bluuebunny/crossref_metadata_2025 huggingface dataset:
Centrosome Cycle
Authors: Marteil Gaëlle , Bettencourt‐Dias Mónica
Published: November 2017

Centrosomes are the major microtubule‐organising centres of animal cells. These small organelles participate in diverse cellular functions such as cell division, polarity, migration and signalling and are often deregulated in diseases such as cancer and microcephaly. Over the past two decades, technical advances enabled a deeper knowledge of the molecular composition and mechanisms of centrosome assembly and function. These progresses also allowed a better understanding on how the centrosome cycle is coordinated with the cell cycle to ensure that centrosomes duplicate once and only once. These discoveries together with the emergence of
in vivo
models of centrosome deregulation have consolidated the 100‐year‐old pioneer view of Theodor Boveri about the role of centrosome amplification (more than two centrosomes per cell) in abnormal cell division, tumorigenesis and developmental diseases such as microcephaly.

Key Concepts

Centrosomes are made of two orthogonally oriented centrioles surrounded by the pericentriolar material.

The ninefold symmetry of centrioles is mostly defined by the cartwheel, that is, the initial structure formed during centriole assembly made of SAS‐6 oligomers. This protein is highly evolutionarily conserved, being present in the last common ancestor of eukaryotes.

Centrosomes are not only the main microtubule organisers of animal cells but also actin‐organising centres.

Centriole duplication occurs only once per cell cycle and is triggered by a core module composed of PLK4‐SAS‐6‐STIL proteins. Regulation of the level of these components is critical to control centriole number in cells.

Centrosome duplication and cell cycle progression are tightly coupled and share common regulators.

Centrosome loss and amplification can lead to abnormal mitotic spindle formation, chromosome instability and cell cycle arrest.

Centrosome amplification leads to tumorigenesis and microcephaly.
Dominant Traits and Diseases
Authors: Jorde Lynn B
Published: November 2017

The principles of genetic dominance and recessiveness established by Gregor Mendel in his experiments with garden peas equally apply to human genetic diseases. For dominant diseases, which affect approximately 1/70 individuals, the inheritance of one copy of the disease‐causing allele is sufficient to produce disease. Most commonly, an affected heterozygote mates with an unaffected homozygote, resulting in a recurrence risk of 50% for the offspring. In some cases, a parent transmits a de novo mutation to an offspring; the risk to subsequent offspring of this parent is not elevated above that of the general population. Incomplete penetrance, in which a carrier of the disease‐causing allele does not develop the disease phenotype, is a common feature of autosomal dominant diseases. Variable expression, in which genetic and/or nongenetic factors modify the severity of the phenotype, is another common feature of autosomal dominant diseases.

Key Concepts

Recurrence risks for autosomal dominant diseases are 50% for a carrier × unaffected mating and 75% for a carrier × carrier mating.

For autosomal dominant diseases resulting from a new mutation transmitted by a parent, the recurrence risk for siblings of the affected individual is the same as that of the general population, whereas the recurrence risk for the individual's offspring is typically 50%.

Incomplete penetrance, which is seen in familial retinoblastoma, familial breast/ovarian cancer and many other dominant diseases, occurs when a carrier of the disease‐causing allele does not manifest the disease phenotype.

Many dominant diseases are characterised by age‐dependent penetrance, in which the probability of manifesting the disease phenotype increases with age.

Several factors can influence the severity of expression of a dominant disease, including the location and type of disease‐causing allele, the effects of modifier loci and the effects of the nongenetic environment.

Many autosomal dominant diseases involve locus heterogeneity, in which mutations at different disease‐causing loci can cause the same disease phenotype.

Pleiotropy, as seen in Marfan syndrome and osteogenesis imperfecta, is a frequent feature of genetic diseases and describes the fact that a single disease‐causing allele can affect multiple aspects of the patient's phenotype.
Pathogenetic Mechanisms in
A
lagille Syndrome
Authors: Hakimjavadi Roya , Olayinka Abidemi , Luca Mariana Di , Guha Shaunta , Walls Dermot , Redmond Eileen M , Cahill Paul A
Published: November 2017

Alagille syndrome (ALGS), also known as arteriohepatic dysplasia, is a rare autosomal dominant genetic disorder caused by mutations in the Notch signalling pathway. The Notch pathway controls mammalian cell fate during embryonic development but also dictates several cell phenotypes in adult cells. The most common mutations affect the Notch ligand, JAG1 (ALGS type 1) or the NOTCH2 receptor (ALGS type 2) genes, and have a significant impact on multiple organ systems. ALGS primarily affects the liver, heart, skeleton, eye, face and kidney. Using animal models, loss‐of‐function mutations in JAG1 reveal that JAG‐1 haploinsufficiency promotes disease phenotypes in most target tissues. Expression and conditional gene knockout studies of JAG1 have further correlated with tissue‐specific disease phenotypes and have provided significant insight into disease pathogenesis. The majority of JAG1 mutations present in ALGS patients are null alleles, suggesting that JAG1 haploinsufficiency is the primary cause of this disorder in humans.

Key Concepts

Alagille syndrome is an autosomal dominant disorder with variable expression.

Alagille syndrome and associated abnormalities include those of the liver, heart, eye, skeleton and kidneys and characteristic facial features. Mild‐to‐moderate mental retardation may also be present.

Alagille syndrome is most often caused by a mutation, or defect, in the
JAGGED1
(JAG1) or
NOTCH2
receptor gene.

Alagille syndrome has been mapped to the 20p12‐jagged‐1 locus, JAG1, which encodes a ligand critical to the
NOTCH
gene‐signalling cascade that is important in foetal development.

Notch signalling has been found to regulate formation of three‐dimensional intrahepatic biliary architecture in murine models and vascular cell phenotype during development.

A minority (6–7%) of patients have complete deletion of JAG1, and approximately 15–50% of mutations are spontaneous.

Deaths in people with Alagille syndrome are most often caused by liver failure, heart problems and blood vessel abnormalities.

Therapy is focused on the consequences of liver disease, as well as the surgical and medical treatment of congenital heart defects.
Subject Clitics and (Complex) Inversion
Authors: Pollock Jean‐Yves , Poletto Cecilia
Published: November 2017

In this work, we will first examine the intricate properties of the bafflingly rich syntax of French interrogatives, which display a complex set of restrictions on different types of subjects. We will start off by taking advantage of a set of tests going back to early generative work by R. Kayne showing that the DP subject position in complex inversion (CI) constructions is not to be analyzed as a left dislocation. We will show further that the only analysis that takes care of two apparently contradicting properties of CI – it is a main‐clause phenomenon, although what looks like its displaced subject DP also has properties of IP‐internal subjects in affirmative sentences– must involve remnant IP‐movement to a highly split left periphery also targeted by various (remnant) IP subconstituents. This allows for accounts not only of the specific properties of CI, but also of a large set of French interrogatives, among them subject clitic inversion and stylistic inversion. In addition, we shall show that what has been up to now considered a purely phonological entity, namely the so‐calledepenthetic “‐t‐”showing up in both subject clitic inversion and CI, has syntactic import. Finally, our analysis will attempt to capture the main properties of a similar though crucially distinct construction in Valdôtain. In short, ours will also be a microcomparative analysis building on the morphological clues that we believe guide the speaker in his or her analysis of syntactic structures.
Quantified Expressions and Quantitative Clitics
Authors: Cardinaletti Anna , Giusti Giuliana
Published: November 2017

This chapter provides a discussion of the major issues raised by the syntax of quantified expressions and quantitative clitics, starting from the very early stages of the Extended Standard Theory up to recent developments in generative grammar. It addresses the issue of the categorial status of the quantity items and quantified phrases, some of which occur with quantitative clitics, showing how the literature has accounted for such possible and impossible co‐occurrence facts. It then offers an overview of a number of PPs that induce “partitive” interpretation in a broad sense, showing how they relate to quantified and referential expressions, and whether they can co‐occur with quantitative clitics. Finally, it addresses the issue of the categorial status of quantitative clitics, what portion of the quantitative expression they resume, how they are different to other DP‐ and PP‐clitics, and how they relate to the null portions of nominal expressions known as nominal ellipsis.
TheSpray/LoadAlternation
Authors: Beavers John
Published: November 2017

In the Englishspray/loaddiathesis alternation (also sometimes known as the “locative alternation”) causative verbs with meanings in which some locatum is moved into or onto some location allow either non‐causer argument to be realized as the object, with the other argument realized as an oblique (e.g.,John sprayed the paint on the wallvs.John sprayed the wall with the paint). For several decades this alternation has been a significant, cross‐linguistically attested phenomenon that has served as a major testing ground for theories of the nature of argument realization and the relationship of syntax to lexical semantics. This chapter offers a comprehensive empirical overview of the phenomenon, focusing on the variable realization of the non‐subject arguments of verbs that show the alternation, the corresponding semantics whereby whichever argument of the verb is the object receives a “holistic” interpretation, and the connection to related alternations in English and other languages. Various analyses are discussed that have used this alternation to argue for particular views of the syntax of argument realization and the syntax–lexical semantics link, including purely syntactic alternations that take the derivation to be transformational in nature, and approaches that have argued for particular views of the nature of lexical meanings and the mapping to syntax, including traditional thematic role, event structural, lexical aspectual, and lexical entailment‐based approaches. Theories that have argued that the relevant aspects of lexical meaning are encoded syntactically rather than lexically are also discussed, as are theories that have looked at the more fine‐grained microvariation in which verbs show the alternation and why. The ultimate conclusion is that lexical variation in which verbs show the alternation and their properties when they do is one of the largest unanswered questions regarding this phenomenon and will require more detailed work on how lexical idiosyncrasy figures into argument realization.
Clitic Doubling
Authors: Anagnostopoulou Elena
Published: November 2017

In this chapter I investigate the syntax of clitic doubling constructions focusing on the question of variation within and across languages. In the course of the discussion, two different patterns of clitic doubling emerge, with different factors causing variation across languages in each case. In the first case – direct object (DO) clitic doubling – languages vary with respect to whether they permit it: (i) only with pronouns or also with DPs; (ii) with humans, animates, or also with inanimates; and (iii) with specific indefinites, partitives, or only definites. DO clitic doubling of DPs is generally optional (doubling of pronouns is in many cases obligatory). In the second case – indirect object (IO) doubling – languages vary with respect to whether (i) doubling is obligatory in the double object construction or (ii) doubling is optional in the double object construction. The research on clitic doubling is presented from a historical perspective focusing on the nature of the Clitic Doubling Parameter and its potential implications for the syntax of cliticization.
The Accusative Plus Infinitive Construction in English
Authors: Runner Jeffrey T. , Moulton Keir
Published: November 2017

This chapter focuses on the English accusative plus infinitive (A + I) construction, which in the generative literature is known as the raising to object construction and the exceptional case‐marking construction. The A + I construction is an examplepar excellenceof a syntax–semantics mismatch and so has played a central role in our understanding of grammatical relations, semantic relations, and the ways in which syntax coordinates both of these. This chapter discusses what we call the two major “brands” of analysis: raising to object and exceptional case‐marking. We provide an overview of the evidence that has accumulated both for and against each of the brands over the decades. Further, we discuss more recent analyses that countenance the possibility that both brands may coexist. We review more recent research that investigates cases where A + I is interestingly blocked, a topic with renewed interest in the last decade. Finally, we discuss semantic issues associated with A + I and facts that challenge the assumption that A + I and related finite clauses are synonymous.
Resumption
Authors: McCloskey James
Published: November 2017

In many languages and in a range of circumstances, a pronominal element may appear in a position in which one might have expected to see a gap bound by a clause‐peripheral element (in relative clauses, constituent questions, cleft constructions, and the like). Such elements (often, but not exclusively, personal pronouns) are known asresumptive elements. Since they are formally pronouns but serve many of the core semantic functions associated with movement constructions, the study of resumptive elements raises fundamental questions about the nature of movement, about the nature of anaphoric elements and relationships, and about the nature of the interaction between these two spheres. These questions have been the focus of a great deal of work, beginning especially in the middle 1970s; this chapter surveys that work – the questions that have been asked, the phenomena that have been discovered, and the current state of thinking about the relevant questions. Consideration of the theoretical questions is organized around the asking of three questions: (i) what are the properties of resumptive elements; (ii) in what ways do they share, or fail to share, properties of movement constructions (island phenomena, reconstruction effects); and (iii) in what ways do they share, or fail to share, properties of anaphoric elements and interactions? In recent years especially, the study of resumption has been enriched by a great deal of experimental work, aimed not only at establishing some basic properties of resumptive elements, but also at better understanding the mechanisms involved in their production and comprehension. The chapter ends with a consideration of that work and its implications. Here, the central question that emerges quickly is that of how theories of competence and theories of performance interact with one another.
Arts‐Based Methods
Authors: Faulkner Sandra L. , Trotter Stormy P.
Published: November 2017

Arts‐based research (ABR) is a diverse qualitative research method that relies on an aesthetic process of imagination and artistic expression through various art mediums as a way to understand and examine a research problem, subject, or text. Arts‐based research is the use of art for/in/as research practice, pedagogy, and method and includes varied art forms such as dance, film, music, drama, and the visual and literary arts. Arts‐based research allows for multiple ways of understanding and experiencing and presenting social research.
Axial Coding
Authors: Scott Cliff , Medaugh Melissa
Published: November 2017

Axial coding is the second phase of the constant comparative analysis technique for analyzing qualitative data inductively for purposes of theory development. Compared to the more descriptive open coding that constitutes the first phase of constant comparative analysis, axial coding involves a greater degree of theoretical inference and analytic induction. Axial coding requires researchers to continually modify and reshape their emerging conceptual framework as more data are examined. It results in a coding framework from which to synthesize and organize data into more coherent, hierarchically structured categories and subcategories.
Effect Size
Authors: Grizzard Matthew , Shaw Allison Z.
Published: November 2017

Effect sizes are statistical indicators of the strength of relationship between variables. Effect sizes can summarize standardized differences between means for two groups, the extent to which variables predict values of other variables, or the amount of variance one or more variables explain in another variable. Effect sizes allow for the comparison of effect between studies that vary in operational definitions, sample sizes, and methods. Thus, effect sizes are preferable to
p
values observed in null hypothesis significance testing for estimating the strength of effect, yet effect sizes still require a deeper conceptual understanding for accurate interpretation.
Measurement Error
Authors: Weber Patrick
Published: November 2017

Measurement error is the difference between the true value and the observed score of a concept in measurement. Measurement error can be random or systematic and it affects the quality of measurements and the reliability of statistical analyses.
Measurement Invariance (Time, Samples, Contexts)
Authors: Kühne Rinaldo
Published: November 2017

Communication researchers regularly conduct comparisons between populations and comparisons over time. Typically, the objects of a comparison are relationships between constructs, such as media effects, or the means of constructs, such as average media use. Importantly, comparisons of relationships and means are based on the assumption that the involved constructs are measured the same way across populations or over time. If this assumption holds, the measurements are invariant across populations or over time. However, most comparative studies do not explicitly test for measurement invariance. This is problematic because results of comparisons can be biased when invariance assumptions are violated. Measurement invariance must thus be tested in all comparative communication studies. This entry discusses the different forms of measurement invariance for continuous data and how they can be tested in multigroup confirmatory factor analyses. Furthermore, partial measurement invariance, and invariance tests for ordinal data and for formative measurement models are discussed.
Membership Categorization Analysis
Authors: Milburn Trudy , Hansen Alan
Published: November 2017

Membership categorization analysis (MCA) has its origins with the work of American sociologist Harvey Sacks in the 1960s. MCA has developed alongside conversation analysis (CA). Like CA, MCA is grounded in understanding social order as the ongoing achievement of practical actors who
themselves
are trying to understand how their world is organized. MCA research relies upon an analytic apparatus to learn more about members' procedures for positing and accepting or denying categories for both persons and actions. Contexts such as family, police interrogations, broadcast news, examination of ethnicity and gender as well as the impact of technology provide a researcher with omnirelevant categories, those culturally and socially known to the researcher. Within these contexts, conversational participants use devices including turn‐taking sequences, to establish the ways membership categories are built. Researchers use additional tools including: the consistency and economy rules, hearer's/viewer's maxims, and category‐tied predicates, to explicate relevant member categories.
Meta‐Analysis
Authors: Allen Mike , Dilbeck Keith
Published: November 2017

This entry provides a definition of meta‐analysis as well as examines the justifications for the process. The entry includes an examination of the three steps involved in a meta‐analysis: (i) literature search, (ii) statistical conversion to a common metric and correction for artifact and error, and (iii) calculation of an average effect as well as examination of extent and sources of variability. A discussion of the distinction between random and fixed models is offered to discuss one of the important elements distinguishing assumptions between the two broad techniques.
Multilevel Modeling
Authors: Zhang Jinguang , Reid Scott A.
Published: November 2017

Multilevel modeling (MLM) is a statistical technique that models nonindependence due to the clustering of individual observations under higher‐level units. This nonindependence is inherent in many communicative phenomena and is sometimes intentionally introduced to research design. To account for nonindependence due to clustering, MLM separates the effects on an outcome variable of predictors measured at different levels and provides unbiased parameter estimation and tests. In this entry, we introduce the basic concepts and modeling considerations of MLM by fitting a two‐level model. We discuss the distinction between fixed and random effects, ways of estimating nonindependence, choice of different mean‐centering methods, the computation of different effect‐size measures, and methods of probing ML interaction effects. We conclude by briefly discussing the test of ML indirect effects and the use of MLM to analyze data of group‐interaction studies and complex repeated‐measures designs.
Participatory/Action Research/
CBPR
Authors: Huffman Tim
Published: November 2017

Community‐based, participatory, and action research methods seek to contribute to scholarly discourse and social action. Often called community‐based participatory research (CBPR) or participatory action research (PAR), these methods use research and activist practices to produce knowledge and at the same time engage broad community stakeholders in order to produce meaningful social change. CBPR and PAR are driven by three key ideas: participation, action, and community. These methods involve creating partnerships, building coalitions, developing relationships, planning and replanning, and coordinating action.
Textual Analysis
Authors: Smith Jason A.
Published: November 2017

Textual analysis is a method of study utilized by researchers to examine messages as they appear through a variety of mediums. The data generated for textual analysis can come from documents, films, newspapers, paintings, web pages, and so forth. These forms of data serve as the “texts” under study and are used to assess the meanings, values, and messages being sent through them.
Vignette Research
Authors: Engelmann Ines
Published: November 2017

Vignette research uses short descriptions of hypothetical situations, objects, or persons (vignettes) that are presented to respondents in order to receive judgments or to simulate decisions concerning these scenarios. Vignette research is applied in various disciplines. In some disciplines it is referred to as conjoint analysis; in other disciplines as factorial survey. This method enables simultaneously manipulating various factors and factor levels in text or visual vignettes. The vignette method has been a promising approach in quantitative research, because it combines advantages of traditional surveys and classical experimental designs without integrating the weaknesses of these two approaches.
Visual Presentation of Data
Authors: Schmuck Desirée
Published: November 2017

This entry gives an overview of the most commonly used types of visual data presentation in the social sciences: bar chart, dot chart, pie chart, box‐and‐whisker plot, line graph, histogram, and scatterplot. Several factors that influence the choice for the appropriate type of graph are discussed.
Visual Research Methods
Authors: Lobinger Katharina
Published: November 2017

Visual communication research is a vivid research field that has recently developed a broad and multifaceted methodological repertoire. In this regard, two different kinds of “visual methods” can be differentiated: Quantitative and qualitative visual methods that are used to examine visual media content, on the one hand, and visual methods using visuals for research purposes and in research settings, on the other. While the former are mainly relevant for the field of visual communication research, the latter represent approaches whose analytical potential can be fruitfully exploited by media and communication research in general.
Rivastigmine decreases brain damage in HIV patients with mild cognitive deficits
Authors: Perrotta Gaetano , Bonnier Guillaume , Meskaldji Djalel‐Eddine , Romascano David , Aydarkhanov Ruslan , Daducci Alessandro , Simioni Samanta , Cavassini Matthias , Metral Melanie , Lazeyras François , Meuli Reto , Krueger Gunnar , Du Pasquier Renaud A. , Granziera Cristina
Published: November 2017

Rivastigmine has been shown to improve cognition in HIV+ patients with minor neurocognitive disorders; however, the mechanisms underlying such beneficial effect are currently unknown. To assess whether rivastigmine therapy is associated with decreased brain inflammation and damage, we performed T1/T2* relaxometry and magnetization transfer imaging in 17 aviremic HIV+ patients with minor neurocognitive disorders enrolled on a crossed over randomized rivastigmine trial. Rivastigmine therapy was associated with changes in MRI metrics indicating a decrease in brain water content (i.e., edema reabsorption) and/or reduced demyelination/axonal damage. Furthermore, MRI changes correlated with cognitive improvement on rivastigmine therapy.
Association of Femoroacetabular Impingement and Delayed Gadolinium‐Enhanced Magnetic Resonance Imaging of Cartilage: A Population‐Based Study
Authors: Guo Yimeng , Zhang Honglin , Qian Hong , Wilson David R. , Wong Hubert , Barber Morgan , Forster Bruce B. , Esdaile John , Cibere Jolanda ,   and The Investigations of Mobility, Physical Activity, and Knowledge Translation in Hip Pain Team
Published: November 2017

Objective

To assess the association of femoroacetabular impingement (FAI) and delayed gadolinium‐enhanced magnetic resonance imaging of cartilage (dGEMRIC) T1 relaxation values (RVs), and to evaluate whether subtypes of FAI (cam, pincer, and mixed) are associated with region‐specific dGEMRIC T1 RVs.

Methods

A population‐based sample of white subjects with and without hip pain, ages 20–49 years, was selected through random‐digit dialing. A sample of 128 subjects underwent hip‐joint 3T dGEMRIC scans. Radiographic cam FAI was defined as an alpha angle >55°, while pincer FAI was defined by a lateral center edge angle >40°, or a positive cross‐over sign. Mixed impingement was defined by the presence of both cam and pincer impingement. Overall and region‐specific T1 RVs were compared between all FAI subtypes, using weighted linear regression analysis to account for sampling design of the study.

Results

Subjects had a mean age of 38 years and 51% were female. We did not find an association of FAI with overall hip T1 RV (mean difference −15.5 [95% confidence interval −77.23, 47.14]). Significant associations of cartilage degeneration in anterior superior and central superior regions were found in subjects with mixed FAI compared to other FAI subtypes and non‐FAI subjects.

Conclusion

Subjects with mixed FAI had reduced T1 RVs compared to other FAI subtypes. No substantial cartilage degeneration was found in pure cam or pincer FAI compared to no‐FAI hips. These results indicate that the presence of cam or pincer impingements alone does not suggest the beginning of cartilage degeneration. In contrast, the presence of both FAI subtypes is a risk factor for early cartilage damage.
Application of FMRAC to fault‐tolerant cooperative control of a wind farm with decreased power generation due to blade erosion/debris buildup
Authors: Badihi Hamed , Zhang Youmin , Pillay Pragasen , Rakheja Subhash
Published: November 2017

Wind energy has shown a remarkable potential for fulfilling the increasing world's energy demand in a clean and sustainable way. The wind energy industry has installed increasingly sophisticated and larger wind turbines particularly in offshore regions to capture such energy as efficiently and cost effectively as possible. The rapid growth in size and capacity of wind turbines together with harsh climate conditions and limited accessibility in offshore regions all result in higher failure rates and increased maintenance requirements and costs. Such difficulties motivate the use of advanced fault detection and diagnosis and fault‐tolerant control schemes in wind farms to improve their reliability and availability. Given the importance of this issue, this paper uses a fuzzy model reference adaptive control approach in a cooperative framework that is oriented to the design and development of a novel fault‐tolerant cooperative control scheme in a wind farm. This scheme handles decreased power generation faults in a wind farm caused by turbine blade erosion and debris buildup on the blades over time. The effectiveness and performance of the proposed scheme is demonstrated by a series of simulations on an advanced large offshore wind farm benchmark model in the presence of wind turbulence, measurement noise, load variations, and realistic fault scenarios.
Unusual Twisting Phonons and Breathing Modes in Tube‐Terminated Phosphorene Nanoribbons and Their Effects on Thermal Conductivity
Authors: Liu Xiangjun , Gao Junfeng , Zhang Gang , Zhang Yong‐Wei
Published: November 2017

By studying tube‐terminated phosphorene nanoribbons (PNRs), it is found that unusual phonon and thermal properties can emerge from topologically new edges. The lattice dynamics calculations show that in tube‐terminated PNRs, the breaking of rotation symmetry suppresses the degeneracy of phonon modes, causing the emergence of twisting mode. An anomalous change of an out‐of‐plane acoustic mode to breathing modes with nonzero energy at the center of Brillouin zone occurs when the phosphorene sheet is converted into a tube‐terminated PNR. These unusual twisting and breathing modes provide a larger phase space for scattering phonons, thus explaining the low thermal conductivity of tube‐terminated PNRs revealed by molecular dynamics calculations. Due to the change in the stress field distribution caused by the tube edge, a nearly strain‐independent thermal conductivity in tube‐terminated PNRs is observed, which is in contrast to the apparent enhancement of thermal conductivity in pristine and dimer‐terminated PNRs under tensile strain. The work reveals intriguing phononic and thermal behaviors of tube‐terminated 2D materials.
High Seebeck Coefficient in Mixtures of Conjugated Polymers
Authors: Zuo Guangzheng , Liu Xianjie , Fahlman Mats , Kemerink Martijn
Published: November 2017

A universal method to obtain record‐high electronic Seebeck coefficients is demonstrated while preserving reasonable conductivities in doped blends of organic semiconductors through rational design of the density of states (DOSs). A polymer semiconductor with a shallow highest occupied molecular orbital (HOMO) level‐poly(3‐hexylthiophene) (P3HT) is mixed with materials with a deeper HOMO (PTB7, TQ1) to form binary blends of the type P3HTx:B1‐x (0 ≤ x ≤ 1) that is p‐type doped by F4TCNQ. For B = PTB7, a Seebeck coefficient S = 1100 µV K−1 with conductivity σ = 0.3 S m−1 at x = 0.10 is achieved, while for B = TQ1, S = 2000 µV K−1 and σ = 0.03 S m−1 at x = 0.05 is found. Kinetic Monte Carlo simulations with parameters based on experiments show good agreement with the experimental results, confirming the intended mechanism. The simulations are used to derive a design rule for parameter tuning. These results can become relevant for low‐power, low‐cost applications like (providing power to) autonomous sensors, in which a high Seebeck coefficient translates directly to a proportionally reduced number of legs in the thermogenerator, and hence in reduced fabrication cost and complexity.
Liquid‐Tin‐Assisted Molten Salt Electrodeposition of Photoresponsive n‐Type Silicon Films
Authors: Peng Junjun , Yin Huayi , Zhao Ji , Yang Xiao , Bard Allen J. , Sadoway Donald R.
Published: November 2017

Production of silicon film directly by electrodeposition from molten salt would have utility in the manufacturing of photovoltaic and optoelectronic devices owing to the simplicity of the process and the attendant low capital and operating costs. Here, dense and uniform polycrystalline silicon films (thickness up to 60 µm) are electrodeposited on graphite sheet substrates at 650 °C from molten KCl–KF‐1 mol% K2SiF6 salt containing 0.020–0.035 wt% tin. The growth of such high‐quality tin‐doped silicon films is attributable to the mediation effect of tin in the molten salt electrolyte. A four‐step mechanism is proposed for the generation of the films: nucleation, island formation, island aggregation, and film formation. The electrodeposited tin‐doped silicon film exhibits n‐type semiconductor behavior. In liquid junction photoelectrochemical measurement, this material generates a photocurrent about 38–44% that of a commercial n‐type Si wafer.
Investigation of the High Electron Affinity Molecular Dopant F6‐TCNNQ for Hole‐Transport Materials
Authors: Zhang Fengyu , Kahn Antoine
Published: November 2017

2,2′‐(perfluoronaphthalene‐2,6‐diylidene)dimalononitrile (F6‐TCNNQ) is investigated as a molecular p‐type dopant in two hole‐transport materials, 2,2′,7,7′‐tetrakis(N,N‐diphenylamino)‐9,9‐spirobifluorene (Spiro‐TAD) and tris(4‐carbazoyl‐9‐ylphenyl)amine (TCTA). The electron affinity of F6‐TCNNQ is determined to be 5.60 eV, one of the strongest organic molecular oxidizing agents used to date in organic electronics. p‐Doping is found to be effective in Spiro‐TAD (ionization energy = 5.46 eV) but not in TCTA (ionization energy = 5.85 eV). Optical absorption measurements demonstrate that charge transfer is the predominant doping mechanism in Spiro‐TAD:F6‐TCNNQ. The host–dopant interaction also leads to a significant alteration of the host film morphology. Finally, transport measurements done on Spiro‐TAD:F6‐TCNNQ as a function of dopant concentration and temperature, and using a highly doped contact layer to ensure negligible hole injection barrier, lead to an accurate measurement of the film conductivity and hole‐hopping activation energy.
Photoswitchable Nanomaterials Based on Hierarchically Organized Siloxane Oligomers
Authors: Zha R. Helen , Vantomme Ghislaine , Berrocal José Augusto , Gosens Ronald , de Waal Bas , Meskers Stefan , Meijer E. W.
Published: November 2017

Materials with highly ordered molecular arrangements have the capacity to display unique properties derived from their nanoscale structure. Here, the synthesis and characterization of azobenzene (AZO)‐functionalized siloxane oligomers of discrete length that form photoswitchable supramolecular materials are described. Specifically, synergy between phase segregation and azobenzene crystallization leads to the self‐assembly of an exfoliated 2D crystal that becomes isotropic upon photoisomerization with UV light. Consequently, the material undergoes a rapid athermal solid‐to‐liquid transition which can be reversed using blue light due to the unexpectedly fast 2D crystallization that is facilitated by phase segregation. In contrast, enabling telechelic supramolecular polymerization through hydrogen bonding inhibits azobenzene crystallization, and nanostructured pastes with well‐ordered morphologies are obtained based on phase segregation alone, thus demonstrating block copolymer‐like behavior. Therefore, by tailoring the balance of self‐assembly forces in the azobenzene‐functionalized siloxane oligomers, fast and reversible phase‐changing materials can be engineered with various mechanical properties for applications in photolithography or switchable adhesion to lubricant properties.
Highly Condensed Boron Cage Cluster Anions in 2D Carrier and Its Enhanced Antitumor Efficiency for Boron Neutron Capture Therapy
Authors: Choi Goeun , Jeon Ie‐Rang , Piao Huiyan , Choy Jin‐Ho
Published: November 2017

An attempt is made to apply layered double hydroxide (LDH) as a boron delivery carrier for boron neutron capture therapy (BNCT), which needs a sufficient amount of boron in tumor cells for its successful administration. To meet this requirement, a nanohybrid (BSH‐LDH), mercaptoundecahydro‐closo‐dodecaborate (BSH) anionic molecules in LDH, is developed as a boron delivery system. The cellular boron content upon permeation of BSH‐LDH nanoparticles (42.4 µg 10B 10−6 cells) in U87 glioblastoma cell line is found to be ≈2000 times larger than the minimum boron requirement (≈0.02 µg 10B 10−6 cells) for BNCT and also orders of magnitude higher than the previous results (0.2–1.5 µg 10B 10−6 cells) by those applied with other targeting strategies, and eventually results in excellent neutron capture efficiency even under such low dose (30 µg 10B mL−1) and weak irradiation (1 × 1012 n cm−2 corresponding to 20 min) condition. According to the biodistribution studies in xenograft mice model, the tumor‐to‐blood ratio of BSH in the BSH‐LDH‐treated‐group is found to be 4.4‐fold higher than that in the intact BSH treated one in 2 h after drug treatment. The present BNCT combined with boron delivery system provides a promising integrative therapeutic platform for cancer treatment.
Probing the Dynamic Nature of Self‐Assembling Cyclic Peptide–Polymer Nanotubes in Solution and in Mammalian Cells
Authors: Rho Julia Y. , Brendel Johannes C. , MacFarlane Liam R. , Mansfield Edward D. H. , Peltier Raoul , Rogers Sarah , Hartlieb Matthias , Perrier Sébastien
Published: November 2017

Self‐assembling cyclic peptide–polymer nanotubes have emerged as a fascinating supramolecular system, well suited for a diverse range of biomedical applications. Due to their well‐defined diameter, tunable peptide anatomy, and ability to disassemble in situ, they have been investigated as promising materials for numerous applications including biosensors, antimicrobials, and drug delivery. Despite this continuous effort, the underlying mechanisms of assembly and disassembly are still not fully understood. In particular, the exchange of units between individual assembled nanotubes has been overlooked so far, despite its knowledge being essential for understanding their behavior in different environments. To investigate the dynamic nature of these systems, cyclic peptide–polymer nanotubes are synthesized, conjugated with complementary dyes, which undergo a Förster resonance energy transfer (FRET) in close proximity. Model conjugates enable to demonstrate not only that their self‐assembly is highly dynamic and not kinetically trapped, but also that the self‐assembly of the conjugates is strongly influenced by both solvent and concentration. Additionally, the versatility of the FRET system allows studying the dynamic exchange of these systems in mammalian cells in vitro using confocal microscopy, demonstrating the exchange of subunits between assembled nanotubes in the highly complex environment of a cell.
All‐Polymer Solar Cells Based on a Conjugated Polymer Containing Siloxane‐Functionalized Side Chains with Efficiency over 10%
Authors: Fan Baobing , Ying Lei , Zhu Peng , Pan Feilong , Liu Feng , Chen Junwu , Huang Fei , Cao Yong
Published: November 2017

A novel wide‐bandgap conjugated copolymer based on an imide‐functionalized benzotriazole building block containing a siloxane‐terminated side‐chain is developed. This copolymer is successfully used to fabricate highly efficient all‐polymer solar cells (all‐PSCs) processed at room temperature with the green‐solvent 2‐methyl‐tetrahydrofuran. When paired with a naphthalene diimide‐based polymer electron‐acceptor, the all‐PSC exhibits a maximum power conversion efficiency (PCE) of 10.1%, which is the highest value so far reported for an all‐PSC. Of particular interest is that the PCE remains 9.4% after thermal annealing at 80 °C for 24 h. The resulting high efficiency is attributed to a combination of high and balanced bulky charge carrier mobility, favorable face‐on orientation, and high crystallinity. These observations indicate that the resulting copolymer can be a promising candidate toward high‐performance all‐PSCs for practical applications.
High Integration of Microfluidic Circuits Based on Hydrogel Valves for MEMS Control
Authors: Haefner Sebastian , Koerbitz Rene , Frank Philipp , Elstner Martin , Richter Andreas
Published: November 2017

Integrated circuits (ICs) are the key to powerful microarchitectures for lab on a chip applications. High actuator densities can enable the control of several thousand of reactions executed in parallel on a single chip. Hydrogels can act as self‐contained sensor–actuator materials, which control fluid flows depending on local physicochemical conditions. A concept is described for the preparation of highly integrated circuits based on stimuli‐sensitive hydrogels. The concept allows to adjust the working point and fulfill the free swelling condition of the hydrogels, which is favorable for the dynamic performance of the actuators. The components are polymerized on a glass substrate, which is also used to seal the microfluidic system. Therefore, the hydrogel integration is conducted within the standard microfluidic system set‐up procedure. For a first demonstration integration densities of microfluidic valves of up to 172 gels cm−2 in a single microfluidic circuit are realized. Furthermore, control of microfluidic valves fabricated by the demonstrated high integration procedure via an optoelectrothermic transducer setup is shown.
A Triphenylamine–Naphthalenediimide–Fullerene Triad: Synthesis, Photoinduced Charge Separation and Solution‐Processable Bulk Heterojunction Solar Cells
Authors: Srivani Doli , Gupta Akhil , Bhosale Sidhanath V. , Ohkubo Kei , Bhosale Rajesh S. , Fukuzumi Shunichi , Bilic Ante , Jones Lathe A. , Bhosale Sheshanath V.
Published: November 2017

A new naphthalenediimide (NDI) derivative linked to triphenylamine (TPA) and fullerene (TPA–NDI–C60 triad; S3) was designed, synthesized and characterized. Femtosecond laser transient absorption spectral measurements revealed that fast electron transfer from TPA to the singlet‐excited state of NDI occurred to form a charge‐separated state (TPA.+–NDI.−–C60) with a rate constant of approximately 1012 s−1, followed by the charge‐shift reaction from NDI.− to C60 to produce the charge‐separated state (TPA.+–NDI–C60.−) that decayed by back electron transfer with a rate constant of 4.4×109 s−1 (with a corresponding lifetime of 230 ps). Organic bulk heterojunction solar cells were fabricated using the triad S3 as an n‐type semiconductor along with the conventional donor polymer poly(3‐hexylthiophene). The power conversion efficiency reached 3.03 % before annealing and 4.85 % after annealing in the optimized devices. To rationalize the performance of these organic photovoltaic devices, atomic force microscopy was used to study the morphology of poly(3‐hexylthiophene):S3 blend surfaces, which were found to be well interlaced and free from projections, lumps, or indentations.
Stay Positive: How and Why Joy and Serenity Emerge at the Bargaining Table
Authors: Creo Robert A.
Published: November 2017

Emotions are present in all mediation‐session participants, including the mediator. The dynamics of the overwhelming majority of litigated cases and interpersonal claims involve negative emotions.
Room‐Temperature‐Phosphorescence‐Based Dissolved Oxygen Detection by Core‐Shell Polymer Nanoparticles Containing Metal‐Free Organic Phosphors
Authors: Yu Youngchang , Kwon Min Sang , Jung Jaehun , Zeng Yingying , Kim Mounggon , Chung Kyeongwoon , Gierschner Johannes , Youk Ji Ho , Borisov Sergey M. , Kim Jinsang
Published: November 2017

The highly sensitive optical detection of oxygen including dissolved oxygen (DO) is of great interest in various applications. We devised a novel room‐temperature‐phosphorescence (RTP)‐based oxygen detection platform by constructing core–shell nanoparticles with water‐soluble polymethyloxazoline shells and oxygen‐permeable polystyrene cores crosslinked with metal‐free purely organic phosphors. The resulting nanoparticles show a very high sensitivity for DO with a limit of detection (LOD) of 60 nm and can be readily used for oxygen quantification in aqueous environments as well as the gaseous phase.
Asymmetric Traceless Petasis Borono‐Mannich Reactions of Enals: Reductive Transposition of Allylic Diazenes
Authors: Jiang Yao , Thomson Regan J. , Schaus Scott E.
Published: November 2017

The traceless Petasis borono‐Mannich reaction of enals, sulfonylhydrazines, and allylboronates, catalyzed by chiral biphenols, results in an asymmetric reductive transposition of the in situ generated allylic diazene. Acyclic 1,4‐diene products bearing either alkyl‐ or aryl‐substituted benzylic stereocenters are afforded in excellent yields and enantiomeric ratios of up to 99:1. The use of crotylboronates in the reaction results in concomitant formation of two stereocenters in either a 1,4‐syn or anti relationship from the corresponding E‐ or Z‐crotylboronate used in the reaction. The use of β‐monosubstituted enals in the asymmetric traceless Petasis borono‐Mannich reaction of crotylboronates installs tertiary methyl‐bearing stereocenters in good yields and high enantioselectivities.
Toblerols: Cyclopropanol‐Containing Polyketide Modulators of Antibiosis in Methylobacteria
Authors: Ueoka Reiko , Bortfeld‐Miller Miriam , Morinaka Brandon I. , Vorholt Julia A. , Piel Jörn
Published: November 2017

Trans‐AT polyketide synthases (PKSs) are a family of biosynthetically versatile modular type I PKSs that generate bioactive polyketides of impressive structural diversity. In this study, we detected, in the genome of several bacteria a cryptic, architecturally unusual trans‐AT PKS gene cluster which eluded automated PKS prediction. Genomic mining of one of these strains, the model methylotroph Methylobacterium extorquens AM1, revealed unique epoxide‐ and cyclopropanol‐containing polyketides named toblerols. Relative and absolute stereochemistry were determined by NMR experiments, chemical derivatization, and the comparison of CD data between the derivatized natural product and a synthesized model compound. Biosynthetic data suggest that the cyclopropanol moiety is generated by carbon–carbon shortening of a more extended precursor. Surprisingly, a knock‐out strain impaired in polyketide production showed strong inhibitory activity against other methylobacteria in contrast to the wild‐type producer. The activity was inhibited by complementation with toblerols, thus suggesting that these compounds modulate an as‐yet unknown methylobacterial antibiotic.
Reduction of Dioxygen by Radical/B(p‐C6F4X)3 Pairs to Give Isolable Bis(borane)superoxide Compounds
Authors: Tao Xin , Daniliuc Constantin G. , Janka Oliver , Pöttgen Rainer , Knitsch Robert , Hansen Michael Ryan , Eckert Hellmut , Lübbesmeyer Maximilian , Studer Armido , Kehr Gerald , Erker Gerhard
Published: November 2017

Triplet dioxygen was reduced by TEMPO or trityl radicals in the presence of two molar equivalents of the strong B(p‐C6F4X)3 (X: F or H) boron Lewis acids under mild conditions to give the bis(borane)superoxide systems 2. The sensitive radical anion species were isolated and characterized by methods including X‐ray crystal structure analysis and EPR spectroscopy.