bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single step syntheses of (1S)-aryl-tetrahydroisoquinolines by norcoclaurine synthases
Authors: Roddan Rebecca , Sula Altin , Méndez-Sánchez Daniel , Subrizi Fabiana , Lichman Benjamin R. , Broomfield Joseph , Richter Michael , Andexer Jennifer N. , Ward John M. , Keep Nicholas H. , Hailes Helen C. 
Published: November 2020

AbstractThe 1-aryl-tetrahydroisoquinoline (1-aryl-THIQ) moiety is found in many biologically active molecules. Single enantiomer chemical syntheses are challenging and although some biocatalytic routes have been reported, the substrate scope is limited to certain structural motifs. The enzyme norcoclaurine synthase (NCS), involved in plant alkaloid biosynthesis, has been shown to perform stereoselective Pictet–Spengler reactions between dopamine and several carbonyl substrates. Here, benzaldehydes are explored as substrates and found to be accepted by both wild-type and mutant constructs of NCS. In particular, the variant M97V gives a range of (1 S)-aryl-THIQs in high yields (48–99%) and e.e.s (79–95%). A co-crystallised structure of the M97V variant with an active site reaction intermediate analogue is also obtained with the ligand in a pre-cyclisation conformation, consistent with (1 S)-THIQs formation. Selected THIQs are then used with catechol O-methyltransferases with exceptional regioselectivity. This work demonstrates valuable biocatalytic approaches to a range of (1 S)-THIQs.
Solar-to-hydrogen peroxide energy conversion on resorcinol–formaldehyde resin photocatalysts prepared by acid-catalysed polycondensation
Authors: Shiraishi Yasuhiro , Hagi Takumi , Matsumoto Masako , Tanaka Shunsuke , Ichikawa Satoshi , Hirai Takayuki 
Published: November 2020

AbstractThe photocatalytic generation of hydrogen peroxide from water and dioxygen (H2O + 1/2O2 → H2O2, ΔG° = +117 kJ mol–1) under sunlight is a promising strategy for the artificial photosynthesis of a liquid fuel. We had previously found that resorcinol–formaldehyde (RF) resin powders prepared by the base-catalysed high-temperature hydrothermal method act as semiconductor photocatalysts for H2O2 generation. Herein, we report that RF resins prepared by the acid-catalysed high-temperature hydrothermal method (~523 K) using common acids at pH < 4 exhibit enhanced photocatalytic activity. The base- and acid-catalysed methods both produce methylene- and methine-bridged resins consisting of π-conjugated and π-stacked benzenoid–quinoid donor–acceptor resorcinol units. The acidic conditions result in the resins with a lower bandgap (1.7 eV) and higher conductivity because the lower-degree of crosslinking creates a strongly π-stacked architecture. The irradiation of the RF-acid resins with simulated sunlight in water with atmospheric-pressure O2 generates H2O2 at a solar-to-chemical conversion efficiency of 0.7%, which is the highest efficiency ever reported for powder catalysts used in artificial photosynthesis.
Non-Hermitian effects of the intrinsic signs in topologically ordered wavefunctions
Authors: Zhang Qi , Xu Wen-Tao , Wang Zi-Qi , Zhang Guang-Ming 
Published: November 2020

AbstractNegative signs in many-body wavefunctions play an important role in quantum mechanics because interference relies on cancellation between amplitudes of opposite signs. The ground-state wavefunction of double semion model contains negative signs that cannot be removed by any local transformation. Here we study the quantum effects of these intrinsic negative signs. By proposing a generic double semion wavefunction in tensor network representation, we show that its norm can be mapped to the partition function of a triangular lattice Ashkin-Teller model with imaginary interactions. We use numerical tensor-network methods to solve this non-Hermitian model with parity-time symmetry and determine a global phase diagram. In particular, we find a dense loop phase described by non-unitary conformal field theory and a parity-time-symmetry breaking phase characterized by the zeros of the partition function. Therefore, our work establishes a connection between the intrinsic signs in the topological wavefunction and non-unitary phases in the parity-time-symmetric non-Hermitian statistical model.
A paired electrolysis approach for recycling spent lithium iron phosphate batteries in an undivided molten salt cell
Authors: Zhang Beilei , Qu Xin , Qu Jiakang , Chen Xiang , Xie Hongwei , Xing Pengfei , Wang Dihua , Yin Huayi 
Published: November 2020

A molten salt paired electrolysis, installed with dual LiFePO4 electrodes, employs electrons as both reducing and oxidizing agents and the molten salt as the solvent to efficiently reclaim end-of-life LiFePO4 batteries.
Structural characterization and pharmacological assessment in vitro/in vivo of a new copper(ii)-based derivative of enrofloxacin
Authors: Guo Rui-Feng , Yan Hou-Tian , Liu Rui-Xue , Li Hong-Chang , Liu Yan-Cheng , Chen Zhen-Feng , Liang Hong 
Published: November 2020

Abstract
Enrofloxacin (EFX) was selected as the medicinal ligand to afford a new copper(ii)-based complex, EFX-Cu, which was structurally characterized by spectroscopic analyses including X-ray single crystal diffraction. It was also stable and could retain the coordination state in aqueous solution. The in vitro antibacterial activity of EFX-Cu against a panel of pathogenic bacteria was about the same as that of EFX, except that it was twice as active against E. coli. The in vivo test on mice gave a LD50 value of 8148 mg kg−1 for EFX-Cu, which was much lower than those for EFX (LD50, 5312 mg kg−1) and its clinically used sodium salt, EFX-Na (LD50, 1421 mg kg−1). In addition, no obvious lesions in the organs of the dead mice were found by histopathological examination. Pharmacokinetic studies on rats suggested similar pharmacokinetics between EFX-Cu and EFX. On the other hand, EFX-Cu showed higher acute toxicity than EFX-Na in zebrafish, which was inconsistent with that in mice. The ROS-related inflammation and anti-inflammatory assay of EFX-Cu, respectively, in normal cells and zebrafish could be ascribed to its ROS-related redox property. Unfortunately, the final in vivo therapeutic assay in the E. coli-infected mouse model indicated that the therapeutic effect of EFX-Cu, mainly in terms of mortality in mice, was found to be lower than that of EFX-Na at the same dosage (800 mg kg−1, continuous gavage), although the contradictory factors between toxicity and antibacterial activity could not be excluded in this trial.
Genomic islands and the evolution of livestock-associatedStaphylococcus aureusgenomes
Authors: Rao Relangi Tulasi , Sharma Shivani , Sivakumar Natesan , Jayakumar Kannan 
Published: November 2020

AbstractBackground: Genomic Islands (GIs) are commonly believed to be relics of horizontal transfer and associated with specific metabolic capacities, including virulence of the strain. Horizontal gene transfer (HGT) plays a vital role in the acquisition of GIs and the evolution and adaptation of bacterial genomes.Objective: The present study was designed to predict the GIs and role of HGT in evolution of livestock-associated Staphylococcus aureus (LA-SA).Methods: GIs were predicted with two methods namely, Ensemble algorithm for Genomic Island Detection (EGID) tool, and Seq word Sniffer script. Functional characterization of GI elements was performed with clustering of orthologs. The putative donor predictions of GIs was done with the aid of the pre_GI database.Results: The present study predicted a pan of 46 GIs across the LA-SA genomes. Functional characterization of GI sequences revealed few unique results like the presence of metabolic operons like leuABCD and folPK genes in GIs and showed the importance of GIs in the adaptation to the host niche. The developed framework for GI donor prediction results revealed Rickettsia and Mycoplasma as the major donors of GI elements.Conclusions: The role of GIs during the evolutionary race of LA-SA could be concluded from the present study. Niche adaptation of LA-SA enhanced presumably due to these GIs. Future studies could focus on the evolutionary relationships between Rickettsia and Mycoplasma sp. with S. aureus and also the evolution of Leucine/Isoleucine mosaic operon (leuABCD).
Facile synthesis and characterisation of green luminescent carbon nanodots prepared from tender coconut water using the acid‐assisted ultrasonic route
Authors: Manoharan Preethi , Dhanabalan Sathish Chander , Alagan Muthulakshmi , Muthuvijayan Santhoshbalaji , Ponraj Joice Sophia , Somasundaram Chandra Kishore 
Published: November 2020

In the present investigation, the authors have adopted a simple and economical method for the synthesis of bright green photoluminescent carbon nanodots (CNDs) from tender coconut water via acid‐assisted ultrasonic route. Tender coconut water is used as a less expensive and eco‐friendly carbon precursor to produce well‐dispersed CNDs possessing a hybrid structural behaviour of both nanocrystalline and amorphous carbon phases. The monodispersed CNDs with spherical morphology and particle size (4 ± 1 nm) were confirmed with the aid of high‐resolution transmission electron microscopy. The functional groups attached to CNDs are held responsible for the fluorescence nature and mono‐dispersion that were assessed using Fourier transform infrared spectroscopy. The green fluorescence nature of CNDs was evaluated at a maximum emission at 510 nm with an excitation wavelength of 450 nm, using ultraviolet–visible absorption spectrum and photoluminescence spectra. The CNDs with a carbon core and chemical groups over their surface exhibited a fluorescence quantum yield of 60.18%. The stability, low‐cost precursor, rapid reaction and uniform dispersion without chemical functionalisation makes these CNDs synthesised from tender coconut water more advantageous than other sources. This research mainly emphasis on synthesis and characterisation of CNDs with a detailed mechanism for CND formation.
Einsatz von Community-Masken in der Bevölkerung: Praxis und Anwendungsfehler während der COVID-19 Pandemie in Deutschland
Authors: Mattner Frauke , Neuwirth Meike Maria , Otchwemah Robin , Duman Deniz , Neuwirth Martin , Teves Stefanie 
Published: November 2020

Zusammenfassung
Ziel der Studie Die COVID-19 Pandemie hat erhebliche gesellschaftliche Auswirkungen. Die Transmissionsvorbeugung in der Bevölkerung beinhaltet u. a. das Tragen von textilen Mund-Nasen-Bedeckungen. Voraussetzung des Schutzeffekts ist der korrekte Maskeneinsatz, wobei Anwendungsfehler selbst unter medizinischem Fachpersonal beobachtet wurden. In der vorliegenden Arbeit wurde analysiert, welche Masken im öffentlichen Raum als Mund-Nasen-Bedeckung zum Einsatz kamen, ob der Einsatz korrekt erfolgte und welcher Art die beobachteten Anwendungsfehler waren.
Methodik Es erfolgte eine prospektive Beobachtungsstudie in Bereichen, für die eine textile Mund-Nasen-Bedeckungspflicht nach der Coronaschutzverordnung NRW galt.
Ergebnisse Zwischen dem 07.05.2020 und 13.05.2020 wurden 2721 Personen in maskenpflichtigen Bereichen beobachtet. Die Gesamtcompliance zu Mund-Nasen-Bedeckungen betrug 97,2%. Am häufigsten kam der chirurgische Mund-Nasen-Schutz (MNS) (44,9%) zum Einsatz, gefolgt von Stoffmasken (39,8%), FFP-Masken (7,1%) sowie Schals (5,4%). Keine Maske trugen 2,8% der Beobachteten. In 30,4% der Fälle wurde die Mund-Nasen-Bedeckung fehlerhaft getragen. Die häufigsten Anwendungsfehler fielen in die Kategorien „Maske unter der Nase getragen“ (41,4%) und „Nasenbügel nicht angepasst“ (20,8%). Der MNS wurden deutlich häufiger fehlerhaft eingesetzt als die übrigen Masken- Typen (p<0,001).
Schlussfolgerung In der vorliegenden Untersuchung zeigte sich eine hohe Gesamtcompliance der Bevölkerung von 97% zum Einsatz von Mund-Nasen-Bedeckungen im Rahmen des COVID-19 Pandemie- Managements. Die Masken wurden in 30% der Fälle fehlerhaft genutzt. Hieraus ergibt sich die Notwendigkeit einer gezielten, intensivierten Wissensvermittlung zur Maskenanwendung an die Bevölkerung, die die beobachteten Defizite berücksichtigt.
Protocol for Palladium/N-Heterocyclic Carbene-Catalyzed Suzuki–Miyaura Cross-Coupling of Amides by N–C(O) Activation
Authors: Lei Peng , Li Guangchen , Szostak Michal , Ling Yun , An Jie , Nolan Steven P. 
Published: November 2020

AbstractAmides are among the most important and ubiquitous functional groups in organic chemistry and process development. In this Practical Synthetic Procedure, a protocol for the Suzuki–Miyaura cross-coupling of amides by selective N–C(O) bond activation catalyzed by commercially available, air- and moisture-stable palladium/N-heterocyclic carbene (NHC) complexes is described. The procedure described involves [Pd(IPr)(cin)Cl] [IPr = 2,6-(diisopropylphenyl)imidazol-2-ylidene, cin = cinnamyl] at 0.10 mol% at room temperature and is performed on decagram scale. Furthermore, a procedure for the synthesis of amide starting materials is accomplished via selective N-tert-butoxycarbonylation, which is the preferred method over N-acylation. The present protocol carries advantages of operational simplicity, commercial availability of catalysts, and excellent conversions at low catalyst loadings. The method is generally useful for activation of N–C(O) amide bonds in a broad spectrum of amide precursors. The protocol should facilitate the implementation of amide cross-coupling reactions.
Routine Ultrasound Control after Successful Intussusception Reduction in Children: Is It Really Necessary?
Authors: Delgado-Miguel Carlos , García Antonella , Delgado Bonifacio , Muñoz-Serrano Antonio Jesús , Miguel-Ferrero Miriam , Barrena Saturnino , Lopez Santamaria Manuel , Martinez Leopoldo 
Published: November 2020

Abstract
Introduction Recurrence of ileocolic intussusception (ICI) has been related to residual bowel wall edema after enema reduction. Early oral tolerance has been associated with a higher risk of re-intussusception, so an imaging test (ultrasound) has traditionally been performed before restarting oral tolerance. Our aim is to analyze the cost-effectiveness of performing a routine ultrasound in patients who remain asymptomatic after successful enema reduction.
Materials and Methods A retrospective observational study was performed in patients with ICI who underwent a successful enema reduction between 2005 and 2019 and distributed in two groups according to whether or not a routine ultrasound was performed before restarting oral tolerance: group A (ultrasound) or B (no ultrasound). We analyzed demographic, clinical and laboratory variables, length of hospital stay, and recurrence rate.
Results We included 366 patients who presented 373 ICI episodes (165 in group A and 208 in group B), without significant differences in gender and age. Group A patients presented a higher percentage of vomiting and bloody stools than those in group B without differences in the other clinical features studied, time of evolution, or laboratory variables. Group A presented a higher length of hospital stay than group B (36 vs. 24 hours), although it was not statistically significant (p = 0.30). No statistically significant differences were observed in the recurrence rate between both groups (10.3% A vs. 10.8% B; p = 0.83).
Conclusion Performing routine ultrasound before restarting oral tolerance in asymptomatic patients after successful ICI reduction does not decrease the risk of re-intussusception and should not be routinely encouraged.
Clinical Features and Outcome of Thrombotic Microangiopathies: Comparison between Patients with and without Malignancy
Authors: Van de Louw Andry , Cohrs Austin , Leslie Douglas 
Published: November 2020

AbstractThrombotic microangiopathy (TMA) is an uncommon complication of cancers, related to the malignancy itself, antineoplastic drugs, or hematopoietic stem cell transplant. It was reported mostly as case series but large data are lacking. We used the large U.S. MarketScan database to compare TMA between patients with and without malignancy. Adult patients hospitalized between 2005 and 2014 with a diagnosis of TMA were included; cancer patients were defined by a diagnosis of cancer within 1 year prior to or during the admission with TMA. Associated inpatient diagnoses, procedures, hospital mortality, and long-term survival were collected. We included 3,227 patients; 617 (19.1%) had cancer (age 54 [44–60] years, 58% female), which was a new diagnosis for 23% of patients. Two-thirds of cancer patients had solid tumors (mostly pancreas, lung, breast, colorectal, and hepatobiliary, half of them metastatic) and one-third had hematological malignancies (lymphoma, acute leukemia, and multiple myeloma); TMA patients with cancer were older, more often men, had more noncancer-related comorbidities, and developed more sepsis and coagulopathy than TMA patients without cancer. Hospital mortality was significantly higher in cancer patients (16.6% vs. 6.1%, p < 0.001) and reached 30% in transplant recipients; malignancy was an independent risk factor for hospital mortality in multivariate analysis and sensitivity analyses excluding patients with metastases or patients who did not undergo plasmapheresis led to similar results. Malignancy was also associated with decreased long-term survival.
The Spaced Learning Concept Significantly Improves Acquisition of Laparoscopic Suturing Skills in Students and Residents: A Randomized Control Trial
Authors: Boettcher Johannes , Mietzsch Stefan , Wenkus Julia , Mokhaberi Nariman , Klinke Michaela , Reinshagen Konrad , Boettcher Michael 
Published: November 2020

Abstract
Introduction Spaced learning consists of blocks with highly condensed content that interrupted by breaks during which distractor activities, such as physical activity, are performed. The concept has been shown to be superior in complex motor skill acquisition like laparoscopic suturing and knot tying. Preliminary studies have solely been conducted with medical students. Therefore, it remained unanswered if the spaced learning concept would also work for pediatric surgery residents.
Materials and Methods The study aimed to evaluate the effectiveness of spaced learning, students, and residents were asked to perform four surgeons' square knots on a bowel model within 30 minutes prior and post 3 hours of hands-on training. To examine the long-term skills, the same subjects were asked to perform a comparable, but more complex task 12 months later without receiving training in the meantime. Total time, knot stability, suture accuracy, knot quality, and laparoscopic performance were assessed. Additionally, motivation was accessed by using the questionnaire on current motivation. Differences were calculated using mixed analysis of variance, Mann–Whitney U test, and multivariate analysis of covariance.
Results A total of 20 medical students and 14 residents participated in the study. After randomization, 18 were trained using the spaced learning concept and 16 via conventional methods. Both groups had comparable baseline characteristics and improved significantly after training in all assessed measures. The spaced learning concept improved procedure performance as well as knot quality and stability in both students and residents. However, residents that trained via spaced learning showed significantly better long-term results regarding knot quality and speed in comparison to students. Although anxiety was significantly reduced in both training groups over time, residents were significantly more interested regarding knot tying than students.
Conclusion This study dispels any remaining doubt that the spaced learning concept might only work for medical students. It appears that the spaced learning concept is very suitable for residents in acquiring complex motor skills. It is superior to conventional training, resulting in improved procedural performance as well as knot quality and speed. Hence, tailored training programs should not only be integrated early on in students' curricula but also in surgical training programs.
Ionization behavior of nanoporous polyamide membranes
Authors: Ritt Cody L. , Werber Jay R. , Wang Mengyi , Yang Zhongyue , Zhao Yumeng , Kulik Heather J. , Elimelech Menachem 
Published: November 2020

Significance
Novel membrane processes and materials are needed to combat global water scarcity. The advancement of membrane materials for water purification processes such as desalination is hindered by our limited understanding of structure–property–performance relationships. We address this knowledge gap by elucidating the mechanisms which govern the ionization behavior of nanoporous polyamide films and their influence on membrane performance. Polyamide ionization is key to enhancing the separation efficiency of charged constituents in aqueous solutions. Our results illustrate that a large portion of the ionizable moieties in polyamide films remain uncharged during typical operation due to extreme confinement effects, thus going unutilized. Complete ionization of state-of-the-art polyamide membranes offers selectivity improvements that could markedly improve desalination process efficiency.
To hón ich imma insistieat
Authors: Flores Cristina , Rinke Esther , Wagner Claudia 
Published: November 2020

AbstractThis paper investigates syntactic variation in Hunsrückisch German, spoken in a language enclave in South Brazil over eight generations. The aim is to analyse whether this heritage language maintains asymmetric verb placement, i.e. verb-second in main clauses and verb-final in subordinate clauses, a prominent syntactic feature of German varieties. The analysis is based on a sample of 5000 sentences, produced by participants belonging to two generations of Hunsrückisch speakers: 10 older speakers (age: 55–75), and 10 younger adults (age: 25–40). The results show a general stability of asymmetric verb placement in both speaker groups, as has also been observed for other German language islands. This stability is a consequence of the active use of this minority language, not only by the older, but also by the younger generation of speakers, who are dominant in Brazilian Portuguese (BP). Variation to verb-second and verb-final order is conditioned by the same factors as in colloquial and dialectal German, and cannot be attributed to cross-linguistic influence from BP.
Impact of oxide gate electrode for ferroelectric field-effect transistors with metal-ferroelectric-metal-insulator-semiconductor gate stack using undoped HfO2 thin films prepared by atomic layer deposition
Authors: Choi Se-Na , Moon Seung-Eon , Yoon Sung-Min 
Published: November 2020

Abstract
Ferroelectric field-effect transistors (FETs) with a metal-ferroelectric-metal-insulator-semiconductor (MFMIS) gate stack were fabricated and characterized to elucidate the key process parameters and to optimize the process conditions for guaranteeing nonvolatile memory operations of the device when the undoped HfO2 was employed as ferroelectric gate insulator. The impacts of top gate (TG) for the MFM part on the memory operations of the MFMIS-FETs were intensively investigated when the TG was chosen as metal Pt or oxide ITO electrode. The ferroelectric memory window of the MFMIS-FETs with ITO/HfO2/TiN/SiO2/Si gate stack increased to 3.8 V by properly modulating the areal ratio between two MFM and MIS capacitors. The memory margin as high as 104 was obtained during on- and off-program operations with a program pulse duration as short as 1 μs. There was not any marked degradation in the obtained memory margin even after a lapse of retention time of 104 s at 85 °C and repeated program cycles of 10,000. These obtained improvements in memory operations resulted from the fact that the choice of ITO TG could provide effective capping effects and passivate the interfaces.