bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation for time‐fractional nonlinear reaction–diffusion system on a uniform and nonuniform time stepping
Authors: Zahra Waheed K. , Hikal Manal M. , Baleanu Dumitru
Published: March 2021

In this article, two nonstandard high‐order schemes on a uniform and nonuniform time stepping combined with the multi‐parameter exponential fitting technique (MPEF) have been developed to solve the time‐fractional nonlinear reaction–diffusion system. The first method based on the MPEF combined with the 3‐weighted shifted‐Grünwald–Letnikov approximation with uniform time stepping, this scheme leads to a numerical solution that suffers from the singularity neart= 0. In order to frustrate this singularity, a nonstandard higher‐order L1‐approximation for a nonuniform time‐stepping scheme is developed. The developed scheme's convergence and unconditionally stability analysis have been verified. Numerical results effectively validate the theoretical aspects.
Chemiewettbewerbe: Aus Osaka keine Neuigkeiten
Authors: Zbikowski Frauke
Published: March 2021

Die Teilnehmer der internationalen Chemieolympiade blieben im letzten Jahr zu Hause und schrieben eine Klausur, anstatt sich in Istanbul mit Chemiebegeisterten zu messen. Ähnlich erging es Teilnehmern anderer Wettbewerbe, und die Organisatoren mussten umdenken.
Kinetics of poly(3‐methacryloylamido propyl trimethyl ammonium chloride) initiated by different initiators
Authors: Wang Yongji , Zhang Yuejun
Published: March 2021

The poly(3‐methacryloylamido propyl trimethyl ammonium chloride) (PMAPTAC) was synthesized by radical polymerization in aqueous solution polymerization using ammonium persulfate (APS) and 2,2′‐azobis(2‐methylpropionamide) dihydrochloride (V50) as initiator, respectively. The kinetics of polymerization were examined by changing various monomer and initiator concentrations via the dilatometer method at a low conversion level. The results showed that the polymerization rate grew with increasing monomer, initiator concentrations, and temperatures. The activation energies of polymerization were EaA = 153.09 kJ/mol and Eav = 144.76 kJ/mol. The overall polymerization rate equation for the PMAPTAC were Rp = k[MA]1.64[IA]0.71 and Rp = k[MV]1.57[IV]0.91 at the temperature of 45°C for APS and V50, respectively. Based on the experimental results, the effect on the polymerization rate of different initiators was discussed. The studies supplied the experimental basis of the kinetics for the reaction control of PMAPTAC production.
CO2 Hydrogenation to Methanol on ZnO/ZrO2 Catalysts: Effects of Zirconia Phase
Authors: Lin Lili , Wang Guihui , Zhao Fuzhen
Published: March 2021

ZnO/ZrO2 samples were obtained by impregnation ZnO on three different ZrO2 polymorphic phases: monoclinic, tetrahedral and amorphous. The catalysts were tested for CO2 hydrogenation to methanol and the structure was determined using nitrogen physisorption, scanning electron microscope (SEM), Fourier transform infrared (FT‐IR) pyridine adsorption, hydrogen temperature‐programmed desorption (H2‐TPD), CO2‐TPD and X‐ray photoelectron spectroscopy (XPS). The results showed that the ZnO/tm‐ZrO2‐500 catalyst, with a mixture of both tetrahedral and monoclinic ZrO2 phases, had the highest CH3OH yield among all the samples. The yield of methanol is correlated to the lattice oxygen content for all the catalysts. During the reaction, formate and methoxy species seemed to be the active intermediate species.
Visible‐Light Driven Ni‐Incorporated CdS Photocatalytic Activities for Azo‐Bond Cleavages with Hydrogenation Reaction
Authors: Abdullah Hairus , Siburian Rikson , Pasaribu Subur P. , Panggabean Aman S.
Published: March 2021

Ni‐incorporated CdS (Ni‐CdS) photocatalysts with different amounts of Ni dopant have been synthesized, characterized, and examined toward azo‐bond cleavages in visible‐light illuminated conditions. The optimum performance was achieved with a relatively low amount of Ni dopant (2 % atomic mass). The azo bonds of azobenzene (AB) and methyl orange (MO) compounds were hydrogenated with the in‐situ generated hydrogen on Ni‐CdS catalyst surfaces. The hydrogen evolution reaction was proved and measured with GC measurement during the photocatalytic session with an incandescent halogen lamp. Furthermore, the experimental data of UV‐vis spectra analyses suggested the formation of aniline or sodium sulfanilate and p‐aminodimethylaniline with the emerged peaks at ∼240 nm, indicating azo‐bond has been cleaved in AB or MO compounds, respectively. The catalytic performances of 2 % Ni‐CdS are also supported with electrical and photoresponse analyses. To demonstrate the possibility of industrial application, Ni‐CdS catalyst stability is also tested for several runs in reusability experiments and examined with cyclic voltammetry for 100 cycles without any significant degradation. The cleavage mechanisms of azo bonds in AB and MO compounds were discussed and proposed in this work.
Green Approach for Preparation of New Hybrids of 5‐Substituted‐1H‐Tetrazoles Using Novel Recyclable Nanocatalyst based on Copper(II) Anchored onto Glucosamine Grafted to Fe3O4@SiO2
Authors: Eslahi Hassan , Reza Sardarian Ali , Esmaeilpour Mohsen
Published: March 2021

The novel copper(II) ions decorated Fe3O4@SiO2 composite magnetic spheres were synthesized by grafting copper(II) ions onto glucosamine modified Fe3O4@SiO2 NPs. The magnetic Fe3O4@SiO2−TCT−GA−Cu(II) catalyst were characterized by varies physicochemical techniques such as FT‐IR, FE‐SEM, TEM, DLS, XRD, EDX, VSM, TGA, VSM, ICP, and UV‐Vis. The catalytic performance of this novel catalyst was studied in the green preparation of 5‐substituted 1H‐tetrazole based hybrids via three‐component and one‐pot reaction of sodium azide, hydroxylamine hydrochloride, and various aldehydes in water and ethylene glycol, as a green solvent mixture. This green protocol provides significant advantages such as non‐vigorous conditions, short reaction times, outstanding yield of desired tetrazoles, minimizing of chemical waste, wide‐ranging substrate, quick and efficient work‐up procedure and using environmentally benign, durable, cost effective, magnetically separable, reusable nanocatalyst.
Detection of Melamine by Using Fluorescent Nanocomposites with Specific Recognition Sites
Authors: Üzek Recep , Sari Esma , Denizli Adil
Published: March 2021

In this study, the novel nanocomposite was prepared by the coating of the semiconductor quantum dots (QDs) with the molecularly imprinted shell by mini‐emulsion polymerization to form the specific recognition sites on the surface for the detection of melamine. After the characterization of nanocomposites, the detection performance of the nanosensor was investigated by fluorescence measurements in aqueous solutions and milk samples. The aqueous solutions of melamine were used for the detection of melamine and the optimum conditions were determined as pH 5.0, melamine concentration (100 ppm), interaction time (6 min), and temperature (40 °C). The competitor molecules such as aniline, phenol, and cyanuric acid were used to determine the selectivity of the quantum dot‐based nanosensor system. The limit of detection (LOD) was obtained as 0.14±0.08 ppm. The reusability performance was investigated for 20 cycles by using the same nanocomposites and relative standard deviation (RSD) values of the nanosensor system were calculated as 11 % after 20 recycles. According to the results, the nanosensor system has shown that it is a favorable alternative to existing systems for the melamine detection.
Controlled Crystallization of CsRb‐Based Multi‐Cation Perovskite Using a Blended Sequential Process for High‐Performance Solar Cells
Authors: Zhang Huimin , Liang Chunjun , Sun Mengjie , Sun Fulin , Ji Chao , Wan Xuejian , Li Dan , You Fangtian , He Zhiqun
Published: March 2021

High‐quality perovskite films with low defect densities and high carrier‐diffusion lengths are essential for high‐performance perovskite devices. Herein, a modified two‐step sequential method is proposed, in which equal amounts of Cs+ and Rb+ ions (Cs+Rb+) are added to a PbI2 solution in the first step of perovskite deposition. The incorporation of Cs+Rb+ results in trace amounts of δ‐CsPbI3, leading to a reduction in the grain size in the PbI2 layer that facilitates better penetration of the organic salts in the second step of the precursor deposition. Meanwhile, the low density of the δ‐CsPbI3 crystals act as seeds to regulate the nucleation and growth of the perovskite crystals. A single‐layered columnar large‐grain perovskite film is obtained. The addition of Cs+Rb+ promotes crystal growth along the (100) orientation, which is beneficial for the reduction of surface defects. The incorporated Rb+ ions can regulate the remaining PbI2 in the perovskite. The improved quality of the perovskite film results in a significantly prolonged carrier lifetime of ≈7.01  and an enhanced electron diffusion length of ≈2.84 . As a result, the photovoltaic parameters are all improved in the established devices and a power conversion efficiency of 21.49% is reached.
Experimental study of the seismic behavior of obliquely loaded concrete columns reinforced with high‐strength steel bars
Authors: Liu Chunyang , Yu Guixin , Li Fei , Guo Changqun , Fan Xisen
Published: March 2021

In order to further study the seismic behavior and working performance improvement path of reinforced concrete columns under oblique earthquake action, seven concrete columns with HTRB630 steel bars were designed. The loading direction axial compression ratio and column end restrained pattern were chosen as the main design parameters. The low cyclic reversed load test has been carried out on understanding the seismic performance of the specimen. Based on the test study, the characteristics including the failure mode, hysteresis loops behavior, carrying capacity, ductility, stiffness degradation and energy dissipation ability were demonstrated. The results show that under the axial compression ratio of 0.6, the compressive carrying capacity and deformation capacity in 45 degree direction was about 82% and 78% of that in the principal axis direction, respectively. The load carrying capacity and deformation capacity in 45 degree direction under the axial compression ratio of 1.0 can be significantly improved by using steel plate mesh and carbon fiber cloth restrained manner. It is necessary to further study the effective measures to improve the restrained degree on damage development of inner concrete for the local area grid restrained manner. A method for calculating the normal‐section flexural capacity of a column based on the equivalence principle was also developed, and its results were found to be consistent with those of the tests.
The effect of parked wind turbines on wind flow and turbulence over a complex terrain
Authors: Kozmar Hrvoje , Bartoli Gianni , Borri Claudio
Published: March 2021

Wind‐tunnel experiments were performed to study the wind characteristics on a parked wind turbine downwind of three types of hill and over a flat terrain. The focus of the study is on comparing wind characteristics on (a) a wind turbine standing alone and (b) this same type of wind turbine embedded in a wind farm. Particular emphasis is placed on the hill size and shape and the distance between the hill and the wind farm. The hill and wind‐farm models were subjected to an atmospheric boundary layer simulation to create realistic atmospheric conditions. Flow and turbulence were analyzed based on the measured mean flow velocity, Reynolds shear stress, turbulence intensity, and the power spectral density of velocity fluctuations. The experimental results reveal similar trends concerning (a) the wind characteristics obtained on a parked wind turbine embedded in a wind farm downwind of hills of various sizes and shapes and (b) the wind characteristics on this same type of parked wind turbine standing alone in the same position downwind of the same hills. In particular, the discrepancies in the mean flow velocity and turbulence intensity between these test cases are mostly below 5%, thus indicating that a complex terrain clearly has a dominant effect on the wind characteristics, while the effects of parked wind turbines on the wind characteristics are negligible. This important finding indicates that the structural loading of parked wind turbines situated on a complex terrain may be well calculated using the same procedures both for wind turbines standing alone and wind turbines embedded in wind farms if they are both placed at the same distance downwind of the same hills.
Die Universitätsmedizin in Bayern im Rahmen der COVID-19-Pandemie
Authors: Dommasch M. , Zimmermann M. , Kanz K.-G. , Spinner C. D.
Published: March 2021

Hintergrund

Anfang 2020 wurde deutschlandweit das Gesundheitswesen bedingt durch die coronavirus disease 2019 (COVID-19)-Pandemie auf einen Notbetrieb umgestellt. In Bayern wurde durch das zuständige Innen- und Gesundheitsministerium zu Beginn der ersten Welle eine Allgemeinverfügung erlassen, in der unter anderem die Organisation der Krankenhausbelegung, Neukonzeption der Informationstechnologie(IT)-Steuerung und Meldepflichten angeordnet wurden. Ziel dieser Auswertung war es, die Bedeutung der universitären Medizin für die stationäre Behandlung von COVID-19-Patienten in Bayern zu untersuchen.

Methoden

Es erfolgte eine retrospektive Auswertung aller stationär behandelten COVID-19-Patienten, die über das Modul IVENA Sonderlage (IVENA eHealth, [IVENA, interdisziplinärer Versorgungsnachweis, mainis IT-Service GmbH, Offenbach am Main, Deutschland]) gemeldet wurden. Hierbei wurden die gemeldeten Behandlungstage aller bayerischen Kliniken, die an der Versorgung von COVID-19-Patienten teilgenommen haben, ausgewertet.

Ergebnisse

Im Rahmen der ersten Welle der COVID-19-Pandemie wurden 90,9 % der Behandlungstage von kommunalen und öffentlichen sowie privaten Krankenhäusern in Bayern bereitgestellt. Neben der medizinischen Versorgung von COVID-19-Patienten mit komplexen Verläufen (20 % der Intensivstations[ICU]- und Intermediate-care-Stations [IMC]-Behandlungstage) leistete die Universitätsmedizin in Bayern mit ihren Kliniken einen relevanten wissenschaftlichen Beitrag und war wesentlich an der Beratung von Ärzten, Krankenhäusern und Politik zur Pandemie beteiligt.
SMEs with legally restricted banking access: evidence from the US marijuana industry
Authors: Merz Markus , Riepe Jan
Published: March 2021

This paper examines how legally restricted access to banking services affects small and medium-sized enterprises (SMEs) in a highly developed country. Using a mixed-method approach, we examine the unique situation of the US marijuana industry. The industry benefits from the superior institutional environment in terms of legal protection and the labor market of the United States. However, due to conflicting state and federal laws it has no legal access to banking. We find significant value effects around three major events that affected future access to banking. These results indicate that banking access remains desirable for the marijuana industry. A survey taken by marijuana SMEs provides insights into what banking services are considered most valuable. We find that marijuana SMEs have problems to obtain financing and handle their transactions largely in cash, resulting in transaction inefficiency and high security concerns. Thereby, we shed light on the value of banks for SMEs in developed countries. We complement the literature on financial transaction services by highlighting the value for SMEs in developed markets.
A Prospective Observational Study to Determine Rate of Thromboprophylaxis in Oncology Patients Undergoing Abdominal or Pelvic Surgery
Authors: Shrikhande Shailesh V. , Verma Manish
Published: March 2021

Venous thromboembolism (VTE) is common in patients with cancer and is a leading cause of death. In addition to the hypercoagulable state associated with malignancy, cancer-related surgery and subsequent immobilization further increase the risk of VTE. Guidelines suggest extended prophylaxis up to 4 weeks with low-molecular-weight heparin (LMWH) in such patients. This study is conducted to determine the proportion of patients receiving thromboprophylaxis among those undergoing surgery for malignant abdominal or pelvic tumor. This prospective, multicenter, observational study included 300 patients (217 [72.3%] were women). Mean age and duration of cancer were 53.2 and 1.2 years, respectively. A total of 162 (54%) patients received thromboprophylaxis of which only pharmacological in 78 [48.1%], only mechanical in 27 [16.7%], and both pharmacological and mechanical in 57 [35.2%] patients. LMWH (128, 79.0%) and graduated compression stockings (74, 45.7%) were the commonly used modalities. VTE prophylaxis was given in only half of the patients. Physician education to increase adherence to international guidelines is very important. Trial Registration No. CTRI/2013/05/003617.
Computational analysis of the effects of nitrogen source and sin1 knockout on biosilica morphology in the model diatom Thalassiosira pseudonana
Authors: Horvát Szabolcs , Fathima Adeeba , Görlich Stefan , Schlierf Michael , Modes Carl D. , Kröger Nils
Published: March 2021

Morphogenesis of the silica based cell walls of diatoms, a large group of microalgae, is a paradigm for the self-assembly of complex 3D nano- and microscale patterned inorganic materials. In recent years, loss-of-function studies using genetic manipulation were successfully applied for the identification of genes that guide silica morphogenesis in diatoms. These studies revealed that the loss of one gene can affect multiple morphological parameters, and the morphological changes can be rather subtle being blurred by natural variations in morphology even within the same clone. Both factors severely hamper the identification of morphological mutants using subjective by-eye inspection of electron micrographs. Here we have developed automated image analysis for objectively quantifying the morphology of ridge networks and pore densities from numerous electron micrographs of diatom biosilica. This study demonstrated differences in ridge network morphology and pore density in diatoms growing on ammonium rather than nitrate as the sole nitrogen source. Furthermore, it revealed shortcomings in previous by-eye evaluation of the biosilica phenotype of the silicanin-1 knockout mutant. We anticipate that the computational methods established in the present work will be invaluable for unraveling genotype–phenotype correlations in diatom biosilica morphogenesis.
The Growth and Regulatory Impact of Climate Change Litigation
Authors: Osofsky Hari
Published: March 2021

Hari Osofsky began by making a statement of support for Black Lives Matter. Her presentation then focused on the evolution and regulatory impact of climate change litigation around the world, examining its role within the broader context of multi-level climate change governance and as a form of strategic litigation.
From the Inuit Petition to the Teitiota Case: Human Rights and Success in Climate Litigation
Authors: Magraw Daniel
Published: March 2021

Daniel Magraw emphasized the human rights turn in climate litigation. There is a well-established relationship between human rights and the environment, and it is now generally acknowledged that a healthy environment is necessary for the enjoyment of a vast array of human rights. Importantly, environmental harm—including climate change—interferes with human rights.
Defending Those Who Protect Refugees
Authors: Kuykendall Greg
Published: March 2021

The United States government created and then nourished an ever-growing humanitarian aid crisis over the last twenty-five years in the borderlands of Arizona. Many thousands have perished and many thousands more have suffered unconscionable hardship and horrific abuse as a direct result of this crisis of the government's own making. Making matters excruciatingly worse, recently the Trump administration's Department of Justice escalated the crisis by prosecuting humanitarian aid workers for their life-saving actions.
A Brief Discussion on the United States’ Sanctions Program and Venezuela
Authors: Parkhurst Kory
Published: March 2021

States interact with other states in a myriad of ways. One such way is by the issuance of economic sanctions intended to impact another state's policies or practices. Economic sanctions are an “old tool,” which historically have been grounded on the issuing state's own overarching goals and policies. However, economic sanctions are becoming more and more a means of exerting political influence over another state. One can question whether this is in fact “using an old tool in a new way.” I would suggest this practice, when implemented in particular ways, can complicate the “new economic world order” in such a way as to create perverse incentives within a state's own sanctions regime.
Introductory Remarks By Kimberly Brown
Authors: Brown Kimberly , Gibson Catherine , Sumar Fatema , Thomas Chantal
Published: March 2021

This session explored the compatibility of some of the world's most prominent international organizations and legal regimes with three Sustainable Development Goals (SDGs): SDG 5 (Achieve gender equality and empower all women and girls); SDG 10 (Reduce inequality within and among countries); and SDG 16 (Promote peaceful and inclusive societies, access to justice, and accountable and inclusive institutions at all levels). Panelists reflected on whether international legal rules and organizations addressed or hindered these goals across three dimensions.
The Normativity of Public International Law Reconsidered
Authors: Wolfrum Rüdiger
Published: March 2021

The Order of the International Court of Justice (ICJ) of January 23, 2020 on the Application of the Convention on the Prevention and Punishment of the Crime of Genocide (The Gambia v. Myanmar) might form a preliminary starting point for this brief address. The Order confirms that public international law defines through international treaties, customary international law, and general principles legally binding commitments and rights of states. As a matter of consequence, based upon those norms, judgments, orders, and awards of international courts and tribunals are legally binding on the parties to the dispute in question to the extent the adjudicating body has jurisdiction.
Remarks by Ana Santos Rutschman
Authors: Rutschman Ana Santos
Published: March 2021

Good afternoon—and in some cases, good evening. I am very grateful to the American Society of International Law, the Vagts family, our convener, Professor Rochelle Dreyfuss, and the panelists on this roundtable for the opportunity to reflect on the interplay between our international and global intellectual property (IP) regime and the determinants of health, which I discuss in a piece scheduled to be published by the Vanderbilt Journal of Transnational Law in early 2021.
Remarks by Gian Luca Burci
Authors: Burci Gian Luca
Published: March 2021

I would like to thank Professor Dreyfuss for inviting me to participate in such an interesting panel and even more to applaud the family of late Professor Vagts for honoring his memory and keeping alive his scholarship through these annual events.
Welcoming Participation, Avoiding Capture: A Five-Part Framework
Authors: Durkee Melissa J.
Published: March 2021

What role should non-state actors have in the work of international organizations? It is particularly fitting that this panel is titled “between participation and capture,” because the phrase calls up the conflicting values that animate this question. When we think of non-state actors “participating” in the work of international organizations, we think about open, transparent organizations that are receiving the benefit of diverse perspectives and expertise. We may associate this phrase with process, access, and legitimacy in governance. On the other hand, when we think about non-state actors “capturing” the agenda of international organizations, we have a conflicting set of mental images: we imagine corruption, mission-drift, and the erosion of legitimacy in global governance. Openness is both valuable and dangerous.
Cities in International Law – From Outsiders to Insiders?
Authors: Aust Helmut Philipp
Published: March 2021

A warm thank you also from my part to the City of The Hague, the Asser Institute, and to everyone involved in this panel.
Introductory Remarks by Peter D. Trooboff
Authors: Trooboff Peter D. , North Cara , Nishitani Yuko , Sastry Shubha , Chanda Riccarda
Published: March 2021

On behalf of the American Society of International Law and as part of its first virtual annual meeting, I am pleased to welcome you to this panel on the promise and prospects of the 2019 Hague Convention on the Recognition and Enforcement of Foreign Judgments in Civil or Commercial Matters. As many of those listening know, the negotiations for this newest Hague Convention were concluded at the Hague Conference on Private International Law on July 2, 2019.
Assembly Keynote
Authors: Haines Avril , Burns William J.
Published: March 2021

Thank you so much, Catherine, and to Sean and to Mark and all of you who have put this together. The annual ASIL event is something all of us lawyers look forward to every year, where we have an opportunity to hear some of the remarkable things that people are doing and thinking about and moving the conversation forward, and I agree it is a critical moment.
Obligations erga omnes and the question of standing before the International Court of Justice
Authors: Urs Priya
Published: March 2021

A number of states have in recent years sought to invoke the responsibility of other states for breaches of their international obligations erga omnes. Their contention is that these obligations are not owed to them bilaterally but in the collective interest, whether as states parties to multilateral treaties or as members of the international community as a whole. This growing interest in the invocation of responsibility for breaches of obligations erga omnes is discussed primarily in relation to the International Law Commission’s Articles on the Responsibility of States for Internationally Wrongful Acts. The Articles being a statement of principle, and indeed, a progressive development of the law on the issue, attention must also be paid to the decisions and dicta of the International Court of Justice. Of particular interest, and the focus of this article, is the question of a state’s standing to institute proceedings before the Court to invoke responsibility for the breach of an obligation erga omnes even in the absence of any injury on its part. The most recent manifestation of this position is The Gambia’s institution in 2019 of proceedings against Myanmar, solely on the basis that all states parties to the Genocide Convention have a legal interest in compliance with the obligations therein. By scrutinizing the practice of the Court to date, the article examines the limits and consequences of an expansive right of standing for states seeking to enforce obligations erga omnes at the Court.
Constraint cumulativity in phonotactics: evidence from artificial grammar learning studies
Authors: Breiss Canaan
Published: March 2021

An ongoing debate in phonology concerns the treatment of cumulative constraint interactions, or ‘gang effects’, and by extension the question of which phonological frameworks are suitable models of the grammar. This paper uses a series of artificial grammar learning experiments to examine the inferences that learners draw about cumulative constraint violations in phonotactics in the absence of a confounding natural-language lexicon. I find that learners consistently infer linear counting and ganging cumulativity across a range of phonotactic violations.
Structural characterization of the microbial enzyme urocanate reductase mediating imidazole propionate production
Authors: Venskutonytė Raminta , Koh Ara , Stenström Olof , Khan Muhammad Tanweer , Lundqvist Annika , Akke Mikael , Bäckhed Fredrik , Lindkvist-Petersson Karin
Published: March 2021

The human microbiome can produce metabolites that modulate insulin signaling. Type 2 diabetes patients have increased circulating concentrations of the microbially produced histidine metabolite, imidazole propionate (ImP) and administration of ImP in mice resulted in impaired glucose tolerance. Interestingly, the fecal microbiota of the patients had increased capacity to produce ImP, which is mediated by the bacterial enzyme urocanate reductase (UrdA). Here, we describe the X-ray structures of the ligand-binding domains of UrdA in four different states, representing the structural transitions along the catalytic reaction pathway of this unexplored enzyme linked to disease in humans. The structures in combination with functional data provide key insights into the mechanism of action of UrdA that open new possibilities for drug development strategies targeting type 2 diabetes.
Potentially bioavailable iron produced through benthic cycling in glaciated Arctic fjords of Svalbard
Authors: Laufer-Meiser Katja , Michaud Alexander B. , Maisch Markus , Byrne James M. , Kappler Andreas , Patterson Molly O. , Røy Hans , Jørgensen Bo Barker
Published: March 2021

The Arctic has the highest warming rates on Earth. Glaciated fjord ecosystems, which are hotspots of carbon cycling and burial, are extremely sensitive to this warming. Glaciers are important for the transport of iron from land to sea and supply this essential nutrient to phytoplankton in high-latitude marine ecosystems. However, up to 95% of the glacially-sourced iron settles to sediments close to the glacial source. Our data show that while 0.6–12% of the total glacially-sourced iron is potentially bioavailable, biogeochemical cycling in Arctic fjord sediments converts the glacially-derived iron into more labile phases, generating up to a 9-fold increase in the amount of potentially bioavailable iron. Arctic fjord sediments are thus an important source of potentially bioavailable iron. However, our data suggests that as glaciers retreat onto land the flux of iron to the sediment-water interface may be reduced. Glacial retreat therefore likely impacts iron cycling in coastal marine ecosystems.
Modulating electronic structure of metal-organic frameworks by introducing atomically dispersed Ru for efficient hydrogen evolution
Authors: Sun Yamei , Xue Ziqian , Liu Qinglin , Jia Yaling , Li Yinle , Liu Kang , Lin Yiyang , Liu Min , Li Guangqin , Su Cheng-Yong
Published: March 2021

Developing high-performance electrocatalysts toward hydrogen evolution reaction is important for clean and sustainable hydrogen energy, yet still challenging. Herein, we report a single-atom strategy to construct excellent metal-organic frameworks (MOFs) hydrogen evolution reaction electrocatalyst (NiRu0.13-BDC) by introducing atomically dispersed Ru. Significantly, the obtained NiRu0.13-BDC exhibits outstanding hydrogen evolution activity in all pH, especially with a low overpotential of 36 mV at a current density of 10 mA cm−2 in 1 M phosphate buffered saline solution, which is comparable to commercial Pt/C. X-ray absorption fine structures and the density functional theory calculations reveal that introducing Ru single-atom can modulate electronic structure of metal center in the MOF, leading to the optimization of binding strength for H2O and H*, and the enhancement of HER performance. This work establishes single-atom strategy as an efficient approach to modulate electronic structure of MOFs for catalyst design.
Chemogenetic ON and OFF switches for RNA virus replication
Authors: Heilmann E. , Kimpel J. , Hofer B. , Rössler A. , Blaas I. , Egerer L. , Nolden T. , Urbiola C. , Kräusslich H. G. , Wollmann G. , von Laer D.
Published: March 2021

Therapeutic application of RNA viruses as oncolytic agents or gene vectors requires a tight control of virus activity if toxicity is a concern. Here we present a regulator switch for RNA viruses using a conditional protease approach, in which the function of at least one viral protein essential for transcription and replication is linked to autocatalytical, exogenous human immunodeficiency virus (HIV) protease activity. Virus activity can be en- or disabled by various HIV protease inhibitors. Incorporating the HIV protease dimer in the genome of vesicular stomatitis virus (VSV) into the open reading frame of either the P- or L-protein resulted in an ON switch. Here, virus activity depends on co-application of protease inhibitor in a dose-dependent manner. Conversely, an N-terminal VSV polymerase tag with the HIV protease dimer constitutes an OFF switch, as application of protease inhibitor stops virus activity. This technology may also be applicable to other potentially therapeutic RNA viruses.
Optimized collusion prevention for online exams during social distancing
Authors: Li Mengzhou , Luo Lei , Sikdar Sujoy , Nizam Navid Ibtehaj , Gao Shan , Shan Hongming , Kruger Melanie , Kruger Uwe , Mohamed Hisham , Xia Lirong , Wang Ge
Published: March 2021

Online education is important in the COVID-19 pandemic, but online exam at individual homes invites students to cheat in various ways, especially collusion. While physical proctoring is impossible during social distancing, online proctoring is costly, compromises privacy, and can lead to prevailing collusion. Here we develop an optimization-based anti-collusion approach for distanced online testing (DOT) by minimizing the collusion gain, which can be coupled with other techniques for cheating prevention. With prior knowledge of student competences, our DOT technology optimizes sequences of questions and assigns them to students in synchronized time slots, reducing the collusion gain by 2–3 orders of magnitude relative to the conventional exam in which students receive their common questions simultaneously. Our DOT theory allows control of the collusion gain to a sufficiently low level. Our recent final exam in the DOT format has been successful, as evidenced by statistical tests and a post-exam survey.
Binocular summation is affected by crowding and tagging
Authors: Siman-Tov Ziv , Lev Maria , Polat Uri
Published: March 2021

In perceptual crowding, a letter easily recognized on its own, becomes unrecognizable if it is surrounded by other letters, an effect that confers a limit on the visual processing. Models assume that crowding is a hallmark of the periphery but that it is almost absent in the fovea. However, recently it was shown that crowding occurs in the fovea of people with an abnormal development of functional vision (amblyopia), when the stimulus is presented for a very short time. When targets and flankers are dissimilar, the crowding is reduced (tagging). Since a combination of binocular inputs increases the processing load, we investigated whether color tagging the target reduces crowding in the fovea of subjects with normal vision and determined how crowding is combined with binocular vision. The crowding effect at the fovea was significantly reduced by tagging with a color target. Interestingly, whereas binocular summation for a single letter was expected to be about 40%, it was significantly reduced and almost absent under crowding conditions. Our results are consistent with the notion that the crowding effect produces a high processing load on visual processing, which interferes with other processes such as binocular summation. We assume that the tagging effect in our experiment improved the subject's abilities (sensitivity and RT) by creating a "segmentation", i.e., a visual simulated separation between the target letter and the background. Interestingly, tagging the target with a distinct color can eliminate or reduce the crowding effect and consequently, binocular summation recovers.
The effect of electroconvulsive therapy on neuroinflammation, behavior and amyloid plaques in the 5xFAD mouse model of Alzheimer’s disease
Authors: Svensson Martina , Olsson Gustaf , Yang Yiyi , Bachiller Sara , Ekemohn Maria , Ekstrand Joakim , Deierborg Tomas
Published: March 2021

Microglial cells are affected in Alzheimer’s disease (AD) and interact with amyloid-beta (Aβ) plaques. Apart from memory loss, depression is common in patients with AD. Electroconvulsive therapy (ECT) is an anti-depressive treatment that may stimulate microglia, induce neuroinflammation and alter the levels of soluble Aβ, but the effects of ECT on microglia and Aβ aggregation in AD are not known. We investigated the short- and long-term effects of ECT on neuroinflammation and Aβ accumulation. 5xFAD mice received either electroconvulsive stimulation (ECS n = 26) or sham treatment (n = 25) for 3 weeks. Microglia and Aβ were analyzed in samples collected 24 h, 5 weeks, or 9 weeks after the last treatment. Aβ plaques and microglia were quantified using immunohistochemistry. The concentration of soluble Aβ and cytokines was quantified using ELISA and levels of Aβ aggregates were measured with Western Blot. Microglial phagocytosis of Aβ in the hippocampus was evaluated by flow cytometry in Methoxy-X04 injected mice 24 h following the last ECS treatment. Y-maze and Elevated plus maze were performed to study behavior after 5 weeks. We could not detect any significant short- or long-term effects of ECS on Aβ pathology or neuroinflammation, but ECS reduced abnormal behavior in the Elevated Plus maze.
A straightforward, environmentally beneficial synthesis of spiro[diindeno[1,2-b:2′,1′-e]pyridine-11,3′-indoline]-2′,10,12-triones mediated by a nano-ordered reusable catalyst
Authors: Fathi Mahsa , Naimi-Jamal M. Reza , Dekamin Mohammad G. , Panahi Leila , Demchuk Oleg M.
Published: March 2021

A library of new spiro[diindeno[1,2-b:2′,1′-e]pyridine-11,3′-indoline]-2′,10,12-trione derivatives has been prepared in an efficient, one-pot pseudo four-component method mediated by a reusable heterogeneous nano-ordered mesoporous SO3H functionalized-silica (MCM-41-SO3H) catalyst. Excellent yields, short reaction times, as well as convenient non-chromatographic purification of the products and environmental benefits such as green and metal-free conditions constitute the main advantages of the developed synthetic methodology. The obtained fused indole-indenone dyes would be of interest to pharmaceutical and medicinal chemistry. Furthermore, due to their sensitivity to pH changes, they could be used as novel pH indicators.
Attentional and cognitive monitoring brain networks in long-term meditators depend on meditation states and expertise
Authors: Yordanova Juliana , Kolev Vasil , Nicolardi Valentina , Simione Luca , Mauro Federica , Garberi Patrizia , Raffone Antonino , Malinowski Peter
Published: March 2021

Meditation practice is suggested to engage training of cognitive control systems in the brain. To evaluate the functional involvement of attentional and cognitive monitoring processes during meditation, the present study analysed the electroencephalographic synchronization of fronto-parietal (FP) and medial-frontal (MF) brain networks in highly experienced meditators during different meditation states (focused attention, open monitoring and loving kindness meditation). The aim was to assess whether and how the connectivity patterns of FP and MF networks are modulated by meditation style and expertise. Compared to novice meditators, (1) highly experienced meditators exhibited a strong theta synchronization of both FP and MF networks in left parietal regions in all mediation styles, and (2) only the connectivity of lateralized beta MF networks differentiated meditation styles. The connectivity of intra-hemispheric theta FP networks depended non-linearly on meditation expertise, with opposite expertise-dependent patterns found in the left and the right hemisphere. In contrast, inter-hemispheric FP connectivity in faster frequency bands (fast alpha and beta) increased linearly as a function of expertise. The results confirm that executive control systems play a major role in maintaining states of meditation. The distinctive lateralized involvement of FP and MF networks appears to represent a major functional mechanism that supports both generic and style-specific meditation states. The observed expertise-dependent effects suggest that functional plasticity within executive control networks may underpin the emergence of unique meditation states in expert meditators.
Plasma C-reactive protein is lower among marijuana using HIV-negative individuals but not among persons living with HIV
Authors: Morgan Ethan , Hudson Hannah , D’Aquila Richard , Mustanski Brian
Published: March 2021

The use of marijuana is highly prevalent among young men who have sex with men (YMSM). Past work has also shown that inflammation is elevated among YMSM, independent of HIV status. Here, we aim to examine the relationship between marijuana use and inflammation among this high-risk cohort, relative to use of other substances. Data were collected among YMSM aged 16–29 in Chicago. Multiplex cytokine and inflammatory biomarker assays were run on plasma from all persons living with HIV (PLWH) (n = 195) and a subset of HIV-negative participants (n = 489). Bivariate analyses and multivariable models assessed relationships between various substances and inflammatory biomarkers. Models were stratified by HIV status and adjusted for demographic characteristics. Most participants reported use of marijuana in the past 30 days (416, 60.8%). Mean blood C-reactive protein (CRP) levels were above the upper limit of normal (3.0 mg/L), indicative of increased risk for cardiovascular disease (mean CRP was 3.9 mg/L; SD = 8.5). In adjusted, stratified analyses, CRP was significantly lower among participants reporting frequent marijuana use (≥ 6 times per month), relative to those reporting never using marijuana, (β = − 0.38; 95% CI: − 0.73, − 0.03). However, this was entirely accounted for by an association among the HIV-negative participants and there was no significant association between marijuana use and blood CRP level among the PLWH. In summary, YMSM had markedly elevated marijuana use and blood CRP levels. Frequent marijuana use was associated with lower inflammation among only those not diagnosed with HIV. Further research is needed to explicate why there are differences between HIV-negative participants and PLWH and to leverage this information to characterize biological mechanisms by which marijuana decreases inflammation.
Analysis of dynamic contact network of patients with COVID-19 in Shaanxi Province of China
Authors: Yang Zhangbo
Published: March 2021

The spread of COVID-19 is closely related to the structure of human social networks. Based on 237 cases, by using epidemiological retrospective statistics, data visualization, and social network analysis methods, this paper summarized characteristics of patients with COVID-19 in Shaanxi, China, and analyzed these patients’ dynamic contact network structure. The study found that there are many clustered infections through strong ties, about one-third of cases are caused by relatives' infection. In early stages of the epidemic, imported cases were the most, and in the later stages, local infection cases were the most. The infected people were mostly middle-aged men. Symptoms of imported cases occurred on average of 3 days after they arrived, and medical measures were taken 5 days later on average. All cases showed symptoms in less than 2 days on average and were then taken to medical treatment. The contact network can be divided into multiple disconnected components. The largest component has 12 patients. The average degree centrality in the network is 0.987, average betweenness degree is 0, average closeness degree is 0.452, and average PageRank index is 0.0042. The number of contacts of patients is unevenly distributed in the network.
3D bioprinting of tissue-specific osteoblasts and endothelial cells to model the human jawbone
Authors: Amler Anna-Klara , Thomas Alexander , Tüzüner Selin , Lam Tobias , Geiger Michel-Andreas , Kreuder Anna-Elisabeth , Palmer Chris , Nahles Susanne , Lauster Roland , Kloke Lutz
Published: March 2021

Jawbone differs from other bones in many aspects, including its developmental origin and the occurrence of jawbone-specific diseases like MRONJ (medication-related osteonecrosis of the jaw). Although there is a strong need, adequate in vitro models of this unique environment are sparse to date. While previous approaches are reliant e.g. on scaffolds or spheroid culture, 3D bioprinting enables free-form fabrication of complex living tissue structures. In the present work, production of human jawbone models was realised via projection-based stereolithography. Constructs were bioprinted containing primary jawbone-derived osteoblasts and vasculature-like channel structures optionally harbouring primary endothelial cells. After 28 days of cultivation in growth medium or osteogenic medium, expression of cell type-specific markers was confirmed on both the RNA and protein level, while prints maintained their overall structure. Survival of endothelial cells in the printed channels, co-cultured with osteoblasts in medium without supplementation of endothelial growth factors, was demonstrated. Constructs showed not only mineralisation, being one of the characteristics of osteoblasts, but also hinted at differentiation to an osteocyte phenotype. These results indicate the successful biofabrication of an in vitro model of the human jawbone, which presents key features of this special bone entity and hence appears promising for application in jawbone-specific research.
Latent traits of lung tissue patterns in former smokers derived by dual channel deep learning in computed tomography images
Authors: Li Frank , Choi Jiwoong , Zou Chunrui , Newell John D. , Comellas Alejandro P. , Lee Chang Hyun , Ko Hongseok , Barr R. Graham , Bleecker Eugene R. , Cooper Christopher B. , Abtin Fereidoun , Barjaktarevic Igor , Couper David , Han MeiLan , Hansel Nadia N. , Kanner Richard E. , Paine Robert , Kazerooni Ella A. , Martinez Fernando J. , O’Neal Wanda , Rennard Stephen I. , Smith Benjamin M. , Woodruff Prescott G. , Hoffman Eric A. , Lin Ching-Long
Published: March 2021

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease and the traditional variables extracted from computed tomography (CT) images may not be sufficient to describe all the topological features of lung tissues in COPD patients. We employed an unsupervised three-dimensional (3D) convolutional autoencoder (CAE)-feature constructor (FC) deep learning network to learn from CT data and derive tissue pattern-clusters jointly. We then applied exploratory factor analysis (EFA) to discover the unobserved latent traits (factors) among pattern-clusters. CT images at total lung capacity (TLC) and residual volume (RV) of 541 former smokers and 59 healthy non-smokers from the cohort of the SubPopulations and Intermediate Outcome Measures in the COPD Study (SPIROMICS) were analyzed. TLC and RV images were registered to calculate the Jacobian (determinant) values for all the voxels in TLC images. 3D Regions of interest (ROIs) with two data channels of CT intensity and Jacobian value were randomly extracted from training images and were fed to the 3D CAE-FC model. 80 pattern-clusters and 7 factors were identified. Factor scores computed for individual subjects were able to predict spirometry-measured pulmonary functions. Two factors which correlated with various emphysema subtypes, parametric response mapping (PRM) metrics, airway variants, and airway tree to lung volume ratio were discriminants of patients across all severity stages. Our findings suggest the potential of developing factor-based surrogate markers for new COPD phenotypes.