bluuebunny/crossref_metadata_2025 huggingface dataset:
Unraveling the Influence of Thermal Drawing Parameters on the Microstructure and Thermo–Mechanical Properties of Multimaterial Fibers
Authors: Richard Inès , Maurya Anjani K. , Shadman Shahrzad , Masquelier Eloïse , Marthey Lison S. , Neels Antonia , Sorin Fabien
Published: November 2021

Multimaterial thermally drawn fibers are becoming important building blocks in several foreseen applications in surgical probes, protective gears, or medical textiles. Here, the influence of the thermal drawing parameters on the degree of polymer chain orientation, the related thermal shrinkage behavior, and the mechanical properties of the final fibers is investigated via thermo–mechanical testing and small‐ and wide‐angle X‐ray scattering (SAXS and WAXS) analyses. This study on polyetherimide fibers reveals that the drawing stress, which depends on the drawing speed and temperature, controls the thermal shrinkage behavior and mechanical properties. Furthermore, SAXS and WAXS analyses show that the degree of chain orientation increases with drawing stresses below 8 MPa and then saturates, which correlates with the amount of observed shrinkage. The use of this process‐dependent polymer chain alignment to tune the mechanical and shrinkage properties of the fibers is highlighted and controlled bending multimaterial fibers made of two polymethyl methacrylates having different molecular weights are developed. Finally, a heat treatment procedure is proposed to relax the chain alignment and increase the dimensional stability of devices such as temperature sensors. This deeper understanding can serve as a guide for the processing of complex fibers requiring specific mechanical properties or enhanced thermal stability.
Revealing Size Dependent Structural Transitions in Supported Gold Nanoparticles in Hydrogen at Atmospheric Pressure
Authors: Nassereddine Abdallah , Wang Qing , Loffreda David , Ricolleau Christian , Alloyeau Damien , Louis Catherine , Delannoy Laurent , Nelayah Jaysen , Guesmi Hazar
Published: November 2021

The enhancement of the catalytic activity of gold nanoparticles with their decreasing size is often attributed to the increasing proportion of low‐coordinated surface sites. This correlation is based on the paradigmatic picture of working gold nanoparticles as perfect crystal forms having complete and static outer surface layers whatever their size. This picture is incomplete as catalysts can dynamically change their structure according to the reaction conditions and as such changes can be eventually size‐dependent. In this work, using aberration‐corrected environmental electron microscopy, size‐dependent crystal structure and morphological evolution in gold nanoparticles exposed to hydrogen at atmospheric pressure, with loss of the face‐centered cubic crystal structure of gold for particle size below 4 nm, are revealed for the first time. Theoretical calculations highlight the role of mobile gold atoms in the observed symmetry changes and particle reshaping in the critical size regime. An unprecedented stable surface molecular structure of hydrogenated gold decorating a highly distorted core is identified. By combining atomic scale in situ observations and modeling of nanoparticle structure under relevant reaction conditions, this work provides a fundamental understanding of the size‐dependent reactivity of gold nanoparticles with a precise picture of their surface at working conditions.
LncRNA, PLXDC2-OT Promoted the Osteogenesis Potentials of MSCs by Inhibiting the Deacetylation Function of RBM6/SIRT7 Complex and OSX Specific Isoform
Authors: Liu Huina , Hu Lei , Yu Guoxia , Yang Haoqing , Cao Yangyang , Wang Songlin , Fan Zhipeng
Published: November 2021

Bone regeneration and remodeling are complex physiological processes that are regulated by key transcription factors. Understanding the regulatory mechanism of key transcription factors on the osteogenic differentiation of mesenchymal stem cells (MSCs) is a key issue for successful bone regeneration and remodeling. In the present study, we investigated the regulatory mechanism of the histone deacetylase Sirtuin 7 (SIRT7) on the key transcription factor OSX and osteogenesis of MSCs. In this study, we found that SIRT7 knockdown increased ALP activity and in vitro mineralization and promoted the expression of the osteogenic differentiation markers DSPP, DMP1, BSP, OCN, and the key transcription factor OSX in MSCs. In addition, SIRT7 could associate with RNA binding motif protein 6 (RBM6) to form a protein complex. Moreover, RBM6 inhibited ALP activity, the expression of DSPP, DMP1, BSP, OCN, and OSX in MSCs, and the osteogenesis of MSCs in vivo. Then, the SIRT7/RBM6 protein complex was shown to downregulate the level of H3K18Ac in the OSX promoter by recruiting SIRT7 to the OSX promoter and inhibiting the expression of OSX isoforms 1 and 2. Furthermore, lncRNA PLXDC2-OT could associate with the SIRT7/RBM6 protein complex to diminish its binding and deacetylation function in the OSX promoter and its inhibitory function on OSX isoforms 1 and 2 and to promote the osteogenic potential of MSCs.
Characterization of Highly Proliferative Decidual Precursor Cells During the Window of Implantation in Human Endometrium
Authors: Diniz-da-Costa Maria , Kong Chow-Seng , Fishwick Katherine J. , Rawlings Thomas , Brighton Paul J. , Hawkes Amelia , Odendaal Joshua , Quenby Siobhan , Ott Sascha , Lucas Emma S. , Vrljicak Pavle , Brosens Jan J.
Published: November 2021

Pregnancy depends on the wholesale transformation of the endometrium, a process driven by differentiation of endometrial stromal cells (EnSC) into specialist decidual cells. Upon embryo implantation, decidual cells impart the tissue plasticity needed to accommodate a rapidly growing conceptus and invading placenta, although the underlying mechanisms are unclear. Here we characterize a discrete population of highly proliferative mesenchymal cells (hPMC) in midluteal human endometrium, coinciding with the window of embryo implantation. Single-cell transcriptomics demonstrated that hPMC express genes involved in chemotaxis and vascular transmigration. Although distinct from resident EnSC, hPMC also express genes encoding pivotal decidual transcription factors and markers, most prominently prolactin. We further show that hPMC are enriched around spiral arterioles, scattered throughout the stroma, and occasionally present in glandular and luminal epithelium. The abundance of hPMC correlated with the in vitro colony-forming unit activity of midluteal endometrium and, conversely, clonogenic cells in culture express a gene signature partially conserved in hPMC. Cross-referencing of single-cell RNA-sequencing data sets indicated that hPMC differentiate into a recently discovered decidual subpopulation in early pregnancy. Finally, we demonstrate that recurrent pregnancy loss is associated with hPMC depletion. Collectively, our findings characterize midluteal hPMC as novel decidual precursors that are likely derived from circulating bone marrow-derived mesenchymal stem/stromal cells and integral to decidual plasticity in pregnancy.
Vascularization of Human Brain Organoids
Authors: Matsui Takeshi K. , Tsuru Yuichiro , Hasegawa Koichi , Kuwako Ken-ichiro
Published: November 2021

Human brain organoids are three-dimensional tissues that are generated in vitro from pluripotent stem cells and recapitulate the early development of the human brain. Brain organoids consist mainly of neural lineage cells, such as neural stem/precursor cells, neurons, astrocytes, and oligodendrocytes. However, all human brain organoids lack vasculature, which plays indispensable roles not only in brain homeostasis but also in brain development. In addition to the delivery of oxygen and nutrition, accumulating evidence suggests that the vascular system of the brain regulates neural differentiation, migration, and circuit formation during development. Therefore, vascularization of human brain organoids is of great importance. Current trials to vascularize various organoids include the adjustment of cultivation protocols, the introduction of microfluidic devices, and the transplantation of organoids into immunodeficient mice. In this review, we summarize the efforts to accomplish vascularization and perfusion of brain organoids, and we discuss these attempts from a forward-looking perspective.
An Aged Bone Marrow Niche Restrains Rejuvenated Hematopoietic Stem Cells
Authors: Guidi Novella , Marka Gina , Sakk Vadim , Zheng Yi , Florian Maria Carolina , Geiger Hartmut
Published: November 2021

Aging-associated leukemia and aging-associated immune remodeling are in part caused by aging of hematopoietic stem cells (HSCs). An increase in the activity of the small RhoGTPase cell division control protein 42 (Cdc42) within HSCs causes aging of HSCs. Old HSCs, treated ex vivo with a specific inhibitor of Cdc42 activity termed CASIN, stay rejuvenated upon transplantation into young recipients. We determined in this study the influence of an aged niche on the function of ex vivo rejuvenated old HSCs, as the relative contribution of HSCs intrinsic mechanisms vs extrinsic mechanisms (niche) for aging of HSCs still remain unknown. Our results show that an aged niche restrains the function of ex vivo rejuvenated HSCs, which is at least in part linked to a low level of the cytokine osteopontin found in aged niches. The data imply that sustainable rejuvenation of the function of aged HSCs in vivo will need to address the influence of an aged niche on rejuvenated HSCs.
Fluid Shear Stress Promotes Embryonic Stem Cell Pluripotency via Interplay Between β-Catenin and Vinculin in Bioreactor Culture
Authors: Nath Suman C. , Day Bradley , Harper Lane , Yee Jeffrey , Hsu Charlie Yu-Ming , Larijani Leila , Rohani Leili , Duan Nicholas , Kallos Michael S. , Rancourt Derrick E.
Published: November 2021

The expansion of pluripotent stem cells (PSCs) as aggregates in stirred suspension bioreactors is garnering attention as an alternative to adherent culture. However, the hydrodynamic environment in the bioreactor can modulate PSC behavior, pluripotency and differentiation potential in ways that need to be well understood. In this study, we investigated how murine embryonic stem cells (mESCs) sense fluid shear stress and modulate a noncanonical Wnt signaling response to promote pluripotency. mESCs showed higher expression of pluripotency marker genes, Oct4, Sox2, and Nanog in the absence of leukemia inhibitory factor (LIF) in stirred suspension bioreactors compared to adherent culture, a phenomenon we have termed mechanopluripotency. In bioreactor culture, fluid shear promoted the nuclear translocation of the less well-known pluripotency regulator β-catenin and concomitant increase of c-Myc expression, an upstream regulator of Oct4, Sox2, and Nanog. We also observed similar β-catenin nuclear translocation in LIF-free mESCs cultured on E-cadherin substrate under defined fluid shear stress conditions in flow chamber plates. mESCs showed lower shear-induced expression of pluripotency marker genes when β-catenin was inhibited, suggesting that β-catenin signaling is crucial to mESC mechanopluripotency. Key to this process is vinculin, which is known to rearrange and associate more strongly with adherens junctions in response to fluid shear. When the vinculin gene is disrupted, we observe that nuclear β-catenin translocation and mechanopluripotency are abrogated. Our results indicate that mechanotransduction through the adherens junction complex is important for mESC pluripotency maintenance.
Acute myeloid leukemia-induced functional inhibition of healthy CD34+ hematopoietic stem and progenitor cells
Authors: Jäger Paul , Geyh Stefanie , Twarock Sören , Cadeddu Ron-Patrick , Rabes Pablo , Koch Annemarie , Maus Uwe , Hesper Tobias , Zilkens Christoph , Rautenberg Christina , Bormann Felix , Köhrer Karl , Petzsch Patrick , Wieczorek Dagmar , Betz Beate , Surowy Harald , Hildebrandt Barbara , Germing Ulrich , Kobbe Guido , Haas Rainer , Schroeder Thomas
Published: November 2021

Acute myeloid leukemia (AML) is characterized by an expansion of leukemic cells and a simultaneous reduction of normal hematopoietic precursors in the bone marrow (BM) resulting in hematopoietic insufficiency, but the underlying mechanisms are poorly understood in humans. Assuming that leukemic cells functionally inhibit healthy CD34+ hematopoietic stem and progenitor cells (HSPC) via humoral factors, we exposed healthy BM-derived CD34+ HSPC to cell-free supernatants derived from AML cell lines as well as from 24 newly diagnosed AML patients. Exposure to AML-derived supernatants significantly inhibited proliferation, cell cycling, colony formation, and differentiation of healthy CD34+ HSPC. RNA sequencing of healthy CD34+ HSPC after exposure to leukemic conditions revealed a specific signature of genes related to proliferation, cell-cycle regulation, and differentiation, thereby reflecting their functional inhibition on a molecular level. Experiments with paired patient samples showed that these inhibitory effects are markedly related to the immunomagnetically enriched CD34+ leukemic cell population. Using PCR, ELISA, and RNA sequencing, we detected overexpression of TGFβ1 in leukemic cells on the transcriptional and protein level and, correspondingly, a molecular signature related to TGFβ1 signaling in healthy CD34+ HSPC. This inhibitory effect of TGFβ1 on healthy hematopoiesis was functionally corrobated and could be pharmacologically reverted by SD208, an inhibitor of TGFβ receptor 1 signaling. Overall, these data indicate that leukemic cells induce functional inhibition of healthy CD34+ HSPC, at least in part, through TGFβ1, suggesting that blockage of this pathway may improve hematopoiesis in AML.
Bone Marrow-Derived Progenitor Cells Contribute to Remodeling of the Postpartum Uterus
Authors: Tal Reshef , Kisa Jacqueline , Abuwala Nafeesa , Kliman Harvey J. , Shaikh Shafiq , Chen Alice Y. , Lyu Fang , Taylor Hugh S.
Published: November 2021

Endometrial stem/progenitor cells play a role in postpartum uterine tissue regeneration, but the underlying mechanisms are poorly understood. While circulating bone marrow (BM)-derived cells (BMDCs) contribute to nonhematopoietic endometrial cells, the contribution of BMDCs to postpartum uterus remodeling is unknown. We investigated the contribution of BMDCs to the postpartum uterus using 5-fluorouracil-based nongonadotoxic BM transplant from green fluorescent protein (GFP) donors into wild-type C57BL/6J female mice. Flow cytometry showed an influx of GFP+ cells to the uterus immediately postpartum accounting for 28.7% of total uterine cells, followed by a rapid decrease to prepregnancy levels. The majority of uterine GFP+ cells were CD45+ leukocytes, and the proportion of nonhematopoietic CD45−GFP+ cells peaked on postpartum day (PPD) 1 (17.5%). Immunofluorescence colocalization of GFP with CD45 pan-leukocyte and F4/80 macrophage markers corroborated these findings. GFP+ cells were found mostly in subepithelial stromal location. Importantly, GFP+ cytokeratin-positive epithelial cells were found within the luminal epithelium exclusively on PPD1, demonstrating direct contribution to postpartum re-epithelialization. A subset (3.2%) of GFP+ cells were CD31+CD45− endothelial cells, and found integrated within blood vessel endothelium. Notably, BM-derived GFP+ cells demonstrated preferential proliferation (PCNA+) and apoptosis (TUNEL+) on PPD1 vs resident GFP− cells, suggesting an active role for BMDCs in rapid tissue turnover. Moreover, GFP+ cells gradually acquired cell senescence together with decreased proliferation throughout the postpartum. In conclusion, BM-derived progenitors were found to have a novel nonhematopoietic cellular contribution to postpartum uterus remodeling. This contribution may have an important functional role in physiological as well as pathological postpartum endometrial regeneration.
Bone-Forming Perivascular Cells: Cellular Heterogeneity and Use for Tissue Repair
Authors: Xu Jiajia , Wang Yiyun , Gomez-Salazar Mario A. , Hsu Ginny Ching-Yun , Negri Stefano , Li Zhao , Hardy Winters , Ding Lijun , Peault Bruno , James Aaron W.
Published: November 2021

Mesenchymal progenitor cells are broadly distributed across perivascular niches—an observation conserved between species. One common histologic zone with a high frequency of mesenchymal progenitor cells within mammalian tissues is the tunica adventitia, the outer layer of blood vessel walls populated by cells with a fibroblastic morphology. The diversity and functions of (re)generative cells present in this outermost perivascular niche are under intense investigation; we have reviewed herein our current knowledge of adventitial cell potential with a somewhat narrow focus on bone formation. Antigens of interest to functionally segregate adventicytes are discussed, including CD10, CD107a, aldehyde dehydrogenase isoforms, and CD140a, among others. Purified adventicytes (such as CD10+, CD107alow, and CD140a+ cells) have stronger osteogenic potential and promote bone formation in vivo. Recent bone tissue engineering applications of adventitial cells are also presented. A better understanding of perivascular progenitor cell subsets may represent a beneficial advance for future efforts in tissue repair and bioengineering.
A Protein-Centric View of in Vitro Biological Model Systems for Schizophrenia
Authors: Chandrasekaran Abinaya , Jensen Pia , Mohamed Fadumo A. , Lancaster Madeline , Benros Michael E. , Larsen Martin R. , Freude Kristine K.
Published: November 2021

Schizophrenia (SCZ) is a severe brain disorder, characterized by psychotic, negative, and cognitive symptoms, affecting 1% of the population worldwide. The precise etiology of SCZ is still unknown; however, SCZ has a high heritability and is associated with genetic, environmental, and social risk factors. Even though the genetic contribution is indisputable, the discrepancies between transcriptomics and proteomics in brain tissues are consistently challenging the field to decipher the disease pathology. Here we provide an overview of the state of the art of neuronal two-dimensional and three-dimensional model systems that can be combined with proteomics analyses to decipher specific brain pathology and detection of alternative entry points for drug development.
Spatiotemporal Extracellular Matrix Modeling forin SituCell Niche Studies
Authors: Olesen Kim , Rodin Sergey , Mak Wing Cheung , Felldin Ulrika , Österholm Cecilia , Tilevik Andreas , Grinnemo Karl-Henrik
Published: November 2021

Extracellular matrix (ECM) components govern a range of cell functions, such as migration, proliferation, maintenance of stemness, and differentiation. Cell niches that harbor stem-/progenitor cells, with matching ECM, have been shown in a range of organs, although their presence in the heart is still under debate. Determining niches depends on a range of in vitro and in vivo models and techniques, where animal models are powerful tools for studying cell-ECM dynamics; however, they are costly and time-consuming to use. In vitro models based on recombinant ECM proteins lack the complexity of the in vivo ECM. To address these issues, we present the spatiotemporal extracellular matrix model for studies of cell-ECM dynamics, such as cell niches. This model combines gentle decellularization and sectioning of cardiac tissue, allowing retention of a complex ECM, with recellularization and subsequent image processing using image stitching, segmentation, automatic binning, and generation of cluster maps. We have thereby developed an in situ representation of the cardiac ECM that is useful for assessment of repopulation dynamics and to study the effect of local ECM composition on phenotype preservation of reseeded mesenchymal progenitor cells. This model provides a platform for studies of organ-specific cell-ECM dynamics and identification of potential cell niches.
Intranasal Delivery of Mesenchymal Stem Cells-Derived Extracellular Vesicles for the Treatment of Neurological Diseases
Authors: Herman Shay , Fishel Idan , Offen Daniel
Published: November 2021

Neurological disorders are diseases of the central nervous system (CNS), characterized by a progressive degeneration of cells and deficiencies in neural functions. Mesenchymal stem cells (MSCs) are a promising therapy for diseases and disorders of the CNS. Increasing evidence suggests that their beneficial abilities can be attributed to their paracrine secretion of extracellular vesicles (EVs). Administration of EVs that contain a mixture of proteins, lipids, and nucleic acids, resembling the secretome of MSCs, has been shown to mimic most of the effects of the parental cells. Moreover, the small size and safety profile of EVs provide a number of advantages over cell transplantation. Intranasal (IN) administration of EVs has been established as an effective and reliable way to bypass the blood-brain barrier and deliver drugs to the CNS. In addition to pharmacological drugs, EVs can be loaded with a diverse range of cargo designed to modulate gene expression and protein functions in recipient cells, and lead to immunomodulation, neurogenesis, neuroprotection, and degradation of protein aggregates. In this review, we will explore the proposed physiological pathways by which EVs migrate through the nasal route to the CNS where they can actively target a region of injury or inflammation and exert their therapeutic effects. We will summarize the functional outcomes observed in animal models of neurological diseases following IN treatment with MSC-derived EVs. We will also examine key mechanisms that have been suggested to mediate the beneficial effects of EV-based therapy.
High‐entropy alloys and compounds for electrocatalytic energy conversion applications
Authors: Liu Hang , Syama Lenus , Zhang Like , Lee Carmen , Liu Chuntai , Dai Zhengfei , Yan Qingyu
Published: November 2021

High‐entropy materials, composed of five or more elements in near‐equiatomic percentage, have been attracting tremendous interests due to their advantageous properties in a variety of applications. Recently, electrocatalysis on high‐entropy alloys (HEAs) and high‐entropy compounds (HECs) has emerged as a new and promising material owing to the tailored composition and the disordered configuration of HEAs and HECs. Though extensive efforts have been devoted to investigating the catalytic nature of HEAs and HECs, the details related to the active sites and intrinsic activity of such catalysts still remain uncertain due to the complexity of the multicomponent systems. In this review, the recent progress of HEAs and HECs is systematically reviewed in terms of their synthetic strategies and electrocatalytic applications. Importantly, the computationally assisted methods (e.g., density functional theory [DFT]) are also presented to discover and design the optimum HEA‐ and HEC‐based catalysts. Subsequently, the applications of HEAs and HECs in electrocatalytic energy conversion reactions will be discussed, including hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, methanol oxidation reaction, and ethanol oxidation reaction (EOR). Moreover, the prospects and future opportunities for this research field are cautiously discussed. A series of upcoming challenges and questions are thoroughly proposed from the experimental and theoretical aspects as well as other future applications in electrocatalysis.
Implicit alignment: India's National Water Policy and a human rights‐based approach to water management
Authors: Schiff Jennifer S.
Published: November 2021

As a potential solution to water scarcity, the United Nations advocates for a human rights‐based (HRB) approach to water management, characterized by a focus on the provision of safe drinking water and sanitation, stakeholder participation, and the realization of water equity for traditionally marginalized communities. Although most states around the world suffer from some form of water scarcity or stress, not all governments have officially recognized the validity of an HRB approach to water management. India stands as an instructive case study in this regard. The Indian state suffers from physical and economic water scarcity across its urban and rural communities, but the Indian federal government has not yet explicitly recognized the human right to water as a legitimate policy approach. Interestingly, though, the right to water has been tacitly recognized within India's legal system; thus, it is worth examining whether a tacit recognition of an HRB approach to water management exists in other aspects of India's national policy. This article utilizes content analysis to explore that question by, first, identifying seven key concepts within an HRB water management approach and, second, tracing those concepts through the 1987, 2002, and 2012 iterations of India's National Water Policy. The results help to illustrate that India's National Water Policy is congruent with an HRB approach to water management, although challenges remain due to a lack of both accountability and clarification of responsibilities between the national and subsidiary governments within India.

This article is categorized under:

Human Water > Rights to Water

Human Water > Water Governance
Chapter 10: Agri-Food Trade Between the United States and Russia: From Divergence to Irrelevance
Authors: Wegren Stephen K.
Published: November 2021

This chapter investigates the impact of political relations on U.S. food exports to the Soviet Union and Russia. The chapter finds that during the Cold War, political relations between the United States and Russia and agricultural trade were divergent, which means that food trade was not much affected by poor relations. In the post-Soviet period, the relationship between politics and agricultural exports has become convergent, which means that political relations and U.S. exports move in the same direction. With Putin in office, U.S. agricultural exports have fallen into irrelevance, a trend that predates Russia’s 2014 food embargo against the West.
Chapter 8: Russia’s Agri-Food Trade Within the Eurasian Economic Union
Authors: Dragneva Rilka
Published: November 2021

This chapter examines the role of the Eurasian Economic Union (EAEU) in Russia’s agricultural food trade. The discussion focuses on four of the most important areas affecting agri-food trade, namely the food safety regime, the effects of Russia’s food import ban, the agenda for agricultural cooperation, and the external free trade agreements of the bloc. The analysis identifies the critical role of structural factors in the build-up of obstacles to trade, including the weak common regime and its inability to constrain unilateral actions at the cost of integration. The chapter concludes that despite some recognition of the issues, fundamental changes are unlikely.
SL(3, ℤ) Modularity and New Cardy limits of the $$ \mathcal{N} $$ = 4 superconformal index
Authors: Jejjala Vishnu , Lei Yang , van Leuven Sam , Li Wei
Published: November 2021

Abstract

The entropy of 1/16-th BPS AdS5 black holes can be microscopically accounted for by the superconformal index of the $$ \mathcal{N} $$
N
= 4 super-Yang-Mills theory. One way to compute this is through a Cardy-like limit of a formula for the index obtained in [1] using the “S-transformation” of the elliptic Γ function. In this paper, we derive more general SL(3, ℤ) modular properties of the elliptic Γ function. We then use these properties to obtain a three integer parameter family of generalized Cardy-like limits of the $$ \mathcal{N} $$
N
= 4 superconformal index. From these limits, we obtain entropy formulae that have a similar form as that of the original AdS5 black hole, up to an overall rescaling of the entropy. We interpret this both on the field theory and the gravitational side. Finally, we comment on how our work suggests a generalization of the Farey tail to four dimensions.
Chern-Weil global symmetries and how quantum gravity avoids them
Authors: Heidenreich Ben , McNamara Jacob , Montero Miguel , Reece Matthew , Rudelius Tom , Valenzuela Irene
Published: November 2021

Abstract

We draw attention to a class of generalized global symmetries, which we call “Chern-Weil global symmetries,” that arise ubiquitously in gauge theories. The Noether currents of these Chern-Weil global symmetries are given by wedge products of gauge field strengths, such asF2∧H3and tr($$ {F}_2^2 $$F22), and their conservation follows from Bianchi identities. As a result, they are not easy to break. However, it is widely believed that exact global symmetries are not allowed in a consistent theory of quantum gravity. As a result, any Chern-Weil global symmetry in a low-energy effective field theory must be either broken or gauged when the theory is coupled to gravity. In this paper, we explore the processes by which Chern-Weil symmetries may be broken or gauged in effective field theory and string theory. We will see that many familiar phenomena in string theory, such as axions, Chern-Simons terms, worldvolume degrees of freedom, and branes ending on or dissolving in other branes, can be interpreted as consequences of the absence of Chern-Weil symmetries in quantum gravity, suggesting that they might be general features of quantum gravity. We further discuss implications of breaking and gauging Chern-Weil symmetries for particle phenomenology and for boundary CFTs of AdS bulk theories. Chern-Weil global symmetries thus offer a unified framework for understanding many familiar aspects of quantum field theory and quantum gravity.
Local Variations in Broadband Sensor Installations: Orientations, Sensitivities, and Noise Levels
Authors: Ringler A. T. , Anthony R. E.
Published: November 2021

As
seismologists continue to place more stringent demands on data quality, accurately described metadata are becoming increasingly important. In order to better constrain the orientation and sensitivities of seismometers deployed in U.S. Geological Survey networks, the Albuquerque Seismological Laboratory (ASL) has recently begun identifying true north with a fiber optic gyroscope (FOG) and has developed methodologies to constrain mid-band, vertical component sensitivity levels to less than 1% in a controlled environment. However, questions remain regarding the accuracy of this new alignment technique as well as if instrument sensitivities and background noise levels are stable when the seismometers are installed in different environmental settings. In this study, we examine the stability and repeatability of these parameters by reinstalling two high-quality broadband seismometers (Streckeisen STS-2.5 and Nanometrics T-360 Global Seismographic Network (GSN) version) at different locations around the ASL and comparing them to each other and a reference STS-6 seismometer that stayed stationary for the duration of the experiment. We find that even in different environmental conditions, the sensitivities of the two broadband seismometers stayed stable to within 0.1% and that orientations attained using the FOG are generally accurate to within a degree. However, one install was off by 5° due to a mistake made by the installation team. These results indicate that while technology and methodologies are now in place to calibrate and orient a seismometer to within 1°, human error both during the installation and while producing the metadata is often a limiting factor. Finally, we find that background noise levels at short periods (0.1–1 s) become noisier when the sensors are emplaced in unconsolidated materials, whereas the noise levels at long periods (30–100 s) are not sensitive to local geological structure on the vertical components.
Modified scattering for the nonlinear nonlocal Schrödinger equation in one-dimensional case
Authors: Hayashi Nakao , Naumkin Pavel I.
Published: November 2021

We study the large time asymptotics of solutions to the Cauchy problem for the nonlinear nonlocal Schrödinger equation with critical nonlinearity $$\begin{aligned} \left\{ \begin{array}{l} i\partial _{t}\left( u-\partial _{x}^{2}u\right) +\partial _{x}^{2}u-a\partial _{x}^{4}u=\lambda \left| u\right| ^{2}u,\text { } t>0,{\ }x\in {\mathbb {R}}\mathbf {,} \\ u\left( 0,x\right) =u_{0}\left( x\right) ,{\ }x\in {\mathbb {R}}\mathbf {,} \end{array} \right. \end{aligned}$$

i

∂
t

u
-

∂

x

2

u

+

∂

x

2

u
-
a

∂

x

4

u
=
λ

u

2

u
,

t
>
0
,

x
∈
R
,

u

0
,
x

=

u
0

x

,

x
∈
R
,

where $$a>\frac{1}{5},$$

a
>

1
5

,

$$\lambda \in {\mathbb {R}}$$

λ
∈
R

. We continue to develop the factorization techniques which was started in papers Hayashi and Naumkin (Z Angew Math Phys 59(6):1002–1028, 2008) for Klein–Gordon, Hayashi and Naumkin (J Math Phys 56(9):093502, 2015) for a fourth-order Schrödinger, Hayashi and Kaikina (Math Methods Appl Sci 40(5):1573–1597, 2017) for a third-order Schrödinger to show the modified scattering of solutions to the equation. The crucial points of our approach presented here are based on the $${\mathbf {L}}^{2}$$

L

2

-boundedness of the pseudodifferential operators.
Drag reduction mechanisms on a generic square-back vehicle using an optimised yaw-insensitive base cavity
Authors: Urquhart Magnus , Varney Max , Sebben Simone , Passmore Martin
Published: November 2021

Regulations on global greenhouse gas emission are driving the development of more energy-efficient passenger vehicles. One of the key factors influencing energy consumption is the aerodynamic drag where a large portion of the drag is associated with the base wake. Environmental conditions such as wind can increase the drag associated with the separated base flow. This paper investigates an optimised yaw-insensitive base cavity on a square-back vehicle in steady crosswind. The test object is a simplified model scale bluff body, the Windsor geometry, with wheels. The model is tested experimentally with a straight cavity and a tapered cavity. The taper angles have been optimised numerically to improve the robustness to side wind in relation to drag. Base pressures and tomographic Particle Image Velocimetry of the full wake were measured in the wind tunnel. The results indicate that a cavity decreases the crossflow within the wake, increasing base pressure, therefore lowering drag. The additional optimised cavity tapering further reduces crossflow and results in a smaller wake with less losses. The overall wake unsteadiness is reduced by the cavity by minimising mixing in the shear layers as well as dampening wake motion. However, the coherent wake motions, indicative of a balanced wake, are increased by the investigated cavities.

Graphical abstract
Quality of life of locally advanced pancreatic cancer patients after FOLFIRINOX treatment
Authors: van der Sijde Fleur , Schafthuizen Laura , van ’t Land Freek R. , Moskie Miranda , van Laarhoven Hanneke W. M. , van Dijk Monique , van Eijck Casper H. J.
Published: November 2021

Background

Quality of life in cancer patients might be affected by chemotherapy-induced toxicity. Especially in patients with pancreatic ductal adenocarcinoma (PDAC), with a short life expectancy, fear of poor quality of life is often a reason for both patients and medical oncologists to refrain from further treatment. In this study, we investigated quality of life (QoL), pain, sleep, and activity levels in locally advanced pancreatic cancer (LAPC) patients after FOLFIRINOX treatment.

Methods

A total of 41 LAPC patients with stable disease or partial response were included after completion of at least four cycles of FOLFIRINOX. QoL was measured with the EORTC QLQ-C30 and NRS pain scores. Patients completed the Richards-Campbell Sleep Questionnaire (RCSQ) for five consecutive nights and wore a GENEActiv tri-axial accelerometer (Actiwatch) for 7 days, registering sleep duration, efficiency, and activity.

Results

Mean EORTC QLQ-C30 score for global health status was 78.3 (± 17.3), higher than reference values for cancer patients (P < 0.001) and general population (P = 0.045). LAPC patients reported few disease-related symptoms. Two patients (5%) reported pain scores > 3. Mean sleep duration was 8 h/night (± 1.2 h) and sleep efficiency 70% (± 9%) with high patient-reported quality of sleep (mean RCSQ score 72.0 ± 11.4). Mean duration of moderate-vigorous activity was 37 min/week (± 103 min/week).

Conclusions

QoL is very good in most LAPC patients with disease control after FOLFIRINOX, measured with validated questionnaires and Actiwatch registration. The fear of clinical deterioration after FOLFIRINOX is not substantiated by this study and should not be a reason to refrain from treatment.

Trial registration

Dutch trial register NL7578.
Electrostatic charge distribution in armchair and zigzag carbon nanotubes: a numerical comparison of CNT charge models
Authors: Lönnecke K. , Eberhardt O. , Wallmersperger T.
Published: November 2021

In engineering—especially in mechanics, lightweight engineering, aerospace engineering, electrical engineering as well as bioengineering—there is a desire of developing materials enabling an excellent performance with respect to mechanical, thermal, and electrical properties. One of the most promising materials are carbon nanotubes (CNTs), as they show excellent mechanical and electrical properties. To improve the understanding of the electrical behavior, i.e., the charge distribution in single-walled carbon nanotubes, both open ended armchair and zigzag types are investigated. In the present research, three different modeling approaches, a classic electrostatic model, the model by Li and Chou and the model by Mayer, are analyzed and compared with respect to their further applicability. In the numerical investigations, different test cases are performed: (i) the carbon nanotubes are charged with an overall charge, (ii) the CNTs are exposed to an external electric field, and (iii) the test cases (i) and (ii) are combined. Furthermore, the influence of different geometric parameters is investigated. It is shown that the charge applied to the CNTs distributes over the whole CNT having maxima at the ends of the tubes. These maxima can be influenced by both, the geometric parameters and the electric field strength.
Exposure to virtual nature: the impact of different immersion levels on skin conductance level, heart rate, and perceived relaxation
Authors: Knaust Thiemo , Felnhofer Anna , Kothgassner Oswald D. , Höllmer Helge , Gorzka Robert-Jacek , Schulz Holger
Published: November 2021

It is generally accepted that natural environments reduce stress and improve mood. Since access to natural environments is sometimes limited, virtual natural environments, especially monoscopic 360° nature videos, offer a viable alternative. However, it remains unclear whether presenting monoscopic 360° nature videos via a head-mounted display (HMD) or a PC monitor results in larger relaxation effects. Therefore, this study examined whether a monoscopic 360° beach video presented with an HMD is significantly more relaxing than the same video presented via a PC screen, or no video at all (control condition), in altering skin conductance level (SCL), heart rate (HR), and perceived relaxation. Overall, 102 adults (40.2% females, age range 19–62 years) participated in a counterbalanced, randomized, controlled, within-subject experiment. All participants were subjected to three stressors comprising different mental arithmetic tasks, followed by three different recovery phases (HMD, PC, control). For SCL, the results showed a significantly larger decrease in the HMD and PC than in the control condition, but no significant differences between the HMD and PC condition. For HR, there were no significant differences between the recovery conditions. However, the HMD condition was rated significantly more relaxing than the other conditions, with no significant differences between the PC and control condition. Exploratory analyses showed that these results were not moderated by the participants’ age, gender, or technology anxiety. Overall, the psychophysiological results showed no significant benefit favoring the HMD over PC condition, although the self-reported relaxation ratings did. Future studies are warranted to clarify this divergence.
Social network and institution-based strategy research
Authors: Opper Sonja
Published: November 2021

Almost two decades ago,Asia Pacific Journal of Management, 19(2/3): 251–267 Peng (2002) called attention to the promise of institution-based strategy research. The puzzle was to explain differences in strategies around the globe. Building on the work accomplished so far, I ask: Can institution-based strategy succeed when embedded in inappropriate social networks? Institutions and networks are usually studied as separate phenomena, yet each also defines the capabilities of the other. Institutions shape social network contacts and structures because institutions define opportunities for affiliation and the relative value of distinct contacts and network structures. At the same time, social networks shape institutions and organizations’ capabilities for institutional innovation. Thus, the social network in which a manager or organization is embedded can either amplify or counteract success in implementing institution-based strategy. After I review the co-constitutional nature of institutions and networks and discuss a number of sample studies using China as a productive research site, I sketch questions that need to be answered to more tightly integrate network behavior into institutional strategy research, and discuss four emerging areas of research into how network-strategy fit affects performance: (1) network fit to adaptive strategy, (2) network fit to change strategy, (3) institutional dynamics and network-strategy fit, and (4) institutional distance and network-strategy fit.
New developments in the field of genomic technologies and their relevance to conservation management
Authors: Segelbacher Gernot , Bosse Mirte , Burger Pamela , Galbusera Peter , Godoy José A. , Helsen Philippe , Hvilsom Christina , Iacolina Laura , Kahric Adla , Manfrin Chiara , Nonic Marina , Thizy Delphine , Tsvetkov Ivaylo , Veličković Nevena , Vilà Carles , Wisely Samantha M. , Buzan Elena
Published: November 2021

Recent technological advances in the field of genomics offer conservation managers and practitioners new tools to explore for conservation applications. Many of these tools are well developed and used by other life science fields, while others are still in development. Considering these technological possibilities, choosing the right tool(s) from the toolbox is crucial and can pose a challenging task. With this in mind, we strive to inspire, inform and illuminate managers and practitioners on how conservation efforts can benefit from the current genomic and biotechnological revolution. With inspirational case studies we show how new technologies can help resolve some of the main conservation challenges, while also informing how implementable the different technologies are. We here focus specifically on small population management, highlight the potential for genetic rescue, and discuss the opportunities in the field of gene editing to help with adaptation to changing environments. In addition, we delineate potential applications of gene drives for controlling invasive species. We illuminate that the genomic toolbox offers added benefit to conservation efforts, but also comes with limitations for the use of these novel emerging techniques.
Technical Brokering of Immigrant Adolescents in Switzerland: A Developmental-Acculturative Perspective
Authors: Aumann Lara , Titzmann Peter F.
Published: November 2021

In the present digital age, intrafamilial dynamics and adolescents’ support of their parents in media use (technical brokering, Katz, 2010) are increasing in attention. However, the significance of migration-specific processes in adolescents’ technical brokering is less understood. In immigrant families, adolescents’ technical brokering may help families in adapting to the host culture and in keeping contact with friends and family abroad. This study investigated differences in the level of technical brokering between German immigrant and native Swiss adolescents and tested whether migration-unrelated (family life) or migration-related (i.e., culture brokering, Tse, 1995) factors are better predictors of interindividual differences in technical brokering in high SES immigrant families. The sample comprised 301 adolescents in Switzerland: 136 German immigrant adolescents (average age = 15.3, 65% female) and 165 native Swiss adolescents (average age = 15.9, 61% female). Adolescents stated the frequency of technical brokering tasks as well as culture brokering and migration-related processes. The results revealed that German immigrant adolescents provided technical brokering more frequently than native Swiss adolescents. Hierarchical regressions confirmed that technical brokering in German immigrant families is best explained by adolescents’ supporting their family in mastering the transition to a new country, as predictors pertaining to culture brokering, and host culture orientation explained most of the variance. This interpretation received further support by an interaction effect showing that technical brokering is particularly frequent when adolescents act as a culture broker in families with substantial socio-cultural adaptation difficulties. This study complements an often deficit-oriented view on immigrant youth with a view of their active and constructive role in immigrant family processes.
Impact of Conformational Substates and Energy Landscapes on Understanding Hemoglobin Kinetics and Function
Authors: Eaton William A.
Published: November 2021

Hans Frauenfelder’s discovery of conformational substates in studies of myoglobin carbon monoxide geminate rebinding kinetics at cryogenic temperatures (Austin RH, Beeson KW, Eisenstein L, Frauenfelder H, & Gunsalus IC (1975) Dynamics of Ligand Binding to Myoglobin. Biochemistry 14(24):5355–5373) followed by his introduction of energy landscape theory with Peter Wolynes (Frauenfelder H, Sligar SG, & Wolynes PG (1991) The Energy Landscapes and Motions of Proteins. Science 254(5038):1598–1603) marked the beginning of a new era in the physics and physical chemistry of proteins. Their work played a major role in demonstrating the power and importance of dynamics and of Kramers reaction rate theory for understanding protein function. The biggest impact of energy landscape theory has been in the protein folding field, which is well-known and has been documented in numerous articles and reviews, including a recent one of my own (Eaton WA (2021) Modern Kinetics and Mechanism of Protein Folding: a Retrospective. J. Phys. Chem. B. 125(14):3452–3467). Here I will describe the much less well-known impact of their modern view of proteins on both experimental and theoretical studies of hemoglobin kinetics and function. I will first describe how Frauenfelder’s experiments motivated and influenced my own research on myoglobin, which were key ingredients to my work on understanding hemoglobin.