bluuebunny/crossref_metadata_2025 huggingface dataset:
Social Justice and Religious Participation: A Qualitative Investigation of Christian Perspectives
Authors: Todd Nathan R. , Rufa Anne K.
Published: September 2012

This investigation examines how self‐identified Christians in the Midwest U.S. understand and work for social justice, with a focus on their process of social justice development and the role of religious congregations in promoting social justice. Using a grounded theory analysis of 15 in‐depth interviews, results indicated multiple understandings of social justice such as meeting basic needs, fixing social structures and systems to create equal distributions of resources, promoting human rights and dignity, and as a religious responsibility. Participants also described a process of social justice development facilitated by exposure to injustice, mentors, educating others, and the importance of finding a social justice community. Distinct personal barriers to social justice engagement were identified such as resources and negative emotions, whereas congregational leadership was important for congregational involvement. General frustration with congregations was expressed regarding low social justice engagement; however, participants balanced this frustration with hope for the positive potential of congregations to promote social justice. Together these findings show multifaceted understandings of social justice and a dynamic process of social justice development for these self‐identified Christians. Implications for future research and partnership with religious individuals and congregations also are discussed.
Corticocancellous Olecranon Autograft for Metacarpal Defect Reconstruction: A Case Report
Authors: Babushkina Anna , Edwards Scott
Published: September 2012

Background

High-energy injuries to the hand frequently lead to bone defects as well as soft tissue loss. Early bone grafting of defects is well established in the literature; however, few options are available for autologous corticocancellous grafts. Most frequently cited studies describe the iliac crest or the distal radius donor sites.

Methods

In this case report, we describe a new technique of obtaining corticocancellous bone graft from the olecranon. Results Complete union of the segmental defect was achieved with this technique.

Conclusions

The olecranon donor site is outside the zone of injury and therefore safe to access, but within the upper extremity, thus avoiding the need for harvest from a distant site such as the iliac crest or the distal femur. Additional benefits of this site are the greater volume of graft that can be harvested compared to the distal radius as well as a more optimal ratio of cancellous to cortical graft available, compared to the iliac crest where the graft may be excessively cortical in nature.
Synthesis, Surface Properties, Synergism Parameter and Inhibitive Performance of Novel Cationic Gemini Surfactant on Carbon Steel Corrosion in 1 M HCl Solution
Authors: Hegazy Mohamed A. , El‐Tabei Aziza S.
Published: September 2012

Electrochemical and gravimetric measurements were performed to investigate the effectiveness of a synthesized cationic gemini surfactant as corrosion inhibitor for carbon steel in 1 M HCl solution. The inhibition efficiency obtained from all methods are in good agreement. Potentiodynamic polarization measurements showed that, the prepared surfactant hinders both anodic and cathodic processes, i.e. acted as mixed‐type inhibitor. It was found that the adsorption of the synthesized inhibitor followed the Langmuir adsorption isotherm and showed a mixed physical and chemical adsorption. Kinetic parameters were calculated and discussed. The inhibitor exhibited a synergistic effect with Sn2+ more than with Cu2+. The synthesized cationic gemini surfactant exhibited good surface properties.
Where Do I Come From? Using Student’s Mitochondrial DNA to Teach About Phylogeny, Molecular Clocks, and Population Genetics
Authors: Maroja Luana S. , Wilder Jason A.
Published: September 2012

Phylogenetic reconstruction, divergence times, and population genetics are critical concepts for a complete understanding of evolution. Unfortunately, students generally lack “tree-thinking” skills and are often unmotivated to explore these concepts using typical classroom exercises that feature taxa unknown to students or simulated datasets. To generate greater student interest, we have developed an affordable practical lab ($16 dollars per student) where students extract and sequence their own mtDNA and use it for exercises involving phylogenetic reconstruction (placement of own DNA into the world tree), divergence (speciation) time (comparing current student population with chimps, gorillas, and Neanderthal), and population genetics (demographic change calculation based on student’s sample). In contrast to traditional labs, we found that students were highly motivated and enthusiastic throughout the four-week activity. Students had a 100% rate of success in obtaining DNA sequences and their evaluations report high satisfaction with the learning outcome. Here we provide all details and datasets needed to run the lab and discuss a series of assessments and possible exercises.
Role of paediatric intensive care following adenotonsillectomy for severe obstructive sleep apnoea: criteria for elective admission
Authors: Walker P , Whitehead B , Rowley M
Published: September 2012

Aims:

This study aimed to critically review our criteria for elective admission to the paediatric intensive care unit following adenotonsillectomy for obstructive sleep apnoea.

Materials and methods:

We reviewed 122 children electively admitted between 1997 and 2011. During this time, our criteria for admission evolved.

Results:

In these 122 children, the respiratory disturbance index during rapid eye movement sleep ranged from 6 to 159 (mean, 83). Forty-one per cent of the children had a recognised co-morbidity. Nine children required extra intervention, i.e. in addition to re-positioning and/or supplemental oxygen. One child was an unplanned re-admission after discharge from the paediatric intensive care unit. Over the same period, five children required unplanned transfers into the paediatric intensive care unit following adenotonsillectomy for sleep-disordered breathing.

Conclusion:

Based upon these results, we describe our current criteria for elective admission to the paediatric intensive care unit following adenotonsillectomy for severe obstructive sleep apnoea.
Tacrolimus enhances the recovery of normal laryngeal muscle fibre distribution after reinnervation
Authors: Gorphe P , Guerout N , Birchall M , Terenghi G , Marie J-P
Published: September 2012

Objectives:

To assess the recovery of various muscle fibre types in the posterior cricoarytenoid muscle after laryngeal reinnervation in the rat, and to determine the influence of tacrolimus on this process.

Methods:

Four groups of rats underwent resection and anastomosis of the left vagus nerve, and were administered either tacrolimus at a low dose or an immunosuppressive dose, or cyclosporin A at a low dose or an immunosuppressive dose. A fifth group received surgery alone, and a sixth group received neither surgery nor drug treatment (healthy group). Muscles were removed for immunohistochemical analysis 45 days after surgery.

Results:

There was no difference in the proportion of types 1, 2a and 2b muscle fibres, comparing the immunosuppressive tacrolimus group and the healthy group, whereas there were fewer type 1 fibres in the group receiving surgery alone, compared with the healthy group (7vs12.1 per cent, respectively;p = 0.0303).

Conclusion:

Tacrolimus enhanced the recovery of normal laryngeal muscle fibres after reinnervation in the rat, indicating a possible role in laryngeal transplantation.
Treatment and prognosis of nasopharyngeal angiofibroma involving the eye and optic nerve
Authors: Xu Y , Lin G , Lin C , Fang Z , Li Z , Zhou A , Lan S , Xu G , Yi Z
Published: September 2012

Objective:

To discuss the minimally invasive treatment and prognosis of juvenile nasopharyngeal angiofibroma involving the eye and optic nerve.

Methods:

Retrospective analysis of clinical data for 18 large juvenile nasopharyngeal angiofibromas, with reports of three typical cases.

Results:

The tumour invaded the orbit, eye, optic nerve and optic chiasm in 18, 9, 8 and 5 patients, respectively. Twelve patients were cured after surgery, with the affected eye and vision essentially returning to normal. In six patients, tumour residue was found in the middle cranial fossa; two of these six did not return for follow up. Four patients underwent radiotherapy; all four regained placement of the eye in a normal or near-normal position. One of these four patients regained normal visual acuity, two experienced no improvement in visual acuity, and one became blind.

Conclusion:

In patients with this tumour, surgery may return the eye to the normal position and may restore visual acuity if the optic fundus, macula, retina and optic nerve are only mildly affected. Modern radiotherapy can treat the intracranial residue effectively. A combined approach via the antrum, infratemporal fossa and nasal cavity, using a Caldwell–Luc incision, provides minimally invasive surgical access.
A comparison of the fish assemblages on natural and artificial reefs off Sal Island (Cape Verde)
Authors: Santos Miguel N. , Oliveira Miguel T. , Cúrdia João
Published: September 2012

Tourism is a growing activity in Cape Verde, which can lead to more intensive and uncontrolled fishing and diving activities, affecting the quality of marine habitats. To mitigate this biodiversity problem, a private diving operator, supported by the local authorities, decided to deploy the first artificial reefs (ARs) in the Archipelago just off Santa Maria Bay (Sal Island). To evaluate the ARs capacity to promote marine fish biodiversity in Santa Maria Bay, the fish assemblages were compared to those from nearby natural reefs (NRs), located at the same depth (10 and 28 m depth), by means of visual census. All study sites were surveyed by visual census in August 2009. A total of 64 species were recorded, mostly consisting of sedentary and/or benthophagous demersal species, followed by highly-sedentary benthic cryptic species. ‘Tchuklassa’ NR showed the highest species richness (58 species), while the lowest was recorded at ‘Santo Antão’ AR (48 species). An overall positive relationship was observed between habitat rugosity and mean species richness. The results showed a high percentage of common species on both reef types. Higher mean values of community descriptors (number of species, Shannon–Weaver diversity index, Simpson dominance index and equitability) and fish density were found on the ARs, with slightly higher densities recorded on the deeper reefs. These results suggest that ARs can have an important role promoting the local fish biodiversity and supporting local sustainable development of diving tourism.
The Survey of Sources for American Studies in the United Kingdom
Authors: Crick Bernard
Published: September 2012

(As the work of the Survey nears completion, its officers have little time to spare for tasks other than those that are necessary to bring this pioneering project to a conclusion. We are, therefore, indebted to Dr. Bernard Crick, Assistant-Director of the Survey, now in the throes of the last round-up, for the following letter from the field. We notice that Dr. Crick has strayed a little outside his province in his admonitions to some historians. But as he and his assistants have had a unique opportunity of examining local historical sources in this country, his opinion deserves a hearing, and we hope that his advice to historians whoso footsteps are led almost magnetically to Chancery Lane will not pass unnoticed.)
Overcoming European Civil War: Patterns of Consolidation in Divided Societies, 2010–1800
Authors: Dénes Iván Zoltán
Published: September 2012

Divided, sometimes antagonistic, communities in officially unified nations seem to be the rule in Europe. In some cases, they conjure up the most painful memories of actual civil-war events, but usually they constitute the common experience of most Europeans, who lived through different kinds of war, revolutions, counter-revolutions, coups d’état, dictatorships, totalitarian systems, regime changes, territorial losses, ethnic cleansings, and exchanges of population. In spite of major breakthroughs, we find all over Europe that the experiences and humiliations of previous generations have remained mainly unspoken and unelaborated at both individual and community levels. Dangerous as they are, such narratives and undigested traumas necessarily call for well-advised, learned and thoughtful acts of overwriting and reworking. A broadly based, well-founded, historical, multi- and interdisciplinary research project for the comparison of the various modes of trauma management in the different countries and regions of Europe can open up new perspectives and provide essential tools for working out individual and collective traumatic historical experiences. Its main question is how different communities were able to process their collective traumatic historical experiences, and what can be learned from the outcomes of these processes. The project will compare the common and different characteristics of the various regimes of memory and patterns of consolidation.
Galen and Roman Medicine: or can a Greek become a Latin?
Authors: Nutton Vivian
Published: September 2012

The history of medicine in the Roman world has frequently been viewed from the perspective of the Elder Pliny (ca. AD 70), who described an invasion of incompetent, worthless charlatans from Greece and beyond. This extreme viewpoint was not shared by many of the inhabitants of Italy and the Western provinces, who welcomed these outsiders. This paper looks at the reasons why Greek-speaking doctors migrated westwards, and, through the writings of their most famous representative, Galen of Pergamum (127–216), how they became integrated into a Latin society.
The Jewish Contribution to the Transmission of the Classical Legacy
Authors: Ferre Lola
Published: September 2012

The transmission and acquisition of the wisdom of the ancients throughout the Middle Ages is a fascinating phenomenon in which languages served as the primary vehicles for this journey of classical culture. The main route – but not the only one – was located on the Mediterranean coasts and incorporated Asia, Europe and Africa. It was a multidirectional journey.
Patterns of Reassurance Seeking and Reassurance-Related Behaviours in OCD and Anxiety Disorders
Authors: Kobori Osamu , Salkovskis Paul M.
Published: September 2012

Background: Reassurance seeking is particularly prominent in obsessive-compulsive disorder (OCD) and may be important in OCD maintenance. Aims: This study used a new self-report questionnaire to measure the range of manifestations of reassurance-seeking behaviours, describing their sources from which they seek, frequency, process (how they seek), and consequences (as opposed to triggers and motivations). This study also attempts to identify the degree to which reassurance is specific to OCD as opposed to panic disorder. Method: Reassurance Seeking Questionnaire (ReSQ) was administered to 153 individuals with OCD, 50 individuals with panic disorder with/without agoraphobia, and 52 healthy controls. The reliability and validity of the measure was evaluated and found to be satisfactory. Results: Reassurance seeking was found to be more frequent in both anxiety disorders relative to healthy controls. Individuals diagnosed with OCD were found to seek reassurance more intensely and carefully, and were more likely to employ “self-reassurance” than the other two groups. Conclusions: Further investigation of reassurance will enable better understanding of its role in the maintenance of anxiety disorders in general and OCD in particular.
Analysis of 34 candidate genes in bupropion and placebo remission
Authors: Tiwari Arun K. , Zai Clement C. , Sajeev Gautam , Arenovich Tamara , Müller Daniel J. , Kennedy James L.
Published: September 2012

There is considerable variability in the rate of response and remission following treatment with antidepressant drugs or placebo in depression patients. No pharmacogenetic studies of bupropion response have been done. We investigated 532 tagging single nucleotide polymorphisms (SNPs) in 34 candidate genes for association with remission and response to either bupropion (n=319) or placebo (n=257) in patients with major depressive disorder. Analyses were performed using conditional logistic regression. Significant association (gene-wide correction) was observed for remission following treatment with bupropion for a SNP within the serotonin receptor 2A gene (HTR2A rs2770296, pcorrected=0.02). Response to bupropion treatment was significantly associated with a SNP in the dopamine transporter gene (rs6347, pcorrected=0.013). Among the patients who received placebo, marginal association for remission was observed between a SNP in HTR2A (rs2296972, pcorrected=0.055) as well as in the serotonin transporter gene (5-HTT or SLC6A4 rs4251417, pcorrected=0.050). Placebo response was associated with SNPs in the glucocorticoid receptor gene (NR3C1; rs1048261, pcorrected=0.040) and monoamine oxidase A gene (MAOA; rs6609257, pcorrected=0.046). Although the above observations were significant after gene-wide corrections, none of these would be significant after a more conservative study-wide correction for multiple tests. These results suggest a possible role for HTR2A in remission to bupropion treatment. In accordance with bupropion pharmacology, dopamine transporter may play a role in response. The MAOA gene may be involved in placebo response.
Loss of asymmetric spine synapses in prefrontal cortex of motor-asymptomatic, dopamine-depleted, cognitively impaired MPTP-treated monkeys
Authors: Elsworth John D. , Leranth Csaba , Redmond D. Eugene , Roth Robert H.
Published: September 2012

Parkinson's disease is usually characterized as a movement disorder; however, cognitive abilities that are dependent on the prefrontal cortex decline at an early stage of the disease in most patients. The changes that underlie cognitive deficits in Parkinson's disease are not well understood. We hypothesize that reduced dopamine signalling in the prefrontal cortex in Parkinson's disease is a harbinger of detrimental synaptic changes in pyramidal neurons in the prefrontal cortex, whose function is necessary for normal cognition. Our previous data showed that monkeys exposed to the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), but not exhibiting overt motor deficits (motor-asymptomatic), displayed cognitive deficits in prefrontal cortex-dependent tasks. The present results demonstrate that motor-asymptomatic MPTP-treated monkeys have a reduced dopamine concentration and a substantially lower number (50%) of asymmetric (excitatory) spine synapses in layer II/III, but not layer V, of the dorsolateral prefrontal cortex, compared to controls. In contrast, neither dopamine concentration nor asymmetric synapse number was altered in the entorhinal cortex of MPTP-treated monkeys. Together, these findings suggest that the number of asymmetric spine synapses on dendrites in the prefrontal cortex is dopamine-dependent and that the loss of synapses may be a morphological substrate of the cognitive deficits induced by a reduction in dopamine neurotransmission in this region.
Esthetic and spiritual values motivating collective action for the conservation of cultural landscape—A case study of rice terraces in Japan
Authors: Kieninger Pia R. , Penker Marianne , Yamaji Eiji
Published: September 2012

Japan's rice terrace landscapes are not only used for food production but also appreciated as a place of high biocultural value. This paper pursues the question as to how far esthetic and spiritual values influence the motivation to participate in collective agricultural actions aiming at the conservation of traditional land use systems, the respective cultural (= traditional rural) landscapes and their biocultural diversity. Our results show that in the Ownership System of Ōyamasenmaida (Chiba Prefecture, Japan) landscape beauty is the main motivator for the mainly urban volunteers (the ‘tenants’) to participate in activities of the local Preservation Association, as well as for visitors who merely come to enjoy the scenery of the rice terraces. The active tenants, however, differ from the ‘passive’ visitors in their ecological interest and emotional attachment to the area. Interestingly, there is also a difference regarding the belief in nature spirits. A higher percentage of people who can imagine that such spirits are always present have been found among the tenants than among the visitors. Even more significant in this respect was the difference between female tenants and female visitors. To what extent spirituality is the cause for or an effect of involvement in nature conservation activities cannot be concluded from this survey. Future studies should therefore take a closer look at the connection between spirituality/religiosity and engagement in nature conservation activities. In Western countries (mainly in Central Europe or North America), nature conservation works on a more ‘scientific’ level, mobilizing engagement through scientific evidence on, for example, losses of species or biodiversity. Addressing the motivations of the volunteers on an emotional, esthetic or social level could be a promising way forward.
The medicalisation of health inequalities and the English NHS: the role of resource allocation
Authors: Asthana Sheena , Gibson Alex , Halliday Joyce
Published: September 2012

Tackling health inequalities (HI) has become a key policy objective in England in recent years. Yet, despite the wide-ranging policy response of the 1997–2010 Labour Government, socio-economic variations in health continued to widen. In this paper, we seek to explore why. We propose that a meta-narrative has emerged in which the health problems facing England's most deprived areas, and the solution to those problems, have increasingly come to be linked to levels of National Health Service (NHS) funding. This has been, in part, a response to key shortcomings in previous rounds of resource allocation. The very significant sums of money allocated with respect to ‘health inequalities’ reflects and reinforces the belief that the NHS can and should play a central role in promoting health equity. This medicalisation of HI focuses attention on the role of individual risk factors that lend themselves to medical management, but effectively sidelines the macroprocesses of social inequality, legitimising the kind of society that neo-liberal government has produced in the United Kingdom – one in which health (like other assets) has become a matter of individual and not collective responsibility.
Rewriting the Language of Creativity: The Five A's Framework
Authors: Glăveanu Vlad Petre
Published: September 2012

For the past 5 decades the psychology of creativity has been influenced by what is known as the 4 P's of creative expression: person, process, product, and press. This conceptual schema, initially proposed by Rhodes (1961) , helped researchers structure their thinking about the phenomenon. However, it also supported an individualistic, static, and oftentimes disjointed vision of creativity. The present article aims to rewrite this fundamental language of the discipline by using terms that explicitly endorse a systemic, contextual, and dynamic approach. The 5 A's framework—actor, action, artifact, audience, affordances—is grounded in current literature from sociocultural and ecological psychology as well as theories of the distributed mind and tries to achieve a more comprehensive and unitary perspective on creativity. Several theoretical, methodological, and practical implications are considered.
Bafilomycin A1 activates HIF-dependent signalling in human colon cancer cells via mitochondrial uncoupling
Authors: Zhdanov Alexander V. , Dmitriev Ruslan I. , Papkovsky Dmitri B.
Published: September 2012

Mitochondrial uncoupling is implicated in many patho(physiological) states. Using confocal live cell imaging and an optical O2 sensing technique, we show that moderate uncoupling of the mitochondria with plecomacrolide Baf (bafilomycin A1) causes partial depolarization of the mitochondria and deep sustained deoxygenation of human colon cancer HCT116 cells subjected to 6% atmospheric O2. A decrease in iO2 (intracellular O2) to 0–10 μM, induced by Baf, is sufficient for stabilization of HIFs (hypoxia inducible factors) HIF-1α and HIF-2α, coupled with an increased expression of target genes including GLUT1 (glucose transporter 1), HIF PHD2 (prolyl hydroxylase domain 2) and CAIX (carbonic anhydrase IX). Under the same hypoxic conditions, treatment with Baf causes neither decrease in iO2 nor HIF-α stabilization in the low-respiring HCT116 cells deficient in COX (cytochrome c-oxidase). Both cell types display equal capacities for HIF-α stabilization by hypoxia mimetics DMOG (dimethyloxalylglycine) and CoCl2, thus suggesting that the effect of Baf under hypoxia is driven mainly by mitochondrial respiration. Altogether, by activating HIF signalling under moderate hypoxia, mitochondrial uncoupling can play an important regulatory role in colon cancer metabolism and modulate adaptation of cancer cells to natural hypoxic environments.
Effects of the β‐agonist, isoprenaline, on the down‐regulation, functional responsiveness and trafficking of β2‐adrenergic receptors with N‐terminal polymorphisms
Authors: Koryakina Yulia , Jones Stacie M. , Cornett Lawrence E. , Seely Kathryn , Brents Lisa , Prather Paul L. , Kofman Alexander , Kurten Richard C.
Published: September 2012

The β2‐AR (β2‐adrenergic receptor) is an important target for respiratory and CVD (cardiovascular disease) medications. Clinical studies suggest that N‐terminal polymorphisms of β2‐AR may act as disease modifiers. We hypothesized that polymorphisms at amino acids 16 and 27 result in differential trafficking and down‐regulation of β2‐AR variants following β‐agonist exposure. The functional consequences of the four possible combinations of these polymorphisms in the human β2‐AR (designated β2‐AR‐RE, β2‐AR‐GE, β2‐AR‐RQ and β2‐AR‐GQ) were studied using site‐directed mutagenesis and recombinant expression in HEK‐293 cells (human embryonic kidney cells). Ligand‐binding assays demonstrated that after 24 h exposure to 1 μM isoprenaline, isoforms with Arg16(β2‐AR‐RE and β2‐AR‐RQ) underwent increased down‐regulation compared with isoforms with Gly16(β2‐AR‐GE and β2‐AR‐GQ). Consistent with these differences in down‐regulation between isoforms, prolonged isoprenaline treatment resulted in diminished cAMP response to subsequent isoprenaline challenge in β2‐AR‐RE relative to β2‐AR‐GE. Confocal microscopy revealed that the receptor isoforms had similar co‐localization with the early endosomal marker EEA1 following isoprenaline treatment, suggesting that they had similar patterns of internalization. None of the isoforms exhibited significant co‐localization with the recycling endosome marker Rab11 in response to isoprenaline treatment. Furthermore, we found that prolonged isoprenaline treatment led to a higher degree of co‐localization of β2‐AR‐RE with the lysosomal marker LAMP1 (lysosome‐associated membrane protein 1) compared with that of β2‐AR‐GE. Taken together, these results indicate that a mechanism responsible for differential responses of these receptor isoforms to the β‐agonist involves differences in the efficiency with which agonist‐activated receptors are trafficked to the lysosomes for degradation, or differences in degradation in the lysosomes.
À la recherche d’une ligne céphalométrique de
référence
Authors: Philippe Julien
Published: September 2012

La variabilité des lignes céphalométriques de référence est examinée à la lumière de la
typologie, de l’orientation naturelle de la tête, de l’orientation vestibulaire et de
l’anatomie. Il apparaît que ces lignes ont une orientation propre au sujet, c’est-à-dire
qu’elle n’est pas la même chez celui-ci et chez le modèle théorique qui exprime les
valeurs moyennes. Il s’en suit que l’écart observé entre la mesure du patient et la
moyenne peut provenir aussi bien des variations de la ligne de référence que de celles de
la structure étudiée. Une telle mesure ne peut alors servir de base à un diagnostic
morphologique. Un autre système céphalométrique de référence est évoqué. Il présente, pour
le diagnostic orthognathique, bien des avantages sur le système classique, mais reste
imparfait.
Top electrode size effect on hysteresis loops in piezoresponse force microscopy of Pb(Zr,Ti)O3-film on silicon structures
Authors: Bravina S. L. , Morozovsky N. V. , Eliseev E. A. , Morozovska A. N. , Costecalde J. , Soyer C. , Remiens D. , Deresmes D.
Published: September 2012

Experimental and theoretical studies of hysteresis loops in piezoresponse force microscopy (PFM) directed on elucidating the influence of top electrode lateral sizes on loop peculiarities were performed for Pt/Pb(Zr, Ti)O3/Pt/TiOx/SiO2/Si-substrate structures. The set of top Pt electrodes (50 nm to 10 μm of lateral size) was deposited on the Pb(ZrxTi1−x)O3 film (x = 0.54, thickness ≈1 μm) by RF magnetron sputtering. Under approaching the top electrode lateral size to the film thickness, the transition-like behaviour of PFM response amplitude and coercive tip voltage was observed. The existence of the critical value of dimensionless electrode size parameter γd/h ≈ 1 (γ is the dielectric anisotropy factor, d is the electrode size parameter, and h is the film thickness) was interpreted in the framework of the model based on Landau-Ginzburg-Devonshire theory combined with the decoupling approximation subject to the nonlinear electric field dependence of the ferroelectric polarization and dielectric permittivity.
Analyzing piezoresponse force microscopy for reconstruction of probed ferroelectric structures
Authors: Pan K. , Liu Y. Y. , Liu Y. M. , Li J. Y.
Published: September 2012

Piezoresponse force microscopy (PFM) has emerged as the tool of choice for characterizing piezoelectric and ferroelectric materials at nanoscale, yet the interpretation of PFM remains to be difficult and sometimes ambiguous. Built on earlier works, we developed a numerical integration scheme to analyze the expected PFM response in ferroelectrics with arbitrary domain configurations, with the ultimate goal to accurately reconstruct the underlying ferroelectric structure from PFM measurements. Using such technique, we demonstrated that the relationship between the effective and intrinsic piezoelectric coefficients is sensitive to a variety of factors that are intrinsic to the probed materials, and showed that the PFM mapping is not only influenced by polarization distribution on the sample surface but also three-dimensional polarization distribution inside the material. While relatively simple domain structures were used for demonstration, the approach is general, and can be applied to ferroelectrics with arbitrary polarization distributions.
Structural study in highly compressed BiFeO3 epitaxial thin films on YAlO3
Authors: Liu Heng-Jui , Chen Hsiang-Jung , Liang Wen-I , Liang Chen-Wei , Lee Hsin-Yi , Lin Su-Jien , Chu Ying-Hao
Published: September 2012

We report a study on the thermodynamic stability and structure analysis of the epitaxial BiFeO3 (BFO) thin films grown on YAlO3 (YAO) substrate. First, we observe a phase transition of MC–MA–T occurs in thin sample (<60 nm) with an utter tetragonal-like phase (denoted as MII here) with a large c/a ratio (∼1.23). Specifically, MII phase transition process refers to the structural evolution from a monoclinic MC structure at room temperature to a monoclinic MA at higher temperature (150 °C) and eventually to a presence of nearly tetragonal structure above 275 °C. This phase transition is further confirmed by the piezoforce microscopy measurement, which shows the rotation of polarization axis during the phase transition. A systematic study on structural evolution with thickness to elucidate the impact of strain state is performed. We note that the YAO substrate can serve as a felicitous base for growing T-like BFO because this phase stably exists in very thick film. Thick BFO films grown on YAO substrate exhibit a typical “morphotropic-phase-boundary”-like feature with coexisting multiple phases (MII, MI, and R) and a periodic stripe-like topography. A discrepancy of arrayed stripe morphology in different direction on YAO substrate due to the anisotropic strain suggests a possibility to tune the MPB-like region. Our study provides more insights to understand the strain mediated phase co-existence in multiferroic BFO system.
Local conductivity and the role of vacancies around twin walls of (001)−BiFeO3 thin films
Authors: Farokhipoor S. , Noheda B.
Published: September 2012

BiFeO 3 thin films epitaxially grown on SrRuO3-buffered (001)-oriented SrTiO3 substrates show orthogonal bundles of twin domains, each of which contains parallel and periodic 71° domain walls. A smaller amount of 109° domain walls are also present at the boundaries between two adjacent bundles. All as-grown twin walls display enhanced conductivity with respect to the domains during local probe measurements, due to the selective lowering of the Schottky barrier between the film and the AFM tip [S. Farokhipoor and B. Noheda, Phys. Rev. Lett. 107, 127601 (2011)]. In this paper, we further discuss these results and show why other conduction mechanisms are discarded. In addition, we show the crucial role that oxygen vacancies play in determining the amount of conduction at the walls. This prompts us to propose that the oxygen vacancies migrating to the walls locally lower the Schottky barrier. This mechanism would then be less efficient in non-ferroelastic domain walls where one expects no strain gradients around the walls and thus (assuming that walls are not charged) no driving force for accumulation of defects.
Domain relaxation dynamics in epitaxial BiFeO3 films: Role of surface charges
Authors: Chen Yi-Chun , Ko Cheng-Hung , Huang Yen-Chin , Yang Jan-Chi , Chu Ying-Hao
Published: September 2012

The thermodynamic parameters of domain relaxation process in the absence of external electric fields are related to the intrinsic electrostatic and stress/strain conditions inside the materials, such as the states at surface, states at interface with the electrode, and the atomic defects in the bulk. In order to perform systematical studies of these intrinsic effects, we investigated domain relaxation in a monodomain environment, which was obtained in strained epitaxial BiFeO3 (BFO)(111) films. Without as-grown domain walls and grain boundaries, the epitaxial BFO(111) film provided an ideal system for the dynamic observation of 180-degree domain wall motion. Nano-domains were initially created by writing voltage pulses under the tip of a scanning force microscope and then relaxed through time. The downward polarized domains exhibited much better retention behaviors than the upward domains. A two-step backswitching process was observed, and the behaviors varied with the initial domain sizes. Surface potential measurement showed the dissipation of surface screen charges with time, which was strongly coupled with the 1st step relaxation. The asymmetry behaviors for upward and downward backswitchings, and the two-stage relaxation processes can be explained by the mobile vacancies and the redistribution of surface charges. This study provides the basic understanding of the role of surface charges during the ferroelectric domain relaxation.
Complex domain structure in relaxed PbTiO3 thick films grown on (100)cSrRuO3//(100)SrTiO3 substrates
Authors: Yasui Shintaro , Ehara Yoshitaka , Utsugi Satoru , Nakajima Mitsumasa , Funakubo Hiroshi , Gruverman Alexei
Published: September 2012

Domain structures of epitaxial PbTiO3 films grown on (100)cSrRuO3//(100)SrTiO3 substrates by metalorganic chemical vapor deposition were investigated by x-ray diffraction (XRD) and piezoresponse force microscopy (PFM) techniques. It was found that with increasing film thickness, the domain structure changed from simple (001) polarization orientation to a complicated mixture of (001) and (100) orientations. PFM mappings showed that in the thicker films (∼1100 nm), the zigzag (001)/(100) domain boundaries made an angle of approximately 87° instead of 90° typically observed in (001)/(100) domain patterns in thinner (<300 nm) films. Full-relaxed tilting angle θ1 + θ2 + θ3 = 3.4° obtained from cross-sectional profile analysis of topological step-terrace structure was in good agreement with 3.4° and 3.6° angle values obtained from XRD measurements and theoretical prediction, respectively.
Laser beam scanning microscope and piezoresponse force microscope studies on domain structured in 001-, 110-, and 111-oriented NaNbO3 films
Authors: Yamazoe Seiji , Kohori Akihiro , Sakurai Hiroyuki , Kitanaka Yuuki , Noguchi Yuji , Miyayama Masaru , Wada Takahiro
Published: September 2012

NaNbO3 (NN) films were epitaxially grown on SrRuO3/(001), (110), and (111)SrTiO3 substrates, and these NN films were characterized by a laser beam scanning microscope and a piezoresponse force microscope. The 001-oriented NN film had antiferroelectric 90° domains with 100 and 010 polarization axes and 90° domain walls exhibiting piezoresponse. The piezoresponding domain walls would be induced by ferroelasticity. On the other hand, the 110- and 111-oriented NN films possessed 60° domains. The 60° domains of 110-oriented NN film were constructed by antiferroelectric 11¯0 domain and piezoresponding {101} and {011} domains. In the case of 111-oriented NN, three kinds of 60° domains (11¯0 and 01¯1, 01¯1 and 101¯, and 101¯ and 11¯0) were observed. The fine domains with piezoresponse were also observed in the mixed region with the three 60° domains. From the stress measurement, we found that the difference in the domain structure of 001-, 110-, and 111-oriented NN films depends not only on the orientation direction but also on the stress from the substrate. Moreover, the stress and the induction of the piezoelectric domain also influence the dielectric behavior.
Dynamic piezoresponse force microscopy: Spatially resolved probing of polarization dynamics in time and voltage domains
Authors: Kumar A. , Ehara Y. , Wada A. , Funakubo H. , Griggio F. , Trolier-McKinstry S. , Jesse S. , Kalinin S. V.
Published: September 2012

An approach for probing dynamic phenomena during hysteresis loop measurements in piezoresponse force microscopy (PFM) is developed. Dynamic PFM (D-PFM) necessitates development of 5-dimensional (5D) data acquisition protocols and associated methods for analysis and visualization of multidimensional data. Using a combination of multivariate statistical analysis and phenomenological fitting, we explore dynamic behavior during polarization switching in model ferroelectric films with dense ferroelastic domain structures and in ferroelectric capacitors. In polydomain films, multivariate analysis of the switching data suggests that ferroelectric and ferroelastic components can be decoupled and time dynamics can be explored. In capacitors, a strong correlation between polarization dynamics and microstructure is observed. The future potential of D-PFM for probing time-dependent hysteretic phenomena in ferroelectrics and ionic systems is discussed.
Three-dimensional vector electrochemical strain microscopy
Authors: Balke N. , Eliseev E. A. , Jesse S. , Kalnaus S. , Daniel C. , Dudney N. J. , Morozovska A. N. , Kalinin S. V.
Published: September 2012

Three-dimensional vector imaging of bias-induced displacements of surfaces of ionically conductive materials using electrochemical strain microscopy (ESM) is demonstrated for model polycrystalline LiCoO2 surface. We demonstrate that resonance enhanced imaging using band excitation detection can be performed both for out-of-plane and in-plane response components at flexural and torsional resonances of the cantilever, respectively. The image formation mechanism in vector ESM is analyzed and relationship between measured signal and grain orientation is discussed.
Characterization of local piezoelectric behavior of ferroelectric GeTe and Ge2Sb2Te5 thin films
Authors: Gervacio-Arciniega J. J. , Prokhorov E. , Espinoza-Beltrán F. J. , Trapaga G.
Published: September 2012

We studied the ferroelectric properties of GeTe and Ge2Sb2Te5 thin films through the analysis of capacitance-temperature, contact resonance piezoresponse force, resonance tracking piezoresponse force, and switching piezoresponse force microscopy measurements. These alloys are non-typical ferroelectric materials with low electrical resistivity, which makes their ferroelectric properties difficult to investigate by other conventional techniques. On the basis of measurement values of the Curie temperature, ferroelectric domain structure, piezoelectric coefficient d33, and coercive voltage were obtained. For the first time, hysteresis loops, and switching effects of domains under electrical field were observed in chalcogenide materials.
Domain evolution in lead-free thin film piezoelectric ceramics
Authors: Rogers Meredith E. , Fancher Chris M. , Blendell John E.
Published: September 2012

Due to environmental and health concerns lead-free piezoelectric systems are currently being evaluated for use as replacements for lead-based ceramics. (1-x)Na0.5Bi0.5TiO3 – xBaTiO3 (NBT-xBT) is a promising alternative. In order to develop materials with improved performance, it is necessary to understand local structure effects on the piezoelectric response at the grain level. Using piezoresponse force microscopy (PFM), we have studied the domain evolution under locally applied electric fields. Using pulsed laser deposition thin films are deposited on Pt/Ti/SiO2/Si substrates at a temperature of 650 °C in a 150 mTorr O2 environment. In NBT-0.05BT films, domains are clearly visible after the application of a bias field and they relax after a period of time. After the films are exposed to ambient conditions for several weeks, they must be annealed before domains are again visible with PFM. Domain images after poling indicate that the polarization direction is rotating in the plane of the sample.
Preface: Special Topic Section on Photochemistry at Surfaces
Authors: Metiu Horia
Published: September 2012

This Special Topic Section on Photochemistry at Surfaces contains invited essays by several leading scientists in the field. These essays present personal perspectives on the field and provide an overview of promising areas for future research on photo-initiated processes at surfaces using advanced experimental techniques. The authors focus on fundamental aspects of the field, which also has significant future applications in photovoltaic solar cells and photocatalytic water splitting.
Electron stimulated desorption, DIET, and photochemistry at surfaces: A personal recollection
Authors: Yates John T.
Published: September 2012

A personal recollection of the beginning of the field of photochemistry on surfaces is given.
Photoexcitation of adsorbates on metal surfaces: One-step or three-step
Authors: Petek Hrvoje
Published: September 2012

In this essay we discuss the light-matter interactions at molecule-covered metal surfaces that initiate surface photochemistry. The hot-electron mechanism for surface photochemistry, whereby the absorption of light by a metal surface creates an electron-hole pair, and the hot electron scatters through an unoccupied resonance of adsorbate to initiate nuclear dynamics leading to photochemistry, has become widely accepted. Yet, ultrafast spectroscopic measurements of molecule-surface electronic structure and photoexcitation dynamics provide scant support for the hot electron mechanism. Instead, in most cases the adsorbate resonances are excited through photoinduced substrate-to-adsorbate charge transfer. Based on recent studies of the role of coherence in adsorbate photoexcitation, as measured by the optical phase and momentum resolved two-photon photoemission measurements, we examine critically the hot electron mechanism, and propose an alternative description based on direct charge transfer of electrons from the substrate to adsorbate. The advantage of this more quantum mechanically rigorous description is that it informs how material properties of the substrate and adsorbate, as well as their interaction, influence the frequency dependent probability of photoexcitation and ultimately how light can be used to probe and control surface femtochemistry.
Toward photochemistry of integrated heterogeneous systems
Authors: Matsumoto Yoshiyasu
Published: September 2012

This paper begins with describing the excitation mechanisms in surface photochemistry and nuclear dynamics of adsorbate induced by electronic excitation. An illustrative example is Cs adsorbate on a Cu(111) surface. This adsorption system shows drastic changes in the electronic structure with coverage; this allows us to examine different types of electronic excitations that stimulate nuclear motions of Cs. Remarks are made on challenges in photoinduced processes at well-defined surfaces: direct observations of adsorbate-substrate vibrational modes and photoinduced reactions between adsorbates. Then, the paper addresses some issues in more complex systems: metal-liquid interfaces and powdered photocatalysts of metal oxides. Photochemistry and photoinduced nuclear dynamics at metal-liquid interfaces have not been well explored. Studies on this subject may make it possible to bridge the gap between surface photochemistry and electrochemistry. Photocatalysis with powdered catalysts has been extensively studied and is still an active area, but our understanding of the mechanism of photocatalysis is far from satisfactory. Although complicated, the highly integrated systems provide an opportunity to extend our knowledge of surface photochemistry.