efficacy of daily enteral DHA supplementation (50 mg/day) in addition to standard nutrition for preterm infants (24–34 weeks gestational age) beginning in the first week of life. Blood FA levels were analyzed at baseline, full feedings and near discharge in DHA (n = 31) or placebo supplemented (n = 29) preterm infants. Term peers (n = 30) were analyzed for comparison. Preterm infants had lower baseline DHA levels (p < 0.0001). Those receiving DHA had a progressive increase in circulating DHA over time (from 3.33 to 4.09 wt% or 2.88 to 3.55 mol%, p < 0.0001) while placebo‐supplemented infants (receiving standard neonatal nutrition) had no increase over time (from 3.35 to 3.32 wt% or 2.91 to 2.87 mol%). Although levels increased with additional DHA supplementation, preterm infants still had lower blood DHA levels than term peers (4.97 wt% or 4.31 mol%) at discharge (p = 0.0002). No differences in adverse events were observed between the groups. Overall, daily enteral DHA supplementation is feasible and alleviates deficiency in premature infants. 相似文献
128.
Scaling Effects in Perovskite Ferroelectrics: Fundamental Limits and Process‐Structure‐Property Relations 下载免费PDF全文
Jon F. Ihlefeld David T. Harris Ryan Keech Jacob L. Jones Jon‐Paul Maria Susan Trolier‐McKinstry 《Journal of the American Ceramic Society》2016,99(8):2537-2557
Ferroelectric materials are well‐suited for a variety of applications because they can offer a combination of high performance and scaled integration. Examples of note include piezoelectrics to transform between electrical and mechanical energies, capacitors used to store charge, electro‐optic devices, and nonvolatile memory storage. Accordingly, they are widely used as sensors, actuators, energy storage, and memory components, ultrasonic devices, and in consumer electronics products. Because these functional properties arise from a noncentrosymmetric crystal structure with spontaneous strain and a permanent electric dipole, the properties depend upon physical and electrical boundary conditions, and consequently, physical dimension. The change in properties with decreasing physical dimension is commonly referred to as a size effect. In thin films, size effects are widely observed, whereas in bulk ceramics, changes in properties from the values of large‐grained specimens is most notable in samples with grain sizes below several micrometers. It is important to note that ferroelectricity typically persists to length scales of about 10 nm, but below this point is often absent. Despite the stability of ferroelectricity for dimensions greater than ~10 nm, the dielectric and piezoelectric coefficients of scaled ferroelectrics are suppressed relative to their bulk counterparts, in some cases by changes up to 80%. The loss of extrinsic contributions (domain and phase boundary motion) to the electromechanical response accounts for much of this suppression. In this article, the current understanding of the underlying mechanisms for this behavior in perovskite ferroelectrics is reviewed. We focus on the intrinsic limits of ferroelectric response, the roles of electrical and mechanical boundary conditions, grain size and thickness effects, and extraneous effects related to processing. In many cases, multiple mechanisms combine to produce the observed scaling effects. 相似文献
129.
Effect of Mechanical Constraint on Domain Reorientation in Predominantly {111}‐Textured Lead Zirconate Titanate Films 下载免费PDF全文
Giovanni Esteves Margeaux Wallace Raegan Johnson‐Wilke Chris M. Fancher Rudeger H. T. Wilke Susan Trolier‐McKinstry Jacob L. Jones 《Journal of the American Ceramic Society》2016,99(5):1802-1807
Ferroelectric/ferroelastic domain reorientation was measured in 2.0 μm thick tetragonal {111}‐textured PbZr0.30Ti0.70O3 thin films using synchrotron X‐ray diffraction (XRD). Lattice strain from the peak shift in the 111 Bragg reflection and domain reorientation were quantified as a function of applied electric field amplitude. Domain reorientation was quantified through the intensity exchange between the 112 and 211 Bragg reflections. Results from three different film types are reported: dense films that are clamped to the substrate (as‐processed), dense films that are partially released from the substrate, and films with 3% volume porosity. The highest amount of domain reorientation is observed in grains that are misoriented with respect to the {111} preferred (domain engineered) orientation. Relative to the clamped films, films that were released from the substrate or had porosity exhibited neither significant enhancement in domain reorientation nor in 111 lattice strain. In contrast, similar experiments on {100}‐textured and randomly oriented films showed significant enhancement in domain reorientation in released and porous films. Therefore, {111}‐textured films are less susceptible to changes in properties due to mechanical constraints because there is overall less domain reorientation in {111} films than in {100} films. 相似文献
130.
Bin Qiu Susan E. Luczak Tamara L. Wall Aaron M. Kirchhoff Yuxue Xu Mimy Y. Eng Robert B. Stewart Weinian Shou Stephen L. Boehm II Julia A. Chester Weidong Yong Tiebing Liang 《International journal of molecular sciences》2016,17(8)
FKBP5 encodes FK506-binding protein 5, a glucocorticoid receptor (GR)-binding protein implicated in various psychiatric disorders and alcohol withdrawal severity. The purpose of this study is to characterize alcohol preference and related phenotypes in Fkbp5 knockout (KO) mice and to examine the role of FKBP5 in human alcohol consumption. The following experiments were performed to characterize Fkpb5 KO mice. (1) Fkbp5 KO and wild-type (WT) EtOH consumption was tested using a two-bottle choice paradigm; (2) The EtOH elimination rate was measured after intraperitoneal (IP) injection of 2.0 g/kg EtOH; (3) Blood alcohol concentration (BAC) was measured after 3 h limited access of alcohol; (4) Brain region expression of Fkbp5 was identified using LacZ staining; (5) Baseline corticosterone (CORT) was assessed. Additionally, two SNPs, rs1360780 (C/T) and rs3800373 (T/G), were selected to study the association of FKBP5 with alcohol consumption in humans. Participants were college students (n = 1162) from 21–26 years of age with Chinese, Korean or Caucasian ethnicity. The results, compared to WT mice, for KO mice exhibited an increase in alcohol consumption that was not due to differences in taste sensitivity or alcohol metabolism. Higher BAC was found in KO mice after 3 h of EtOH access. Fkbp5 was highly expressed in brain regions involved in the regulation of the stress response, such as the hippocampus, amygdala, dorsal raphe and locus coeruleus. Both genotypes exhibited similar basal levels of plasma corticosterone (CORT). Finally, single nucleotide polymorphisms (SNPs) in FKBP5 were found to be associated with alcohol drinking in humans. These results suggest that the association between FKBP5 and alcohol consumption is conserved in both mice and humans. 相似文献