bluuebunny/crossref_metadata_2025 huggingface dataset:
Homeomorphisms of 1‐Manifolds and ω‐Bounded 2‐Manifolds
Authors: GAULD DAVID
Published: December 2006

ABSTRACT. A classification is given of continuous functions on the long line up to homotopy and homeomorphisms of the long line up to isotopy. The analogous problem for ω‐bounded 2‐manifolds is also investigated.
The Structure of Locally Compact Connected Groups and Metrizabilitya
Authors: ITZKOWITZ GERALD , WU TA SUN
Published: December 2006

ABSTRACT. A conjecture of Wilcox that states that a compact connected group is metrizable iff every element of the group is a metric element is considered. The stronger result that Wilcox's conjecture is valid for locally compact connected groups is proved. The method is to make diligent use of the structure theorem of Pontryagin‐Weil and the Iwasawa Decomposition Theorem. It turns out that the Pontryagin‐Weil structure theorem for compact connected groups yields a simple proof of the generalization of some well‐known facts for compact connected Lie groups. This in turn implies a quick proof of Mycielski's work with compact connected groups. Then making use of these facts, some structure theorems of Comfort, Robertson, and Soundararajan, and the duality theory for LCA groups, a number of theorems involving cardinal invariants of compact connected groups are established. These results imply the Wilcox theorem. Finally it is shown that the set of nonmetric elements in a compact connected group G is a dense nonmeasurable pseudocompact subset of G.
Intrinsic Spectral Topologies
Authors: PRIESTLEY H. A.
Published: December 2006

ABSTRACT:Given a poset (X; ≤), any spectral topology with specialisation order ≤ lies between the upper topology and the Scott topology. Conditions are given under which these extreme topologies are indeed spectral. The results contribute to the understanding ofspeectral sets, that is, posets which arise as the prime ideals of commutative rings with 1, ordered by inclusion, or equivalently as the prime ideals of distributive lattices with 0 and 1, ordered by inclusion.
A Step Beyond Topology
Authors: PROKOP FRANK P.
Published: December 2006

ABSTRACT: The questions which motivated the development of neighborhood (nbhd) lattices as a generalization of topological (top) spaces are discussed. Nbhd systems, which are shown to be appropriate for characterizing continuity, are defined on ^‐semilattices, and are used to define open elements. The duals of nbhd systems are used to define closed elements in a lattice, independently of closure operators or complementation. In addition, the top continuity of a function f: X→Y is characterized in terms of the nbhd continuity of the direct image function mapping P(X), the power set of X, into P(Y). T1‐nbhd lattices are defined, independently of points. Finally, the relationship between continuity and convergence is established by proving that a residuated function between conditionally complete T1‐nbhd lattices is continuous iff it preserves the limit of convergent nets.
Some Properties of Shimrat's Spaces
Authors: YANG ZHANBO
Published: December 2006

ABSTRACT: Shimrat has proved in 1954 that any space can be embedded in a homogeneous space. The procedure that he used nicely transmitted separation properties and connectedness properties, but it has a very bad behavior with respect to countability and covering properties.

This essay more closely investigates the behavior of Shimrat's procedure. Some common properties that can be transmitted by Shimrat's spaces from its underlying spaces and others that can not are discussed.
Graphical Dimension for Line Segments
Authors: EVAKO ALEXANDER V. , MELTER ROBERT A.
Published: December 2006

ABSTRACT: The authors give a new definition of dimension for a graph. It turns out that the graph obtained from a line segment in Euclidean n‐space by means of a construction involving n‐cubes is always 1‐dimensional.
Partial Metric Topology
Authors: MATTHEWS S. G.
Published: December 2006

ABSTRACT: Metric spaces are inevitably Hausdorff and so cannot, for example, be used to study non‐Hausdorff topologies such as those required in the Tarskian approach to programming language semantics. This paper presents a symmetric generalised metric for such topologies, an approach which sheds new light on how metric tools such as Banach's Theorem can be extended to non‐Hausdorff topologies.
Normality and the Weak Topology on a Locally Compact Abelian Group
Authors: TRIGOS‐ARRIETA F. JAVIER
Published: December 2006

ABSTRACT: If G is a locally compact Abelian group, let G+ denote the underlying group of G equipped with the weakest topology that makes all the continuous characters of G continuous. Thus defined, G+ is a totally bounded topological group. We present the original proof of the following result:

Theorem: For G discrete, G+ is normal if and only if G is countable.

Corollary: For G locally compact, G+ is normal if and only if G is s̀‐compact.

Our technics make use of the notion of z‐embedding. The theorem answers in the negative a question posed in 1990 by E. van Douwen, and it partially solves a problem posed in 1945 by A. Markov.
Biseparating Maps and Rings of Continuous Functions
Authors: ARAUJO JESÚS , BECKENSTEIN EDWARD , NARICI LAWRENCE
Published: December 2006

ABSTRACT: C(T) and C(S) denote the rings of real‐ or complex‐valued continuous functions on the Tihonov spaces T and S endowed with their respective compact‐open topologies. An additive bijection H:C(T)→C(S) such that xy= 0 ⇔HxHy= 0 is called biseparating. As shown in 4.5, the existence of such an H implies that the repletions (= realcompactifications) rep T and rep S of T and S are homeomorphic, thus generalizing Hewitt's well‐known result about isomorphisms of rings of continuous functions. “Separating maps” (defined in the first section) serve as a general utensil for investigating rings of continuous functions and automatic continuity results between them. Their utility stems principally from the fact that a separating map H: C(T)→C(S) induces a continuous “support” map h:S→cT, where cT denotes a compactification of T. This notion of support of a separating map is introduced and discussed in the second section.
ASCA Observations of SS 433
Authors: KAWAI NOBUYUKI
Published: December 2006

The X‐ray emission of SS 433 is considered to be generated in the vicinity of the base of the jet, at a distance probably two orders of magnitude or more smaller than the optical emission region1. It is therefore expected that the detailed study in X‐ray would reveal the clearer information of the “central monster” who creates the antiparallel pair of the relativistic precessing jets. With the high resolution spectroscopic capability of ASCA2, the thermal and dynamical properties of the X‐ray emission region of the jets is starting to be studied in detail. Here we present the diagnosis of the jet using the X‐ray emission lines observed in the early phase of the ASCA mission. The temperature at the base of the jet (∼ 10 keV) and the kinetic luminosity (∼ 1039erg s−1) were derived.

We also report the result of the recent contemporaneous spectroscopic observations of SS 433 in X‐ray and optical bands. The precession phase at the observation in October – November 1994 was significantly advanced compared with the prediction of the earlier model parameters3. It can be interpreted either as a result of random walk of the precession phase, or due to the secular decrease of the precession period.
The History of Neuropeptide Research: Version 5.a
Authors: KASTIN ABBA J. , ZADINA JAMES E. , OLSON RICHARD D. , BANKS WILLIAM A.
Published: December 2006

Two reviews published recently reflect the history of neuropeptide research. One of them1 reports the results of a computer search of the scientific literature since 1966. It found more than a quarter of a million papers published concerning those peptides that now are known to be able to exert some effects on the central nervous system (CNS).
Studies on the Metabolism and Biological Function of APLP2a
Authors: SISODIA S. S. , THINAKARAN G. , SLUNT H. H. , KITT C. A. , VON KOCH C. S. , REED R. R. , ZHENG H. Z. , PRICE D. L.
Published: December 2006

Amyloid precursor proteins (APP) are a member of a larger family of proteins that include the amyloid precursor‐like proteins (APLP) APLP1 and APLP2. We have examined the expression and metabolism of APLP2 and document that APLP2 is expressed at high levels in the nervous system and in peripheral tissues. Furthermore, several APLP2 isoforms encoded by alternatively spliced transcripts are posttranslationally modified by a chondroitin sulfate glycosaminoglycan (CSGAG) chain. Furthermore, CSGAG modification is regulated by the insertion of sequences encoded by an alternatively spliced exon. Notably, expression of the CSGAG form of APLP2 appears restricted to embryonic neurons and mature neuronal populations that undergo regeneration, such as olfactory sensory neurons. Thus, differences in posttranslational modifications between the APLP2 isoforms and APP are likely to underlie differences in the regulation and function of these homologues. Our present efforts are directed towards using gene targeting strategies to disrupt the expression of the mouse APP/APLP2 genes to define the normative roles of the encoded molecules in development, plasticity, regeneration, and repair.
Structure, Microtubule Interactions, and Phosphorylation of Tau Proteina
Authors: MANDELKOW E.‐M. , SCHWEERS O. , DREWES G. , BIERNAT J. , GUSTKE N. , TRINCZEK B. , MANDELKOW E.
Published: December 2006

This paper summarizes recent structural and functional studies on tau protein, its interactions with microtubules, its self‐assembly into paired helical filaments (PHF)‐like fibers, and its modification by phosphorylation. The structure of tau in solution resembles that of a random coil. Both tau and Alzheimer PHFs have very little secondary structure, making it improbable that the assembly of tau into PHFs is based on interacting beta sheets. Tau's binding to microtubules can be described by a “jaws” effect. The domain containing the repeats binds very weakly, while the flanking regions (jaws) bind strongly, even without the repeats. However, only the combination of flanking regions and repeats makes binding productive in terms of microtubule nucleation and assembly. Although the majority of Alzheimer‐like phosphorylation sites are outside the repeats they have only a weak influence on binding, whereas the phosphorylation at Ser262 inside the repeats inhibits binding and makes microtubules dynamically unstable. This site can be phosphorylated by kinases present in brain tissue, and it is uniquely phosphorylated in Alzheimer brain.
Regulation of Tau Phosphorylation in Alzheimer's Disease
Authors: LEE V. M.‐Y.
Published: December 2006

Alzheimer's disease (AD) is a heterogeneous dementing disorder of the elderly that is characterized by progressive cognitive impairments and the accumulation of abundant amyloid or senile plaques (SPs) and neurofibrillary tangles (NFTs) as well as the massive loss of neutrons in the AD brain. Indeed, a secure diagnosis of AD in patients with a chronic progressive dementia requires evidence of numerous SPs and NFTs in the postmortem brain. Although the deposition of fibrillar amyloid or Aβ‐peptides in extracellular plaques and the accumulation of tau‐rich intraneuronal NFTs are not restricted exclusively to AD, there is a close correlation between the burden of tau‐rich neurofibrillary lesions in selected telencephalic regions of the brain and the dementia in AD. Since the formation of neurofibrillary lesions from hyperphosphorylated tau proteins may compromise the function and viability of neurons in the AD brain, this review summarizes recent insights into mechanisms that regulate the phosphorylation state of tau in AD.
Molecular Mechanism of Alzheimer's Neurofibrillary Degeneration and Therapeutic Interventiona
Authors: IQBAL K. , GRUNDKE‐IQBAL I.
Published: December 2006

Microtubule‐associated protein tau is abnormally hyperphosphorylated in the brain of patients with Alzheimer's disease (AD) and the abnormal tau is the major protein subunit of paired helical filaments (PHF). The abnormal phosphorylation of tau probably precedes its polymerization into PHF. The abnormal tau does not bind to tubulin, but competes with tubulin in binding to normal tau and thereby inhibits the assembly of microtubules in the affected neurons. The abnormal tau can be dephosphorylated enzymatically and by this way its microtubule assembly promoting activity can be restored. The activities of protein phosphatases might be decreased in the affected neurons in AD brain, allowing the abnormal hyperphosphorylation of tau. Neurofibrillary degeneration can probably be inhibited by increasing the activities of protein phosphatases in the brain of patients with Alzheimer's disease.
Morphological, Biochemical, and Genetic Support for an Apolipoprotein E Effect on Microtubular Metabolisma
Authors: ROSES A. D. , EINSTEIN G. , GILBERT J. , GOEDERT M. , HAN S‐H. , HUANG D. , HULETTE C. , MASLIAH E. , PERICAK‐VANCE M. A. , SAUNDERS A. M. , SCHMECHEL D. E. , STRITTMATTTER W. J. , WEISGRABER K. H. , XI P.‐T.
Published: December 2006

There are two distinct viewpoints on the association of the inheritance of apolipoprotein E (APOE) alleles and the age of onset distribution of Alzheimer's disease (AD): genetic and phenotypic expression. There have been multiple corroborations of the APOE‐ε4 association with Alzheimer's disease in populations around the world in clinic based studies as well as emerging epidemiological studies. The genetic data do not imply mechanism of pathogenesis. The phenotypic expression of AD has been based in theories based on amyloid plaques or neurofibrillary tangles. ApoE protein interacts with both β‐amyloid and tau in an isoform‐specific manner. The interaction with tau had been thought to be an in vitro artifact, since apoE had not been previously localized to the
Atrophy of the Hippocampal Formation in Early Familial Alzheimer's Disease
Authors: FOX N. C. , WARRINGTON E. K. , STEVENS J. M. , ROSSOR M. N.
Published: December 2006

The hippocampal formation (HF) is known from pathological and magnetic resonance imaging (MRI) studies to become severely atrophied in established Alzheimer's disease (AD). This study examined whether changes in the HF could also be detected in very early AD by scanning subjects at risk of developing familial AD (FAD). Five at risk members of a pedigree with the amyloid precursor protein (APP) 717 valine to glycine mutation underwent serial MRI scanning with volumetric measurement of the HF as well as neurological and neuropsychological assessments. Over a period of two years two subjects became clinically affected, a loss of up to 20% of the volume of the HF occurred in the two years over which symptoms first appeared. Asymmetrical HF atrophy was shown to have been present before the development of overt symptoms. This may have important implications for early diagnosis in AD more generally.
Participation of Gene Expression in the Protection against Amyloid β‐Peptide Toxicity by the β‐Amyloid Precursor Proteina
Authors: BARGER S. W. , MATTSON M. P.
Published: December 2006

The amyloid β‐peptide (Aβ) is a toxic derivative of the β‐amyloid precursor protein. Alternative processing of this precursor also yields large soluble forms (APPSs) which are secreted from many cell types. These APPSs have neuritogenic and neuroprotective activities; indeed, APPSs can protect primary neurons from the toxicity of Aβ itself. To begin to explore the regulation of gene expression by APPS, we have focused on the NF‐κB transcription factor family. NF‐κB is induced by conditions of stress, including cellular oxidation. We report that NF‐κB can also be induced by APPS. Furthermore, we effected direct activation of NF‐κB through disinhibition using antisense oligonucleotide technology. This means of activating NF‐κB resulted in protection of neuroblastoma cells from the toxicity of a calcium ionophore and protection of primary hippocampal neurons from the toxicity of Aβ. Together, these data suggest that NF‐κB may exist as a common agent inducing a neuroprotective pattern of gene expression in response to either trophic cytokines or stress itself.
The Role of Heparan Sulfate Proteoglycans in the Pathogenesis of Alzheimer's Diseasea
Authors: SMALL D. H. , WILLIAMSON T. , REED G. , CLARRIS H. , BEYREUTHER K. , MASTERS C. L. , NURCOMBE V.
Published: December 2006

The hallmark of Alzheimer's disease (AD) is the deposition of amyloid plaques and neurofibrillary tangles in the brain. The relationship between amyloid deposition and the cognitive deficit is still unclear. The amyloid βA4 protein is produced by proteolytic cleavage of the amyloid protein precursor (APP). Very little is known about the normal function of APP and the role the protein may play in pathogenesis. Several studies have shown that APP is important for the regulation of neurite outgrowth. Our studies support these findings and indicate that the neurite outgrowth‐promoting effects of APP are stimulated by an interaction between APP and specific proteoglycans. Using site‐directed mutagenesis, a heparan sulfate binding site which mediates this effect has been mapped to the N‐terminus of APP (residues 96‐110, HBD‐1). A peptide homologous to HBD‐1 blocks the trophic effects of APP in cell culture. To purify specific proteoglycans which stimulate the action of APP, an affinity column was constructed using a biotinylated peptide homologous to HBD‐1 coupled to streptavidin‐agarose. Two proteoglycans were isolated from a crude brain cell conditioned medium by affinity chromatography. The purified proteoglycans bound APP saturably with high affinity and stimulated the action of APP on neurite outgrowth from chick sympathetic neurons. Digestion of the proteoglycan fraction with heparitinase I or chondroitinase ABC demonstrated the presence of two major proteins, a heparan sulfate proteoglycan with a core protein of 63‐67 kD molecular mass and a chondroitin sulfate proteoglycan with a core protein of 100‐110 kD molecular mass. The results demonstrate that APP binds to at least two proteoglycans and that this interaction may regulate the trophic effects of the protein. The interaction of specific APP‐binding proteoglycans with amyloid plaques may disturb the normal function of APP and contribute to the neuritic degeneration that is commonly seen around the amyloid plaque cores.
Tameness and Movability in Proper Shape Theory
Authors: ČERIN ZVONKO , GIANELLA GIAN MARIO
Published: December 2006

We study properly MBC‐tame and properly MB ‐movable spaces, where B and C denote classes of topological spaces. Both proper tameness and proper movability are invariants of a recently invented first author's proper shape theory and are described by the use of proper multivalued functions. The first is analogous to L. Siebenmann's notion of a tame at infinity space while the second is modelled on Borsuk's concept of movability in shape theory.
Molecular Physiology, Biochemistry, and Pharmacology of Alzheimer's Amyloid Precursor Protein (APP)a
Authors: SUH YOO‐HUN , CHONG YOUNG HAE , KIM SEONG‐HUN , CHOI WOONG , JEONG SUNG‐JIN , FRASER S. P. , DJAMGOZ M. B. A. , MIN KYEONGSIK
Published: December 2006

SUMMARY
"One Nation … Indivisible": Jacques Derrida on the Autoimmunity of Democracy and the Sovereignty of God
Authors: Naas Michael
Published: December 2006

During the final decade of his life, Jacques Derrida came to use the trope of autoimmunity with greater and greater frequency. Indeed it today appears that autoimmunity was to have been the last iteration of what for more than forty years Derrida called deconstruction. This essay looks at the consequences of this terminological shift for our understanding not only of Derrida's final works (such as Rogues) but of his entire corpus. By taking up a term from the biological sciences that describes the process by which an organism turns in quasi-suicidal fashion against its own self-protection, Derrida was able to rethink the very notion of life otherwise and demonstrate the way in which every sovereign identity, from the self to the nation-state to, most provocatively, God, is open to a process that both threatens to destroy it and gives it its only chance of living on.
All of Us Program Illustrates What Less-Diverse Genomics Studies Might Be Missing
Authors: Rubin Rita
Published: March 2024

This Medical News story discusses new findings from genomics studies involving diverse cohorts.
Consent and Identifiability for Patient Images in Research, Education, and Image-Based Artificial Intelligence
Authors: Salvador Trina , Gu Lilly , Hay Jennifer L. , Kurtansky Nicholas R. , Masterson-Creber Ruth , Halpern Allan C. , Rotemberg Veronica
Published: March 2024

This survey study reports the perspectives and preferences of US adults regarding use of photographs of their skin in medical research, education, and development of image-based artificial intelligence (AI).
Physical features and social analysis of Gozar: The case of Quzzat quarter of Herat Old City, Afghanistan
Authors: Asim Ghulam Mohammad , Shimizu Hajime
Published: March 2024

The study aims to discover the formation, functions, typology, and development process of the Gozar system in the Herat Old City in Afghanistan. Traditional local administrative units, or Gozar, consist of residential areas, facilities, and functions performed by their residents. The paper examines the physical characteristics of the Gozar as well as its social functions. The boundaries of Gozar were plotted, urban types classified, and a typology of Gozar, explained by age, was developed. Even though Gozar's physical situation has dramatically changed, the three main functions, political, social, and environmental, have mostly stayed the same.
High‐Temperature Creep Behavior and Damage Mechanism of an Advanced Powder Metallurgy Ni‐Based Superalloy
Authors: Li Xinyu , Zhang Haopeng , Li Xiaokun , Jia Jian , Liu Changsheng , Liu Jiantao , Zhang Yiwen
Published: March 2024

The creep behavior of a novel powder metallurgy (PM) Ni‐based superalloy is investigated at temperatures ranging from 760 to 815 °C and stress levels in the 480–620 MPa. The steady‐state creep rate, strain to rupture, and rupture time are analyzed based on the Monkman–Grant relation (MGR) and the modified MGR (MMGR). The creep damage factor is redefined by the analysis of Monkman–Grant ductility (MGD). A general relationship between the time reaching MGD and creep life is established. The sharply accelerated creep stage is proposed and the MMGR of the transient creep parameters in this stage is established. The nucleation, growth, and connection of grain‐boundary creep cavities dominate the creep damage of the alloy. The stress concentration caused by the accumulation of dislocations at grain boundaries and σ‐phase interfaces and the grain‐boundary slipping are the main reasons for the nucleation of grain‐boundary cavities. The coupling effect of the temperature and the stress aggravates the damage of grain boundary and the degradation of microstructure.
Grayscale to Multicolor Laser Writing Inside a Label‐Free Metal‐Organic Frameworks
Authors: Zhestkij Nikolaj A. , Efimova Anastasiia S. , Kenzhebayeva Yuliya , Povarov Svyatoslav A. , Alekseevskiy Pavel V. , Rzhevskiy Sergey S. , Shipilovskikh Sergei A. , Milichko Valentin A.
Published: March 2024

Direct laser writing (DLW), being a universal tool for fast creating colorless/color images on different substrates, still suffers from simultaneous writing grayscale and color images inside the transparent media. Here, it is discovered that a unique set of porosity, coordination bonding between organic and inorganic building blocks, and the lack of inversion symmetry of the label‐free metal‐organic frameworks (MOFs), on the one hand, provides the possibility of laser writing the grayscale images through the amorphization/carbonization. On the other hand, the reduction of the laser writing power leads to controllable creation of color images via defect formation with sub‐diffraction resolution inside the MOF crystals. The latter is due to the processes of self‐absorption of generated optical harmonics by nonlinear MOFs within the visible spectral range. As a result, simultaneous grayscale and multicolor writing of QR codes and images are demonstrated with up to 400 nm resolution inside optically transparent MOF crystals, thereby discovering a new family of functional materials for DLW.
Neutrophil Hitchhiking Biomimetic Nanozymes Prime Neuroprotective Effects of Ischemic Stroke in a Tailored “Burning the Bridges” Manner
Authors: Song Junyan , Yang Guang , Song Yan , Jiang Zeyu , Jiang Yue , Luan Yuxia , He Wenxiu
Published: March 2024

Reperfusion injury of ischemic stroke, characterized by the uncontrolled production of reactive oxygen species (ROS) and inflammatory reactions, continues to present a major problem in clinical treatment. Neutrophils are forerunners to infiltrate cerebral ischemic regions and contribute to reperfusion injury. Herein, this study reports a tailored “burning the bridges” strategy by designing biomimetic nanozymes (D@HPB@SPM NPs) to diminish reperfusion injury of ischemic stroke. D@HPB@SPM NPs are composed of a sialic acid (SA)‐modified platelet membrane shell and a hollow Prussian blue nanoparticle core loaded with Deoxyribonuclease I (DNase I). Due to the unique binding affinity of SA to L‐selectin, which is abundantly expressed in circulating neutrophils, D@HPB@SPM NPs can effectively hitchhike on neutrophils across the blood‐brain barrier into the injured brain parenchyma after intravenous injection. Following this, neutrophils are activated and unleash D@HPB@SPM NPs through producing neutrophil extracellular traps (NETs). D@HPB@SPM NPs not only relieve oxidative stress injury by efficiently scavenging ROS, but also mitigate neutrophil‐induced reperfusion injury by degrading NETs in a manner similar to “burning the bridges”. The encouraging accumulation of D@HPB@SPM NPs to cerebral ischemic regions and their efficient therapeutic efficacy are systematically validated in ischemic stroke rats. This work offers a fresh insight for ischemic stroke treatment.
Bimetallic Sulfides with Vacancy Modulation Exhibit Enhanced Electrochemical Performance
Authors: Guo Jiawei , Zhao Hongbo , Yang Zhongwei , Wang Longwei , Wang Aizhu , Zhang Jian , Ding Longhua , Wang Longfei , Liu Hong , Yu Xin
Published: March 2024

Transition bimetallic sulfides show significant promise for energy‐related applications because of their plentiful active sites and synergistic redox activity. However, limited pore size and low‐conductivity issues hinder their application. The structure of NiCo–S with rich sulfur vacancies is first predicted by density functional theory (DFT) calculations. Different sulfur vacancy concentrations are modeled by DFT calculations, and the results confirm that sulfur vacancies enhance the conductivity of the electrode material and are more beneficial for the adsorption of OH* species. It is verified by the differential charge density that the electric field formed on the surface of the electrode can lead to strong interfacial interactions by electron aggregation, which promotes electron/ion transfer kinetics. Furthermore, NiCo–S nanosheets are prepared on carbon cloth enriched with different concentrations of sulfur vacancies (denoted as NiCo‐Sv‐x, with x representing the concentration of sulfur vacancies) by sulfide etching NiCo‐MOF and annealing under H2/Ar atmosphere. The NiCo‐Sv‐x electrodes obtained are applied to the cathode of supercapacitors and the anode of the oxygen evolution reaction. Through combining experimental and theoretical analysis, the effect of vacancy defect engineering on the electrochemical performance of the electrode materials is further confirmed.
Perovskite‐Oxide‐Based Ferroelectric Synapses Integrated on Silicon
Authors: Zheng Ningchong , Zang Yipeng , Li Jiayi , Shen Cong , Jiao Peijie , Zhang Lunqiang , Wang He , Han Lu , Liu Yuwei , Ding Wenjuan , Yang Xinrui , Nian Leyan , Ma Jianan , Jiang Xingyu , Yin Yuewei , Xia Yidong , Deng Yu , Wu Di , Li Xiaoguang , Pan Xiaoqing , Nie Yuefeng
Published: March 2024

Perovskite‐oxide‐based ferroelectric tunnel junctions (FTJs) hold great potential for applications in non‐volatile memory and neuromorphic computing due to their unique properties. However, the challenges in synthesizing high crystalline quality perovskite oxides directly on silicon wafer limit the applications of these FTJs in conventional Si‐based integrated circuits, let alone the neural networks. Herein, perovskite oxide FTJs with an ON/OFF ratio up to 1.2×106, writing/erasing speed down to 1 nanosecond, and cycling endurance (>106) are achieved by integrating ultrathin freestanding ferroelectric perovskite oxide membranes directly on silicon wafers using a wet‐transfer method. Moreover, synapses based on these FTJs exhibit long‐term plasticity. For handwritten digits recognition task, the convolutional neural network (CNN) simulation is implemented achieving a recognition accuracy up to 98.9% based on the experimental performance, close to the result of 99.2% by software‐floating‐point‐based CNN. This work sheds light on the integration of ferroelectric perovskite oxides directly on silicon for high‐performance FTJ‐based non‐volatile memory and synaptic devices.
Chirality Triggered Biferroicity in a 3D Rubidium Based Perovskite
Authors: Ju Tong‐Yu , Fan Chang‐Chun , Liang Bei‐Dou , Liu Cheng‐Dong , Jin Ming‐Liang , Chai Chao‐Yang , Zhang Wen
Published: March 2024

Multiferroics refer to materials with two or more ferroic orders in one phase within a specific temperature range, including ferroelectricity, ferroelasticity, and ferromagnetism which have been widely used in sensors, actuators, and memory devices. Among them, hybrid perovskites exhibiting multiferroicity are generally limited to low dimensions (0D–2D). Designing 3D lead‐free perovskite multiferroics remains a challenge due to Goldschmidt's tolerance factor limitation. Here, a multiferroic perovskite (R‐3AP)RbBr3 (1; 3AP = 3‐ammoniopyrrolidinium) is successfully synthesized by introducing homochirality to the 3D ferroelectric (Rac‐3AP)RbBr3, achieving both ferroelasticity and ferroelectricity. Compound 1 undergoes a structure phase transition at 401 K belonging to Aizu notation 432F2(s), which has 12 ferroelectric equivalent polarization directions and 6 polar axes. Furthermore, 1 exhibits reversible second harmonic generation switching effects. Moreover, while the temperature varies, the reversible and rapid changes of ferroelastic domains in 1 are observed using a polarizing microscope, indicating that it is a ferroelastic material. This work provides a practical method for designing and synthesizing molecule‐based multiferroics.
Ferroelectric Modulation of ReS2‐Based Multifunctional Optoelectronic Neuromorphic Devices for Wavelength‐Selective Artificial Visual System
Authors: Dang Zhaoying , Guo Feng , Zhao Yifei , Jin Kui , Jie Wenjing , Hao Jianhua
Published: March 2024

Neuromorphic optoelectronic vision system inspired by the biological platform displays potential for in‐sensor computing. However, it is still challenge to process multiwavelength image in noisy environment with simple device configuration and light‐tunable biological plasticity. Here, a prototype visual sensor is demonstrated based on ferroelectric copolymer poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) and 2D rhenium disulfide (ReS2) with integration of recognition, memorization, and pre‐processing functions in the same device. Such synaptic devices achieve impressive electronic characteristics, including a current on/off ratio of 109 and mobility of 45 cm2 V−1 s−1. Various synaptic plasticity behaviors have been achieved owing to the switchable ferroelectricity, enabling them to establish an artificial neural network (ANN) with high digit recognition accuracy of 89%. Through constructing optoelectronic device array, object extraction is achieved with wavelength‐selective capability in noisy environment, closely resembling human retina for color recognition. Above outcomes bring a notable improvement in the image recognition rate from 72% to 96%. Besides, low energy consumption comparable to single biological event can be realized. With these multifunctional features, this work inspires highly integrated neuromorphic systems and the development of wavelength‐selective artificial visual platform.
A Polyanionic Hydrogel Electrolyte with Ion Selective Permeability for Building Ultra‐Stable Zn/I2 Batteries with 100 °C Wide Temperature Range
Authors: Liu Yangyang , Li Fujun , Hao Junnan , Li Hongbao , Zhang Shilin , Mao Jianfeng , Zhou Tengfei , Wang Rui , Zhang Longhai , Zhang Chaofeng
Published: March 2024

The practical applications of aqueous Zn/I2 batteries (AZIBs) operating within a wide temperature range are severely hindered by the uncontrolled shutting of polyiodide ions (I3−/ I5−) and rampant side reactions. In this study, a wide temperature tolerant polyanionic hydrogel (borax‐bacteria cellulose / p(AMPS‐AM)) with ion selective permeability is designed for inhibiting shutting effect and side reactions under extreme temperatures range from −50 to 50 °C. The zincophilic R−SO3− significantly enhances the transport of Zn2+ cations and promotes uniform growth of Zn metal along the (002) plane. Moreover, the abundant hydrophilic groups in hydrogels effectively suppress both the hydrogen evolution reaction and the formation of by‐products by reducing the water reactivity. Furthermore, theoretical calculations, visualization experiment and in situ Raman spectroscopy confirm that R−SO3− group effectively hinders the shuttle process of I3−/I5− anions through electrostatic repulsion. Consequently, this gel electrolyte facilitates the ultra‐stable Zn/I2 full cell at a low current density of 2 C over a wide temperature range of 100 °C. A Zn/I2 pouch cell with a low negative/positive capacity ratio of 3.3 exhibits a stable performance over 350 cycles with an impressive high‐areal capacity of 2.03 mA h cm−2, thereby establishing a solid foundation for its practical applications.
Enhancing Oxygen Reduction Activity and CO2 Tolerance by a Bismuth Doping Strategy for Solid Oxide Fuel Cell Cathodes
Authors: Jin Fangjun , Liu Xiaowei , Tian Yunfeng , Ling Yihan
Published: March 2024

Layered perovskite related oxides, LnBaCo2O5+δ (Ln = rare‐earth element) are potential ceramic cathodes for intermediate temperature solid oxide fuel cells. Herein, a simple way to tune the performance of NdBaCo2O5+δ (NBC) perovskite as a cathode by doping the Co‐site with bismuth cation is reported. Compared with the parent oxide, the obtained stabilized double perovskites NdBaCo2−xBixO5+δ (x = 0.1 and 0.2) show a much improved electrocatalytic activity, achieving area‐specific resistance of 0.268, 0.107 and 0.152 Ω cm2 at 700 °C in air for NBC, x = 0.1, and 0.2, respectively. Density functional theory results demonstrate that bismuth doping effectively reduces the formation energy of oxygen vacancies. Moreover, the bismuth doping of NdBaCo2−xBixO5+δ cathode is much more robust against CO2 than that of NBC cathode. This work indicates that bismuth doping in the B‐site of LnBaCo2O5+δ may be a highly attractive strategy for the future development of cathode materials.
Biobased Thermoset Substrate for Flexible and Sustainable Organic Photovoltaics
Authors: Tian Jingfu , You Yang , Zhou Han , Li Haojie , Hu Lin , Tian Yaozhu , Xie Haibo , Xie Yuanpeng , Hu Xiaotian
Published: March 2024

Toward a sustainable development of the flexible electronics industry, the design and facile preparation of sustainable flexible substrates with satisfactory mechanical properties and transparency is still a challenge. Herein, taking structural advantages of biobased eugenol and vanillin, a polymerizable aromatic carbonate monomer with α,ω‐diene functionality (2E), and a robust aromatic acetal monomer with α,ω‐tetraene functionality (4E), are designed and prepared. Then, they are cross‐linked with pentaerythritol tetrakis(2‐mercaptoacetate) (4SH) via thiol‐ene click reaction to generate a series of ternary poly(thioether carbonate acetal) thermosets. It is found that the introduction of 4E allows the production of thiol‐ene thermosets with higher crosslink density, which can balance their mechanical, optical, and surface properties. In addition, the thermoset shows good resistance against various natural environmental conditions and can be decomposed into recyclable small molecules under harsher conditions (3 m NaOH, 80 °C). As a result, the optimal thermoset is well‐suited for the fabrication of flexible organic solar cells (OSCs), yielding a power conversion efficiency of 15.41%, which is superior to polyethylene terephthalate‐based OSC. The results provided significant insights for the design and preparation of sustainable polymer substrates for OSCs, even flexible electronics.
Ion‐Engineered Microcryogels via Osteogenesis‐Angiogenesis Coupling and Inflammation Reversing Augment Vascularized Bone Regeneration
Authors: Wang Yue , Wang Xinyu , Pang Yanyun , Li Xiaomin , Gao Chenyuan , Zhang Daixing , Li Guangyu , Yu Yingjie , Yang Xiaoping , Cai Qing
Published: March 2024

Native bone inherently requires a balanced ionic microenvironment to maintain bone homeostasis. Hence, scaffolds designed for the sustained release of therapeutic ions into bone defects hold great promise for bone regeneration. Magnesium (Mg) and silicon (Si) are essential elements, which play crucial roles in the process of bone regeneration, impacting immunomodulation, angiogenesis, and osteogenesis. Herein, porous cryogel‐type organic–inorganic composite microspheres are developed as injectable microscaffolds (denoted as GMN). GMN enables sustained release of Mg/Si ions at an optimized ratio, achieving the most significant synergistic effect on vascularized bone regeneration. Various conditioned media are obtained to explore angiogenesis‐osteogenesis coupling, as well as the crosstalk between bone marrow mesenchymal stromal cells (BMSCs) and macrophages. Meanwhile, autocrine and paracrine effects simultaneously play synergistic modulating functions in determining cell fates under the guidance of Mg/Si ions and biofactors secreted by cells. Overall, the Mg/Si ion‐engineering microscaffolds create a conducive microenvironment to efficiently augment the regeneration of vascularized bone tissue in vivo, offering a versatile platform for tissue engineering.
Screening Spinel Oxide Supports for RuO2 to Boost Bifunctional Electrocatalysts for Advanced Zn–Air Batteries
Authors: Zou Xiaohong , Lu Qian , Wu Jie , Zhang Kouer , Tang Mingcong , Wu Baoxin , She Sixuan , Zhang Xiao , Shao Zongping , An Liang
Published: March 2024

The compositing strategy offers great potential in designing bifunctional oxygen electrocatalysts for Zn–air batteries. Recent reports reveal that the couple of RuO2, serving as a benchmark oxygen evolution reaction (OER) catalyst, with other oxygen reduction reaction (ORR) catalysts is a wise choice to build highly efficient bifunctional electrocatalysts. However, the design criteria for ORR and OER activities of RuO2‐based composite catalysts are still unclear. Herein, a series of transition metal (Fe, Co, Mn, and Ni)‐doped spinel oxides are designed to support RuO2 nanorods for exploring the reaction mechanism. Through advanced technology, it is considered that increasing the content and binding energy of Co3+ and enhancing the oxidation state of Ru4+ is an efficient strategy to promote ORR and OER activities for RuO2/Co‐based spinel oxide composite catalysts. It is found that coupling Mn‐doping Co3O4 (CMO) supports with RuO2 can induce the highest catalytic activities in ORR/OER and excellent performance in rechargeable Zn–air batteries. Operando electrochemical impedance spectroscopy and theoretical calculation further prove the synergistic effect between RuO2 and CMO supports originated from the oxygen overflow to overcome the large barrier for oxygen desorption on RuO2 during OER and oxygen adsorption on CMO supports during ORR.
Constructing Covalent Organic Polymers through Dative B─N Bonds: Synthesis, Single Crystal Structures, and Physical Properties
Authors: Wang Xin , Zhang Lei , Wang Xiang , Cheng Tianqi , Xue Miaomiao , Dong Qiang , Peng Yungkang , Zhang Qichun
Published: March 2024

Growing single crystals of covalent organic polymers (COPs) for single‐crystal X‐ray diffraction analysis is very important and highly desirable because such strategy provides a deep understanding of crystallization kinetics and the structure‐property relationship of COPs. Based on the strategy that dynamic covalent bonds can allow self‐correction of structures during crystal growth, single crystals of two COPs (CityU‐15 and CityU‐16) based on dative boron‐nitrogen (B─N) bonds have been successfully obtained. Detailly, tetra(4‐pyridyl)tetrathiafulvalene (TTF(py)4) and tetra(4‐pyridyl)porphine (TPYP) are employed as N‐donor ligands to react with 1,4‐bis(benzodioxaborole) benzene to prepare single crystals of COPs, named as CityU‐15 and CityU‐16, respectively. CityU‐16 exhibits enhanced stability compared to CityU‐15, and the size of CityU‐16 single crystals can reach up to 0.7 cm. CityU‐15 shows good recyclability and reveals noticeable photosensitivity upon iodine doping. After treatment with iodine, both crystals display obvious color changes. Specially, the device based on I2‐treated CityU‐15 exhibits excellent low‐voltage operation and low energy consumption of 3.3 fJ, facilitating the development of artificial vision. This work highlights the successful introduction of functional groups into B‐N‐containing COPs, opening up new avenues for expanding their applications.
Design of a Novel Delivery Efficiency Feedback System for Biphasic Dissolving Microarray Patches Based on Poly(Lactic Acid) and Moisture‐Indicating Silica
Authors: Li Huanhuan , Anjani Qonita Kurnia , Hutton Aaron R. J. , Paris Juan Luis , Moreno‐Castellanos Natalia , Himawan Achmad , Larrañeta Eneko , Donnelly Ryan F.
Published: March 2024

Dissolving microarray patches (DMAPs) represent an innovative approach to minimally invasive transdermal drug delivery, demonstrating efficacy in delivering both small and large therapeutic molecules. However, concerns raised in end‐user surveys have hindered their commercialization efforts. One prevalent issue highlighted in these surveys is the lack of clear indicators for successful patch insertion and removal time. To address this challenge, a color‐change‐based feedback system is devised, which confirms the insertion and dissolution of DMAPs, aiming to mitigate the aforementioned problems. The approach combines hydrophilic needles containing model drugs (fluorescein sodium and fluorescein isothiocyanate (FITC)‐dextran) with a hydrophobic poly(lactic acid) baseplate infused with moisture‐sensitive silica gel particles. The successful insertion and subsequent complete dissolution of the needle shaft are indicated by the progressive color change of crystal violet encapsulated in the silica. Notably, distinct color alterations on the baseplate, observed 30 min and 1 h after insertion for FITC‐dextran and fluorescein sodium DMAPs respectively, signal the full dissolution of the needles, confirming the complete cargo delivery and enabling timely patch removal. This innovative feedback system offers a practical solution for addressing end‐user concerns and may significantly contribute to the successful commercialization of DMAPs by providing a visualized drug delivery method.
Unveiling the Synergistic Role of Frustrated Lewis Pairs in Carbon‐Encapsulated Ni/NiOx Photothermal Cocatalyst for Enhanced Photocatalytic Hydrogen Production
Authors: Yang Zhi , Huang Taiyu , Li Meng , Wang Xudong , Zhou Xiaosong , Yang Siyuan , Gao Qiongzhi , Cai Xin , Liu Yingju , Fang Yueping , Wang Yu , Zhang Shanqing , Zhang Shengsen
Published: March 2024

The development of high‐density and closely spaced frustrated Lewis pairs (FLPs) is crucial for enhancing catalyst activity and accelerating reaction rates. However, constructing efficient FLPs by breaking classical Lewis bonds poses a significant challenge. Here, this work has made a pivotal discovery regarding the Jahn–Teller effect during the formation of grain boundaries in carbon‐encapsulated Ni/NiOx (Ni/NiOx@C). This effect facilitates the formation of high‐density O (VO) and Ni (VNi) vacancy sites with different charge polarities, specifically FLP‐VO‐C basic sites and FLP‐VNi‐C acidic sites. The synergistic interaction between FLP‐VO‐C and FLP‐VNi‐C sites not only reduces energy barriers for water adsorption and splitting, but also induces a strong photothermal effect. This mutually reinforcing effect contributes to the exceptional performance of Ni/NiOx@C as a cocatalyst in photothermal‐assisted photocatalytic hydrogen production. Notably, the Ni/NiOx@C/g‐C3N4 (NOCC) composite photocatalyst exhibits remarkable hydrogen production activity with a rate of 10.7 mmol g−1 h−1, surpassing that of the Pt cocatalyst by 1.76 times. Moreover, the NOCC achieves an impressive apparent quantum yield of 40.78% at a wavelength of 380 nm. This work paves the way for designing novel defect‐state multiphase cocatalysts with high‐density and adjacent FLP sites, which hold promise for enhancing various catalytic reactions.
Full‐Length Single Protein Molecules Tracking and Counting in Thin Silicon Channels
Authors: Ohayon Shilo , Taib Liran , Verma Navneet Chandra , Iarossi Marzia , Bhattacharya Ivy , Marom Barak , Huttner Diana , Meller Amit
Published: March 2024

Emerging single‐molecule protein sensing techniques are ushering in a transformative era in biomedical research. Nevertheless, challenges persist in realizing ultra‐fast full‐length protein sensing, including loss of molecular integrity due to protein fragmentation, biases introduced by antibodies affinity, identification of proteoforms, and low throughputs. Here, a single‐molecule method for parallel protein separation and tracking is introduced, yielding multi‐dimensional molecular properties used for their identification. Proteins are tagged by chemo‐selective dual amino‐acid specific labels and are electrophoretically separated by their mass/charge in custom‐designed thin silicon channel with subwavelength height. This approach allows analysis of thousands of individual proteins within a few minutes by tracking their motion during the migration. The power of the method is demonstrated by quantifying a cytokine panel for host‐response discrimination between viral and bacterial infections. Moreover, it is shown that two clinically‐relevant splice isoforms of Vascular endothelial growth factor (VEGF) can be accurately quantified from human serum samples. Being non‐destructive and compatible with full‐length intact proteins, this method opens up ways for antibody‐free single‐protein molecule quantification.
3D Printing Bio‐Inspired Micro Soft Robot with Programming Magnetic Elastic Composites
Authors: Peng Zilong , Zhang Hao , Wang Mengjie , Zhang Shuailong , Jiang Yifan , Li Yinan , Zhu Xiaoyang , Zhang Guangming , Niu Geng , Zhang Jia , He Jiankang , Lan Hongbo
Published: March 2024

Bio‐inspired micro soft robots mimic biologically specific body structures and movement mechanisms by utilizing bionic principles. Because of its soft body, it can adapt to complex external environments. However, the existing polymer material system is single and the fabrication process is limited. How to further reduce soft robot size has become a key issue. In this work, a Programming Magnetic Elastic Composites (PMEC) is proposed for 3D printing to manufacture micro soft robots. The PMEC has the advantage of changing the direction of the internal magnetic field in response to changes in the external magnetic field. A Microsoft robot is designed and fabricated using PMEC inspired by an inchworm. Numerical simulations are also used to study the effect of soft robot size parameters on local stresses and optimize the structure. The results show that the microscale soft robot can crawl with a load of 2 times its weight at a speed of 6.67 mm s−1, crawl on slopes from 0° to 90°, and crawl over obstacles with a maximum height of 7 mm. In addition, active adaptation of soft robots to complex tunnel models based on external stimuli is achieved by magnetic field control.