bluuebunny/crossref_metadata_2025 huggingface dataset:
Young measure solutions for nonlinear evolutionary systems of mixed type
Authors: Demoulini Sophia
Published: July 2002

This is a study of measure-valued solutions for systems of mixed type modelled by a hyperbolic-elliptic and a dispersive-parabolic system in arbitrary dimension. Existence is established by time-discretisation of the equations which is solved by the minimisation of a non-convex functional. By relaxation, a Young measure solution is obtained for every time step. Uniform bounds derived by energy considerations allow passage to the limit of continuous time. The potential gradient and the identity are shown to be independent with respect to the Young measure.

Ceci est une étude des mesures, solutions des systèmes de type mixte, modélisés par un système hyperbolique-elliptique et un système dispersif-parabolique, en dimension quelconque. Un résultat d’existence est établi par une discrétisation en la variable temps d’une équation qui est équivalente à la minimisation d’une fonctionnelle non convexe. Par relaxation, une solution, mesure de Young, est obtenue à chaque étape. Des bornes uniformes dérivant de la fonction énergie permettent de passer à la limite en temps continu. Nous prouvons que le gradient du potentiel et l’identité sont indépendants par rapport à la mesure de Young.
Homoclinic tangencies near cascades of period doubling bifurcations
Authors: Catsigeras Eleonora , Enrich Heber
Published: July 2002

We consider perturbations of the Feigenbaum map in

n

dimensions. In the analytic topology we prove that the maps that are accumulated by period doubling bifurcations are approximable with homoclinic tangencies. We also develop a

n

-dimensional Feigenbaum theory in the

C^r

topology, for

r

large enough. We apply this theory to extend the result of approximation with homoclinic tangencies for

C^r

maps.

On considère des perturbations de la transformation de Feigenbaum en dimension

n

. Dans la topologie analytique on prouve que les transformations qui sont accumulées par des bifurcations de duplication de période sont approchées par des tangences homocliniques. On développe aussi une théorie de Feigenbaum

n

-dimensionelle dans la topologie

C^r

, avec

r

suffisamment grand. Cette théorie est appliquée pour étendre le résultat d’approximation par tangences homocliniques pour les transformations

C^r

.
On nonlinear stability of polytropic galaxies
Authors: Wolansky G.
Published: July 2002

We consider a certain class of stationary solutions of the Vlasov–Poisson system with a Newtonian potential. These solutions represent some spherically-symmetric, rotating galaxies obeying the generalized Emden–Fowler law. A nonlinear stability under spherically symmetric perturbations is proved. The proof is based on an adaptation of the energy-Casimir method, which implies a uniform estimate on the mass distribution of the perturbed solutions.

Nous considérons une certaine classe de solutions stationnaires du système de Vlasov–Poisson avec un potentiel Newtonien. Ces solutions décrivent des galaxies tournantes, à symétrie sphérique, obéissant à la loi d’Emden–Fowler. La stabilité nonlinéaire aux perturbations sphériquement symétriques est démontrée. La preuve repose sur une adaptation de la méthode d’énergie-Casimir, laquelle implique une estimation uniforme sur la distribution de masse des solutions perturbées.
Comparison results for solutions of elliptic problems via symmetrization
Authors: Trombetti Guido , Lions Pierre-Louis , Matarasso Silvano , Alvino Angelo
Published: July 2002

We give some comparison results for solutions of Dirichlet problems of elliptic equations and variational inequalities by means of Schwarz symmetrization.

Nous donnons divers résultats de comparaison obtenus par la symétrisation de Schwarz pour les solutions d’équations et inéquations elliptiques.
Concentration of low energy extremals
Authors: Flucher M. , Müller S.
Published: July 2002

We study variational problems of the form

\sup \left\{\int _{\Omega }F\left(u\right):\int _{\Omega }\left|\nabla u\right|^{2} \leq \varepsilon ^{2},u = 0\text{ on }\partial \Omega \right\}

with small

ε

and

0 \leq F\left(t\right) \leq c\left|t\right|^{\frac{2n}{n - 2}}

on a domain of dimension

n ≥ 3

. The corresponding Euler Lagrange equation is a semilinear Dirichlet problem

\begin{gather*} - \Delta u = \lambda f\left(u\right)\text{ in }\Omega , \\
u = 0\text{ on }\partial \Omega
\end{gather*}

with

f = F'

and a large Lagrange multiplier

λ

. Our goal is to obtain qualitative information on the extremals

u_ε

for small

ε

. The integrand

F

can be nonconvex and discontinuous. Thus our results apply to nonlinear eigenvalue problems as well as to certain free-boundary problems.

Our starting point is a generalized Sobolev inequality that covers the classical Sobolev inequality and the isoperimetric inequality relating capacity and volume as special cases. Using a local version of this inequality we prove a generalized concentration-compactness alternative and show that as

ε → 0

the extremals concentrate at a single point. The local behaviour of the extremals near the concentration point depends only on

F

. On a microscopic scale they tend to an extremal for the generalized Sobolev constant on

ℝ^n

provided that

F

satisfies certain growth conditions at 0 and infinity.

Nous étudions des problèmes variationnels

\sup \left\{\int _{\Omega }F\left(u\right):\int _{\Omega }\left|\nabla u\right|^{2} \leq \varepsilon ^{2},u = 0\text{ sur }\partial \Omega \right\}

où

ε

est petit et

0 \leq F\left(t\right) \leq c\left|t\right|^{\frac{2n}{n - 2}}

et

ω

est un domaine de dimension

n ≥ 3

. L'équation d'Euler–Lagrange correspondante est un problème de Dirichlet semilinéaire

\begin{gather*}
- \Delta u = \lambda f\left(u\right)\text{ in }\Omega , \\
u = 0\text{ on }\partial \Omega
\end{gather*}

où

f = F′

et

λ

est un multiplicateur de Lagrange grand. Notre objectif est d'obtenir des informations qualitatives concernant les solutions extrémales

u_ε

pour

ε

petit. La fonction

F

peut être non convexe et discontinue.

Nos résultats s'appliquent par conséquent à des problèmes aux valeurs propres non linéaires et à certains problèmes à frontière libre. Notre point de départ est une inégalité de Sobolev généralisée qui contient l'inégalité de Sobolev classique et l'inégalité isopérimétrique qui relie la capacité et le volume. En utilisant une version locale de cette inégalité nous démontrons une version généralisée de l'alternative concentration-compacitée de Lions et nous montrons que les solutions extrémales se concentrent en un seul point lorsque

ε → 0

. Le comportement local de ces solutions extrémales au voisinage du point de concentration dépend uniquement de

F

. A une échelle microscopique elle tend vers la solution extrémale de la constante de Sobolev généralisée dans

ℝ^n

à condition que

F

vérifie certaines conditions d'accroissement en zéro et à l'infini.
Evolution equations governed by families of weighted operators
Authors: Couchouron J.F. , Ligarius P.
Published: July 2002

In order to develop a Lebesgue approach for the fully non-linear non autonomous evolution problem,

CP_{A}^{\alpha } = \left\{\frac{du}{dt} + \alpha \left(t\right)A_{\alpha }\left(t\right)u∍0\right\}

with

t\in I ⊆ [0,T]

, in an arbitrary Banach space

X

, we define an abstract

L^1

-comparison mode (called
coherence
) between multivalued time dependent families of operators

(A_α(s))_{s\in I}

and

(B_β(t))_{t\in J}

defined on compact subintervals

I

and

J

of

[0,T]

and weighted by functions

α

and

β

which belong to

L^∞([0,T];ℝ^+)

. The solutions of these problems are limit of discrete schemes and the crucial point is to define these approximations in a Lebesgue sense. The results about this Cauchy problem consist in existence of an evolution operator, integral inequalities (extending Bénilan's inequalities for integral solutions), and continuous properties; they extend the theory of evolution equations initiated at the beginning of the seventeenth by Crandall, Liggett, Bénilan, Kobayashi, Evans, ([10], [12], …), and include more recent generalizations as in [18] and [6]. This general study motivated by the observation problem of a heat exchanger (see [16]) where a

L^∞

control multiplies an unbounded operator, establishes in Theorem 3.4 a suitable continuity property with respect to the weak

^∗

topology on the weights (see applications in [3], [7], [20], …).

Ce papier esquisse une approche de type Lebesgue des problèmes d'évolution pleinement non linéaires

CP_{A}^{\alpha } = \left\{\frac{du}{dt} + \alpha \left(t\right)A_{\alpha }\left(t\right)u∍0\right\}

avec

t\in I ⊆ [0,T]

dans un espace de Banach quelconque. Pour cela nous définissons un mode de comparaison (nommé
cohérence
) entre familles d'opérateurs multivoques

(A_α(s))_{s\in I}

et

(B_β(t))_{t\in J}

définies sur des sous-intervalles compacts

I

et

J

de

[0,T]

et pondérées par des fonctions

α

et

β

de

L^∞([0,T];ℝ^+)

. Pour les problèmes d'évolution considérés les solutions sont des limites de schémas discrets: le point crucial est alors de définir ces approximations sur un ensemble dénombrable de noeuds (et donc de mesure nulle) en un sens compatible avec une infinité de classes de fonctions Lebesgue intégrables générées par notre approche. Nous mettons ainsi en évidence pour les problèmes de Cauchy

CP_A^α

un opérateur d'évolution, des inégalités intégrales (généralisant les inégalités des solutions intégrales de Bénilan) et des propriétés de continuité: ces résultats étendent des travaux de Crandall, Liggett, Bénilan, Kobayashi, Evans, ([10], [12], …), et absorbent des généralisations plus récentes obtenues dans [18] et [6]. Cette étude motivée par un problème d'observabilité pour un échangeur thermique (voir [16]) où un contrôle

L^∞

agit multiplicativement sur un opérateur non borné, contient en outre (Théorème 3.4) une propriété de continuité vis-à-vis de la topologie

^∗

-faible des poids dans

L^∞

(cf. [3], [7], [20], … pour les applications).
Existence and uniqueness results on Single-Peaked solutions of a semilinear problem
Authors: Cao Daomin , Noussair Ezzat S. , Yan Shusen
Published: July 2002

A one to one correspondence is established between the nondegenerate critical points of

Q(x)

in

Ω

and single peaked solutions of the problem

\begin{cases}
- \epsilon^{2}\Delta u + u = Q\left(x\right)u^{p - 1} & \text{in }\Omega \\
u > 0& \text{in }\Omega \text{ and }\\
u = 0 & \text{on }\partial \Omega
\end{cases}

where

Ω

is a bounded domain,

2 < p < (N + 2)/(N - 2)

,

\epsilon > 0

, and

Q(x) \in C(\overline \Omega) \cap C^{2}(\Omega)

.

In particular, we establish the uniqueness of the least energy solution when

Q(x)

attains its maximum in

\overline \Omega

at only one nondegenerate critical point in

Ω

.

On établit une correspondance biunivoque entre les points critiques non-dégénérés de

Q(x)

en

ω

, et les solutions à un seul pic du problème

\begin{cases}
- \epsilon^{2}\Delta u + u = Q\left(x\right)u^{p - 1} & \text{in }\Omega \\
u > 0& \text{in }\Omega \text{ and }\\
u = 0 & \text{on }\partial \Omega
\end{cases}

où

Ω

est un domaine borné,

2 < p < (N + 2)/(N - 2)

,

\epsilon > 0

, et

Q(x) \in C(\overline \Omega) \cap C^{2}(\Omega)

.

En particulier, nous démontrons l’unicité de la solution de moindre énergie lorsque

Q(x)

achève son maximum dans

Ω

en un seul point critique non-dégénéré.
Global strong solution of the Navier–Stokes equations in 4 and 5 dimensional unbounded domains
Authors: Sohr Hermann , Kozono Hideo
Published: July 2002

Global strong solutions of the Navier–Stokes equations in 4 and 5 dimensional domains with
non-compact
boundaries are constructed. We prove also their asymptotic behaviour as

t → ∞

.
Qualitative properties of positive solutions of semilinear elliptic equations in symmetric domains via the maximum principle
Authors: Damascelli Lucio , Grossi Massimo , Pacella Filomena
Published: July 2002

In this paper we study the positive solutions of the equation

−Δu + λu = f(u)

in a bounded symmetric domain

Ω

in

ℝ^N

, with the boundary condition

u = 0

on

∂Ω

. Using the maximum principle we prove the symmetry of the solutions

v

of the linearized problem. From this we deduce several properties of

v

and

u

; in particular we show that if

N = 2

there cannot exist two solutions which have the same maximum if

f

is also convex and that there exists only one solution if

f(u) = u^p

and

λ = 0

.

In the final section we consider the problem

−Δu = u^p + μu^q

in

Ω

with

u = 0

on

∂Ω

, and show that if

1 < p <\frac{N + 2}{N - 2}

,

q

on

]0,1[

there are exactly two positive solutions for

μ

sufficiently small and some particular domain

Ω

.

Dans ce travail nous étudions les solutions positives du problème

\begin{cases}
- \Delta u + \lambda = f\left(u\right) & \text{dans }\Omega \\
u = 0 & \text{sur le bord }\Omega
\end{cases}

où

Ω

est un domaine borné et symétrique dans

ℝ^N

.

Avec l’aide du principe de maximum nous prouvons la symétrie des solutions

v

du problème linéarisé. A partir de ce résultat nous déduisons plusieurs propriétés de

v

et

u

; en particulier nous montrons que si

f

est convexe et

N = 2

on ne peut pas avoir deux solutions différentes qui ont le même maximum. On prouve aussi qu’il y a une seule solution si

f(u) = u^p

et

λ = 0

.

Dans la dernière section nous étudions le problème

\begin{cases}
- \Delta u = u^{p} + \mu u^{q} & \text{dans }\Omega \\
u = 0 & \text{sur le bord de }\Omega
\end{cases}

et montrons que si

1 < p < N + 2/N − 2

,

0 < q < 1

et

μ

est petite il y a exactement deux solutions positives dans quelques domaines particuliers.
Spread of infection, in an animal model, after intramedullary nailing of an infected external fixator pin track
Authors: Clasper J. C. , Stapley S. A. , Bowley D. M. G. , Kenward C. E. , Taylor V. , Watkins P. E.
Published: July 2002

Implant sepsis, due to previous external fixator pin track infection, is the most common complication of secondary intramedullary (IM) nailing of the tibia. We have developed an animal model, which allows different treatment methods to be studied. Using an established ovine model of a pin track infection, Staphylococcus aureus was used to infect the external fixator pins, two weeks prior to reamed IM nailing. In the control group, the animals were killed at a mean of 10.5 days following nailing, when widespread infection was evident, with septic arthritis, abscess formation, and infection of the entire length of the tibia in all six animals. In the treatment group, before IM nailing, the pin sites were débrided, and both local and systemic antibiotics were administered. All surgical wounds healed without evidence of infection, 4 of the 6 animals survived for 28 days, and bacteria were only isolated from 1 of the 6 implants. Treatment was successful at reducing, but not eliminating, infection after secondary nailing. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Glutamate dependent dendritic outgrowth in developing neuronal networks of rat hippocampal cells in vitro
Authors: Nuijtinck R.R.H. , Baker R.E. , Tergast E. , Struik M.L. , Mud M.T.
Published: July 2002

The present study was undertaken to determine whether release of glutamate is capable of influencing dendritic morphology in a developing network of rat hippocampal neurons in vitro. Control cultures developed a dense network of fibers and evinced spontaneous electrical activity from the third day in vitro. Dendrites were examined in cultures maintained for 2 weeks in vitro: the experimental group grown in medium containing the glutamate receptor antagonists AP‐5 and DNQX. Dendritic extensions were analyzed as a function of time (days in vitro) using a number of morphometric parameters, viz. the number of processes, the number and length of intermediate and terminal segments, as well as the total length of all segments. We found that the effect of age and treatment was most prominently reflected in the length of the terminal segments. Chronic addition of ionotropic glutamate receptor antagonists from day 2 in culture arrested all dendrite parameters at the prefunctional level. The results suggest that glutamate release is crucial for the onset of dendritic morphological development in hippocampal neurons.
Measuring Outcomes of Midwifery Care: Development of An Instrument To Assess Optimality
Authors: Murphy Patricia Aikins , Fullerton Judith T.
Published: July 2002

Research on the outcomes of midwifery care is hampered by the lack of appropriate instruments that measure both process and outcomes of care in lower risk women. This article describes an effort to adapt an existing measurement instrument focused on the optimal outcomes of care (The Optimality Index—US) to reflect the contemporary style of U.S.‐based nurse‐midwifery practice. Evidence for content validity of the instrument was derived from literature reports of randomized clinical trials, synthetic reviews, and the clinical consensus of professional reviewers. Eleven perinatal health professionals and consumers, representing disciplines of obstetrics and gynecology, midwifery, epidemiology, and neonatology reviewed the instrument. The instrument was then applied to an existing data set of women who intended to give birth at home (N = 1,286 women) to determine its utility in measuring events in the process and outcome of perinatal health care as managed by nurse‐midwives. Results suggest that the tool holds promise for use in outcomes studies of U.S. perinatal care. Further testing of the instrument among diverse multicultural population groups, with various providers, and in diverse birth settings is warranted.
Street, Brian V. (1943–2017)
Authors: Castanheira Maria Lucia , Bloome David
Published: January 2021

Brian Street was a British social anthropologist noted for his theorizing of literacy as social practices. His theorizing, fieldwork, and educational efforts related to literacy were part of a broader intellectual and activist agenda to supplant the deficit representations in social science, literature, and governmental policies of marginalized, colonized, working‐class, nonwhite, and ordinary people. Through the lens of “culture as a verb,” he examined the cultural values and practices involved in structuring power relations; constructing and assigning identities; defining what counts as being, knowing, and doing; and how such processes are maintained. Street's theorizing of literacy as social practices relocated “literacy” as indexical of deficit models, providing a language for researchers, people engaged with educational and development policy, and educators to use in designing curricula and instruction and in representing the social, cultural, and linguistic assets that people, including minoritized people, employ in their uses of written language.
Gender, the Environment, and Ecofeminism
Authors: Gatt Caroline
Published: January 2021

The world is facing what commentators, ranging from student activist Greta Thunberg to UN Secretary General António Guterres, are now calling an “environmental emergency” or “climate crisis.” The debates surrounding the environment in anthropology and beyond emphasize that all global processes necessarily emerge through locally embedded complex relationships, and bring to the fore the tension at the heart of the anthropological project between the diversity of human experience and the question of alterity in a common world we all inhabit. This entry reviews how all these environmental processes are gendered. Further, the specific questions surrounding a critical rethinking of the nature/culture divide resonate with crucial problematics in discussions of gender and essentialism that therefore make joint questions about gender and the environment highly pertinent. Finally, the entry reviews past and current developments in ecofeminism, highlighting areas that are calling for further anthropological collaboration and research.
Conspiracy Theories
Authors: Drążkiewicz Elżbieta , Rabo Annika
Published: January 2021

Conspiracy theories are one way of dealing with gaps between hopes and reality, between the visible and the hidden, and between expert and lay knowledge. They are meaning systems that either explain or make sense of specific events or of social, political, or economic systems of power. Conspiracy theories assume that some actors intentionally conspire to harm others for their own benefit. Often they are linked to feelings of persecution against a way of life; against whole ethnic, racial, or religious groups; or against specific groups. They frequently address fundamental questions about the presence of good and evil, and purport to unveil hidden forces in the world. Thus, they are often connected to cosmologies in ways that make for interesting anthropological scrutiny.
Protective behavioral strategies for sexual aggression and risky sexual behavior
Authors: Treat Teresa A. , Corbin William R. , Viken Richard J.
Published: January 2021

Sexual aggression (SA) is a serious public‐health problem on college campuses, and there is a pressing need for basic research fostering the development of novel prevention strategies. The current study (a) developed measures of protective behavioral strategies (PBS) for sexual aggression (SA) and risky sex (RS); (b) characterized college men's PBS use; and (c) evaluated whether those who reported engaging in SA and RS showed lower PBS use. Undergraduate men from two universities (n = 567) who endorsed sexual attraction toward women completed measures of PBS, SA, RS, rape‐supportive and sociosexual attitudes, and alcohol consumption. On average, participants reported using PBS for SA and RS fairly often, but a sizeable number indicated that they seldom or never used the strategies. Men who reported SA engagement in the last year, relative to their peers, endorsed sharply lower reliance on SA PBS and RS PBS. Men who reported at least one RS behavior in the last year used RS PBS far less often than their peers. The PBS measures converged as expected with other attitudinal and behavioral measures. The new PBS measures reference cognitive‐behavioral approaches that a large percentage of college men use on a regular basis, making them potentially acceptable prevention targets. Further, men at greater risk of exhibiting SA are much less likely to take steps to reduce the risks associated with sexual behavior, in comparison with their peers. Thus, future work could evaluate the potential usefulness of incorporating PBS for SA and RS into primary prevention programming in both domains.
Treatment planning and outcomes effects of reducing the preferred mean esophagus dose for conventionally fractionated non‐small cell lung cancer radiotherapy
Authors: Yorke Ellen D. , Thor Maria , Gelblum Daphna Y. , Gomez Daniel R. , Rimner Andreas , Shaverdian Narek , Shepherd Annemarie F. , Simone Charles B. , Wu Abraham , McKnight Dominique , Jackson Andrew
Published: January 2021

Based on an analysis of published literature, our department recently lowered the preferred mean esophagus dose (MED) constraint for conventionally fractionated (2 Gy/fraction in approximately 30 fractions) treatment of locally advanced non‐small cell lung cancer (LA‐NSCLC) with the goal of reducing the incidence of symptomatic acute esophagitis (AE). The goal of the change was to encourage treatment planners to achieve a MED close to 21 Gy while still permitting MED to go up to the previous guideline of 34 Gy in difficult cases. We compared all our suitable LA‐NSCLC patients treated with plans from one year before through one year after the constraint change. The primary endpoint for this study was achievability of the new constraint by the planners; the secondary endpoint was reduction in symptomatic AE. Planners were able to achieve the new constraint in statistically significantly more cases during the year following its explicit implementation than in the year before (P = 0.0025). Furthermore, 38% of patients treated after the new constraint developed symptomatic AE during their treatment as opposed to 48% of the patients treated before. This is a clinically desirable endpoint although the observed difference was not statistically significant. A subsequent power calculation suggests that this is due to the relatively small number of patients in the study.
Bioorthogonal Coordination Polymer Nanoparticles with Aggregation‐Induced Emission for Deep Tumor‐Penetrating Radio‐ and Radiodynamic Therapy
Authors: Liu Jingjing , Hu Fang , Wu Min , Tian Longlong , Gong Fei , Zhong Xiaoyan , Chen Muchao , Liu Zhuang , Liu Bin
Published: January 2021

Radiodynamic therapy (RDT), an emerging therapeutic approach for cancer treatment by employing ionizing irradiation to induce localized photodynamic therapy (PDT) can overcome the drawbacks of the limited penetration depth for traditional PDT and the unconcentrated energy in the tumor for traditional radiotherapy (RT). Taking advantage of aggregation‐induced emission (AIE) photosensitizers with bright fluorescence and efficient singlet oxygen production in the aggregate state, Hf‐AIE coordination polymer nanoparticles (CPNs), which show both strong RT and RDT effect under X‐ray irradiation, are developed. Furthermore, to enhance the tumor accumulation and prolong the tumor retention of the CPNs, bioorthogonal click chemistry is applied in the system through coupling between dibenzocyclooctyne (DBCO)‐modified CPNs (Hf‐AIE‐PEG‐DBCO) (PEG: poly(ethylene glycol)) and azide groups on the cell membrane formed by metabolic glycoengineering. Thanks to the high penetration of X‐ray irradiation, the bioorthogonal‐assisted RT and RDT combination therapy realizes significant killing of cancer cells without showing noticeable biotoxicity after intravenous administration of CPNs.
Techniques to Facilitate 3D Analysis of Self‐Organized Nanostructure Mechanism in Polymer/Fullerene Bulk Heterojunction Device
Authors: Nikiyan Ashkan , Komilian Soheil , Sadat‐Shafai Torfeh
Published: January 2021

The realization of solution processed polymer/fullerene as a constituent material for an active layer of solar cell raises a fundamental question relating to the nanostructure formation of these devices and its impact on a device's electrical parameters. To have an insight in nanomorphology and nanostructuring, Raman mapping of the scanned surface after each successive chemical etching is performed to build a picture of a vertical profile. To further support this technique, grazing incidence X‐ray diffraction (GIXRD) analysis on an etched surface is also performed. The data generated reveals an accurate correlation between these two techniques. To complete these investigations the impact of blend composition ratios on a nanostructure reveals that fullerene plays a critical role in self‐organization facilitating the rotation of a favorable face‐on the orientation to edge‐on allowing the migration of PC71BM towards the film surface. The impact of these investigations on electrical parameters has been addressed.
An Amorphous Spirobifluorene‐Phosphine‐Oxide Compound as the Balanced n‐Type Host in Bright and Efficient Light‐Emitting Electrochemical Cells with Improved Stability
Authors: Tang Shi , Larsen Christian , Ràfols‐Ribé Joan , Wang Jia , Edman Ludvig
Published: January 2021

A rational host–guest concept design for the attainment of high efficiency at strong luminance from light‐emitting electrochemical cells (LECs) by suppression of exciton‐polaron quenching [Tang et al., Nature Communications 2017, 8, 1190] has been reported. However, a practical drawback with the presented host–guest LEC devices was that the operational stability is insufficient for many applications. Here, a systematic study is performed, revealing that a major culprit for the limited operational stability is that the employed n‐type host, 1,3‐bis[2‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazo‐5‐yl]benzene (OXD‐7), has a strong propensity for crystallization and that this crystallization results in a detrimental phase separation of the constituents in the active material during device operation. The authors, therefore, identify an alternative class of concept‐functional n‐type hosts in the form of spirobifluorene‐phosphine‐oxide compounds, and report that the replacement of OXD‐7 with amorphous 2,7‐bis(diphenylphosphoryl)‐9,9′‐spirobifluorene results in a much improved operational lifetime of 700 h at >100 cd m−2 during constant‐bias driving at an essentially retained high current efficacy of 37.9 cd A−1 and a strong luminance of 2940 cd m−2.
Artificial Neural Networks as Trial Wave Functions for Quantum Monte Carlo
Authors: Kessler Jan , Calcavecchia Francesco , Kühne Thomas D.
Published: January 2021

Inspired by the universal approximation theorem and widespread adoption of artificial neural network techniques in a diversity of fields, feed‐forward neural networks are proposed as a general purpose trial wave function for quantum Monte Carlo simulations of continuous many‐body systems. Whereas for simple model systems the whole many‐body wave function can be represented by a neural network, the antisymmetry condition of non‐trivial fermionic systems is incorporated by means of a Slater determinant. To demonstrate the accuracy of the trial wave functions, an exactly solvable model system of two trapped interacting particles, as well as the hydrogen dimer, is studied.
Flexible Artificial Memristive Synapse Constructed from Solution‐Processed MgO–Graphene Oxide Quantum Dot Hybrid Films
Authors: Chen Tong , Yang Siwei , Wang Jing , Chen Wei , Liu Lifu , Wang Yuan , Cheng Shijie , Zhao Xu
Published: January 2021

Inspired by the low energy consumption and highly parallel processing power of the biological neuromorphic system, the development of a brain‐inspired computing paradigm with electronic devices based artificial synapse may play an essential role in eliminating the Von Neumann bottleneck. Among candidate electronic devices, memristive devices have shown great potential for artificial synapse because of its tunable resistive switching (RS) behaviors. Herein, a biological synapse with solution‐processed MgO‐graphene oxide quantum dots (MgO‐GOQDs) based memristor is developed. The device exhibits highly controllable RS behavior owing to the enhancement of the local electric field by GOQDs and redox of GOQDs under electric fields. Moreover, essential biosynaptic functions including paired‐pulse facilitation, short‐term plasticity (STP)/long‐term plasticity (LTP), STP to LTP transition, and spike‐time‐dependent plasticity are successfully emulated. It is noteworthy that the device fabricated on a polyethylene terephthalate substrate also presents stable RS behavior after a large number of bending cycles. This study demonstrates the great potential of solution‐processed MgO–GOQD hybrid film on its application for the realization of flexible artificial neural networks.
Bifunctional Device with High‐Energy Storage Density and Ultralow Current Analog Resistive Switching
Authors: Liu Qian , Xue Qiang , Wang Yanbin , Wei Xianhua , Hao Jianhua
Published: January 2021

A bifunctional device capable of simultaneously achieving dielectric energy storage and resistive switching is first designed and fabricated based on a conventional metal–insulator–metal (MIM) structure. Typically, Al/TaOx/Pt structure shows a high breakdown strength up to 5.07 MV cm−1 and a relatively high‐energy density of 27.6 J cm−3. Meanwhile, the leakage current of the MIM structure is at the sub‐nanoampere level and exhibits the typical characteristic of analog switching under an applied voltage of about 12 volts. The energy density and the switching current in the developed integrated MIM structure are comparable to the corresponding performances in discrete binary oxides capacitors with linear dielectric and oxide‐based memristors, respectively. Furthermore, synaptic functions with short‐term and long‐term plasticities can be realized. Both of the device properties are found to be correlated to the role of the AlOx interfacial layer between the Al electrode and the dielectric layer, which provides the possibility of coupling between these two functions coexisting in the MIM structure. The prototypical bifunctional device offers a great prospect for multifunctional energy and neuromorphic applications.
Self‐Healing Thin‐Film Transistor Circuits on Flexible Substrates
Authors: Ding Li , Joshi Pushkaraj , Macdonald James , Parab Virendra , Sambandan Sanjiv
Published: January 2021

Thin‐film transistor circuits on flexible substrates hold major promise for next‐generation human–machine interface systems. However, a major bottleneck is the reliability of the interconnect, which is prone to open‐circuit faults due to mechanical, electrical, and environmental stresses. Here, self‐healing interconnects in thin‐film transistor circuits are demonstrated on flexible substrates resulting in the restoration of >99% of the prefault current. The active material for self‐healing is a dispersion of conductive particles in an insulating fluid that is contained over the interconnect. Healing is triggered by the electric field that appears in the open gap during the occurrence of the fault. The engineering of the active material is discussed; self‐healing circuits are demonstrated and analyzed; and methods to package and integrate the self‐healing feature are discussed with the process flow. This work sets a new benchmark for reliable inkjet‐printed thin‐film transistor circuits on flexible substrates.
Ruthenium Core–Shell Engineering with Nickel Single Atoms for Selective Oxygen Evolution via Nondestructive Mechanism
Authors: Harzandi Ahmad M. , Shadman Sahar , Nissimagoudar Arun S. , Kim Dong Yeon , Lim Hee‐Dae , Lee Jong Hoon , Kim Min Gyu , Jeong Hu Young , Kim Youngsik , Kim Kwang S.
Published: January 2021

To develop effective electrocatalytic splitting of acidic water, which is a key reaction for renewable energy conversion, the fundamental understanding of sluggish/destructive mechanism of the oxygen evolution reaction (OER) is essential. Through investigating atom/proton/electron transfers in the OER, the distinctive acid–base (AB) and direct‐coupling (DC) lattice oxygen mechanisms (LOMs) and adsorbates evolution mechanism (AEM) are elucidated, depending on the surface‐defect engineering condition. The designed catalysts are composed of a compressed metallic Ru‐core and oxidized Ru‐shell with Ni single atoms (SAs). The catalyst synthesized with hot acid treatment selectively follows AB‐LOM, exhibiting simultaneously enhanced activity and stability. It produces a current density of 10/100 mA cm−2 at a low overpotential of 184/229 mV and sustains water oxidation at a high current density of up to 20 mA cm−2 over ≈200 h in strongly acidic media.
Preoperative transferrin level is a novel prognostic marker for colorectal cancer
Authors: Sawayama Hiroshi , Miyamoto Yuji , Hiyoshi Yukiharu , Shimokawa Mototsugu , Kato Rikako , Akiyama Takahiko , Sakamoto Yuki , Daitoku Nobuya , Yoshida Naoya , Baba Hideo
Published: January 2021

Aim

This study investigated whether preoperative serum transferrin, a rapid‐turnover protein, was associated with prognosis after colorectal cancer (CRC) resection.

Methods

We evaluated preoperative transferrin, which was calculated as iron and unsaturated iron‐binding capacity, in 501 patients who underwent surgery for Stage I–III CRC. Transferrin level was directly proportional to total iron‐binding capacity (TIBC), and TIBC < 250 μg/dl was defined as low transferrin. The associations between transferrin and prognosis were evaluated in univariate and multivariate Cox proportional hazards analyses.

Results

Fifty‐eight of 501 patients (11.5%) had low transferrin. In these patients, low transferrin was significantly associated with high age, female gender, low body mass index (<18.5), high white blood cell count, low total protein, low albumin, high C‐reactive protein, low hemoglobin, and low neutrophil/lymphocyte ratio. In the univariate analysis, low transferrin was associated with shorter relapse‐free survival (RFS) (hazard ratio [HR] 2.180, 95% confidence interval [CI] 1.417‐3.354, P < .001), overall survival (OS) (HR 2.930, 95% CI 1.784‐4.811, P < .001), and cancer‐specific survival (CSS) (HR 2.122, 95% CI 1.053‐4.275, P = .035). In multivariate analysis, high age (P < .001), Glasgow Prognostic Score (P = .009), and low transferrin (HR 2.336, 95% CI 1.173‐4.654, P = .011) were independently associated with shorter OS, and depth of invasion pT4 (P = .015), presence of lymph node metastasis (P = .001), low hemoglobin (P = .034), and low transferrin (HR 2.638, 95% CI 1.113‐5.043, P = .025) were independently associated with shorter CSS.

Conclusions

Preoperative serum transferrin in Stage I–III CRC patients was identified as a novel prognostic marker by univariate and multivariate analyses.
Memory Devices for Flexible and Neuromorphic Device Applications
Authors: Kim Dongshin , Kim Ik-Jyae , Lee Jang-Sik
Published: January 2021

Recently, consumer electronics have moved toward data‐centric applications due to the development of smart electronic devices. Moreover, electronic devices have become highly portable, wearable, and lightweight. These devices require flexible data storage with high density. Furthermore, with the growing demand for larger memory capacity, faster processing speed, and complex data computation, neuromorphic devices have emerged as the next‐generation memory technologies. To meet the needs of next‐generation memory devices, memory devices based on emerging materials such as 2D, electrochemical, and perovskite materials are suggested. Herein, the recent progress in emerging materials‐based memory devices for flexible and neuromorphic device applications is reviewed. First, the functions and mechanisms of emerging material‐based memory devices are described. Second, applications for emerging material‐based memory devices are reviewed. Finally, the challenges and prospects for the emerging material‐based memory devices are discussed.
Brønsted acid‐catalyzed Reactions of Unprotected N‐heterocycles with Aryl/Aryl Diazoalkanes
Authors: Bahukhandi Srishti Ballabh , Jana Sripati , Koenigs Rene M.
Published: January 2021

The chemoselective C−H functionalization of unprotected N‐heterocycles is a challenging task in organic synthesis. Herein, we report on a Brønsted‐acid catalyzed reaction of aryl/aryl diazoalkanes with unprotected N‐heterocycles to selectively allow for C−H functionalization at the C3‐position under mild reaction conditions and short reaction time without the need of protecting groups. The general applicability of this method was further expanded towards protected indole and unprotected pyrrole heterocycles.
Neuromechanical linkage between the head and forearm during running
Authors: Yegian Andrew K. , Tucker Yanish , Bramble Dennis M. , Lieberman Daniel E.
Published: January 2021

Objectives

The main objective was to test the hypothesis of a neuromechanical link in humans between the head and forearm during running mediated by the biceps brachii and superior trapezius muscles. We hypothesized that this linkage helps stabilize the head and combats rapid forward pitching during running which may interfere with gaze stability.

Materials and methods

Thirteen human participants walked and ran on a treadmill while motion capture recorded body segment kinematics and electromyographic sensors recorded muscle activation. To test perturbations to the linkage system we compared participants running normally as well as with added mass to the face and the hand.

Results

The results confirm the presence of a neuromechanical linkage between the head and forearm mediated by the biceps and superior trapezius during running but not during walking. In running, the biceps and superior trapezius activations were temporally linked during the stride cycle, and adding mass to either the head or hand increased activation in both muscles, consistent with our hypothesis. During walking the forces acting on the body segments and muscle activation levels were much smaller than during running, indicating no need for a linkage to keep the head and gaze stable.

Discussion

The results suggest that the evolution of long distance running in early Homo may have favored selection for reduced rotational inertia of both the head and forearm through synergistic muscle activation, contributing to the transition from australopith head and forelimb morphology to the more human‐like form of Homo erectus. Selective pressures from the evolution of bipedal walking were likely much smaller, but may explain in part the intermediate form of the australopith scapula between that of extant apes and humans.
The diagnostic and prognostic capabilities of plasma biomarkers in Alzheimer's disease
Authors: Simrén Joel , Leuzy Antoine , Karikari Thomas K. , Hye Abdul , Benedet Andréa Lessa , Lantero‐Rodriguez Juan , Mattsson‐Carlgren Niklas , Schöll Michael , Mecocci Patrizia , Vellas Bruno , Tsolaki Magda , Kloszewska Iwona , Soininen Hilkka , Lovestone Simon , Aarsland Dag ,   for the AddNeuroMed consortium, Hansson Oskar , Rosa‐Neto Pedro , Westman Eric , Blennow Kaj , Zetterberg Henrik , Ashton Nicholas J.
Published: January 2021

Introduction

This study investigated the diagnostic and disease‐monitoring potential of plasma biomarkers in mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia and cognitively unimpaired (CU) individuals.

Methods

Plasma was analyzed using Simoa assays from 99 CU, 107 MCI, and 103 AD dementia participants.

Results

Phosphorylated‐tau181 (P‐tau181), neurofilament light, amyloid‐β (Aβ42/40), Total‐tau and Glial fibrillary acidic protein were altered in AD dementia but P‐tau181 significantly outperformed all biomarkers in differentiating AD dementia from CU (area under the curve [AUC] = 0.91). P‐tau181 was increased in MCI converters compared to non‐converters. Higher P‐tau181 was associated with steeper cognitive decline and gray matter loss in temporal regions. Longitudinal change of P‐tau181 was strongly associated with gray matter loss in the full sample and with Aβ measures in CU individuals.

Discussion

P‐tau181 detected AD at MCI and dementia stages and was strongly associated with cognitive decline and gray matter loss. These findings highlight the potential value of plasma P‐tau181 as a non‐invasive and cost‐effective diagnostic and prognostic biomarker in AD.
Enhancement of the Quantum Coherence of the Rydberg Atoms System by Weak Measurement
Authors: Chen Qi , Xu Jing‐Bo
Published: January 2021

The influence of weak measurement along with quantum measurement reversal on the Rydberg atoms system is investigated, and is found to have an important practical significance as both weak measurement along with quantum measurement reversal and Rydberg atoms system can be experimentally realized. The quantum coherence and the entropic uncertainty relation of the system are explored, and it is found that the quantum coherence of the system is enhanced and the values of uncertainty and the uncertainty bound are reduced under some particular weak measurements along with quantum measurement reversals. This indicates that the decoherence effect of the system can be weakened by weak measurement along with quantum measurement reversal. Furthermore, the trace distance which is a reflection of the entanglement is also examined, and it is shown that weak measurement along with quantum measurement reversal can improve the entanglement of the system.
Amino‐Functionalised Hybrid Ultramicroporous Materials that Enable Single‐Step Ethylene Purification from a Ternary Mixture
Authors: Mukherjee Soumya , Kumar Naveen , Bezrukov Andrey A. , Tan Kui , Pham Tony , Forrest Katherine A. , Oyekan Kolade A. , Qazvini Omid T. , Madden David G. , Space Brian , Zaworotko Michael J.
Published: January 2021

Pyrazine‐linked hybrid ultramicroporous (pore size <7 Å) materials (HUMs) offer benchmark performance for trace carbon capture thanks to strong selectivity for CO2 over small gas molecules, including light hydrocarbons. That the prototypal pyrazine‐linked HUMs are amenable to crystal engineering has enabled second generation HUMs to supersede the performance of the parent HUM, SIFSIX‐3‐Zn, mainly through substitution of the metal and/or the inorganic pillar. Herein, we report that two isostructural aminopyrazine‐linked HUMs, MFSIX‐17‐Ni (17=aminopyrazine; M=Si, Ti), which we had anticipated would offer even stronger affinity for CO2 than their pyrazine analogs, unexpectedly exhibit reduced CO2 affinity but enhanced C2H2 affinity. MFSIX‐17‐Ni are consequently the first physisorbents that enable single‐step production of polymer‐grade ethylene (>99.95 % for SIFSIX‐17‐Ni) from a ternary equimolar mixture of ethylene, acetylene and CO2 thanks to coadsorption of the latter two gases. We attribute this performance to the very different binding sites in MFSIX‐17‐Ni versus SIFSIX‐3‐Zn.
Highly Colored Boron‐Doped Thiazolothiazoles from the Reductive Dimerization of Boron Isothiocyanates
Authors: Hagspiel Stephan , Arrowsmith Merle , Fantuzzi Felipe , Vargas Alfredo , Rempel Anna , Hermann Alexander , Brückner Tobias , Braunschweig Holger
Published: January 2021

Reduction of (CAAC)BBr2(NCS) (CAAC=cyclic alkyl(amino)carbene) in the presence of a Lewis base L yields tricoordinate (CAAC)LB(NCS) borylenes which undergo reversible E/Z‐isomerization. The same reduction in the absence of L yields deep blue, bis(CAAC)‐stabilized, boron‐doped, aromatic thiazolothiazoles resulting from the dimerization of dicoordinate (CAAC)B(NCS) borylene intermediates.
Inhibition of Mitochondrial ATP Synthesis and Regulation of Oxidative Stress Based on {SbW8O30} Determined by Single‐Cell Proteomics Analysis
Authors: Gong Lige , Ding Wenqiao , Chen Ying , Yu Kai , Guo Changhong , Zhou Baibin
Published: January 2021

The 10‐nuclear heteroatom cluster modified {SbW8O30} was successfully synthesized and exhibited inhibitory activity (IC50=0.29 μM). Based on proteomics analysis, Na4Ni2Sb2W2‐SbW8 inhibited ATP production by affecting the expression of 16 related proteins, hindering metabolic functions in vivo and cell proliferation due to reactive oxygen species (ROS) stress. In particular, the low expression of FAD/FMN‐binding redox enzymes (relative expression ratio of the experimental group to the control=0.43843) could be attributed to the redox mechanism of Na4Ni2Sb2W2‐SbW8, which was consistent with the effect of polyoxometalates (POMs) and FMN‐binding proteins on ATP formation. An electrochemical study showed that Na4Ni2Sb2W2‐SbW8 combined with FMN to form Na4Ni2Sb2W2‐SbW8‐2FMN complex through a one‐electron process of the W atoms. Na4Ni2Sb2W2‐SbW8 acted as catalase and glutathione peroxidase to protect the cell from ROS stress, and the inhibition rates were 63.3 % at 1.77 μM of NADPH and 86.06 % at 10.62 μM of 2‐hydroxyterephthalic acid. Overall, our results showed that POMs can be specific oxidative/antioxidant regulatory agents.