bluuebunny/crossref_metadata_2025 huggingface dataset:
Correction: A 2-formylphenylboronic acid (2FPBA)-maleimide crosslinker: a versatile platform for Cys-peptide–hydrazine conjugation and interplay
Authors: António João P. M. , Faustino Hélio , Gois Pedro M. P.
Published: September 2021

Correction for ‘A 2-formylphenylboronic acid (2FPBA)-maleimide crosslinker: a versatile platform for Cys-peptide–hydrazine conjugation and interplay’ by João P. M. António et al., Org. Biomol. Chem., 2021, 19, 6221–6226, DOI: 10.1039/D1OB00917F.
Living polymerization of naturally renewable butyrolactone-based vinylidenes mediated by a frustrated Lewis pair
Authors: Bai Yun , Wang Huaiyu , He Jianghua , Zhang Yuetao
Published: September 2021

The frustrated Lewis pair composed of an organophosphorus(iii) superbase and a bulky organoaluminum Lewis acid promoted the living/controlled polymerization of naturally renewable butyrolactone-based vinylidenes.
Cobalt-catalyzed selective hydroacylation of alkynes
Authors: Wu Jian , Gao Wen-Xia , Huang Xiao-Bo , Zhou Yun-Bing , Liu Miao-Chang , Wu Hua-Yue
Published: September 2021

An efficient protocol for alkyne hydroacylation using a catalytic system incorporating Co(acac)3, dppp and AlMe3is disclosed.
High-performance electrocatalyst based on polyazine derived mesoporous nitrogen-doped carbon for oxygen reduction reaction
Authors: Zhao Songlin , Chen Fushan , Zhang Qunfeng , Meng Lingtao
Published: September 2021

Nitrogen-doped porous carbon materials have high potential in metal-free electrocatalysts, which is essential for several renewable energy conversion systems.
Selective formation of dihydrofuran fused [60] fullerene derivatives by TEMPO mediated [3 + 2] cycloaddition of medium chain β-keto esters to C60
Authors: Jakšić Jovana , Mitrović Aleksandra , Tokić Vujošević Zorana , Milčić Miloš , Maslak Veselin
Published: September 2021

In this study, β-keto esters as readily available bio-based building blocks were used to decorate the C60 sphere.
Anhydrous proton conductivity of electrospun phosphoric acid-doped PVP-PVDF nanofibers and composite membranes containing MOF fillers
Authors: Sun Lian , Gu Quanchao , Wang Honglei , Yu Jinshan , Zhou Xingui
Published: September 2021

A composite SA/MIL101@PVP-PVDF membrane was fabricated via electrospinning and reached a conductivity of 0.237 S cm−1 at 160 °C with a moderate acid doping level (12.7).
N-Aryl iminochromenes inhibit cyclooxygenase enzymesviaπ–π stacking interactions and present a novel class of anti-inflammatory drugs
Authors: Nguyen Ha Thi , Vu Thien-Y. , Vijay Kumar A. , Hoang Vo Nguyen Huy , My Pham Thi Ngoc , Mandal Prashant S. , Tatipamula Vinay Bharadwaj
Published: September 2021

Screening ofN-aryl iminochromenes for their anti-inflammatory activities by performingin vitro,in vivo, andin silicostudies.
A microwave radiation-enhanced Fe–C/persulfate system for the treatment of refractory organic matter from biologically treated landfill leachate
Authors: Hu Yuansi
Published: September 2021

A microwave radiation enhanced Fe-C/PS system was used to treat biologically-treated landfill leachate. This process showed wide applicability in treatment of four types of leachates and has a promising potential in landfill leachate treatment.
Recent developments of a co-immobilized laccase–mediator system: a review
Authors: Gu Yaohua , Yuan Lin , Jia Leina , Xue Ping , Yao Huiqin
Published: September 2021

The laccase–mediator is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization.
Iron-containing palygorskite clay as Fenton reagent for the catalytic degradation of phenol in water
Authors: Xu Jie , Yun Xuehai , Li Meng , Tian Ye , Lei Xiaodong , Zhang Fazhi
Published: September 2021

Mechanism diagram of palygorskite clay degradation of phenol-containing wastewater.
Recent advances and perspectives on supramolecular radical cages
Authors: Huang Bin , Mao Lijun , Shi Xueliang , Yang Hai-Bo
Published: September 2021

ThisPerspectivesummarizes the recent developments of supramolecular radical cages including the design and synthesis of radical cages, their interesting host–guest spin–spin interactions and applications in radical-mediated/catalyzed reactions.
Tug-of-war: molecular dynamometers against living cells for analyzing sub-piconewton interaction of a specific protein with the cell membrane
Authors: Liu Huipu , Chen Yunlong , Wang Jiawei , Yang Yuanjiao , Ju Huangxian
Published: September 2021

A molecular dynamometer is designed to analyze the variation of sub-piconewton interaction between a specific protein and the membrane on living cells.
Perovskite indoor photovoltaics: opportunity and challenges
Authors: Wang Kai-Li , Zhou Yu-Hang , Lou Yan-Hui , Wang Zhao-Kui
Published: September 2021

With the rapid development of the Internet of Things (IoTs), photovoltaics (PVs) has a vast market supply gap of billion dollars.
Thermostable carbon-supported subnanometer-sized (<1 nm) Pt clusters for the hydrogen evolution reaction
Authors: Huang Jing-Fang , Zeng Ruo-Hua , Chen Jeng-Lung
Published: September 2021

Thermostable carbon-supported Pt clusters (<1 nm) overcome challenges, thermal stability, high Pt loading and low TOF, in water splitting.
Highly efficient and selective nitrate electroreduction to ammonia catalyzed by molecular copper catalyst@Ti3C2Tx MXene
Authors: Li Lan-Xin , Sun Wu-Ji , Zhang Hao-Yu , Wei Jia-Liang , Wang Shu-Xian , He Jing-Hui , Li Na-Jun , Xu Qing-Feng , Chen Dong-Yun , Li Hua , Lu Jian-Mei
Published: September 2021

The efficient electroreduction reaction of nitrate (NO3−RR) at low concentrations to ammonia is energetically favorable for ammonia production and environmentally essential to treat water contamination.
Correction: Semiconducting polymer contributes favorably to the Seebeck coefficient in multi-component, high-performance n-type thermoelectric nanocomposites
Authors: Tang Junhui , Chen Ruisi , Chen Lidong , Bazan Guillermo C. , Liang Ziqi
Published: September 2021

Correction for ‘Semiconducting polymer contributes favorably to the Seebeck coefficient in multi-component, high-performance n-type thermoelectric nanocomposites’ by Junhui Tang et al., J. Mater. Chem. A, 2020, 8, 9797–9805, DOI: 10.1039/d0ta02388d.
pH-Sensitive branched β-glucan-modified liposomes for activation of antigen presenting cells and induction of antitumor immunity
Authors: Yanagihara Shin , Kasho Nozomi , Sasaki Koichi , Shironaka Naoto , Kitayama Yukiya , Yuba Eiji , Harada Atsushi
Published: September 2021

pH-Sensitive branched β-glucan-modified liposomes promote antigen uptake and activation of dendritic cellsin vitro, inducing anti-tumor immune responsesin vivo.
The effect of the donor moiety of DPP based polymers on the performance of organic electrochemical transistors
Authors: Wang Yazhou , Hamidi-Sakr Amer , Surgailis Jokubas , Zhou Yecheng , Liao Hailiang , Chen Junxin , Zhu Genming , Li Zhengke , Inal Sahika , Yue Wan
Published: September 2021

Two D–A type polymers based on the gTDPP as the acceptor and gTVT and gTBTT as the donor have been developed. The donor unit affects the backbone curvature and the aggregation properties of the mixed conductors, regulating their performance in OECTs.
miRNome profiling in Duchenne muscular dystrophy; identification of asymptomatic and manifesting female carriers
Authors: Mousa Nahla O. , Sayed Ahmed A. , Fahmy Nagia , Elzayat Mariam G. , Bakry Usama , Abdellatif Ahmed , Zahra Waheed K. , Osman Ahmed
Published: September 2021

Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disorder that occurs due to inactivating mutations in DMD gene, leading to muscular dystrophy. Prediction of pathological complications of DMD and the identification of female carriers are important research points that aim to reduce disease burden. Herein, we describe a case of a late DMD patient and his immediate female family members, who all carry same DMD mutation and exhibited varied degrees of symptoms. In our study, we sequenced the whole miRNome in leukocytes and plasma of the family members and results were validated using real-time PCR. Our results highlighted the role of miR-409-3p, miR-424-5p, miR-144-3p as microRNAs that show correlation with the extent of severity of muscular weakness and can be used for detection of asymptomatic carriers. Cellular and circulating levels of miR-494-3p had shown significant increase in symptomatic carriers, which may indicate significant roles played by this miRNA in the onset of muscular weakness. Interestingly, circulating levels of miR-206 and miR-410-3p were significantly increased only in the severely symptomatic carrier. In conclusion, our study highlighted several miRNA species, which could be used in predicting the onset of muscle and/or neurological complications in DMD carriers.
Listening-Related Fatigue in Children With Hearing Loss: Perspectives of Children, Parents, and School Professionals
Authors: Davis Hilary , Schlundt David , Bonnet Kemberlee , Camarata Stephen , Hornsby Benjamin , Bess Fred H.
Published: September 2021

Purpose:

Children with hearing loss (CHL) are considered at risk for listening-related fatigue and its negative consequences. We collected data via focus groups and interviews from three stakeholder groups—CHL, their parents, and teachers/school professionals—in order to define the construct of listening-related fatigue from the perspective of CHL and key stakeholders. This is an important first step in our long-term goal to construct and validate a measure (i.e., scale) of listening-related fatigue for the pediatric population, with a focus on CHL. This article provides an overview of the data gathering process, analysis of qualitative reports, and the development of a theoretical framework for understanding the experience of listening-related fatigue in CHL.

Method:

We conducted focus groups and interviews in school-age children exhibiting bilateral, moderate-to-profound hearing loss (n= 43), their parents (n= 17), and school professionals who work with CHL (n= 28). The discussions were audio-recorded, transcribed, and coded using a hierarchical coding system. Qualitative analysis was conducted using an iterative inductive–deductive approach.

Results:

We identified primary themes from the focus group/interview discussions to develop a theoretical framework of listening-related fatigue in CHL. The framework demonstrates the complex interaction among situational determinants that impact fatigue, symptoms or manifestations of fatigue, and the utilization of, and barriers to, coping strategies to reduce listening-related fatigue.

Conclusions:

Participant discussion suggests that listening-related fatigue is a significant problem for many, but not all, CHL. Qualitative data obtained from these stakeholder groups help define the construct and provide a framework for better understanding listening-related fatigue in children.
Reliability assessment of island multi‐energy microgrids
Authors: Santos Marcos , Huo Da , Wade Neal , Greenwood David , Sarantakos Ilias
Published: September 2021

Multi‐energy microgrids could result in more flexibility and increase reliability by interconnecting networks. Electricity and gas networks exhibit very different dynamic behaviours in response to a fault or failure. Gas networks have built‐in energy storages that can continue to provide a reliable supply if gas inputs to the system are compromised. This study presents a novel reliability assessment method applied to multi‐energy microgrids; the method combines an incidence matrix analysis that identifies the connectivity between sources and load points with a sequential Monte Carlo simulation and generation adequacy evaluation. A case study is conducted by using an electricity‐gas microgrid. The electricity network is a multi‐sourced grid, whereas the gas network is supplied by a biogas plant. The linepack (gas stored along the pipelines) is modelled to account for the slower gas dynamics. The proposed method is evaluated on a real‐world electricity distribution network in Austria. The results indicate the reliability benefits of forming a multi‐energy microgrid.
Electromechanical transient modelling and application of modular multilevel converter with embedded energy storage
Authors: Yu Zheyang , Zhang Zheren , Xu Zheng
Published: September 2021

This paper studies the electromechanical transient modelling techniques of the modified modular multilevel converter (MMC), named active MMC, which is equipped with embedded energy storage in submodules. Firstly, the mathematical model of the active MMC and its equivalent circuits at the AC and DC sides are established. Then, the control scheme of active MMC that focus on the cooperation of the MMC converter and the energy storage submodules is illustrated. The proposed electromechanical transient model are implemented on PSS/E and compared with the electromagnetic transient model on PSCAD in a two terminal active MMC sytem; the results of the active MMC system under AC and DC fault prove the validity of the proposed model. Lastly, stability studies of the practical system are carried out, and the simulation results prove the improvement by the application of the active MMC on the rotor angle stability and frequency stability.
Existence of solutions and continuous and semi-discrete stability estimates for 3D/0D coupled systems modelling airflows and blood flows
Authors: Grandmont Céline , Martin Sébastien
Published: September 2021

In this paper we analyse geometric multiscale models arising in the description of physiological flows such as blood flow in arteries or air flow in the bronchial tree. The geometrical complexity of the networks in which air/blood flows lead to a classical decomposition in two areas: a truncated 3D geometry corresponding to the largest contribution of the domain, and a 0D part connected to the 3D part, modelling air/blood flows in smaller airways/vessels. The fluid in the 3D part is described by the Stokes or the Navier–Stokes system which is coupled to 0D models orso-calledWindkessel models. The resulting Navier–Stokes–Windkessel coupled system involves Neumann non-local boundary conditions that depends on the considered applications. We first show that the different types of Windkessel models share a similar formalism. Next we derive existence results and stability estimates for the continuous coupled Stokes–Windkessel or Navier–Stokes–Windkessel problem as well as stability estimates for the semi-discretized systems with either implicit or explicit treatment of the boundary conditions. In all the calculations, we pay a special attention to the dependency of the various constants and smallness conditions on the data with respect to the physical and numerical parameters. In particular we exhibit different kinds of behavior depending on the considered 0D model. Moreover even if no energy estimates can be derived in energy norms for the Navier–Stokes–Windkessel system, leading to possible and observed numerical instabilities for large applied pressures, we show that stability estimates for both the continuous and semi-discrete problems, can be obtained in appropriate norms for small enough data by introducing a new well chosen Stokes-like operator. These sufficient stability conditions on the data may give a hint on the order of magnitude of the data enabling stable computations without stabilization method for the problem. Numerical simulations illustrate some of the theoretical results.
Wer bin ich – und wenn ja, wie viele? – Berufsidentität
Authors: Schug Corinna , Wleklinski Svenja
Published: September 2021

Die vielfältigen Rollen, die Ergotherapeut*innen einnehmen können, machen es nicht leicht, eine gefestigte Berufsidentität zu bilden. Corinna Schug und Svenja Wleklinski gingen diesem Thema in ihrer Bachelorarbeit nach und beschreiben, wie man sich seiner beruflichen Identität sicherer wird.
Ressourcen ermitteln – Befunderhebung nach Schlaganfall
Authors: Kranz Florence
Published: September 2021

Klient*innen in der chronischen Phase eines Schlaganfalls konnen besonders von einer ressourcenorientierten Befunderhebung und Interventionsplanung profitieren. Trotz intensiver Recherche fand Daniela Kuhrt kein ergotherapeutisches Assessment, das die Ressourcen dieser Klientel problemunabhangig ermittelt. Damit war die Idee fur ihre Bachelorarbeit geboren: einen Selbsteinschatzungsbogen entwickeln.
Die eigene Persönlichkeit bewusst einsetzen – Therapeutic Use of Self
Authors: Hopf Judith
Published: September 2021

Therapeut*innen beeinflussen durch ihre PersÖnlichkeit den Verlauf der Therapie – bewusst und unbewusst. Daher ist es sinnvoll, sich ü ber seine Charakter-eigenschaften im Klaren zu sein, um sie im Beruf gezielt einzusetzen oder auszuklammern.
S3-Leitlinie Sauerstoff in der Akuttherapie beim Erwachsenen
Authors: Gottlieb Jens , Capetian Philipp , Hamsen Uwe , Janssens Uwe , Karagiannidis Christian , Kluge Stefan , König Marco , Markewitz Andreas , Nothacker Monika , Roiter Sabrina , Unverzagt Susanne , Veit Wolfgang , Volk Thomas , Witt Christian , Wildenauer René , Worth Heinrich , Fühner Thomas
Published: September 2021

Hintergrund Sauerstoff (O2) ist ein Arzneimittel mit spezifischen biochemischen und physiologischen Eigenschaften, einem definierten Dosis-Wirkungsbereich und mit unerwünschten Wirkungen. Im Jahr 2015 wurden 14 % von über 55 000 Krankenhauspatienten in Großbritannien mit O2 behandelt. Nur 42 % der Patienten hatten dabei eine O2-Verordnung. Gesundheitspersonal ist oft unsicher über die Relevanz einer Hypoxämie, und es besteht ein eingeschränktes Bewusstsein für die Risiken einer Hyperoxämie. In den letzten Jahren wurden zahlreiche randomisierte kontrollierte Studien zu Zielen der Sauerstofftherapie veröffentlicht. Eine nationale Leitlinie ist deswegen dringend erforderlich.

Methoden Im Rahmen des Leitlinienprogramms der Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e. V. (AWMF) wurde unter Beteiligung von 10 Fachgesellschaften eine S3-Leitlinie entwickelt und im Juni 2021 veröffentlicht. Bis zum 1. 2. 2021 wurde eine Literaturrecherche durchgeführt, um 10 Schlüsselfragen zu beantworten. Zur Klassifizierung von Studientypen hinsichtlich ihrer Validität wurde das Oxford Centre for Evidence-Based Medicine (CEBM) System („The Oxford 2011 Levels of Evidence“) verwendet. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) wurde verwendet und zur Bewertung der Evidenzqualität und zur Einstufung von Leitlinienempfehlungen wurde ein formaler Konsensbildungsprozess durchgeführt.

Ergebnisse Die Leitlinie enthält 34 evidenzbasierte Empfehlungen zu Indikation, Verordnung, Überwachung und Abbruch der Sauerstofftherapie in der Akutversorgung. Die Hauptindikation für die O2-Therapie ist Hypoxämie. In der Akutmedizin sollten sowohl Hypoxämie als auch Hyperoxämie vermieden werden. Hyperoxämie scheint mit einer erhöhten Sterblichkeit verbunden zu sein, insbesondere bei Patienten mit Hyperkapnie. Die Leitlinie empfiehlt Zielsauerstoffsättigung für die Akuttherapie mit O2 ohne Differenzierung zwischen Diagnosen. Zielbereiche sind abhängig vom Hyperkapnierisko und Beatmungsstatus. Die Leitlinie bietet einen Überblick über verfügbare Sauerstoffzufuhrsysteme und enthält Empfehlungen für deren Auswahl basierend auf Patientensicherheit und -komfort.

Fazit Dies ist die erste nationale Leitlinie zum Einsatz von Sauerstoff in der Akutmedizin. Sie richtet sich an medizinisches Fachpersonal, das Sauerstoff außerklinisch und stationär anwendet. Sie ist bis zum 30. 06. 2024 gültig.
Herbal Medicines in the Treatment of Dyspepsia: An Overview
Authors: Boeing Thaise , de Souza Priscila , da Silva Luisa Mota , Gasparotto Junior Arquimedes
Published: September 2021

This review focuses on the efficacy of herbal medicines for managing dyspepsia in humans and animals. Searches were conducted on the PubMed, Science Direct, and Medline databases, for publications in the last 3 years. In each database, the search terms used consisted of the 2 key terms describing the disorder and subtypes plus each of the terms relating to the therapy. The key terms used were “natural product” and “medicinal plant” in a cross-over with “dyspepsia” and “functional dyspepsia” (i.e., gastroprotection, Helicobacter pylori infection, prokinetic). We included all human and animal studies on the effects of herbal medicines reporting the key outcome of dyspepsia symptoms. Preclinical studies using critically validated models showed that most medicinal plants with gastroprotective action had antioxidant, anti-inflammatory, anti-apoptotic, and antisecretory effects. Moreover, several species displayed anti Helicobacter pylori and prokinetic efficacy. The
data availability of controlled clinical studies is currently minimal. The use of different methodologies and the minimal number of patients raise doubts about the effects of these preparations. Only adequate clinical trials with scientifically validated methods can determine whether different herbal medicines can be used as viable alternatives to the conventional pharmacological treatments used to control dyspepsia symptoms.
An in-depth look into a well-known herbal drug: Fingerprinting, isolation, identification, and content estimation of saponins in different Strophanthus seeds
Authors: Włodarczyk Maciej , Gleńsk Michał
Published: September 2021

Seeds of Strophanthus species are known as a source of rapid-acting cardenolides. These water-soluble glycosides are listed as the sole critical constituents of this raw herbal drug. A non-standard cardioprotective medication with ouabain-containing oral remedies has become popular in Europe as a result of the withdrawal of corresponding registered drugs from the market. However, the bioequivalence of pure ouabain solutions, tinctures, and home-made extracts from Strophanthus seeds is unknown. Thus, this study aimed to update the information on the composition of Strophanthus seeds used for this purpose. The distribution of two main saponins and about 90 previously unreported compounds, tentatively identified as saponins in eleven Strophanthus species, was systematically evaluated by ultra-high-performance liquid chromatography mass spectrometry (UHPLC-MS) and -MS/MS. Seeds of S. gratus were selected to isolate the dominant unreported
triterpenoids, bidesmosides of echinocystic and oleanolic acid. Their structures were established by HRMS, MS/MS, as well as by NMR techniques. The total saponin content, estimated by UHPLC-MS, was up to 1%. The detected saponins could influence the peroral bioavailability of hardly absorbable Strophanthus cardenolides and exhibit their own activity. This finding may be relevant when Strophanthus preparations (containing both saponins and cardiac glycosides) are used, particularly when homemade preparations are administered.
Domino Reactions of Chromones with Heterocyclic Enamines
Authors: Langer Peter
Published: September 2021

Domino reactions of heterocyclic enamines with chromone derivatives provides a convenient synthesis of a great variety of annulated heterocyclic ring systems. The course of the reaction depends on the type of substituent located at position 3 of the chromone. Reactions of 3-unsubstituted chromones, 3-nitrochromones, and 3-halochromones proceed by conjugate addition of the carbon atom of the enamine to carbon C-2 of the chromone, ring cleavage, and recyclization via the chromone carbonyl group. In the case of 3-formylchromes, 3-dichloroacetylchromone, 3-perfluoroalkanoylthiochromones, 3-(2-fluorobenzoyl)chromones, and 3-methoxalylchromones the final cyclization proceeds via the carbonyl group located outside the chromone moiety. The functional groups located at the carbonyl group at position 3 of the chromone allow for further synthetic transformations including additional ring closures.

Contents

1 Introduction

2 3-Unsubstituted Chromones

3 3-Nitrochromones

4 3-Formylchromes

5 3-Dichloroacetylchromone

6 3-Perfluoroalkanoylthiochromones

7 3-Methoxalylchromones

8 3-(2-Fluorobenzoyl)chromones

9 3-Halochromones

10 Chromone-3-carboxylic Acids

11 Conclusions
Red Blood Cell Transfusion and its Relationship with Pedicle Thrombosis in Microvascular Free Flaps
Authors: Torres Fuentes Carlos Eduardo , Rodríguez Mantilla Iván Enrique , Cáceres Diego Nicolás Guerrero , Camargo Gonzalez Diego Felipe
Published: September 2021

Background Free flaps have become a highly valuable tool for complex reconstructive surgeries. The requirement of red blood cell transfusion (RBCT) during the perioperative period is common and its effect on the free flap survival is debatable. The aim of this study was to determine the relationship between perioperative RBCT and vascular pedicle thrombosis (VPT).

Methods For this study 302 free flaps performed between January 2006 and December 2019 were retrospectively analyzed. It included their characteristics from before, during, and after the surgical procedure. The incidence of VPT and flap survival were calculated based on Kaplan Meier's method and the relationship between VPT and perioperative variables were analyzed by Cox regression models.

Results The transfusion group was represented by 62 flaps (20.5%) and no transfusion by 240 flaps. The overall transfusion requirement was 20.5% and the cumulative incidence of VPT was 9.11%. A statistically significant relationship was not demonstrated between flap survival and transfusion status (HR = 1.73 IC 95%: 0.5 to 3.96; p = 0.192) (p = 0.192) independently from the number of units transfused, the preoperative diagnosis of anemia, and the type of flap used and did not establish an increased risk of VPT.

Conclusion This study did not demonstrate an association between RBCT during preoperative period and the risk for VPT or microvascular free flap survival rate on postoperative follow up.
Efficient Synthesis and Docking Analysis of Selective CDK9 Inhibitor NVP-2
Authors: Saidahmatov Abdusaid , Liang Xue-Wu , Shi Yu-Qiang , Han Xu , Liu Hong
Published: September 2021

Graphical Abstract

NVP-2 (1), a potent and selective inhibitor of cyclin-dependent kinase 9 (CDK9), showed potent antitumor activity in preclinical studies. In this work, we designed and adopted a convergent synthetic route to efficiently synthesize NVP-2 (1). The key intermediate (7) was synthesized from malononitrile (2) and 1-bromo-2-(2-bromoethoxy)ethane (3) by successive cyclization, reduction, nucleophilic substitution with 2-bromo-6-fluoropyridine, and Suzuki–Miyaura reaction with (5-chloro-2-fluoropyridin-4-yl)boronic acid. Another key intermediate (11) was synthesized from (S)-1-methoxypropan-2-ol (8) by reaction with TsCl, electrophilic substitution reaction with tert-butyl ((1r,4r)-4-aminocyclohexyl)carbamate, and then by deprotection of Boc. Finally, a substitution reaction by the key intermediates (7) and (11) to afford the target product NVP-2 (1). The reaction conditions of the whole synthesis process were simple and mild, free of harsh conditions such as the microwave reaction and dangerous reagents in the original patent, and realized the efficient synthesis of NVP-2. In addition, we analyzed the binding mode of NVP-2 in the active pocket of CDK9 to provide reasonable design ideas for subsequent discovery of novel CDK9 inhibitors.
Strategies and Applications of Antigen-Binding Fragment (Fab) Production in Escherichia coli
Authors: Chen Hui , Chen Jun-Sheng , Paerhati Pameila , Jakos Tanja , Bai Si-Yi , Zhu Jian-Wei , Yuan Yun-Sheng
Published: September 2021

With the advancement of genetic engineering, monoclonal antibodies (mAbs) have made far-reaching progress in the treatment of various human diseases. However, due to the high cost of production, the increasing demands for antibody-based therapies have not been fully met. Currently, mAb-derived alternatives, such as antigen-binding fragments (Fab), single-chain variable fragments, bispecifics, nanobodies, and conjugated mAbs have emerged as promising new therapeutic modalities. They can be readily prepared in bacterial systems with well-established fermentation technology and ease of manipulation, leading to the reduction of overall cost. This review aims to shed light on the strategies to improve the expression, purification, and yield of Fab fragments in Escherichia coli expression systems, as well as current advances in the applications of Fab fragments.
In Vitro PIG-A Gene Mutation Assay in Human B-Lymphoblastoid TK6 Cells
Authors: Zhou Chang-Hui , Yu Chun-Rong , Huang Peng-Cheng , Li Ruo-Wan , Wang Jing-Ting , Zhao Tian-Tian , Zhao Ze-Hao , Ma Jing , Chang Yan
Published: September 2021

The X-linked PIG-A gene is involved in the biosynthesis of glycosylphosphatidylinositol (GPI) anchors. PIG-A mutant cells fail to synthesize GPI and to express GPI-anchored protein markers (e.g., CD59 and CD55). In recent years, in vitro PIG-A assay has been established based on the high conservation of PIG-A/Pig-a loci among different species and the large data from the in vivo system. The purpose of this study was to extend the approach for PIG-A mutation assessment to in vitro human B-lymphoblastoid TK6 cells by detecting the loss of GPI-linked CD55 and CD59 proteins. TK6 cells were treated with three mutagens 7,12-dimethylbenz[a]anthracene (DMBA), N-ethyl-N-nitrosourea (ENU), etoposide (ETO), and two nonmutagens: cadmium chloride (CdCl2) and sodium chloride (NaCl). The mutation rate of PIG-A gene within TK6 cells was determined on the 11th day with flow cytometry analysis for the negative frequencies of CD55 and CD59. The antibodies used in this production were APC mouse-anti-human CD19 antibody, PE mouse anti-human CD55 antibody, PE mouse anti-human CD59 antibody, and nucleic acid dye 7-AAD. An immunolabeling method was used to reduce the high spontaneous level of preexisting PIG-A mutant cells. Our data suggested that DMBA-, ENU-, and ETO-induced mutation frequency of PIG-A gene was increased by twofold compared with the negative control, and the effects were dose-dependent. However, CdCl2 and NaCl did not significantly increase the mutation frequency of PIG-A gene, with a high cytotoxicity at a dose of 10 mmol/L. Our study suggested that the novel in vitro PIG-A gene mutation assay within TK6 cells may represent a complement of the present in vivo Pig-a assay, and may provide guidance for their potential use in genotoxicity even in cells with a significant deficiency of GPI anchor.
Particle-based model captures fine details of complete droplet freezing process
Authors: Rodriguez Jaimee-Ian
Published: September 2021

Particle-based simulations incorporate freezing characteristics irreplicable in mesh-based methods, reproducing the complete two-phase, four-stage icing process in mesoscopic droplets.
Effect of grounding and isolation of the target on the emissive properties of laser-produced plasma
Authors: Krása J. , Nassisi V. , Klír D.
Published: September 2021

During laser ablation, ions are accelerated by electrons, some of which definitely escape from the plasma by passing through a potential barrier that is created on the outer regions of the plasma produced by the laser. The escaping electrons generate a net positive charge at the target surface. Depending on whether the target is grounded or isolated from the vacuum chamber, either this positive charge is neutralized by the current flowing from the ground or generates a voltage on the isolated target corresponding to its capacitance. Under certain experimental conditions, it can be expected that this charge can retroactively affect not only the expansion velocity of the emitted ions and their number, but also the total number of escaped electrons. In this work, we deal with ion emission and measuring the voltage arisen on an isolated target or the current of electrons flowing between the ground and a grounded target. For the first time, this made it possible to estimate the ratio of the number of electrons released from plasma to the number of electrons stopped by a potential barrier. Irradiating various targets with a 60–110 mJ energy delivered by a 23-ns KrF excimer laser, this portion is 10−3 for grounded targets and 10−5 for targets isolated from the vacuum chamber. The observation of target currents also makes it possible to identify the level of influence of the contamination of the target surface with chemisorbed hydrocarbons on plasma production and ion separation caused by their different atomic weights.
Preparation of low resistance fluffy ultrafine filter media by centrifugal electrospinning
Authors: Zeng Jun , Wang Han , Chen Rouxi , Wu Peixuan , Chen Xindu , Chen Xin , Qin Liming , Lan Xingzi , Zhang RongGuang , Lin Zhenpei , Xu Guojie
Published: September 2021

Fluffy poly(vinyl alcohol) fiber filter material was prepared by the centrifugal electrospinning process combined with the opening process, which is used in the field of air filtration. We used a conductive ring to connect the positive high voltage with the centrifugal spinning rotation cup in order to improve the electrostatic loading stability of the centrifugal electrospinning process and make the electric field more concentrated. It can reduce the high voltage attenuation and reduce the voltage deviation from 1.47–1.86 kV to 0.02–0.04 KV. The effects of the loading voltage (0–20 kV) and rotational speed (4000–8000 rpm) of the positive high voltage loading mode on the fiber diameter were investigated. The results show that the voltage loading was beneficial to the formation of fibers with good morphology, especially under the condition of low rotational speed. Moreover, the improvement effect of voltage was more obvious, which can curb the problems caused by insufficient solvent volatilization, such as too thick fiber diameter, fiber dissolution bonding, spot bonding, and so on. In addition, the increase in rotational speed was also beneficial to the refinement of the fiber. We loosened the filter material processed by the centrifugal electrospinning process and explored the effect of the opening process on fibers of different morphologies in order to further promote the application of the centrifugal electrospinning filter material and improve the fluffy degree of the filter material. The results showed that the fiber with good spinning and fewer shift defects has a better opening effect and fluffy degree. Finally, the filtration efficiency of the fiber mat prepared with different process parameters before and after the opening was tested using a filter material tester. The results show that the fiber with few shift defects can effectively reduce the resistance without greatly reducing the filtration efficiency. In fact, the results play a guiding role in the preparation of medium-effect fluffy filter media.
A dynamo effect of resistive tearing modes on current profile flattening
Authors: Luo Yuhang , Gao Zhe
Published: September 2021

The dynamo effect of tearing modes is derived using the resistive magnetohydrodynamics equations. The dynamo effect is divided into two components, parallel and perpendicular to the magnetic field. First, the force-free plasma is considered. It is found that the parallel dynamo effect drives opposite current densities on either sides of the rational surface (k·B=0), completely flattening the λ=j·B/|B|2 profile near the rational surface. This may be a possible explanation for the Taylor relaxation mechanism. In contrast, farther from the rational surface, the parallel dynamo effect is much smaller, and the nonlinear dynamo form approximates the quasilinear form. Second, a pressure gradient is included. It is found that a finite λ gradient can exist after modification by the parallel dynamo effect. The perpendicular dynamo effect is found to eliminate the pressure gradient near the rational surface. Our results provide a further basis for the assumption that the current density is flat in the magnetic island for tearing mode theory.
A novel metamaterial slow wave structure with larger space-charge-limited current
Authors: Kong Xiangtian , He Juntao , Ling Junpu , Pi Mingyao , He Yufang
Published: September 2021

This article proposes a new type of metamaterial slow wave structure with larger space-charge-limited current for high-power microwave sources. In order to avoid the anisotropy effect and improve the uniformity of electromagnetic field distribution, the slow wave structure consisted of two all-metal units arranged by a modified method of broadside-coupled complementary split ring resonant (CSRR) geometry. Moreover, the conductor on the periphery of the CSRR has been removed, and a short shift tube was added to the units for the purpose of obtaining larger space-charge-limited current. High-frequency analysis shows that the new slow wave structure has the basic characteristics of metamaterials, including double negative electromagnetic parameters, peculiar dispersion, and high coupling impedance. More importantly, transmission simulation shows that the space-charge-limited current of the structure is at least 12 kA, which is about twice the maximum beam current that the hollow circular waveguide of the same size can transmit, and it proves that the design method is effective and feasible. Applying the structure to a microwave source will achieve the goal of high-efficiency and high-power output.
Collimated electron sheet driven by an intense Laguerre–Gaussian pulse
Authors: Jiang C. , Wang W. P. , Dong H. , Leng Y. X. , Li R. X. , Xu Z. Z.
Published: September 2021

A collimated electron sheet is generated by using an intense circularly polarized (CP) Laguerre–Gaussian (LG) laser to irradiate the plasma in three-dimensional particle-in-cell simulations. It is found that the CP LGpl(p=0, l=1, σz=1) laser provides a more stable vortex force to ensure the concentrated transport of electrons as compared to a linearly polarized LG laser. Herein, the effects of the laser intensity, target density, and preplasma on collimated sheet formation are discussed in detail. Such collimated electron sheets may be potentially used in various applications such as the generation of vortex radiation sources and electron microscopy.
Microwave-induced optical limiting
Authors: Ghaderi Goran Abad Mohsen , Silatan Abbas , Veisi Mohadeseh , Mahmoudi Mohammad
Published: September 2021

We study the generation and control of the microwave (MW)-induced reverse saturable absorption (RSA) and optical limiting (OL) in a three-level pump-probe V-type quantum system. It is shown that the saturable absorption switches to the RSA by applying the MW field to the transition between two upper levels. Moreover, it is demonstrated that the RSA and the induced OL threshold are controlled by either the intensity or detuning of the MW field. In addition, the effect of the coupling field on the induced optical limiting is studied, and it is obtained that the cross-Kerr nonlinearity has a major role in establishing efficient optical power limiting. In addition, we demonstrate that an increase in the atomic density and length of the medium makes the optical limiter more powerful. Finally, the theoretical Z-scan technique is presented to confirm the obtained results of the microwave-induced OL. The proposed scheme can be used to prepare a controllable optical limiter with various thresholds, which can protect the optical devices with different sensitivities.
Fingerprint building and positioning based on wireless sensor networks for underground
Authors: Cui Lizhen , Yang Yong , Wang QiaoLi , Xu FanFei , Guo Qianqian
Published: September 2021

This paper proposes an algorithm of fingerprint constructing and positioning based on wireless sensor networks. The positioning area of underground is divided into several sub-areas according to the neighborhood principle. The reliability mechanism based on the calibration node is established in each sub-area, and the availability of the reference point fingerprint is later determined by the reliability mechanism of the sub-area. When the fingerprint data of the sub-region reference point changes too much, the neighborhood mapping fingerprint model trained by the back propagaption neural network is used to construct the fingerprint. The principle of the neighborhood mapping model is to train the neighborhood relationship between each reference point and its adjacent calibration node in the offline phase to form a network model structure. Then, we use this model to build the fingerprint of reference point in the online stage. In the real-time positioning stage, we use the positioning model based on the adaptive network-based fuzzy inference system. The average positioning error of our proposed algorithm is 3.03 m, when there is a seven day interval between the training dataset and testing dataset, which confirms that the proposed algorithm can be better adapted to the changing environment and to achieve better positioning results.
A microcanonical approach to temperature-transferable coarse-grained models using the relative entropy
Authors: Pretti Evan , Shell M. Scott
Published: September 2021

Bottom-up coarse-graining methods provide systematic tools for creating simplified models of molecular systems. However, coarse-grained (CG) models produced with such methods frequently fail to accurately reproduce all thermodynamic properties of the reference atomistic systems they seek to model and, moreover, can fail in even more significant ways when used at thermodynamic state points different from the reference conditions. These related problems of representability and transferability limit the usefulness of CG models, especially those of strongly state-dependent systems. In this work, we present a new strategy for creating temperature-transferable CG models using a single reference system and temperature. The approach is based on two complementary concepts. First, we switch to a microcanonical basis for formulating CG models, focusing on effective entropy functions rather than energy functions. This allows CG models to naturally represent information about underlying atomistic energy fluctuations, which would otherwise be lost. Such information not only reproduces energy distributions of the reference model but also successfully predicts the correct temperature dependence of the CG interactions, enabling temperature transferability. Second, we show that relative entropy minimization provides a direct and systematic approach to parameterize such classes of temperature-transferable CG models. We calibrate the approach initially using idealized model systems and then demonstrate its ability to create temperature-transferable CG models for several complex molecular liquids.
A bionic piezoelectric tactile sensor for features recognition of object surface based on machine learning
Authors: Xin Yi , Cui Meng , Liu Chenyang , Hou Tianyuan , Liu Lishuang , Qian Chenghui , Yan Youyu
Published: September 2021

Based on the tactile mechanism of human fingertips, a bionic tactile sensor fabricated from polyvinylidene fluoride piezoelectric film is proposed, which can identify the surface softness, viscoelasticity, thermal conductivity, and texture roughness of the object. The tactile sensor is mounted on the fingertip of the bionic manipulator, which obtains the surface features by touching and sliding the object. The time-domain features of the output signal are used for preliminarily discriminating the softness, viscoelasticity, and heat conduction of the object. Finally, based on the Back Propagation and the Particle Swarm Optimization-Back Propagation neural network algorithm, the recognition experiment of texture roughness is carried out using the PSO algorithm to improve the BP neural network so that the optimized BP algorithm has a higher convergence accuracy. The results show that the PSO-BP algorithm achieved the highest accuracy of 98% for identifying samples with different roughnesses and the average recognition achieved an accuracy of 94%. The bionic piezoelectric tactile sensor proposed in this paper has a good application development prospect in recognizing the surface features of objects and intelligent robots.
A comparative study of structural, electronic, and optical properties of thiolated gold clusters with icosahedral vs face-centered cubic cores
Authors: Miyamoto Maho , Taketsugu Tetsuya , Iwasa Takeshi
Published: September 2021

The structural, electronic, and optical properties of the protected Au clusters with icosahedral (Ih) and face-centered cubic (FCC)-like Au13 cores were studied to understand the origin of the difference in the optical gaps of these clusters. It has been demonstrated that the choice of density functionals does not qualitatively affect the properties of Au23 and Au25 clusters with Ih and FCC cores. The density of states, molecular orbitals, and natural charges were analyzed in detail using the B3LYP functional. The substantial energy difference in the lowest-energy absorption peaks for the clusters with the Ih and FCC cores is attributed to the difference in the natural charges of the central Au atoms (Auc) in the Ih and FCC cores, the former of which is more negative than the latter. Natural population analysis demonstrates that the excess negative charge of the Auc atom in clusters with Ih cores occupies the 6p atomic orbitals. This difference in Auc is attributed to the smaller size of the Ih core compared to the FCC core, as a less bulky ligand allows a smaller core with increased electron density, which, in turn, increases the highest occupied molecular orbital energy and decreases the optical gap.
Effect of the aspect ratio on the dynamics of air bubbles within Rayleigh–Bénard convection
Authors: Kim Jin-Tae , Kim Yongsang , Kang Soohyeon , Nam Jaewook , Lee Changhoon , Chamorro Leonardo P.
Published: September 2021

Laboratory experiments and numerical simulations were performed to quantify the effect of the aspect ratio, Γ, in the dynamics of air bubbles within turbulent Rayleigh–Bénard (RB) convection. We explored four scenarios defined by Γ=1.25, 1.5, 2, and 2.5 under Rayleigh numbers ranging from 2.0×109 to 1.6×1010. Continuous 1-mm bubbles were released at two locations from the bottom along the roll path. Three-dimensional particle tracking velocimetry was used to track a large number of bubbles and determine features of the trajectories and pair dispersion, R2(t), for various initial separations, rp within H/10≤rp≤5H/10; here, H is the height. The R2(t) of the bubbles within a quiescent medium was included for reference. Characterization of the bubble streams, namely, the center of mass (Lc), mean deviation (Rc) to Lc, vertical (vz) and lateral (vL) velocities, and their ratios reveal the strong modulation of the roll structure and Γ. In particular, Lc exhibited an approximately symmetric distribution around the maximum, which occurred at the middle height only in the Γ=1.25 case. Maximum Lc was near the wall top with the highest aspect ratio. However, Rc did not vary substantially among the cases. Bubbles' lateral pair dispersion RL2 shows correlated trends with Γ, particularly at large initial separations and times, whereas the vertical pair dispersion is mainly dominated by buoyancy. The RL2 decreased as Γ increased. It indicates the effect of different-sized roll structures modulated by Γ. In general, R2 embodies distinct features of Γ-modulated bubble dynamics in RB convection.