bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitigation of Electromigration in Metal Interconnects via Hexagonal Boron Nitride as an Ångström‐Thin Passivation Layer
Authors: Jeong Yunjo , Douglas Ossie , Misra Utkarsh , Tanjil Md Rubayat‐E , Watanabe Kenji , Taniguchi Takashi , Wang Michael Cai 
Published: April 2021

AbstractElectromigration in metal interconnects remains a significant challenge in the continued scaling of integrated circuits towards ever‐smaller single‐nanometer nodes. Conventional damascene architectures of barrier/liner layers and conducting metal cause inevitable compromises between device performance and feature dimensions. In contrast to contemporary barrier/liner materials (e.g., Co, Ta, and Ru), an ultrathin passivation layer that can effectively mitigate electromigration is needed. At the ultimate atomically‐thin limit, 2D materials are promising candidates given their exceptional mechanical properties and impermeability. Here, a facile and effective approach is presented to mitigating electromigration in copper (Cu) interconnects via passivation with insulating monolayer 2D hexagonal boron nitride (hBN). The hBN‐passivated Cu interconnects, compared to otherwise identical but bare Cu interconnects, exhibit on average a >20% higher breakdown current density and a >2600% longer lifetime (at a high current density of 5.4 × 107 A cm−2). Post‐mortem metrology elucidates uniform conformal contact between the hBN‐passivated Cu interface and common failure features due to electromigration.
Age‐related calcium dysregulation linked with tau pathology and impaired cognition in non‐human primates
Authors: Datta Dibyadeep , Leslie Shannon N. , Wang Min , Morozov Yury M. , Yang Shengtao , Mentone SueAnn , Zeiss Caroline , Duque Alvaro , Rakic Pasko , Horvath Tamas L. , van Dyck Christopher H. , Nairn Angus C. , Arnsten Amy F.T. 
Published: April 2021

AbstractIntroductionThe etiology of sporadic Alzheimer's disease (AD) requires non‐genetically modified animal models.MethodsThe relationship of tau phosphorylation to calcium‐cyclic adenosine monophosphate (cAMP)‐protein kinase A (PKA) dysregulation was analyzed in aging rhesus macaque dorsolateral prefrontal cortex (dlPFC) and rat primary cortical neurons using biochemistry and immuno‐electron microscopy. The influence of calcium leak from ryanodine receptors (RyRs) on neuronal firing and cognitive performance was examined in aged macaques.ResultsAged monkeys naturally develop hyperphosphorylated tau, including AD biomarkers (AT8 (pS202/pT205) and pT217) and early tau pathology markers (pS214 and pS356) that correlated with evidence of increased calcium leak (pS2808‐RyR2). Calcium also regulated early tau phosphorylation in vitro. Age‐related reductions in the calcium‐binding protein, calbindin, and in phosphodiesterase PDE4D were seen within dlPFC pyramidal cell dendrites. Blocking RyRs with S107 improved neuronal firing and cognitive performance in aged macaques.DiscussionDysregulated calcium signaling confers risk for tau pathology and provides a potential therapeutic target.
Synthese substituierter Dihydropyridine durch Dearomatisierung von Pyridinen
Authors: Heusler Arne , Fliege Julian , Wagener Tobias , Glorius Frank 
Published: April 2021

AbstractDearomatisierung ist eine effektive Methode, um leicht verfügbare N‐Heterozyklen in teilgesättigte Motive zu überführen. Die Manipulation von Dihydro‐Derivaten birgt großes Potenzial und bietet Zugang zu einer Vielzahl von teilgesättigten N‐heterozyklischen Bausteinen. Die derzeitigen Strategien sind jedoch in ihrem Umfang begrenzt, und der Einsatz empfindlicher Reagenzien schränkt die Anwendbarkeit in Syntheselaboren ein. Wir berichten hier erstmals über die Synthese einer breiten Vielfalt von N‐substituierten 1,4‐ und 1,2‐Dihydropyridinen durch sehr milde und selektive Reduktion mit Aminboran.
Bowl‐Shaped Pentagon‐ and Heptagon‐Embedded Nanographene Containing a Central Pyrrolo[3,2‐b]pyrrole Core
Authors: Krzeszewski Maciej , Dobrzycki Łukasz , Sobolewski Andrzej L. , Cyrański Michał K. , Gryko Daniel T. 
Published: April 2021

AbstractA bowl‐shaped nitrogen‐doped nanographene composed of a pyrrolo[3,2‐b]pyrrole core substituted with six arene rings circularly bonded with one another has been prepared via a concise synthetic strategy encompassing the multicomponent tetraarylpyrrolopyrrole (TAPP) synthesis, the Scholl reaction, and intramolecular direct arylation. This synthesis represents the first case of programmed sequential intramolecular direct arylation reactions utilizing the different reactivity of C–Br and C–Cl bonds. The target compound contains two central pentagons confined between two adjacent heptagons—the inverse Stone–Thrower–Wales topology. The presence of both five‐ and seven‐membered rings in the final structure is responsible for interesting properties such as a perpendicularly aligned dipole moment, absorption and fluorescence in the orange‐red region, weak emission originating from the charge‐transfer character of a low‐energy absorption band, and a high lying HOMO. In the solid state slipped convex‐to‐convex π–π stacking dominates.
Exposure of bisphenol A in breast cancer patients—quantitatively assessed by sensitivity‐enhanced high‐performance liquid chromatography coupled with fluorescence detection: A case–control study
Authors: Muthusamy Sivaselvakumar , Palanisamy Susipriya , Ramalingam Sudha 
Published: April 2021

AbstractA simple, reproducible and sensitive liquid chromatography (HPLC) method has been developed and validated for estimation of bisphenol A (BPA) in human urine. A simple liquid–liquid extraction technique was used in BPA sample preparation. The analyte was chromatographed on a Shimadzu Prominence HPLC system using isocratic mobile phase conditions at a flow rate of 0.500 ml/min and a Hypersil Gold C18 column maintained at 40°C. Quantification was performed on a fluorescence detector set at excitation 275 nm, emission 313 nm and bisphenol B was used as internal standard. The total run time was 8 min. The method was found to have acceptable sensitivity, selectivity, accuracy (98.82–103.64%), precision (1.17–5.36) and stability in the validation experiment carried out as per the USFDA guidelines. The method sensitivity was as low as 0.50 ng/ml. The applicability of the validated analytical method was established in human patient urine samples. The mean human urine BPA concentrations were 1.18 ± 2.11 ng/ml in the control group and 5.76 ± 6.00 ng/ml in the patient group (P < 0.001). Therefore, this method could be considered as an alternative for routine bio‐monitoring of BPA which is less expensive and feasible in resource‐poor settings.
High‐resolution mass spectrometry‐based methodology for the identification of the metabolites of pterostilbene produced by rat, dog and human hepatocytes
Authors: Jiang Lingyan , Yin Renlong , Zheng Qiaofei , He Chunyong , Chang Huichao 
Published: April 2021

AbstractPterostilbene, a natural bibenzjyl compound, has been demonstrated to have pleiotropic anticancer effects against a variety of cancer types. The aim of this study was carried out to disclose the metabolic profiles of pterostilbene using rat, dog and human hepatocytes. Metabolites were characterized by ultra‐high‐performance liquid chromatography/quadrupole Orbitrap mass spectrometry with electrospray ionization interface operating in positive ion mode. The structures of the metabolites were proposed by accurate MS, MS/MS spectra and based on their fragmentation patterns. A total of 12 metabolites, including six new ones, were detected and identified. M10 and M12 were unambiguously identified as pinostilbene and 3′‐hydroxy‐pterostilbene, respectively, by using reference standards. Our results revealed that pterostilbene was metabolized through the following pathways: (a) hydroxylation to form 3′‐hydroxy‐pterostilbene (M12), which further undergoes glucuronidation (M9), demethylation (M7) and GSH conjugation through the ortho‐quinone intermediate; (b) demethylation to produce desmethyl‐pterostilbene (M10), which is further subject to glucuronidation (M4); (c) direct conjugation with glucuronide (M11); and (d) direct sulfation (M8). Among the tested species, no significant species difference was observed. The current study provides valuable information on the metabolism of pterostilbene, which is helpful for us to understand the action of this compound.
Screening of hepatotoxic compounds in Psoralea corylifolia L., a traditional Chinese herbal and dietary supplement, using high‐resolution mass spectrometry and high‐content imaging
Authors: Shi Ge‐zi , Song Di , Li Peng‐yan , Chen Shuai‐shuai , Zhang Le , Li Shan‐Shan , Xiao Xiao‐he , Qin Xu‐hua , Wang Jia‐bo 
Published: April 2021

AbstractOwing to the complexity of the composition of herbal and dietary supplements, it is a challenging problem to efficiently screen and identify active or toxic compounds. Psoralea corylifolia L. (PCL) was selected as the subbject to establish a methodology for rapid screening and identification of hepatotoxic compounds. High‐content imaging, ultra‐performance liquid chromatography and high‐resolution mass spectrometry were used in this study to detect the hepatotoxicity and identify unknown compounds in PCL samples. Then, putative toxic compounds which are highly related to hepatotoxicity were screened by spectrum–toxicity correlation analysis, and the toxicity intensity verified by high‐content imaging. The maximum nontoxic dose of processed samples with good detoxification effect reduced more than 9 times compared with unprocessed raw medicinal materials. Spectrum–toxicity correlation analysis showed that bavachinin A, bavachin, isobavachalcone and neobavaisoflavone had high correlation with the hepatotoxicity of PCL, and psoralen and isopsoralen had low correlation with hepatotoxicity. This study verified the hepatotoxicity of these six putative compound monomers, proving the results of spectrum–toxicity correlation analysis. Based on the correlation analysis of high‐resolution mass spectrometry of detection compounds and high‐content imaging of hepatocyte toxicity data, the potential toxic compound of herbal and dietary supplement products can be quickly and accurately screened.
Homicide and the Internet
Authors: Recupero Patricia R. 
Published: April 2021

AbstractThe Internet and social media have grown increasingly relevant in homicide cases in recent years. Although several recent studies have analyzed the relationship between homicide and the Internet, there is a dearth of rigorous scientific research on the subject to date. Although a statistically rare event, Internet‐related homicide may be increasing, and forensic mental health professionals may experience growing demand for consultations in cases where the Internet and social media play a salient role. Understanding some of the ways in which homicide perpetrators have used the Internet can help to inform case formulation and threat assessments in these cases. This article reviews several key themes, including the use of the Internet as a source of information in the commission of homicide, its use to target victims, the spread of self‐publishing and multimedia sharing, conflict escalation through social media, and the threat posed by Internet extremist communities. Finally, suggestions are made to help inform future research regarding the relationship between homicide and the Internet.
Interdisciplinary orthodontic‐periodontal treatment of unerupted permanent maxillary incisors following traumatic injury to deciduous teeth. Case report with long‐term follow‐up (11 years)
Authors: Crescini Aldo , Pini Prato Giovan Paolo , Franceschi Debora 
Published: April 2021

AbstractOrthodontic and periodontal treatment of the permanent maxillary teeth, which were retained due to trauma on the deciduous dentition, showed a perfect alignment of the teeth associated with healthy and stable periodontal tissues during an 11‐year follow‐up.
Unveiling the Role of Active Oxygen Species in Oxidative Dehydrogenation of Ethane with CO2 over NiFe/CeO2
Authors: Guo Man , Feng Kai , Wang Yaning , Yan Binhang 
Published: April 2021

AbstractThe oxidative dehydrogenation of ethane (ODH) assisted by CO2 to produce ethylene is inevitably accompanied by the side reaction of dry reforming (DRE) to produce carbon monoxide. However, the key factor determining the dehydrogenation selectivity is still ambiguous. In this paper, four different NiFe/CeO2 catalysts were synthesized via an impregnation method over four types of CeO2. The dehydrogenation selectivity of the four catalysts ranged from 40 % to 83 %. Temperature‐programmed surface reaction and transient response experiments reveal the existence of two types of oxygen species over NiFe/CeO2 catalysts. FeOx layers exist as an oxygen species supply buffer over CeO2 supports. Weakly electrophilic oxygen species supplied by FeOx overlayers could participate in producing C2H4 while strong electrophilic oxygen species supplied by CeO2 supports could participate in producing CO. The content of weakly electrophilic oxygen species is identified to be a rational descriptor of C2H4 selectivity.
High‐Quality Thin Films of UiO‐66‐NH2 by Coordination Modulated Layer‐by‐Layer Liquid Phase Epitaxy
Authors: Semrau A. Lisa , Fischer Roland A. 
Published: April 2021

AbstractWe report the fabrication of macroscopically and microscopically homogeneous, crack‐free metal‐organic framework (MOF) UiO‐66‐NH2 (UiO: Universitetet i Oslo; [Zr6O4(OH)4(bdc‐NH2)6]; bdc‐NH22−: 2‐amino‐1,4‐benzene dicarboxylate) thin films on silicon oxide surfaces. A DMF‐free, low‐temperature coordination modulated (CM), layer‐by‐layer liquid phase epitaxy (LPE) using the controlled secondary building block approach (CSA). Efficient substrate activation was determined as a key factor to obtain dense and smooth coatings by comparing UiO‐66‐NH2 thin films grown on ozone and piranha acid‐activated substrates. Films of 2.60 μm thickness with a minimal surface roughness of 2 nm and a high sorption capacity of 3.53 mmol g−1 MeOH (at 25 °C) were typically obtained in an 80‐cycle experiment at mild conditions (70 °C, ambient pressure).
Self‐Foaming Metal‐Organic Gels Based on Phytic Acid and Their Mechanical, Moldable, and Load‐Bearing Properties.
Authors: Xiao Yali , Gong Xi , Zhang Jianyong 
Published: April 2021

AbstractA catalogue of metal‐organic gels are synthesized from phytic acid (PA) and a diversity of metal ions (Fe3+, Cr3+, Al3+, Ce3+, Y3+, Co2+, Ni2+, Mn2+, Cu2+, Zn2+, Mg2+) upon heating at 80 °C. PA−M gels have various morphologies, including irregular granular (PA−Fe, PA−Al, PA−Ce, PA−Cr, PA−Ni, PA−Co), spongy (PA−Y), and hollow tremella‐like (PA−Cu) morphologies. Interestingly for PA−Fe‐1 : 4 (PA:Fe3+=1 : 4) a large amount of gas is generated during the gelation process leading to a self‐foaming gel. The PA−Fe‐1 : 4 self‐foaming gel shows reversible gel‐sol phase transition. The gel is unusually weakened and transformed into a sol at room temperature, and the sol is reversed to gelation when heated again at 80 °C. PA−Fe‐1 : 4 gel also shows shapeable and load‐bearing properties, and it can bear up to 200 times of its weight, depending on the gas amount fixed in the foam gel and the aging time. This work provides a catalogue of self‐foaming supramolecular gels with tunable properties based on naturally abundant resources.
The Unusual Photochromic and Hydrochromic Switching Behavior of Cellulose‐Embedded 1,8‐Naphthalimide‐Viologen Derivatives in the Solid‐State
Authors: Sun Zhimin , Ni Yanhai , Prakasam Thirumurugan , Liu Wenqi , Wu Huang , Zhang Zhao , Di Haiting , Baldridge Kim K. , Trabolsi Ali , Olson Mark A. 
Published: April 2021

AbstractStimuli‐responsive chromic materials such as photochromics, hydrochromics, thermochromics, and electrochromics have a long history of capturing the attention of scientists due to their potential industrial applications and novelty in popular culture. However, hybrid chromic materials that combine two or more stimuli‐triggered color changing properties are not so well known. Herein, we report a design strategy that has led to a series of emissive 1,8‐naphthalimide‐viologen dyads which exhibit unusual dual photochromic and hydrochromic switching behavior in the solid‐state when embedded in a cellulose matrix. This behavior manifests as reversible solid state fluorescence hydrochromism upon changes in atmospheric relative humidity (RH), and reversible solid state photochromism upon generation of a cellulose‐stabilized viologen radical cation. In this design strategy, the bipyridinium unit serves as both a water‐sensitive receptor for the hydrochromic fluorophore‐receptor system, and a photochromic group, capable of eliciting its own visible colorimetric response, generating a fluorescence quenching radical cation with prolonged exposure to ultraviolet (UV) light. These dyes can be inkjet‐printed onto cellulose paper or drop‐cast as cellulose powder‐based films and can be unidirectionally cycled between three different states which can be characteristically visualized under UV light or visible light. The material's photochromism, hydrochromism, and underlying mechanism of action was investigated using computational analysis, dynamic vapor sorption/desorption isotherms, electron paramagnetic resonance spectroscopy, and variable humidity UV‐Vis adsorption and fluorescence spectroscopies.
Rhodium‐Catalyzed Enantioselective Synthesis of Highly Fluorescent and CPL‐Active Dispiroindeno[2,1‐c]fluorenes
Authors: Cadart Timothée , Nečas David , Kaiser Reinhard P. , Favereau Ludovic , Císařová Ivana , Gyepes Róbert , Hodačová Jana , Kalíková Květa , Bednárová Lucie , Crassous Jeanne , Kotora Martin 
Published: April 2021

AbstractThe enantioselective synthesis of chiral [7]‐helical dispirodihydro[2,1‐c]indenofluorenes (DSF‐IFs) was achieved for the first time in good yields with high er values (er up to 99 : 1). The crucial step of the whole reaction sequence was the enantioselective intramolecular [2+2+2] cycloaddition of tethered triynediols to indenofluorenediols, which was catalyzed by a Rh/SEGPHOS® complex. Further transformations led to the corresponding DSF‐IFs. The prepared helically chiral DSF‐IFs combine circularly polarized luminescence (CPL) activity (glum=∼10−3) with exceptionally high fluorescence quantum yields (up to Φlum=0.97).
Gradient of vernalization requirement in carrot cultivars from diverse geographical origins
Authors: Wohlfeiler Josefina , Alessandro María Soledad , Cavagnaro Pablo Federico , Galmarini Claudio Rómulo 
Published: April 2021

AbstractOn the basis of their vernalization requirement (VR) for flowering, a genetically conditioned trait, carrots (Daucus carota L.) are typically classified as annuals and biennials. A previous study using F2 populations derived from crosses among carrots from different geographical origins revealed a model of two genes and three alleles controlling VR, with dominance of annuality for both genes. The present work evaluated VR in carrot cultivars from diverse origins, including those used in a previous study. We induced vernalization during different periods of cold exposure (20, 30, 40, 60, and 90 d) and different temperatures (∼5 and ∼15 °C). Increased flowering rates and earlier onset of flowering were associated with longer and more intense cold exposures. In most cultivars, 60–90 d at 5 °C (but not at 15 °C) were enough for vernalizing a large proportion of the plants. In general, biennials required longer cold exposure than annuals to flower, although variation within annuals and biennials was also found, suggesting a gradient of VR in the carrot germplasm, which reinforces our previously proposed genetic model. The plant materials used in this work cover the broadest range of VR in carrot reported to date. These findings contribute to carrot breeding and production, helping to choose the specific genotype and appropriate sowing time in different environments either for root or seed production.
Perivascular macrophages create an intravascular niche for CD8+ T cell localisation prior to the onset of fatal experimental cerebral malaria
Authors: Qin Jim , Lovelace Michael D , Mitchell Andrew J , de Koning‐Ward Tania , Grau Georges ER , Pai Saparna 
Published: April 2021

AbstractObjectivesThe immunologic events that build up to the fatal neurological stage of experimental cerebral malaria (ECM) are incompletely understood. Here, we dissect immune cell behaviour occurring in the central nervous system (CNS) when Plasmodium berghei ANKA (PbA)‐infected mice show only minor clinical signs.MethodsA 2‐photon intravital microscopy (2P‐IVM) brain imaging model was used to study the spatiotemporal context of early immunological events in situ during ECM.ResultsEarly in the disease course, antigen‐specific CD8+ T cells came in contact and arrested on the endothelium of post‐capillary venules. CD8+ T cells typically adhered adjacent to, or were in the near vicinity of, perivascular macrophages (PVMs) that line post‐capillary venules. Closer examination revealed that CD8+ T cells crawled along the inner vessel wall towards PVMs that lay on the abluminal side of large post‐capillary venules. ‘Activity hotspots’ in large post‐capillary venules were characterised by T‐cell localisation, activated morphology and clustering of PVM, increased abutting of post‐capillary venules by PVM and augmented monocyte accumulation. In the later stages of infection, when mice exhibited neurological signs, intravascular CD8+ T cells increased in number and changed their behaviour, actively crawling along the endothelium and displaying frequent, short‐term interactions with the inner vessel wall at hotspots.ConclusionOur study suggests an active interaction between PVM and CD8+ T cells occurs across the blood–brain barrier (BBB) in early ECM, which may be the initiating event in the inflammatory cascade leading to BBB alteration and neuropathology.
Identifying changing interspecific associations along gradients at multiple scales using wavelet correlation networks
Authors: Ding Zhangqi , Ma Keming 
Published: April 2021

AbstractIdentifying interspecific associations is very important for understanding the community assembly process. However, most methods provide only an average association and assume that the association strength does not vary along the environmental gradient or with time. The scale effects are generally ignored. We integrated the idea of wavelet and network topological analysis to provide a novel way to detect nonrandom species associations across scales and along gradients using continuous or presence–absence ecological data. We first used a simulated species distribution data set to illustrate how the wavelet correlation analysis builds an association matrix and demonstrates its statistical robustness. Then, we applied the wavelet correlation network to a presence–absence data set of soil invertebrates. We found that the associations of invertebrates varied along an altitudinal gradient. We conclude by discussing several possible extensions of this method, such as predicting community assembly, utility in the temporal dimension, and the shifting effects of highly connected species within a community. The combination of the multiscale decomposition of wavelet and network topology analysis has great potential for fostering an understanding of the assembly and succession of communities, as well as predicting their responses to future climate change across spatial or temporal scales.