bluuebunny/crossref_metadata_2025 huggingface dataset:
Urban Risks and Violence
Authors: Dallorso Nicolás Santiago
Published: April 2019

Urban risk is the possibility of harm more or less likely to affect life in the city. Likewise, urban violence encompasses actions (and omissions) causing harm to things, individuals, or groups and aimed at maintaining disparities of power in the city. In order to map urban violence and risks, at least five areas of social practices in cities should be included: predatory street crimes, violence against women, racially or ethnically motivated violence, institutional violence, and environmental damage.
Urban System
Authors: van Meeteren Michiel
Published: April 2019

Urban systems research utilizes the language of systems theory to grasp the complexity of the urban and the city. This entry explains the basic principles of urban systems theory and outlines some important pitfalls. Depending on research focus and priority, urban systems have been bracketed geographically and conceptually in different ways in different time periods. In the past, defining the city as a bounded entity was uncontroversial and the difference between interurban and intraurban processes seemed self‐evident. As urbanization intensifies, urban boundaries blur, prompting us to continuously scrutinize the scales of urban systems. The usefulness of urban systems thinking is illustrated through an appreciation of the historical urban systems models of American geographer Allan Pred from the 1960s and 1970s. Pred's work is contextualized in the present by briefly comparing it in terms of continuity and change with world city analysis, an important contemporary application of urban systems analysis.
Vernacular Architecture
Authors: Tjahjono Gunawan
Published: April 2019

Vernacular architecture has held a significant place in architectural discussions for more than half a century. Although it has gained gradual appreciation in architectural theory, it is still considered a minor subject of architecture. The undeniable fact is that vernacular architecture prevails, which further underlines its endurance and the existence of widely spread buildings in urban and rural environments. Yet, the existence of vernacular architecture is severely challenged by rapid, deterministic urban development. This entry emphasizes various aspects in the discussion of vernacular architecture and the virtue of comprehending its relevance. Its endurance provides valuable lessons for architects and urban planners as well as academia.
Village in the City
Authors: Liu Yuting
Published: April 2019

A new type of urban neighborhood, namely the “urban village” or “village in the city” (
chengzhongcun
), has grown out of China's rapid urbanization which is characterized by large‐scale rural–urban migration and radial expansion of urban built‐up areas. The “village in the city” is considered as a community of interest for urbanized villagers, a migrant settlement with low rent housing, and an urban self‐organized grassroots unit, respectively related to the ambiguous property rights, an informal rental market, and the vacuum of state regulation. It is therefore viewed as an unregulated asset despite its unruliness and disorder. In this sense, “village in the city” can be seen as a transitional neighborhood, characterized by unstable land rights and a mixture of rural and urban society.
Special Economic Zones (SEZ)
Authors: Chigurupati Ramachandraiah
Published: April 2019

Economic zones in various forms have undergone significant changes over the years, from isolated enclaves administered by government agencies to wider areas; from import‐substitution policy environments to more open and trade liberalization regimes with emphasis on integration with the host economy. Zone development has accelerated fast since the 1980s in the Asia Pacific region. Special economic zones (SEZs) are characterized by concentration in a few countries, a few product areas, and a heavy reliance on female labor. The success/failure of the zones has been linked to the policy and incentive framework, location, development, and management. India's implementation of SEZ policy has been characterized by approval of a large number of SEZs and land acquisition on an unprecedented scale. The SEZs also fell short significantly in fulfilling the stated objectives in investments, exports, and employment generation. Resistance to forcible acquisition of lands, and active involvement of social movements, led to the enactment of a new law for land acquisition and rehabilitation in India in 2013.
Suburban Poverty
Authors: Kneebone Elizabeth
Published: April 2019

During the 2000s, America's suburbs became home to the nation's largest poor population. A number of factors contributed to the growth of poverty in the suburbs, from shifts in the location of affordable housing and jobs to structural and cyclical economic changes. Many suburbs lack the capacity, infrastructure, and resources to address the needs of a growing poor population. Government and philanthropic funding have often been slow to adapt to the rapidly changing geography of poverty.
Abu‐Lughod, Janet
Authors: Lin Jan
Published: April 2019

Janet Abu‐Lughod (1928–2013) was a great figure in twentieth‐century sociology with expertise in community and urban sociology, comparative/historical sociology, and the sociology of the world‐system. She brought a more global scope to American urban sociology and more attention to non‐Western arenas like the Middle East and Central Asia in the study of the emergence of modern capitalism. She published over 100 articles and 13 books including significant titles on Cairo, Rabat, the thirteenth‐century world‐system, the East Village of New York, and US global cities. She engaged in scholarship on Palestinian issues with her husband Ibrahim Abu‐Lughod, an activist scholar on Middle East affairs, and was known as a passionate teacher and mentor.
Community Studies
Authors: Christmann Gabriela B.
Published: April 2019

Community studies consists of empirically based analyses in which a regional, relatively closely circumscribed local social context is researched. The spatial units can be larger cities (mainly neighborhoods), medium‐sized cities, small towns, or villages. The subjects of investigation are social groups, institutions, and organizations from the local context, whereby typically it is being asked what relationships, social orders, thoughts, actions, or lifestyles are established within and among them, and how they are realigning. Community studies pursues the goal of analyzing macrosocial processes paradigmatically, in miniature, and among circumscribed local groups, in the context of their specific theoretical interests, and in times of social change – for example during processes of urbanization, industrialization, and modernization. In terms of methodology, this field is characterized mostly by ethnographic research designs. This does not exclude the possibility that community studies would not require extensive participatory observation. However, in each case community studies is characterized by complex multimethod approaches.
Creative City
Authors: d'Ovidio Marianna
Published: April 2019

The creative city is the iconic city of the post‐Fordist era and is often used to highlight the transition to an era where the urban economy is based on immaterial cultural production. The term has three different meanings. First, the creative city can be understood as a theoretical model that focuses on the shift from an economy based on manufacturing to an urban economy based on immaterial production. The second meaning conceives of the creative city as a model of development for post‐Fordist cities that need to revamp their economies and promote growth and competitiveness. Third and finally, the creative city is also a brand used to sell and promote the image of the city in the international arena.
Deindustrialization
Authors: Lois González Rubén C.
Published: April 2019

A generic expression used to refer to the loss of significant industrial activities in a city, deindustrialization is a classic phenomenon of European and North American cities, which had strong economic growth in the late nineteenth century and much of the twentieth, as concentrations of many major factories in the booming industrial sectors throughout this period. However, in the last few decades the cities and regions of steel, chemical, shipbuilding, and textile industries, which used to employ a large number of workers, have suffered from the consequences of factory closures and mass unemployment. High labor prices and the obsolescence of many facilities are causes of this process. It has created landscapes of abandoned industrial estates and large isolated plants, which continue through progressively empty residential neighborhoods. Deindustrialization is reflected in urban decline and in the emergence of new categories of analysis, such as the shrinking city.
Ethnoburb
Authors: Li Wei
Published: April 2019

Ethnoburbs (ethnic suburbs) are clusters of suburban ethnic residential and business districts in metropolitan areas in the United States. They are multiethnic communities in which one ethnic minority has a significant concentration without necessarily being the majority group. Ethnoburbs are dynamic communities and can grow by having a higher concentration and expand spatially, or can diminish in size and scale. They are dependent on the size and pace of the inflow of newcomers (international migrants and domestic minorities), the growth or shrinkage of ethnic economies, the welcoming or discouraging attitude and behavior of long‐term residents, and policies that facilitate or hinder ethnoburban development. Research on this phenomenon has been conducted in the major English‐speaking immigrant countries, in other European countries, and in the global cities of some developing countries.
Ghetto
Authors: Hutchison Ray
Published: April 2019

The ghetto has been an important (and contested) concept in urban studies, from its original use in describing the ethnic Jewish ghettos of the early modern era to the racial ghetto of the present day. Drawing from an extensive literature on residential segregation, recent study has focused on comparisons of social exclusion and marginality across cities, countries, and continents, with continuing debate as to whether the black ghetto is a proper reference point for other ethnic and racial groups, and for the patterns of residential segregation found outside the United States.
H
awley,
A
mos
Authors: Appold Stephen J.
Published: April 2019

Amos Henry Hawley (1910–2009) was a key figure in twentieth‐century urban studies whose most enduring contribution is the codification and extension of human ecological theory. Human ecology offers a powerful holistic view of community social structure and change, linking social relations with spatial distributions, which finds its most common application in the study of urban regions. The origins of the theory, its central core – three basic propositions building on five assumptions – and some contemporary applications are discussed.
Insurgent Citizenship
Authors: Lebuhn Henrik
Published: April 2019

The concept of insurgent citizenship emerged in the 1990s; it represents an attempt to better understand practices and discourses addressing entrenched regimes of inegalitarian citizenship. In contrast to much of the social movement literature, insurgent citizenship emphasizes the spatial dimension of citizenship movements as well as citizens' everyday practices in urban space. Hence the concept links concerns about urban planning and development to fundamental questions of social and political change. It also forms part of a broader trend to explore citizenship as a bottom‐up process of participation and contestation rather then a formalized status. Empirically, much of the work on insurgent citizenship has focused on struggles for rights and recognition in Brazilian metrolopolises, but recently scholars have also made use of the concept in exploring urban conflicts over citizenship in other countries of the Global South, as well as in the Global North.
Local Media
Authors: Möhring Wiebke
Published: April 2019

Local communication plays a key role in people's daily life. With the development of professional media, forms of local reporting emerged and evolved. Nowadays media systems in nearly all countries show – alongside national and regional media – various types of local media as well. Local media is an umbrella term for a variety of different news outlets, which cover all categories of news topics. Local media represent their area and enable people to be active citizens of their municipality as well as to identify with it and to orient themselves in their neighbourhood.
New Urban Poverty
Authors: Benassi David , Morlicchio Enrica
Published: April 2019

The urban concentration of deprived masses is the basic mechanism for the reproduction of social disadvantage: space matters indeed. Although large areas of chronic rural poverty exist, especially in the less developed countries, it is the urban environment that has mostly attracted academic as well as political attention to poverty in industrialized countries. Moreover, it was in the urban context that the concept of absolute and relative poverty had been set as a universal standard by which to estimate the extension of the phenomenon. Social and economic transformations during the past few decades have led to the reemergence of severe forms of impoverishment in practically all cities of the industrialized world, helping to maintain this focus.
New York City
Authors: Halle David
Published: April 2019

New York City's population of 8.4 million in 2015 makes this city by far the largest one in the United States, over twice as large as the second and third largest cities, Los Angeles (3.9 million in 2012) and Chicago (2.7 million in 2012). As a global city, New York typically ranks first worldwide. For example, on the five metrics of business activity, human capital, information exchange, cultural experience, and political engagement, New York scores as high as, or higher than, all its global city rivals; only London comes close to it. The next ranking global cities are Paris, Tokyo, Hong Kong, Los Angeles, Chicago, Singapore, Beijing, and Washington, DC.
Place
Authors: Paulsen Krista E.
Published: April 2019

Place refers to specific locations that have been made meaningful and useful by human beings. This entry articulates how location, locale, and sense of place are used to develop the concept of place and how disciplines such as geography, sociology, and anthropology understand and use the concept (including its distinction from
space
). Particular attention is paid to how places develop meaning through deliberate and informal means and to how individuals' status and identity inform their understandings of places. Sense of place and place distinction are covered in detail. Scholarly and practical applications of place are discussed, including the connection of place to urban power and conflict, its relevance for processes of gentrification, complications related to increased mobility and technology, and connections to consumption.
Public Sphere
Authors: Roberts John Michael
Published: April 2019

This entry maps out some of the key debates in defining the public sphere. After a brief definition of this term as comprising a space in society for people to engage in debate and discussion on a range of subjects, the entry goes on to outline some of the main theoretical perspectives on the public sphere. In particular, the entry discusses some of the early and later ideas of the leading theorist of the public sphere, Jürgen Habermas, alongside a similar school of thought known as deliberative democracy. Following this, the entry notes some problems with the deliberative model of the public sphere. Alternative theories of the public sphere are then presented that highlight the inherently conflictual nature of society. Specifically, the entry outlines some of the ideas associated with theories of counterpublics and agonistic publics, especially those related to Nancy Fraser and Chantal Mouffe.
Public/Private Space
Authors: Opazo Daniel
Published: April 2019

The radical distinction between public and private space today is arguably problematic. Both the processes of privatization of the production of space and the plurality of modes of public encounter and social engagement tend to blur the once allegedly strict boundaries between those spaces and categories. There are also different approaches to these categories within urban studies and beyond, which emphasize sociopolitical, technical, or design issues as the main focus while conceiving of the aforementioned distinction. This diversity questions the binary opposition between public and private space and poses methodological and theoretical challenges to scholars who specialize in this field.
Social Cohesion
Authors: Atkinson Rob
Published: April 2019

The notion of social cohesion has taken on increasing prominence in contemporary societies, yet it has a long history dating back to the development of modern societies in the seventeenth century and the problem of order. In recent years the concept has taken on a renewed significance as contemporary societies have experienced a range of fundamental transformations leading to high levels of long‐term unemployment, growing inequality, and fragmentation. The concept is related to, and its meaning is constituted through, a range of other concepts such as social integration, social exclusion, solidarity, and social capital. It also has social and cultural dimensions which further complicate its definition and meaning. More recently, attention has turned to the impacts of (ethnic) diversification on social cohesion as well as its implications for sustainable development – all of which means it is a contested concept.
Mediterranean City
Authors: Leontidou Lila
Published: April 2019

This entry focuses on postwar research on the Mediterranean city and on relevant changes to this topic and its treatment over time. It is structured on the basis of a periodization that starts with the sixteenth‐century shift of the Mediterranean Sea, from acting as a bridge across civilizations to being a border between them. Major dimensions of the topic include the analysis of cultures of urbanism; modernity, informal economy, and housing; Islamic cities and segregation; and transformations brought about by globalization – outlining divided and multicultural cities, urban competition, and digital societies until the 2010s, when migrations and a domino of social movements (from the Arab Spring to the Indignados movement in Spain and the movement of the piazzas in Greece) had a profound effect on cities around the Mediterranean.
Compact City
Authors: Jenks Mike
Published: April 2019

The compact city is an urban form that has claims to sustainability. Typically compact urban forms have higher densities that are contained and reduce urban sprawl, protect agricultural and amenity land, and make more efficient use of the existing urban land. There is a mixture of uses in close proximity, claimed to encourage sustainable modes of travel such as walking, cycling, and the use of public transport. Environmental, social, and economic benefits are suggested to accrue, because there would be less dependency on cars and a reduction in greenhouse gas emissions. Mixed uses and more people living and working in the same place would give rise to social and cultural vitality, with facilities within easy reach of everybody. Higher densities and close proximity of a larger population would mean that local businesses become more viable. Compact city concepts have had a widespread influence on planning policy worldwide. However, evidence for success is mixed, and there are different physical forms and cultural contexts to consider and trade‐offs to be made.
Cosmopolitan Canopy
Authors: Duck Waverly
Published: April 2019

Elijah Anderson describes the “cosmopolitan canopy” as a venue where people from diverse backgrounds set aside their own racial and ethnic identities, as well as those of others, to communicate in more civil and cosmopolitan ways in urban public spaces. According to Anderson, cosmopolitan canopies offer a respite from the tensions of urban life and an opportunity for diverse peoples to come together. Under the canopy, people engage in what Anderson calls “folk ethnography,” a form of people‐watching that allows them to informally gather evidence in support of their own viewpoints, or that transforms their commonsense understandings of social life. Key theoretical concepts developed in Anderson's
The Cosmopolitan Canopy
include
ethnos
and
cosmos
, the
white space
, the
“nigger moment
,
” provisional status
, and the
iconic ghetto
.
Home/House
Authors: Kusenbach Margarethe , Paulsen Krista E.
Published: April 2019

Home encompasses a distinct set of experiences and processes that, while typically associated with houses and dwellings, need not be. People may feel at home in places that are not houses, and within their own dwelling may lack a sense of home. The entry discusses distinct dimensions of the meaning and conception of home that are relevant for urban and community scholars, such as culture, identity, practice, emotion, and belonging. Home can be understood as a set of practices, informed by culture, that facilitates certain emotional experiences and allows individuals to express personal and collective identities in their private dwellings and beyond. Studies of home typically rely on qualitative methods and examine the making of home under challenging circumstances. Increasingly, home and belonging are investigated in relation to mobility and migration while fostering connections with other areas of study.
Pregnancy, Periods, and “The Pill”: Exploring the Reproductive Experiences of Women with Inflammatory Arthritis
Authors: Birru Talabi Mehret , Eudy Amanda M. , Jayasundara Malithi , Haroun Tayseer , Nowell W. Benjamin , Curtis Jeffrey R. , Crow‐Hercher Rachelle , White C. Whitney , Ginsberg Seth , Clowse Megan E. B.
Published: April 2019

Objective

Women with inflammatory arthritis appear to have fewer children as compared with healthy women, but few studies have assessed how patients' attitudes and decision making influence their family sizes. Little is also known about how patients experience other aspects of their reproductive lives, such as menstruation and contraception.

Methods

We partnered with ArthritisPower, a patient‐powered research network, and its associated online patient community, CreakyJoints, to create and disseminate a survey among female members aged 18‐50 years with inflammatory arthritis.

Results

Women in the final sample (n = 267) were 40 years old on average; most had rheumatoid arthritis (79%) and were predominantly white and college educated. Many women chose to limit childbearing because of their arthritis (58%); they feared that their arthritis was heritable, their diseases and medications could directly harm a fetus, they would be incapable of physically caring for a child, and arthritis could cause premature death, preventing them from raising their children. Infertility affected 40% of the sample. Half of women experienced subjective arthritis flares around the time of menstruation. Oral contraceptive pills (OCPs) did not worsen disease activity for most women and even prevented menstrual‐associated arthritis flares for a subset of women.

Conclusion

Our findings suggest that infertility, but also potentially outsized fear and anxiety related to their diagnoses, may affect the family sizes of women with inflammatory arthritis. The observation that menstruation worsens disease activity for some women requires additional study, and OCP use should be explored as a possible treatment for menstrual‐associated arthritis. Clinicians may wish to consider how they communicate patients' individual pregnancy‐associated risks, reassure patients when appropriate, and help to guide and support patients to make well‐informed reproductive decisions.
Advances in Microfluidics‐Based Technologies for Single Cell Culture
Authors: García Alonso Daniel , Yu Mengchao , Qu Haijun , Ma Liang , Shen Feng
Published: April 2019

Single cell culture has been considered one of the fundamental tools for single cell studies. Complex biological systems evolve from single cells, and the cells within biological systems are intrinsically heterogeneous. Therefore, culturing and understanding the behaviors of single cells are of great interest for both biological research and clinical studies. In recent years, advances in microfluidics‐based technologies have demonstrated unprecedented capabilities for single cell studies, and they have made high‐throughput single cell cultures possible. Microfluidic systems enable precise control of the microenvironment for single cell culture and monitoring of the behavior of single cells in real time. In addition, microfluidic devices can consist of upstream cell sorting and cell isolation, and they can also be seamlessly integrated with various downstream analysis methods. Therefore, microfluidic technologies can obtain data about the performance at the single‐cell level, providing information that cannot be achieved by studying the ensemble behavior of cell colonies. In this review, the recent developments in droplet‐based microfluidics, microwell‐based microfluidics, trap‐based microfluidics and SlipChip‐based microfluidics for the study of single cell culture is focused on. Perspectives on future improvement regarding single cell culture and its related research opportunities are also provided.
Sequence‐Optimized Peptide Nanofibers as Growth Stimulators for Regeneration of Peripheral Neurons
Authors: Schilling Corinna , Mack Thomas , Lickfett Selene , Sieste Stefanie , Ruggeri Francesco S. , Sneideris Tomas , Dutta Arghya , Bereau Tristan , Naraghi Ramin , Sinske Daniela , Knowles Tuomas P. J. , Synatschke Christopher V. , Weil Tanja , Knöll Bernd
Published: April 2019

There is an urgent need for biomaterials that support tissue healing, particularly neuronal regeneration. In a medium throughput screen novel self‐assembling peptide (SAP) sequences that form fibrils and stimulated nerve fiber growth of peripheral nervous system (PNS)‐derived neurons are identified. Based on the peptide sequences and fibril morphologies and by applying rational data‐mining, important structural parameters stimulating neuronal activity are elucidated. Three SAPs (SAP1e, SAP2e, and SAP5c) enhance adhesion and growth of PNS neurons. These SAPs form 2D and 3D matrices that serve as bioactive scaffolds stimulating cell adhesion and growth. The newly discovered SAPs also support the growth of CNS neurons and glia cells. Subsequently, the potential of SAPs to enhance PNS regeneration in vivo is analyzed. For this, the facial nerve driving whisker movement in mice is injured. Notably, SAPs persist for up to 3 weeks in the injury site indicating highly adhesive properties and stability. After SAP administration, more motor neurons incorporating markers for successive regeneration are observed. Recovery of whisker movement is elevated in SAP‐injected mice. In summary, short peptides that form fibrils are identified and the adhesion, growth, and regeneration of neurons have been efficiently enhanced without the necessity to attach hormones or growth factors.
A Versatile Biocompatible Antibiotic Delivery System Based on Self‐Assembling Peptides with Antimicrobial and Regenerative Potential
Authors: Koch Franziska , Ekat Katharina , Kilian David , Hettich Timm , Germershaus Oliver , Lang Herrmann , Peters Kirsten , Kreikemeyer Bernd
Published: April 2019

Periodontitis is a chronic inflammatory and tissue‐destructive disease. Since the polymicrobiome in the oral cavity makes it difficult to treat, novel therapeutic strategies are required. Hydrogels based on self‐assembling peptides (SAP) can be suitable candidates for periodontal therapy due to their injectability, biocompatibility, cargo‐loading capacity, and tunable physicochemical and mechanical properties. In this study, two SAP hydrogels (P11‐4 and P11‐28/29) are examined for their intrinsic antimicrobial activity, regenerative potential, and antibiotic delivery capacity. A significant antibacterial effect of P11‐28/29 hydrogels on the periodontal pathogen Porphyromonas gingivalis and a less pronounced effect for P11‐4 hydrogels is demonstrated. The metabolic activity rates of human dental follicle stem cells (DFSCs), which reflect cell viability and may thus indicate the regenerative capacity, are similar on tissue culture polystyrene (TCPS) and on P11‐4 hydrogels after 14 days of culture. Noticeably, both SAP hydrogels strengthen the osteogenic differentiation of DFSCs compared with TCPS. The incorporation of tetracycline, ciprofloxacin, and doxycycline does not affect fibril formation of either SAP hydrogel and results in favorable release kinetics up to 120 h. In summary, this study reveals that P11‐SAP hydrogels combine many favorable properties required to make them applicable as prospective novel treatment strategy for periodontal therapy.
Role of Lone‐Pairs in Driving Ferroelectricity of Perovskite Oxides: An Orbital Selective External Potential Study
Authors: Shen Yang , Cai Jia , Ding Hang‐Chen , Shen Xin‐Wei , Fang Yue‐Wen , Tong Wen‐Yi , Wan Xian‐Gang , Zhao Qingbiao , Duan Chun‐Gang
Published: April 2019

The orbital selective external potential (OSEP) method, recently developed by the authors, allows the energy level of a specific atomic orbital to be shifted, thus allowing for the identification of the role of this orbital in the chemical and physical properties of the system. Using OSEP, the origins of ferroelectricity in two classic ferroelectric perovskites, BaTiO3 and PbTiO3, are systematically revisited. The fact that the hybridization between the Ti 3d state and the O 2p state is essential for the formation of ferroelectricity in both BaTiO3 and PbTiO3 is reproduced, which validates this method. Particularly, for PbTiO3, the Pb 6s lone‐pair electron states can also be tuned using the OSEP method, and its influence on the ferroelectricity is unveiled in detail. Surprisingly, it is found that the electric dipoles formed by lone‐pair lobes contribute only slightly to the overall ferroelectric polarization, whereas the concomitant ionic displacements and lattice distortions are prominently favorable for ferroelectricity. Indeed, it is found that the Pb–O hybridization plays an important role in the ferroelectricity of PbTiO3, which makes the polarization of PbTiO3 significantly larger than that of BaTiO3. This study provides a simple yet straightforward way to demonstrate the mechanisms of ferroelectricity in perovskite oxides, which can be applied to the study of ferroelectric mechanism in other relevant materials.
Mapping Sub‐Surface Structure of Thin Films in Three Dimensions with an Optical Near‐Field
Authors: Fenwick Oliver , Mauthoor Soumaya , Cacialli Franco
Published: April 2019

Subsurface mapping is crucial to understanding many biological systems as well as structured thin films for (opto)electronic or photonic applications. A non‐invasive method is presented to map subsurface nanostructures from scanning near‐field optical microscopy images. The Bethe–Bouwkamp model is used to simulate imaging of buried nano‐objects or subsurface slanted planar interfaces, and it is shown how to determine their depth and size, or the interface inclination, from just one image. It is shown that the steep optical field gradient makes near‐field microscopy a particularly sensitive depth probe for thin films.
Unraveling Photocatalytic Mechanism and Selectivity in PET‐RAFT Polymerization
Authors: Seal Prasenjit , Xu Jiangtao , De Luca Sergio , Boyer Cyrille , Smith Sean C.
Published: April 2019

The photoredox catalysts pheophorbide a (PheoA) and zinc tetraphenylporphine (ZnTPP) under illumination display strong selectivity toward reversible addition–fragmentation chain transfer (RAFT) agents containing thiocarbonylthio groups, namely dithiobenzoates, xanthates, and trithiocarbonates. The underlying mechanism for the process—whether via energy or electron transfer from the photoexcited catalyst to RAFT agent—has remained unclear, as has the reason for the remarkable selectivity. Quantum chemistry and molecular dynamics calculations are utilized to provide strong evidence that none of the common energy‐transfer mechanisms (Förster resonance energy transfer; Dexter electron exchange; or internal conversion followed by vibrational energy transfer) are likely to facilitate polymerization, let alone explain the observed selectivities. In contrast, extensive quantum chemical characterizations of the excited‐state orbitals associated with the catalyst–RAFT agent complexes uncover a clear selectivity pattern associated with charge‐transfer states that is highly consistent with experimental findings. The results shed light on the intrinsic catalytic role of the photocatalysts and provide a strong indication that a reversible electron/charge‐transfer mechanism underpins the remarkable photocatalytic selectivity.
Tracking temporal shifts in area, biomes, and pollinators in the radiation ofSalvia(sages) across continents: leveraging anchored hybrid enrichment and targeted sequence data
Authors: Kriebel Ricardo , Drew Bryan T. , Drummond Chloe P. , González‐Gallegos Jesús G. , Celep Ferhat , Mahdjoub Mohamed M. , Rose Jeffrey P. , Xiang Chun‐Lei , Hu Guo‐Xiong , Walker Jay B. , Lemmon Emily M. , Lemmon Alan R. , Sytsma Kenneth J.
Published: April 2019

Premise of the Study

A key question in evolutionary biology is why some clades are more successful by being widespread geographically, biome diverse, or species‐rich. To extend understanding of how shifts in area, biomes, and pollinators impact diversification in plants, we examined the relationships of these shifts to diversification across the mega‐genusSalvia.

Methods

A chronogram was developed from a supermatrix of anchored hybrid enrichment genomic data and targeted sequence data for over 500 of the nearly 1000Salviaspecies. Ancestral areas and biomes were reconstructed using BioGeoBEARS. Pollinator guilds were scored, ancestral pollinators determined, shifts in pollinator guilds identified, and rates of pollinator switches compared.

Key Results

A well‐resolved phylogenetic backbone ofSalviaand updated subgeneric designations are presented.Salviaoriginated in Southwest Asia in the Oligocene and subsequently dispersed worldwide. Biome shifts are frequent from a likely ancestral lineage utilizing broadleaf and/or coniferous forests and/or arid shrublands. None of the four species diversification shifts are correlated to shifts in biomes. Shifts in pollination system are not correlated to species diversification shifts, except for one hummingbird shift that precedes a major shift in diversification near the crown of New World subgen.Calosphace. Multiple reversals back to bee pollination occurred within this hummingbird clade.

Conclusions

Salviadiversified extensively in different continents, biomes, and with both bee and bird pollinators. The lack of tight correlation of area, biome, and most pollinator shifts to the four documented species diversification shifts points to other important drivers of speciation inSalvia.
The Hyperfine Transition for the Definition of the Second
Authors: Arias Elisa Felicitas , Petit Gérard
Published: April 2019

The unit of time of the International System of Units (SI), the “atomic second” was defined through a constant of physics in 1967. It is derived from the frequency of the hyperfine transition of the atom of cesium 133. From the astronomical definition of the second until today, the accuracy of the realization of the second has improved by eight orders of magnitude, with a rate that has increased since the development of the cesium frequency standards, to reach parts in 1016 for the best clocks today. In 2018, when the new SI was adopted, the time metrology community proved that a new generation of frequency standards operating in optical wavelengths has uncertainties at the level of 10–18, and challenge the implementation of high accurate frequency and time comparison techniques to decide on a revision of the definition of the second. Herein, the progress in the definition and realization of the second from astronomy until today is reviewed, an inventory of the present resources is assembled and a brief view for the future given.
Synthesis, Structures, and Near‐IR Absorption of Heterole‐Fused Earring Porphyrins
Authors: Wu Licheng , Li Feilong , Rao Yutao , Wen Bin , Xu Ling , Zhou Mingbo , Tanaka Takayuki , Osuka Atsuhiro , Song Jianxin
Published: April 2019

A reaction sequence of regioselective peripheral bromination, Suzuki–Miyaura coupling with 2‐borylated thiophene or pyrrole, and oxidative ring‐closure with FeCl3 allowed the synthesis of heterole‐fused earring porphyrins 4Pd and 9Pd from the parent earring porphyrin 1. Differently pyrrole‐fused porphyrins 5H and 6H and their PdII complexes 5Pd and 6Pd were also synthesized. The structures of 4Pd, 5H, 6Pd, and 8Pd have been revealed by X‐ray analysis to be slightly twisted owing to constraints imposed by heterole‐fused structures. 5Pd exhibits an intensified band at 1505 nm, while 4Pd and 9Pd display small but remarkably red‐shifted absorption bands reaching around 2200 nm.
Continuous local anaesthetic wound catheter infiltration after clamshell thoracotomy
Authors: Lan‐Pak‐Kee V. , Egan T. , Tarrell T. , Konig T.
Published: April 2019

We report on the novel and successful use of local anaesthetic wound infusions via elastomeric pumps in a 17‐year‐old male who underwent emergent clamshell thoracotomy after sustaining a stab wound to the flank. This formed one component of a multi‐modal analgesic regimen aimed at reducing opioid requirements and their associated side‐effects. The patient was mobilising and was discharged from the intensive care unit 24 h postoperatively. There was an unplanned break in the local anaesthetic infusion during which the patient's reported pain scores increased significantly. The catheters were removed on the fifth postoperative day and he was discharged from hospital on day 7.
Ultra‐small sugar‐substituted N‐heterocyclic carbene‐protected palladium nanoparticles and catalytic activity
Authors: Zhou Zhonggao , Li Mei , Liu Guangsheng , Xu Guohai , Xue Jun
Published: April 2019

Ultra‐small Pd nanoparticles (UNPs) represent a distinctive type of nanomaterial making them very attractive for a range of applications. Herein, chiral sugar‐substituted N‐heterocyclic carbenes (NHCs) with various lengths of alkyl chain (sugar‐NHCs‐nCnH2n+1) were first used to prepare water‐soluble Pd@NHCs‐sugar UNPs via an efficient ligand‐exchange strategy, which can be handled under air and are stable over 10 months. The Pd@NHCs‐sugar UNPs were highly monodisperse, with tunable core diameters from 1.7 to 2.1 nm, and an effect of the particle size on the N‐substituted aliphatic chains was observed. To investigate the accessibility of the surface, the Pd@NHCs‐sugar UNPs were studied as catalysts for C–C coupling reaction in eco‐friendly ethanol aqueous solution without any precipitation of metallic Pd. The presence of the longest aliphatic group in the Pd@NHCs‐sugar UNPs imparts to them the highest catalyst activity (turnover number and turnover frequency up to 196 000 and 3 920 000 h−1).
Investigation of covalently grafted polyacrylate chains onto graphene oxide for epoxy composites with reinforced mechanical performance
Authors: Xie Yankun , Liu Weiqu , Liu Chunhua , He Sha , Zhang Fengyuan , Shi Hongyi , Yang Maiping , Wang Zhengfang
Published: April 2019

To enhance the dispersion and interfacial interaction of graphene–epoxy matrix, polyacrylate chains grafted graphene oxide (PA‐GO) was manufactured with A‐174 functionalized GO (A‐GO), methyl acrylate, and glycidyl methacrylate via free‐radical random copolymerization technique. Fourier transform infrared, thermogravimetric analysis, X‐ray photoelectron spectrum, Raman spectroscopy, X‐ray diffraction, transmission electron microscopy, and nuclear magnetic resonance were performed to investigate the structure of A‐GO and PA‐GO. Then, the PA‐GO was incorporated into epoxy resin via in situ solution intercalation dispersion method in order to form an interpenetrating network structure with epoxy resin. Field emission scanning electron microscope results indicate that the PA‐GO exhibits excellent dispersion and interfacial compatibility in the epoxy matrix. In compared with pure epoxy, the tensile strength and impact strength of the epoxy composite with 1 wt % PA‐GO were shifted from 62.78 ± 2.54 to 70.68 ± 2.02 MPa (about 12.6%) and 3.55 ± 0.41 to 4.98 ± 0.33 kJ m−2 (about 40.3%), respectively. Moreover, increased storage modulus is also observed in the dynamic mechanical analysis measurements compared with that of neat epoxy resin. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47842.
Turn‐Number‐Dependent Motion Behavior of Catalytic Helical Carbon Micro/Nanomotors
Authors: Xu Dandan , Zhan Chen , Sun Yanming , Dong Zhijun , Wang Guo Ping , Ma Xing
Published: April 2019

Helical micro/nanomotors (MNMs) can be propelled by external fields to swim through highly viscous fluids like complex biological environments, which promises miniaturized robotic tools to perform assigned tasks at small scales. However, the catalytic propulsion method, most widely adopted to drive MNMs, is seldom studied to actuate helical MNMs. Herein, we report catalytic helical carbon MNMs (CHCM) by sputtering Pt onto helical carbon nano‐coils (HCNC) that are in bulk prepared by a thermal chemical vapor deposition method. The Pt‐triggered H2O2 decomposition can drive the MNMs by an electrokinetic mechanism. The MNMs demonstrate versatile motion behaviors including both directional propulsion and rotation depending on the turn number of the carbon helix. Besides, due to the ease of surface functionalization on carbon and other properties such as biocompatibility and photothermal effect, the helical carbon MNMs promise multifunctional applications for biomedical or environmental applications.
Maternal vitamin D deficiency increases the thromboxane/prostacyclin ratio through alterations in the one‐carbon cycle in Wistar rats
Authors: Nandi Anindita A. , Wadhwani Nisha S. , Joshi Sadhana R.
Published: April 2019

This study aims to test the hypothesis that vitamin D deficiency can influence long‐chain polyunsaturated fatty acid metabolism through alterations in the one‐carbon cycle. Wistar rats (n = 8 per group) were given either a control (1,000 IU D3/kg diet) or a vitamin D deficient (VDD) (0 IU D3/kg diet) diet from pre‐pregnancy to delivery. On day 20 of gestation, pregnant female rats were delivered by C‐section to collect placenta and blood. VDD group demonstrated high serum parathyroid hormone, low serum phosphate, low plasma folate, higher plasma homocysteine, and higher plasma malondialdehyde levels (P < 0.05 for all) as compared to control. Lower protein levels of placental cystathionine‐β‐synthase enzyme (P < 0.05) were observed in the VDD group as compared to control. VDD group demonstrated higher placental mRNA levels of the enzymes phospholipase A2 and cyclooxygenase‐2 (P < 0.05 for both) as compared to control. Protein levels of the enzymes phospholipase A2 and cyclooxygenase‐2 were lower (P < 0.05 for both) in the VDD group as compared to the control group. The ratio of thromboxane B2 and 6‐keto prostaglandin F1α in serum was higher (P < 0.05) in the VDD group as compared to control; although the serum levels of 6‐keto prostaglandin F1α and thromboxane B2 were similar in both the groups. Our findings suggest that increased oxidative stress due to maternal vitamin D deficiency results in the imbalance between the vasoconstrictor (thromboxane B2) and vasodilator (6‐keto prostaglandin F1α) eicosanoids, which may lead to endothelial dysfunction and poor pregnancy outcome. © 2019 BioFactors, 45 (4):548–555, 2019
Application of the Bradford Assay for Cell Lysis Quantification: Residual Protein Content in Cell Culture Supernatants
Authors: Sissolak Bernhard , Zabik Christian , Saric Natasa , Sommeregger Wolfgang , Vorauer‐Uhl Karola , Striedner Gerald
Published: April 2019

Frequently measured mammalian cell culture process indicators include viability and total cell concentration (TCC). Cell lysis, an additional important process characteristic that substantially contributes to the overall product purity profiles, is often not addressed in detail. In the present study, an inexpensive and simple application of the Bradford assay is developed to determine the residual protein content (RPC) in cell culture supernatants. The reliability and reproducibility of the method are tested in a long‐term study and compared with lysis quantification via the DNA measurement. The results show that its performance is more robust and accurate over time and the respective concentration range. Additionally, both methods are used for cell lysis process monitoring in a recombinant Chinese hamster ovary fed‐batch process. In the presented process, by applying the established assay, the lysis ratekDLis determined to be constant over time at 4.6 × 10−4lysed cell concentration (LCC) per TCC and time (LCC/TCC/h). In contrast, DNA data did not confirm the constant lysis rate due to variations of the content per cell during cultivation. Thus, information on the RPC can facilitate the determination of the optimal harvest time point with respect to purity and in improving process characterization.
Analysis of phenolic acids and flavonoids in leaves of Lycium barbarum from different habitats by ultra‐high‐performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry
Authors: Zhao Xue‐qin , Guo Sheng , Yan Hui , Lu You‐yuan , Zhang Fang , Qian Da‐wei , Wang Han‐qing , Duan Jin‐ao
Published: April 2019

The leaves of Lycium barbarum (LLB) have been utilized as crude drugs and functional tea for human health in China and Southeast Asia for thousands of years. To control its quality, a rapid and sensitive ultra‐high‐performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry method was established and validated for the first time for simultaneous determination of 10 phenolic acids and flavonoids (including neochlorogenic acid, protocatechuic aldehyde, p‐hydroxybenzoic acid, chlorogenic acid, cryptochlorogenic acid, caffeic acid, p‐coumaric acid, ferulic acid, rutin and kaempferol‐3‐O‐rutinoside) in LLB. The separation was performed on an Acquity UPLC C18 chromatographic column (100 × 2.1 mm internal diameter, 1.7 μm particle size) with 0.1% formic acid in water (A)–acetonitrile (B) as the mobile phase under gradient elution. Multiple reaction monitoring mode was adopted to simultaneously monitor the target components. The developed method was fully validated in terms of linearity (r2 ≥ 0.9860), precision (RSD ≤ 6.58%), repeatability (RSD ≤ 6.60%), stability (RSD ≤ 6.17%), recovery (95.56–108.06%, RSD ≤ 4.64%) and limit of detection (0.021–0.664 ng/mL) and limit of quantitation (0.069–2.210 ng/mL), and then successfully applied to evaluate the quality of 64 batches of LLB collected from 41 producing areas in four different provinces of China. The results showed that the LLB, especially collected from Inner Mongolia regions, were rich in the phenolic acids and flavonoids. Rutin, kaempferol‐3‐O‐rutinoside and chlorogenic acid are the predominant compounds contained in LLB. The above findings will provide helpful information for the effective utilization of LLB.