bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous quantitation of kavalactones in kava dry extracts: comparison of multi‐standards and single standard validation approaches
Authors: Ferreira Juliana Veloso , Pierotte Isabella Campolina , Pianetti Gerson Antônio , César Isabela Costa 
Published: December 2020

AbstractIntroductionDried extracts of Piper methysticum G. Forst, also known as kava, has been widely used due to its anxiolytic and sedative properties. In order to assure the quality of these extracts, it is essential to accurately quantify kavalactones, known as the active principle.ObjectivesTo develop and validate an analytical method for the simultaneous quantification of six major kavalactones (kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin and demethoxyyangonin) in kava extracts, comparing multi‐standards and single standard validation approaches.Material and methodsSeparation was performed using a C18 column, water/methanol/acetonitrile/2‐propanol (66:07:09:18 v/v/v/v) and detection at 245 and 350 nm. A full method validation was performed, employing analytical standards for each compound. Commercial kava dried extracts were assayed and the results obtained using the method validated for six kavalactone standards were compared with those obtained when only kavain was used as standard.ResultsBaseline resolution for all kavalactones was obtained in short run time (15 min). Although the total kavalactone content varied between samples, a similar distribution profile was observed. When the method validated with all six analytical standards was compared to the calibration using only kavain standard, kavalactone contents were considerably different (from 7.57 to 36.53%).ConclusionThe obtained results demonstrate the importance of a validated method using individual kavalactone standards for the effective quality control of kava extracts. In a next step, the method needs to be adapted to also include flavokavin B (FKB), as an important authentication marker to distinguish between the accepted variety “noble Kava” and the toxic “two‐day Kava”.
Comparing teacher stress in Chinese and US elementary schools: Classroom appraisal of resources and demands
Authors: Wang Chuang , Zhang Juan , Lambert Richard G. , Wu Chenggang , Wen Hongbo 
Published: December 2020

AbstractBased on Messick's (1995) framework of construct validity and responses from 521 teachers in the United States and 580 teachers in China, this study provided evidence of the generalizability aspect of construct validity for the Classroom Appraisal of Resources and Demands (CARD) questionnaire originally developed in the United States. Confirmatory factor analysis, factorial invariance testing, and differential item functioning were employed to examine the systematic variation of interpretation by the Chinese and US elementary school teachers with respect to the 65 items in the CARD. Results suggested that responses to CARD follow the same structure from both Chinese and US teachers, and that 83% of items showed no difference. Differences in Chinese and US teachers' interpretations of certain items were discussed with implications to school psychology, school counseling, teacher education, educational administration, and policy research.
Copolymers of 4‐thieno[3,2‐b]thiophen‐3‐ylbenzonitrile with anthracene and biphenyl; synthesis, characterization, electronic, optical, and thermal properties
Authors: Isci Recep , Gunturkun Dilara , Yalin Ahsen Sare , Ozturk Turan 
Published: December 2020

AbstractTwo novel copolymers of 4‐thieno[3,2‐b]thiophen‐3‐ylbenzonitrile (TT‐CN), possessing electron withdrawing cyano moiety, with anthracene (P1) and biphenyl (P2) were prepared via Suzuki coupling. Optic, electronic, and thermal properties of the copolymers were investigated through UV–Vis spectroscopy, cyclic voltammetry, gel permeation chromatography, and thermal gravimetric analysis. The polymers with anthracene and biphenyl had electronic band gaps of 2.01 and 1.90 eV, respectively. Both polymers demonstrated excellent large Stokes shifts of 101 (anthracene) and 105 nm (biphenyl) as well as very good thermal properties. As they had good optical, electronic, and thermal properties, they are promising candidates for electronic applications.
Fuzzy multiobjective system reliability optimization by genetic algorithms and clustering analysis
Authors: Chebouba Billal Nazim , Mellal Mohamed Arezki , Adjerid Smail 
Published: December 2020

AbstractSystem reliability optimization is a key element for a competitive and safe industrial plant. This paper addresses the multiobjective system reliability optimization in the presence of fuzzy data. A framework solution approach is proposed and based on four steps: defuzzify the data into crisp values by the ranking function procedure, the defuzzified problems are solved by the non‐sorting genetic algorithms II and III (NSGA‐II and NSGA‐III), the Pareto fronts are compared by the spacing method for selecting the best one, and then the best Pareto front is reduced by the clustering analysis for helping the decision maker. A case study presented in the literature as a mono‐objective redundancy allocation problem with fuzzy data is investigated in the present paper as multiobjective redundancy allocation and reliability‐redundancy allocation problems show the applicability of the approach.
Further studies on state estimation of discrete‐time nonlinear parameter varying systems based on a new multiinstant switching observer
Authors: Zhou Xia , Xie Xiang‐Peng , Yue Dong , Chadli Mohammed 
Published: December 2020

AbstractThis article is concerned with further studies on state estimation of discrete‐time nonlinear parameter varying systems with the help of an efficient multiinstant switching observer. First, a pair of variable weights for different sampling instants are introduced and thus more featured switching modes for the applied observer are produced by updating and utilizing all the varying elements that vary upon time. Second, an individual designing condition of the developed multiinstant switching observer for each switching mode is derived by considering the specific information of the updated varying elements, respectively. Indeed, the whole obtained result is less conservative than the previous ones. Finally, some comparative simulations are provided in order to illustrate the advantage and benefit of the developed results.
Observer‐based preview repetitive control for uncertain discrete‐time systems
Authors: Li Li 
Published: December 2020

AbstractIn this paper, the preview repetitive control (PRC) problem is considered for uncertain discrete‐time systems subject to a previewable periodic reference signal. First, an augmented system including future information on the previewable reference signal is constructed. Second, considering the state unmeasured and periodic tracking reference signal, state observer and preview repetitive controller (PRCr) are designed in both state feedback and output feedback settings. To achieve signal tracking performance, a two‐dimensional (2D) model approach and some LMI technique are presented to describe the control and learning actions of the PRC system by using the lifting technique. Then, by Lyapunov–Krasovskii functions, sufficient conditions for asymptotic stability of the 2D system are derived in the form of a set of LMIs, and meanwhile, the design of a repetitive controller with preview actions is proposed through the LMI approach. Finally, two examples illustrate the effectiveness of the results.
Influence of coarse‐textured soil layers under crop root zone on soil water and salt dynamics and crop yield in shallow groundwater areas
Authors: Chen Shuai , Mao Xiaomin , Shukla Manoj K. 
Published: December 2020

AbstractCoarse‐textured soil layers under crop root zone could modify soil water and salt dynamics and affect crop growth. However, the influence is not thoroughly investigated, especially under shallow groundwater table and soil salinization conditions. For this purpose, we calibrated and validated a one‐dimensional agro‐hydrological model, LAWSTAC, for soil water and salt movement, and their interactions with maize growth in Northwest China. Simulation results fitted well with the measured values of soil water content, salt concentration, leaf area index, and crop yield for the maize growing seasons of 2012 and 2013. Further simulations were conducted to evaluate the influence of buried depths (80, 90, 100, and 110 cm) and thicknesses (10, 20, 30, 40, and 50 cm) of a coarse sand layer under root zone on soil water storage, salt leaching, and crop yield. Results demonstrated that soil water and salt status in the root zone was related to the water content of the coarse‐textured soil layer. Water percolation increased rapidly when water content in the coarse layer was higher than a critical value, which could be beneficial for salt leaching but unfavorable for water retention in the root zone. These results could help understand the influence of the coarse‐textured soil layer on root zone water storage and salt leaching and provide guidance on the irrigation scheduling for salt leaching and crop growth in areas with salinization problems and shallow groundwater tables.
A Highly Active Catalyst 2,4,6‐Tris (di‐4‐chlorobenzamido)‐1,3,5‐triazine Palladium (II) Chloride for the Green Synthesis of Substituted Dihydrobenzo[b]thiophene in Ionic Liquid
Authors: Sayedul Islam Md. , Abu Sayid Mia Md. 
Published: December 2020

AbstractThe palladium‐metallodendrimer (Pd‐MD) 2,4,6‐tris (di‐4‐chlorobenzamido)‐1,3,5‐triazine palladium (II) chloride was synthesized by the reaction of substituted triazine, substituted benzoyl chloride, and (Ph3P)2PdCl2 in DMF at 100 °C. This Pd‐MD was characterized by FTIR, 1H NMR, 13C NMR, Scanning Electron Microscopy (SEM), Energy Dispersive X‐ray (EDX), mass spectrometry, X‐ray photoelectron spectroscopy (XPS), elemental analysis, Thermogravimetric analysis (TGA), and Differential scanning calorimetry (DSC) methods. This catalyst was successfully applied for the green synthesis of different substituted alkyl 2,3‐dihydrobenzo[b]thiophene‐2‐carboxylates in ionic liquid tetra‐n‐butylammonium bromide (TBAB) solution at 120 °C for 2.5 hours with a good to an excellent percentage of yields (75 % to 96 %). Importantly, this homogeneous catalytic system was easily recoverable and reusable at least five times without a significant loss of activity.
Microwave‐assisted Synthesis of CuCl‐MIL‐47 and Application to Adsorptive Denitrogenation of Model Fuel: Response Surface Methodology
Authors: Bereyhi Mohammad , Zare‐Dorabei Rouholah , Mosavi Seyed Hossein 
Published: December 2020

AbstractToday, energy‐environment concerns are crucial for humans. Environmental pollution will increase as a result of expanding the use of fossil fuels, nitrogen‐containing compounds (NCCs) of which cause destructive effects on the environment. In this study, adsorptive denitrogenation (ADN) was performed by adsorbing indole (IND) from model fuels and gasoline over Metal‐organic frameworks (MOFs) CuCl‐MIL‐47. The MIL‐47 was synthesized by the microwave method with modified CuCl. In the present study, the application of Central Composite Design (CCD) was evaluated in the ADN process optimization for the first time. The maximum adsorption capacity (Q0) CuCl‐MIL‐47 for indole (IND) was 769.2 mg/g. Herein, π‐complexation of IND with Cu has made a synergistic effect leading to an increase in Q0. Moreover, the reusability of CuCl‐MIL‐47 was confirmed through its regeneration via ethanol.
Environmentally Benign One‐pot Synthesis of Benzo‐Fused Seven‐Membered Heterocyclic Compounds Using UiO‐66 Metal‐Organic Framework as Efficient and Reusable Catalyst
Authors: Mirhosseini‐Eshkevari Boshra , Zamani Farzad , Ghasemzadeh Mohammad Ali 
Published: December 2020

AbstractA series of biologically relevant 1,4‐benzoxazepine and 1,4‐benzodiazepine derivatives were synthesized via a one‐pot three‐component reaction of 2‐aminophenol or ortho‐phenylenediamine, dimedone, and aromatic aldehydes catalyzed by UiO‐66 metal‐organic framework (MOF). This methodology provides excellent yields, simple procedure, short reaction time, low‐cost catalyst, and mild reaction conditions. The UiO‐66 MOF, which was characterized by different spectroscopic techniques such as XRD, FT‐IR, and TEM, could be recovered and reused up to eight times with no significant loss of catalytic performance.
Knowledge governance maturity assessment can help software engineers during the design of business digitalization projects
Authors: Sanchez‐Segura Maria‐Isabel , Medina‐Dominguez Fuensanta , de Amescua Antonio , Dugarte‐Peña German‐Lenin 
Published: December 2020

AbstractSoftware engineers and IT professionals face the challenge of envisioning the needs and wishes of their client companies, whose long‐term survivability depends on their adaptability to the digital business ecosystem, which is impregnating more or less every single sector of the economy. Looking at the data reported on the business digitalization project success rate, we realize that there is a lot of room for improvement. In this paper, we focus on the results of developing 10 business digitalization projects for 10 small and medium enterprises, where the software engineers in charge of the projects assessed the knowledge governance maturity of client companies before proposing any specific projects to support their digital businesses. We surveyed the software engineers participating in the above projects to gather their impressions of using knowledge governance assessment as a tool to predictively visualize the digital solution that best fits each digitalization project.
Numerical investigation of the punching shear capacity of unbonded post‐tensioned concrete flat slabs
Authors: Díaz Rafael Sanabria , Trautwein Leandro Mouta , de Almeida Luiz Carlos 
Published: December 2020

AbstractThis paper describes a numerical study of the punching shear resistance of unbonded post‐tensioned slabs without shear reinforcement. This research aimed to develop a methodology for modeling unbonded tendons and numerically evaluate the prestressing effects on the punching shear capacity. To validate the modeling approach, a series of well documented experimental tests were simulated using the finite element software DIANA. The nonlinear analyses were performed using three‐dimensional solid elements, incorporating the cracking behavior of concrete by the smeared crack approach. In addition, interface elements were included, providing bond‐slip properties to simulate the friction between tendons and concrete. A good agreement was found between the numerical results and experimental data. Load capacity, cracks patterns, and the prestressing effects were accurately simulated. After the validation, a parametric study was conducted to analyze the influence of distribution, force and profile of prestressing tendons. Finally, the numerical results were compared with current design code provisions and the approach provided by the Critical Shear Crack Theory.
Experimental study of permeability and elastic modulus of plastic concrete containing nano silica
Authors: Farajzadehha Soroush , Mahdikhani Mahdi , Ziaei Moayed Reza , Farajzadehha Soheil 
Published: December 2020

AbstractCut off walls are used under dams for the control of sub surfaces seepage and permeability of cut off wall was important. In the construction of cut off walls, plastic concrete is used and the amount of plastic concrete permeability is important. In this study, the permeability of plastic concrete was investigated and the effect of replacing nano silica instead of cement to reduce permeability was studied. So in this research, compressive strength, elastic modulus, and permeability parameters of plastic concrete specimens at different ages (7, 14, 28, and 56 days) and with different percentages of nano silica (0, 1.5, 3, 4.5, and 6%) were investigated. Also, scanning electron microscopy was used to investigate the effect of nano silica on plastic concrete specimens. The results show that as the age of the specimens increases, the compressive strength and elastic modulus increase, and the permeability of the plastic concrete decreases. Also, by adding nano silica to plastic concrete, the compressive strength of the plastic concrete increases and the plastic concrete permeability decreases significantly while its elastic modulus is almost constant.
Alleviation of cadmium and lead stress by A‐mycorrhizal fungi and rock phosphate on maize (Zea mays L.) growth under calcareous soil conditions
Authors: Abou El Seoud I. I. , Abo Bakr E. M. 
Published: December 2020

AbstractThis research was carried out to investigate the impact of A‐mycorrhizal fungi (AMF) and rock phosphate (RP) (alone and combined) under polluted soil with lead (Pb) and cadmium (Cd) on maize plant growth and soil nutrients availability under calcareous soil conditions. A greenhouse pot experiment was designed as a two‐factor experiment, remediation sources (RS) as the sub‐main factor with four treatments [control, M (mixed of the two mycorrhizae species,Rhizoglomus irregulareandRhizoglomus macrocarpium), RP, and M + RP], and soil pollution sources (PS) as the main factor with nine treatments [control, Pb1 (100 mg Pb /kg soil), Pb2 (500 mg Pb/kg soil), Cd1 (6 mg Cd/kg soil), Cd2 (24 mg Cd/kg soil), Pb1 + Cd1, Pb1 + Cd2, Pb2 + Cd1, Pb2 + Cd2]. The results showed that, under the same conditions of this study, we can recommend the use of coapplication of AMF and RP (M + RP) particularly in contaminated soil with Pb and/or Cd, which supports plants to (i) confront the pollution stress, (ii) improve plants growth and their nutrients content, and (iii) increase the soil available nutrients. Also, maize plants could be labeled as the accumulator of Pb based on (translocation factor > 1) as control and under calcareous soil conditions.
Einleitung
Authors: Reuter Britta 
Published: December 2020

ZusammenfassungÖffentliche Diskussionen und Demonstrationen wegen verschobener, nicht gewollter oder zu teurer Projekte belegen, dass die Steuerzahler einen transparenten Einsatz der von ihnen erwirtschafteten Steuermittel verlangen. Eine wesentliche Rolle für die Transparenz spielen die vorhandenen Verwaltungsdaten, deren volkswirtschaftliches Potential durch mehrere Untersuchungen aufgezeigt wird. Der öffentliche Einkauf beträgt in Europa im Durchschnitt jährlich etwa 15 % des BIP. Das sind für Deutschland etwa 300–400 Milliarden Euro jährlich. Könnten nur 5 % der geschätzten Ausgaben eingespart werden, entsprächen dies 12,5 Milliarden Euro jährlich. Während der Oberschwellenbereich aufgrund von EU-weiten Ausschreibungsverpflichtungen höheren Transparenzanforderungen genügen muss, ist der Unterschwellenbereich weitgehend intransparent. Der Einsatz von Technologie kann hier eine Brücke schlagen und einen weiteren Beitrag zur Transparenz im öffentlichen Einkauf leisten. Die hiermit verbundenen Potentiale, aber auch Risiken, sollen in dieser Arbeit dargelegt werden.
Die Technikfolgenabschätzung als theoretischer Rahmen
Authors: Reuter Britta 
Published: December 2020

ZusammenfassungDie Technikfolgenabschätzung (TFA) bietet den theoretischen Bezugsrahmen, in den diese Arbeit eingebettet wird. Zum besseren Verständnis der Anwendung in vorliegender Arbeit wird die TFA hier ausführlich erläutert. Im weiteren Verlauf der Arbeit wird die mögliche Öffnung der Daten des öffentlichen Einkaufs mithilfe der Wirkungsdimensionen Strategie, Organisation, Recht, Technologie, Transparenz, Kollaboration und Partizipation untersucht. Diese Dimensionen finden in allen verwendeten Methoden Berücksichtigung. Die Diskussion des Themas anhand der TFA soll erleichtern, die verschiedenen Perspektiven zu analysieren und hieraus abschließend ein Leitbild mit Handlungsempfehlungen zu erstellen.
Kontext des öffentlichen Einkaufs
Authors: Reuter Britta 
Published: December 2020

ZusammenfassungIn Kapitel 5 werden die für die vorliegende Arbeit wesentlichen Begriffe, Akteure, Ziele und Haltungen, die im Zusammenhang mit öffentlichem Einkauf eine Rolle spielen, erläutert. Zu den wesentlichen Akteuren zählen die Wirtschaft, Politik, Verwaltung, Bürger, NGOs, Medien und Wissenschaft. Die Potentiale der Transparenz, ihre Stärken und Chancen, aber auch Schwächen und Risiken werden jeweils dargelegt. Haltungen zur Öffnung der Verwaltungsdaten im Allgemeinen und Einkaufsdaten im Besonderen werden über die internationalen und europäischen Regierungsprogramme adressiert, aber auch durch IGOs und NGOs aufgegriffen.
Online-Befragung „Offenes öffentliches Beschaffungswesen“
Authors: Reuter Britta 
Published: December 2020

ZusammenfassungDie in den vorherigen Kapiteln theoretisch erörterten und anhand von Beispielen illustrierten Aspekte gilt es Kapitel 8 – aus der Perspektive von Führungskräften und Experten – mithilfe einer Online-Befragung zu überprüfen. Ziel der empirischen Studie ist die Bewertung der Möglichkeiten und Grenzen einer Öffnung von öffentlichen Einkaufsdaten. Die Sichtweisen aus der Verwaltungs- und Wirtschaftsinformatik, den Wirtschafts-, Rechts-, Sozial- und Politikwissenschaften werden interdisziplinär berücksichtigt. Die Ergebnisse sollen zudem eine Brücke zwischen dem Status quo und einem künftigen Leitbild schlagen.
Ärztinnen in der Orthopädie und Unfallchirurgie in Deutschland: ein aktueller Status quo
Authors: Lutz Patricia M. , Lenz Julia , Achtnich Andrea , Geyer Stephanie 
Published: December 2020

ZusammenfassungHintergrundGeschlechtsspezifische Unterschiede in der Arbeitswelt allgemein und im Bereich der Orthopädie und Unfallchirurgie im speziellen sind immer noch deutlich erkennbar, geraten aber immer stärker ins gesellschaftliche Bewusstsein.ZielAnalyse der geschlechtsspezifischen Entwicklung im Fachbereich Orthopädie und Unfallchirurgie in Deutschland über die vergangenen 15 Jahre und Erhebung des Status quo.MethodeErfassung der Entwicklung von Absolventinnen des Humanmedizinstudiums, des Frauenanteils in der vertragsärztlichen und klinischen Versorgung und des geschlechtsspezifischen Erwerbs einer orthopädischen/unfallchirurgischen Zusatzbezeichnung. Auswertung der geschlechtsspezifischen Mitglieder- oder Teilnehmerzahlen der entsprechenden Fachgesellschaften und der größten deutschen Kongresse für Orthopädie und Unfallchirurgie sowie der Habilitationszahlen im Bereich Orthopädie.Ergebnisse und DiskussionDer Anteil an Ärztinnen in verschiedenen Bereichen der Orthopädie und Unfallchirurgie in Klinik und Wissenschaft steigt. In Führungspositionen in Kliniken, beim Erwerb von Zusatzbezeichnungen und in den Vorständen von Fachgesellschaften besteht immer noch eine deutliche Diskrepanz. In manchen Bereichen, wie Kinder‑, Hand- oder Fuß‑/Sprunggelenkchirurgie ist der Frauenanteil höher als in anderen Teilbereichen der Orthopädie und Unfallchirurgie.