bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell Staining: Fluorescent Labelling of the Golgi Apparatus
Authors: Dejgaard Selma Y , Dejgaard Kurt , Presley John F
Published: May 2015

Immunofluorescence has been the primary method for labelling the Golgi apparatus for light microscopic observation in fixed cells. The Golgi apparatus was initially labelled in living cells using the fluorescent ceramide analogue
N
‐6[7‐nitro‐2,1,3‐benzoxadiazol‐4‐yl] aminocaproyl sphingosine or by microinjection of fluorescently conjugated antibodies to exposed Golgi epitopes. With the common availability of the green fluorescent protein (GFP) and advanced fluorescence microscopes including confocal microscopes, imaging of the Golgi apparatus in living cells is now a major experimental approach. Time‐lapse imaging of living cells has also been combined with photobleach techniques in order to study the dynamics of transient protein association with the Golgi apparatus. Similar live‐cell imaging approaches have been used to study the dynamics of the cargo transport through the exocytic pathway. Recent advances in microscopy have allowed bypassing the diffraction limit which has traditionally limited image resolution. These new methods may be applied to fluorescence imaging of the Golgi apparatus, although they are not easily applied to living cells at present.

Key Concepts

Immunofluorescence can be used to visualise proteins in the Golgi apparatus or its subdomains.

Live‐cell visualisation of the Golgi apparatus is possible with GFP‐tagged proteins.

Fluorescence images can be quantitated in a rigorous way.

Photobleaching and photoactivation techniques permit visualisation of protein dynamics and flux through the Golgi apparatus in living cells.

Super‐resolution imaging promises a new generation of imaging approaches to the Golgi apparatus.
Chromatofocusing
Authors: El‐Sayed Mayyada MH , Frey Douglas D
Published: May 2015

Chromatofocusing is a form of gradient elution chromatography performed using an ion‐exchange column packing and an internally generated pH gradient that travels through the column as a retained front. The interaction between the pH gradient and amphoteric substances such as proteins causes these substances to exit the chromatographic column at characteristic locations in the effluent as focused bands. The method was first introduced in the 1970s. Over the last several decades, the performance and the range of applications of the method have been significantly increased through the efforts of numerous investigators.

Key Concepts

Proteins can be focused into narrow bands similar to those produced in isoelectric focusing using an ion‐exchange chromatography column and a pH gradient that moves through the column packing more slowly than the interparticle fluid.

The focusing effects produced in chromatofocusing yield unique dynamic behaviour for the species being separated which, if properly optimised, can produce high‐resolution separations.

Numerical simulation methods and analytical local‐equilibrium theories can be used to optimise the compositions of the elution and presaturation buffers used in chromatofocusing.

Chromatofocusing can be applied not only to proteins, but also to related types of amphoteric species including small peptides and macromolecular complexes such as viruses.

Chromatofocusing can usefully employ mixed‐mode column packings where both electrostatic and hydrophobic interactions determine the adsorption affinity of the species being separated.
Peptidyl Prolylcis/transIsomerases
Authors: Schiene‐Fischer Cordelia
Published: May 2015

Peptidyl prolylcis/transisomerases (PPIases) are ubiquitous enzymes that catalyse thecis/transisomerisation of peptide bonds preceding proline in peptides and proteins. PPIases can thus catalyse proline‐limited slow kinetic steps in the folding and rearrangement of proteins. Generally, by the regulation of the biological functions of their target proteins, PPIases are involved in the control of a wide variety of cellular processes, including transcription, cell proliferation, cell differentiation and apoptosis. They are implicated in many diseases such as cancer, inflammation, infection and neurodegeneration. PPIases comprise three families, the cyclophilins, the FK506‐binding proteins (FKBPs) and the parvulins, which are unrelated in their amino acid sequence and their three‐dimensional structure. Binding of cyclophilins and FKBP to their respective tight binding inhibitors, cyclosporin A and FK506, mediates the immunosuppressive action of these drugs by a gain‐of‐function mechanism.

Key Concepts

Peptidyl prolylcis/transisomerases catalyse thecis/transisomerisation of peptide bonds preceding proline in peptides and proteins.

The enzyme class of PPIases comprises three families, the cyclophilins, the FK506‐binding proteins (FKBPs) and the parvulins unrelated in their amino acid sequence and their three‐dimensional structure.

The PPIase activity of members of the cyclophilin family is inhibited by the tight binding inhibitor cyclosporin A.

The PPIase activity of members of the FKBP family is inhibited by FK506 and rapamycin.

Members of the cyclophilin and FKBP families of PPIases are called immunophilins, because they mediate immunosuppression of the immunosuppressive drugs cyclosporin A, FK506 and rapamycin.

Beside a role in protein folding, specific members of the three PPIase families perform specific tasks by the interaction with distinct substrate proteins in their native state, thereby regulating their functional properties.
Genotype Imputation
Authors: Krawczak Michael
Published: May 2015

A missing data problem arises in genetic epidemiological studies when genotypes of particular markers are unavailable for analysis for reasons of data quality, cost efficiency or technical design. In such instances, imputation methods can be used to extend the process of scientific inference making from the typed to the un‐typed markers. The information required to infer unobserved genotypes from observed genotypes is provided by the so‐called imputation base, an internal or external set of comprehensively typed individuals (often taken from HapMap or the 1000 Genomes Project) that is representative of the study population as a whole. The most popular genotype imputation methods, including IMPUTE, fastPHASE, MaCH and BEAGLE, employ a Markov chain model of the haplotype distribution in the population of interest. Although these frameworks have been shown to provide accurate and efficient tools of ‘
in silico
genotyping’ under certain conditions, their uncritical use nevertheless must be cautioned against.

Key Concepts

Relevant genotype data may be missing in genetic epidemiological studies for technical or efficiency reasons.

Scientific inference that takes missing genotype data properly into account can be made using data imputation methods.

Genotype imputation requires an imputation base, that is, a population‐representative set of individuals (such as the HapMap or the 1000 Genomes Project) who are genotyped for all markers of interest.

Established genotype imputation methods employ a Markov chain model of the haplotype distribution in the population under study.

Genotype imputation may achieve 90% accuracy for highly polymorphic markers but performs less well for rare variants.

While genotype imputation may provide valid statistical tests of genotype–phenotype association, their use for effect size estimation and significance assessment must proceed with caution.

Genotype imputation needs to follow the same rules of good scientific practice as laboratory‐based data generation.
Molecular Genetics of Limb‐Girdle Muscular Dystrophies
Authors: Filosto Massimiliano , Scarpelli Mauro , Padovani Alessandro
Published: May 2015

The limb‐girdle muscular dystrophies (LGMDs) are a group of genetically heterogeneous neuromuscular disorders caused by specific protein defects in muscle fibres and characterised by predominant weakness and wasting in proximal limb and axial muscles. Most of these diseases present with wide clinical heterogeneity and the limb‐girdle phenotype should be regarded as one of the possible phenotypic expressions of a specific protein defect.

Therefore, a precise clinical evaluation is often difficult, and an appropriate diagnostic approach using clinical, pathological, biochemical and genetic resources is essential to achieve the correct diagnosis.

The current classification of LGMDs is based on inheritance pattern. Dominant forms are classified as type 1 (LGMD1), whereas the recessive forms are classified as type 2 (LGMD2). A progressive alphabetical letter identifies the different involved genes and indicates the order of identification.

This review reports a comprehensive update on the genetic bases and the main clinical aspects of these groups of diseases according to protein defect and transmission modality.

Key Concepts

The limb‐girdle muscular dystrophies (LGMDs) are a heterogeneous group of hereditary neuromuscular disorders caused by specific protein defects in muscle fibres and characterised by predominant weakness and wasting in proximal limb and axial muscles.

The current classification of LGMDs is based on inheritance pattern. Dominant forms are classified as type 1 (LGMD1), whereas the recessive forms are classified as type 2 (LGMD2). A progressive alphabetical letter identifies the different involved genes and indicates the order of identification.

LGMDs are diseases having wide inter‐ and intra‐familial phenotypic heterogeneity and therefore the limb‐girdle phenotype is often the only one of the possible phenotypic expressions of a specific protein defect.

Four recessive LGMDs are caused by mutations in the genes encoding the four members of the skeletal muscle sarcoglycan complex which is a part of the large macromolecular complex of proteins named the dystrophin‐associated protein complex (DAPC) which is thought to have structural functions in providing membrane stability, maintaining the integrity of sarcolemma and in ensuring transduction during muscle contraction.

Eight genes have been found to be responsible for an LGMD‐dystroglycanopathy until now. Mutations in these genes reduce dystroglycan glycosylation and cause different phenotypes ranging from mild to dramatic conditions. Limb‐girdle muscular dystrophies should to be considered the mildest expression of the phenotypic spectrum of dystroglycanopathies.
Disconnection Syndromes
Authors: Mulroy Eoin , Gleeson Sarah , McCarthy Allan , Kavanagh Eoin , Lynch Tim
Published: May 2015

Evolutionary pressures on a finite amount of cortical space led the cerebral hemispheres to evolve into subspecialised regions subserving specific functions. Impaired communication between these highly specialised brain regions gives rise to a variety of clinical syndromes known as the disconnection syndromes. While some of the original concepts proposed by the initial protagonists of the disconnection theory in the mid‐nineteenth century have been disproved, other conditions are now recognised as having a disconnectionist aetiology (e.g. autism and dyslexia). With improved neuroimaging, especially functional brain imaging, it is conceivable that the number of disorders attributable to disconnection syndromes will continue to increase. Disconnection syndromes may be under‐recognised, owing to both lack of physician knowledge of and difficulties elucidating these disorders, because of their subtle presentations (e.g.
anterior callosal lesions
).

Key Concepts

Disconnection syndromes should be considered when dealing with aphasia, alexia and agnosia and impaired hand function.

Autism and dyslexia can be thought of as congenital disconnection syndromes.

Presentations of disconnection syndromes may be subtle and need to be specifically examined for in order to avoid missing the diagnosis.

Disconnection syndromes involve interruption of communication between highly specialised brain regions.
Hippo Growth Control Pathway and Organ Size
Authors: Waghmare Indrayani , Verghese Shilpi , Kango‐Singh Madhuri
Published: May 2015

In multicellular organisms, regulation of growth control occurs because of the concerted action of multiple growth‐regulatory and patterning pathways. Among these, the Hippo (Hpo) pathway gained notoriety for its unique ability to simultaneously regulate cell proliferation and apoptosis to achieve the correct organ size. Initially discovered in
Drosophila
, this pathway is evolutionarily conserved, and acts as a universal regulator of organ size in metazoa. A complete pathway that integrates signals from the cell membrane to the nucleus has emerged, and multiple modes of Hpo pathway regulation have been elucidated. When the Hpo pathway is active, it acts as a brake on growth – cell proliferation is suppressed and apoptosis is promoted, whereas when the Hpo pathway is inactive, growth occurs – cell proliferation is promoted and apoptosis is suppressed. While the initial discovery of the pathway established its role in regulation of organ size and development, the focus has shifted considerably towards understanding its role in other biological processes such as maintaining tissue homeostasis, stem cell and tissue differentiation, cancer and regeneration. The Hpo signalling pathway functions in organ size control, and understanding its physiological functions will provide insights on its tissue‐ and cell‐type‐specific functions, and its involvement in diseases such as cancer.

Key Concepts

Cell proliferation and cell death must be regulated for balanced growth.

The regulation of Hippo pathway activity is key to regulating cell number to achieve the correct organ size and growth during normal development.

Hippo pathway activation promotes apoptosis and suppresses cell proliferation, whereas Hippo pathway inactivation promotes cell proliferation and suppresses apoptosis.

The Hippo pathway is a network of tumour suppressor genes, and genes regulating cell‐ and planar‐polarity.

Signalling interactions in the Hippo pathway ultimately converge on the regulation of the oncogene Yorkie pathway activity.

The Hippo pathway is conserved across species.

Hippo pathway is dysregulated in human cancer (e.g. loss of tumour suppressor gene neurofibromin 2 (NF2) is causal to schwannomas, and the YAP/TAZ oncoproteins are overexpressed in many human cancers [lung, breast, prostate and liver]).

Hippo pathway regulates stem cell renewal, regeneration and differentiation in a tissue‐ and context‐specific manner.
Alternative Polities
Authors: McIntosh Roderick J.
Published: May 2015

The prehistoric landscape has exploded with examples, just recently recognized, of alternative polities—heterogeneous communities of interaction, of variable territorial and demographic extent, in which the constituent individuals participate in unifying networks of economic or political obligations or share commonalities of beliefs. Archaeologists are no longer constrained to look for the emergence of complex society in a framework of sequential, evolutionary stages the essential elements of which were defined ethnographically (neo‐evolutionism). We can now begin to appreciate the enormous variability in the courses taken, and in the circumstances leading to more and more people living together and interacting in ever more complex ways.
Biology and Culture
Authors: Hobson Robert Peter
Published: May 2015

How are we to think of the developmental relations between individual and social dimensions of human psychology? On the one hand, an individual's mental development depends on social engagement and socially constructed symbolic systems and institutions. On the other hand, the very existence of a social system depends on the biologically provided constitution of the individuals who make up its members. I shall consider these matters at the interface between the behavioral and social sciences through the perspective of developmental psychopathology, and, in particular, the study of autism.
Computer Technology and Children's Mental Health
Authors: Kendall Philip C. , Carper Matthew M. , Khanna Muniya S. , Sue Harris M.
Published: May 2015

Computer technology has sparked rapid change for children's mental health, altering how treatments can be delivered (e.g., stand‐alone, computer‐assisted). Research has found that computerized approaches produce comparable outcomes as treatments provided face‐to‐face. We define terms related to computer‐assisted treatment and, with a focus on anxiety in youth, we consider the outcomes of computer‐based and computer‐assisted interventions (programs for youth, programs for training therapists, and programs for parents). We conclude with consideration of advances in technology and benefits for service providers, consumers, and researchers, and a discussion of key issues.
Cultural Conflict
Authors: Mullins Ian
Published: May 2015

This essay traces the emergence of the concept of cultural conflict as it is commonly used today in the social sciences. I describe the history of social scientific approaches to cultural conflict as they developed from the post‐World War II period through the 1980s; emphasizing how changes in the ways scholars conceptualize culture correspond to changes in how conflict is investigated. I argue that a pendulum‐like swing has occurred between, what I refer to as, inequality‐based approaches and value‐based approaches to the study of conflict. Researchers deploying inequality‐based approaches tend to focus on how inherent antagonisms within political, economic, and religious institutions, to name a few, lead people into contentious relations with others. In these accounts, culture is viewed as a by‐product of a group's position within a particular institution, and as such, is considered to reflect members' collective interests (or institutionally produced needs). Value‐based approaches, on the other hand, are characterized by the researcher's attention to fundamental differences in what people
believe
, and how these beliefs lead to contentious relations between various groups, nations, or even civilizations. In these approaches, culture is seen as enduring sets of schemas, or value systems, that direct action. This essay then turns to the debate over particular value‐based approaches to cultural conflict that emerged in the 1990s and presents emerging alternatives to these approaches. I conclude by presenting work that represent the current state of scholarship on cultural conflict and discuss how increased cross‐disciplinary collaborations contribute to our ability to advance social science research and develop new understandings of how culture relates to conflict.
Disorders of Consciousness
Authors: Monti Martin M.
Published: May 2015

Disorders of consciousness are a spectrum of neurological disorders, encompassing coma, the vegetative state, and the minimally conscious state, in which patients acquire or develop an impairment of the two cardinal elements of consciousness–wakefulness and awareness. One of the main sources of complexity in this context is how to recognize and tell apart patients who retain some level of awareness from patients who do not. Indeed, in the absence of any direct means of assessing one's level of awareness, we are forced to indirectly infer a patient's state on the basis of their ability to perform behaviors that, appearing clearly voluntary, imply the presence of consciousness. In this contribution, we explore recent evidence showing how brain imaging can be harnessed to address the problem of consciousness in patients surviving severe brain injury. First, we focus on recent experiments demonstrating how neuroimaging can be used to detect the presence of voluntary “brain behavior” in otherwise non responsive patients, and to allow a rudimentary form of non muscle‐dependent communication strategy based solely on voluntary brain activity. Second, we discuss recent findings concerning network activity at different levels of awareness, and the relationship between thalamo cortical circuits and consciousness.
Gender Segregation in Higher Education
Authors: Hendley Alexandra , Charles Maria
Published: May 2015

During the second half of the twentieth century, systems of higher education expanded and democratized around the world. Women's participation increased so dramatically that their numbers now surpass men's in many industrialized countries. But gender equalization has not occurred uniformly. Sex segregation of majors and degree programs is a striking feature of modern educational systems and a key reason for the ongoing social and economic inequality of women and men. While significant gender inequality is found within educational systems worldwide, recent evidence shows marked differences among countries and country groups in their degree and pattern of sex segregation. This essay reviews foundational research in this field, identifies emergent trends and cutting‐edge lines of inquiry, and poses questions for future research on men's and women's distribution across educational institutions and fields of study. Much research on sex segregation in higher education has focused on cross‐national differences and historical trends. A major question concerns the persistence of extreme gender differentiation even in the most economically and socially modern contexts. Research findings to date reveal a complex interplay between cultural beliefs, structural forms, and individual cognition in generating and maintaining sex segregation in the modern world. In order to advance research in this field, we suggest that future studies focus on: (i) how patterns of sex segregation differ by race, ethnicity, class, and national origin; (ii) how curricular preferences are formed; (iii) how characteristics of educational systems influence patterns of sex segregation; and (iv) how fields of study (and occupations) become defined as either masculine or feminine.
Media and the Development of Identity
Authors: Manago Adriana M.
Published: May 2015

The shift from “media” to “social media” in the digital age has implications for processes of identity formation during adolescence and the transition to adulthood. First, the Internet provides young people with opportunities to co‐construct entertainment and social environments tailored to their own needs and interests. Second, adolescents' presentations of self take place on the same screens and in the same activity settings in which they access commercial media programming. These changes reflect increasing cultural emphasis on personal agency and self‐expression which brings to bear new tasks for identity development during the transition to adulthood that involve both opportunities and challenges for creating a coherent, stable, and meaningful sense of self. In terms of opportunities, social media give youth enhanced control over presentations of self in social interactions and increased access to social information and large networks of others to solicit feedback and reify self‐concepts. However, social media also bring new demands to negotiate heightened pressure to perform a socially desirable self in a commercial environment that bestows value on attractive images and popularity. Suggestions for future research include methods that bridge youths' offline and online social contexts and that balance enthusiasm for the massive quantities of data that can be aggregated via data mining technologies with qualitative work that examines the lived experiences of adolescents' everyday social practices.
Network Research Experiments
Authors: Linton Allen L. , Sinclair Betsy
Published: May 2015

This essay attempts to lay the foundation of modern social networks research with a jolt toward innovative ways to create data or finding ways to access newly available data to address meaningful political questions. We focus on outlining potential new resources for data, discuss the emergent theoretical arguments involving political networks, and present some current empirical estimates for the magnitude of the effects of political networks. With the rise of social media and new technology, ordinary citizens socialize online with old friends from elementary school, siblings across the country, and local neighbors. While these relationships have long been part of the social fabric of ordinary life, the ability to observe these exchanges directly and on a daily basis is new, for both researchers and citizens. Records of our social interactions have the potential to transform our academic understanding of the relationship between communication among family, friends, and coworkers and how we become informed about politics and act politically. Whether the relationship occurs on or offline, the social element of the relationship can be incredibly vital in understanding the way individuals react and interact with their political environments. Processing and understanding these interactions, however, can be difficult without knowing where to look for new information, what patterns to look for, and how to interpret data in the context of other findings on the effects of social and political networks. We conclude by considering the new and exciting directions this research may take in the future.
Niche Construction: Implications for Human Sciences
Authors: Laland Kevin N. , O'Brien Michael J.
Published: May 2015

Niche construction is the process whereby organisms, through their activities, interactions, and choices, modify their own and each other's niches. By using and transforming natural selection, niche construction generates feedback in evolution at various levels. Niche‐constructing species play important ecological roles by creating and modifying habitats and resources used by other species, thereby affecting the flow of matter and energy through ecosystems. This process is often referred to as
ecosystem engineering
. This engineering can have significant downstream consequences for succeeding generations—often referred to as an
ecological inheritance
. One key emphasis of niche‐construction theory is on the evolutionary role played by acquired characters in transforming selective environments. This is particularly relevant to human evolution, where our species has engaged in extensive environmental modification through cultural practices. Humans can construct developmental environments that feed back to affect how individuals learn and develop and the diseases to which they are exposed. Here we provide an introduction to niche construction and illustrate some of its more important implications for the human sciences.
Organizations and the Production of Systemic Risk
Authors: Perrow Charles
Published: May 2015

Organizations and Systemic Risks

Systemic risks are those threatening multiple parts of an organizations, or other organizations and systems in its environment. Interdependencies abound in our highly technological world and can be unexpected, and in the case of global warming—largely an organizational failure—dire. An 80% reduction in the assets of oil, gas, and coal companies is required to reduce warming but is not anticipated. So‐called “natural” disasters are shown to be enhanced or even caused by organizations. The organizational roots of the 2008 economic meltdown, Fukushima, and chemical plant accidents are examined with regard to regulations, profits, and system interdependencies. With economic systems favoring short‐run concerns, and shareholder rather than stakeholder values, there is little evidence of emerging long‐run visions that could protect future generations.
Political Psychology and International Conflict
Authors: McDermott Rose
Published: May 2015

Political psychology takes an individual level of analysis approach to the study of international conflict. This study has traditionally investigated the psychological foundations of decision making among elite leaders in the area of war and peace. Psychological models that have been applied to the examination of this area include those taken from cognitive psychology and evolutionary models. Such approaches include the application of prospect theory to cases of decision making under conditions of risk. Similar work in this area further explores the nature of psychological biases in decision making, particularly in the area of risk assessment. More recent work has explored the biological underpinnings of aggression, and their contribution to the emergence of violent behavior. Past work has tended to neglect the role of emotion, but more recent work has investigated these forces more fully. Future work that seeks to incorporate both biological and environmental forces in precipitating violence appears challenging but worthwhile. In addition, experimental methods drawn from psychology have been applied to the study of international conflict. The use of field experiments to explore the psychological forces that both motivate and sustain conflict appears promising.
Primate Allomaternal Care
Authors: Tecot Stacey , Baden Andrea L.
Published: May 2015

Allomaternal care (AMC) (i.e., infant care that is provided by group members other than an infant's mother) is a rare, although phylogenetically widespread, mammalian infant care strategy. In primates, however, AMC occurs at unusually high frequencies, particularly among several haplorhine (monkey and ape) taxa. In fact, AMC is present in every major primate radiation and has been described in 74% of 154 species for which data are available. Its widespread presence in the Order Primates suggests that there may have been strong selective pressure for AMC early in primate evolution, but it is currently unknown why these behaviors are so common in primates. Research focused on captive callitrichids (tamarins and marmosets) has contributed greatly to our understanding of the potential causes and consequences of highly derived forms of AMC (i.e., cooperative breeding). Recent efforts have shifted focus to understand the selective pressures leading to the expansion and diversification of AMC throughout the Primate Order, thus expanding research to investigate the causes and consequences of less derived forms of AMC. Here we review the broad‐scale patterns observed in primates and outline innovative and exciting avenues of research moving forward.
Sustainability
Authors: Tainter Joseph A. , Taylor Temis G. , Brain Roslynn G. , Lobo José
Published: May 2015

Research needs in sustainability encompass a range of topics spanning much of social and behavioral science. Sustainability requires understanding human cognition, capacity to reason and make decisions, capacity for long‐term planning, understanding trade‐offs, risk perceptions, communication techniques, innovation, the consequences of improvements in efficiency, energy and other resources, complexity in problem solving, and other matters. We discuss research accomplishments and needs in the four most important areas of sustainability: (i) risk perceptions; (ii) influencing behavior; (iii) resources and economics; and (iv) problem solving and complexity.
The Impact of Bilingualism on Cognition
Authors: Bialystok Ellen
Published: May 2015

In spite of early warnings of dire consequences of bilingualism for children's cognitive development, research in the past 50 years has revealed that bilingualism is in fact a positive developmental experience. These benefits were more recently shown to extend across the life span. New research is incorporating neuroimaging to determine the brain bases of these effects and exploring the possibility that the beneficial effects of bilingualism can compensate for degeneration of other cognitive functions that are associated with dementia, thereby postponing symptom onset.
Additive Manufacturing and Characterization of René 80 Superalloy Processed Through Scanning Laser Epitaxy for Turbine Engine Hot‐Section Component Repair
Authors: Acharya Ranadip , Bansal Rohan , Gambone Justin J. , Kaplan Max A. , Fuchs Gerhard E. , Rudawski N. G. , Das Suman
Published: May 2015

This article demonstrates single‐pass fabrication of thick, crack‐free deposits of René 80, a high gamma‐prime “non‐weldable” superalloy, atop like‐chemistry substrates through scanning laser epitaxy (SLE), a metal powder bed‐based laser additive manufacturing (AM) technique. Microstructural investigations and processing zone identification are presented. Optical microscopy and scanning electron microscopy reveal the segregated dendritic microstructure with the presence of finer carbides and primary γ′ particles. Transmission electron microscopy reveals a bimodal distribution of finer secondary γ′ particles in the deposit region. Microindentation hardness measurements show an increase in the hardness value by 25% in the deposit region compared to the cast substrate due to microstructural refinement. In addition to the achievement of metallurgical continuity across the interface and improved hardness in the deposit, the crack‐free deposits obtained here for René 80 represent one of the few successes reported for a non‐weldable alloy of its kind. The results presented here illustrate the significant potential of SLE for the AM‐based repair of existing and AM‐based construction of entirely new gas turbine hot‐section components utilizing powders of high γ′ nickel‐based superalloys that have long been known to have high tendency for cracking under the processing conditions associated with traditional welding, joining, and cladding approaches.
Layer‐by‐Layer Conjugated Extension of a Semiconducting Polymer for High‐Performance Organic Field‐Effect Transistor
Authors: Jang Mi , Kim Se Hyun , Lee Han‐Koo , Kim Yun‐Hi , Yang Hoichang
Published: May 2015

A donor–acceptor (D–A) semiconducting copolymer, PDPP‐TVT‐29, comprising a diketopyrrolopyrrole (DPP) derivative with long, linear, space‐separated alkyl side‐chains and thiophene vinylene thiophene (TVT) for organic field‐effect transistors (OFETs) can form highly π‐conjugated structures with an edge‐on molecular orientation in an as‐spun film. In particular, the layer‐like conjugated film morphologies can be developed via short‐term thermal annealing above 150 °C for 10 min. The strong intermolecular interaction, originating from the fused DPP and D–A interaction, leads to the spontaneous self‐assembly of polymer chains within close proximity (with π‐overlap distance of 3.55 Å) and forms unexpectedly long‐range π‐conjugation, which is favorable for both intra‐ and intermolecular charge transport. Unlike intergranular nanorods in the as‐spun film, well‐conjugated layers in the 200 °C‐annealed film can yield more efficient charge‐transport pathways. The granular morphology of the as‐spun PDPP‐TVT‐29 film produces a field‐effect mobility (μ
FET) of 1.39 cm2 V−1 s−1 in an OFET based on a polymer‐treated SiO2 dielectric, while the 27‐Å‐step layered morphology in the 200 °C‐annealed films shows high μ
FET values of up to 3.7 cm2 V−1 s−1.
Highly Conductive, Bendable, Embedded Ag Nanoparticle Wire Arrays Via Convective Self‐Assembly: Hybridization into Ag Nanowire Transparent Conductors
Authors: Choi Dong Yun , Oh Yong Suk , Han Donggeon , Yoo Seunghyup , Sung Hyung Jin , Kim Sang Soo
Published: May 2015

The optoelectrical properties of Ag nanowire (NW) networks are improved by incorporating the NWs into highly conductive ordered arrays of Ag nanoparticle wires (NPWs) fabricated via surfactant‐assisted convective self‐assembly. The NPW–NW hybrid conductor displays a transmittance (T) of 90% at 550 nm and a sheet resistance (R
s) of 5.7 Ω sq−1, which is superior to the corresponding properties of the NW network showing a R
s of 14.1 Ω sq−1 at a similar T. By the modified wettability of a donor substrate and the capillarity of water, the sintered NPW–NW hybrid conductors are perfectly transferred onto an UV‐curable photopolymer film, and the embedded hybrid conductors exhibit excellent electromechanical properties. The R
s and T of the NPW arrays can be predicted by using a simple model developed to calculate the width and height of the hexagonal close‐packed particles formed during the convective self‐assembly. The numerical analysis reveals that the maximum Haacke figure of merit of the NW networks is increased considerably from 0.0260 to 0.0407 Ω−1 by integration with the NPW array. The highly conductive NPW arrays generated using a simple, low‐cost, and nonlithographic process can be applied to enhancing the performances of other transparent conductors, such as carbon nanotubes, metal oxides, and graphenes.
Rapid Thiol‐Yne‐Mediated Fabrication and Dual Postfunctionalization of Micro‐Resolved 3D Mesostructures
Authors: Quick Alexander S. , de los Santos Pereira Andres , Bruns Michael , Bückmann Tiemo , Rodriguez‐Emmenegger Cesar , Wegener Martin , Barner‐Kowollik Christopher
Published: May 2015

3D mesostructures with a height of up to 1 mm and micrometer feature size are fabricated employing a writing speed of 1 cm s−1 via direct laser writing utilizing a novel functional photoresist based on the radical coupling reaction of thiols and alkynes. The refractive index of the resist—consisting of a tetrafunctional thiol, a tetrafunctional alkyne and a photoinitiator—is tailored to be compatible with the employed high numerical aperture (NA) objective lens, thus enabling a Dip‐in configuration. Mesostructures are characterized by scanning electron microscopy, optical photography, and nondestructive 3D time‐of‐flight secondary ion mass spectrometry. Woodpile photonic crystals are fabricated as benchmark structures in order to investigate the axial resolution. Verification of the chemical fabrication mechanism is achieved via transmission Fourier transform infrared (FTIR) spectroscopy of fabricated cuboid structures by monitoring the decrease of corresponding thiol and alkyne absorption peaks. Postmodification reactions, namely the thiol‐Michael addition and the copper‐catalyzed azide alkyne cycloaddition, are conducted employing residual thiols and alkynes throughout the cuboid structures. Successful dual and orthogonal modification throughout the structure and on the surface is achieved and verified utilizing transmission FTIR spectroscopy and time‐of‐flight secondary ion mass spectrometry.
Soft Core/Shell Packages for Stretchable Electronics
Authors: Lee Chi Hwan , Ma Yinji , Jang Kyung‐In , Banks Anthony , Pan Taisong , Feng Xue , Kim Jae Soon , Kang Daeshik , Raj Milan S. , McGrane Bryan L. , Morey Briana , Wang Xianyan , Ghaffari Roozbeh , Huang Yonggang , Rogers John A.
Published: May 2015

This paper presents materials and core/shell architectures that provide optimized mechanical properties in packages for stretchable electronic systems. Detailed experimental and theoretical studies quantitatively connect the geometries and elastic properties of the constituent materials to the overall mechanical responses of the integrated systems, with a focus on interfacial stresses, effective modulus, and maximum extent of elongation. Specific results include core/shell designs that lead to peak values of the shear and normal stresses on the skin that remain less than 10 kPa even for applied strains of up to 20%, thereby inducing minimal somatosensory perception of the device on the human skin. Additional, strain‐limiting mesh structures embedded in the shell improve mechanical robustness by protecting the active components from strains that would otherwise exceed the fracture point. Demonstrations in precommercial stretchable electronic systems illustrate the utility of these concepts.
Remarkable Turn‐On and Color‐Tuned Piezochromic Luminescence: Mechanically Switching Intramolecular Charge Transfer in Molecular Crystals
Authors: Qi Qingkai , Qian Jingyu , Tan Xiao , Zhang Jibo , Wang Lijuan , Xu Bin , Zou Bo , Tian Wenjing
Published: May 2015

The molecular crystals of acridonyl‐tetraphenylethene (AD‐TPE) exhibit an intriguing turn‐on and color‐tuned luminescence in response to mechanical grinding and hydrostatic compression. On the basis of in‐depth experimental and computational studies, it is hypothesized that the origin of the piezochromic behavior from the D‐phase to the B‐phase is the change of the intramolecular geometrical conformation, especially for the torsion angle between the TPE and AD moiety. The different molecular conformation in the two distinctive solid phases causes the substantial switching of the intra­molecular charge transfer (ICT) process, which can be directly correlated with the subsequent fluorescence from locally excited (LE) state and ICT state in both phases. The AD‐TPE molecular system presents a very rare example of high‐contrast reversible fluorescence tuning driven by a switching of the excited state in the solid state under the mechanical stimuli, and thus provides a novel mechanism of the piezochromic behavior.
Design of High‐Mobility Diketopyrrolopyrrole‐Based π‐Conjugated Copolymers for Organic Thin‐Film Transistors
Authors: Yi Zhengran , Wang Shuai , Liu Yunqi
Published: May 2015

Since the report of the first diketopyrrolopyrrole (DPP)‐based polymer semiconductor, such polymers have received considerable attention as a promising candidate for high‐performance polymer semiconductors in organic thin‐film transistors (OTFTs). This Progress Report summarizes the advances in the molecular design of high‐mobility DPP‐based polymers reported in the last few years, especially focusing on the molecular design of these polymers in respect of tuning the backbone and side chains, and discussing the influences of structural modification of the backbone and side chains on the properties and device performance of corresponding DPP‐based polymers. This provides insights for the development of new and high‐mobility polymer semiconductors.
Achieving Highly Efficient Photoelectrochemical Water Oxidation with a TiCl4 Treated 3D Antimony‐Doped SnO2 Macropore/Branched α‐Fe2O3 Nanorod Heterojunction Photoanode
Authors: Xu Yang‐Fan , Rao Hua‐Shang , Chen Bai‐Xue , Lin Ying , Chen Hong‐Yan , Kuang Dai‐Bin , Su Cheng‐Yong
Published: May 2015

Utilizing photoelectrochemical (PEC) cells to directly collecting solar energy into chemical fuels (e.g., H2 via water splitting) is a promising way to tackle the energy challenge. α‐Fe2O3 has emerged as a desirable photoanode material in a PEC cell due to its wide spectrum absorption range, chemical stability, and earth abundant component. However, the short excited state lifetime, poor minority charge carrier mobility, and long light penetration depth hamper its application. Recently, the elegantly designed hierarchical macroporous composite nanomaterial has emerged as a strong candidate for photoelectrical applications. Here, a novel 3D antimony‐doped SnO2 (ATO) macroporous structure is demonstrated as a transparent conducting scaffold to load 1D hematite nanorod to form a composite material for efficient PEC water splitting. An enormous enhancement in PEC performance is found in the 3D electrode compared to the controlled planar one, due to the outstanding light harvesting and charge transport. A facile and simple TiCl4 treatment further introduces the Ti doping into the hematite while simultaneously forming a passivation layer to eliminate adverse reactions. The results indicate that the structural design and nanoengineering are an effective strategy to boost the PEC performance in order to bring more potential devices into practical use.
Stabilization of Insoluble Discharge Products by Facile Aniline Modification for High Performance Li‐S Batteries
Authors: Kim Jae Ho , Kim Taehoon , Jeong Yo Chan , Lee Kunsil , Park Kyung Tae , Yang Seung Jae , Park Chong Rae
Published: May 2015

Continuous efforts have been made to attain high performance Li‐S batteries by preventing loss of soluble polysulfides, whereas issues related to insoluble discharge products, Li2S2 and Li2S, have been underestimated. A facile and mild method, diazotization, that enables uniform functionalization on the surface of ordered mesoporous carbon (CMK‐3) with aniline functional groups while not deteriorating the original CMK‐3 microstructure is demonstrated. The aniline groups possess favorable interactions with insoluble discharge products. Thus, they homogeneously distribute the insoluble discharge products during cycling. The proposed materials exhibit outstanding electrochemical properties with regard to stability (920 mAh g−1 at 0.2 C after 100 cycles) and rate capability (814 mAh g−1 at 1 C) when evaluated as a cathode material for Li‐S batteries.
Cumulative role of rare and common putative functional genetic variants at NPAS3 in schizophrenia susceptibility
Authors: González‐Peñas Javier , Arrojo Manuel , Paz Eduardo , Brenlla Julio , Páramo Mario , Costas Javier
Published: May 2015

Schizophrenia may be considered a human‐specific disorder arisen as a maladaptive by‐product of human‐specific brain evolution. Therefore, genetic variants involved in susceptibility to schizophrenia may be identified among those genes related to acquisition of human‐specific traits. NPAS3, a transcription factor involved in central nervous system development and neurogenesis, seems to be implicated in the evolution of human brain, as it is the human gene with most human‐specific accelerated elements (HAEs), i.e., .mammalian conserved regulatory sequences with accelerated evolution in the lineage leading to humans after human‐chimpanzee split. We hypothesize that any nucleotide variant at the NPAS3 HAEs may lead to altered susceptibility to schizophrenia. Twenty‐one variants at these HAEs detected by the 1000 genomes Project, as well as five additional variants taken from psychiatric genome‐wide association studies, were genotyped in 538 schizophrenic patients and 539 controls from Galicia. Analyses at the haplotype level or based on the cumulative role of the variants assuming different susceptibility models did not find any significant association in spite of enough power under several plausible scenarios regarding direction of effect and the specific role of rare and common variants. These results suggest that, contrary to our hypothesis, the special evolution of the NPAS3 HAEs in Homo relaxed the strong constraint on sequence that characterized these regions during mammalian evolution, allowing some sequence changes without any effect on schizophrenia risk. © 2015 Wiley Periodicals, Inc.
Aggregation‐Induced Photon Upconversion through Control of the Triplet Energy Landscapes of the Solution and Solid States
Authors: Duan Pengfei , Yanai Nobuhiro , Kurashige Yuki , Kimizuka Nobuo
Published: May 2015

Aggregation‐induced photon upconversion (iPUC) based on control of the triplet energy landscape is demonstrated for the first time. When a triplet state of a cyano‐substituted 1,4‐distyrylbenzene derivative is sensitized in solution, no upconverted emission based on triplet–triplet annihilation (TTA) was observed. In stark contrast, crystalline solids obtained by drying the solution revealed clear upconverted emission. Theoretical studies unveiled an underlying switching mechanism: the excited triplets in solution immediately decay back to the ground state through conformational twisting around a CC bond and photoisomerization, whereas this deactivation path is effectively inhibited in the solid state. The finding of iPUC phenomena highlights the importance of controlling excited energy landscapes in condensed molecular systems.
Ein PEGyliertes, lichtspaltbares Auxiliar für die sequenzielle enzymatische Glykosylierung und native chemische Ligation von Peptiden
Authors: Bello Claudia , Wang Shuo , Meng Lu , Moremen Kelley W. , Becker Christian F. W.
Published: May 2015

Unser Verständnis der spezifischen biologischen Funktion von Proteinglykosylierungsmustern würde sehr von zusätzlichen Methoden profitieren, die einen direkten Zugang zu homogenen Glykoproteinen ermöglichen. Hier wird die Entwicklung und Anwendung einer effizienten Methode für die Synthese komplexer, homogen glykosylierter Peptide, basierend auf einem multifunktionellen, lichtspaltbaren Auxiliar, beschrieben. Der Einbau eines PEG‐Polymers ins Auxiliar ermöglicht die sequenzielle enzymatische Glykosylierung und einfache Isolierung in sehr guten Ausbeuten. Die modifizierten Peptide können mit Peptidthioestern, die durch direkte Hydrazinolyse und Oxidation der zugehörigen glykosylierten Peptidharze erhalten werden, direkt nativ chemisch ligiert werden. Die ligierten Glykopeptide lassen sich durch UV‐Bestrahlung unter milden Bedingungen entschützen. Die Methode wird für die Synthese von Varianten des Tumormarkers MUC1 mit einem oder mehreren Tn‐, T‐ oder Sialyl‐T‐Antigenen verwendet.