bluuebunny/crossref_metadata_2025 huggingface dataset:
Teacher Support for Argumentation: An Examination of Beliefs and Practice
Authors: Conner AnnaMarie , Singletary Laura Marie
Published: March 2021

Supporting students in making mathematical arguments is an important part of discourse practices in mathematics classrooms. Differences in teachers’ support for collective argumentation have been observed and documented, and the importance of the teacher’s role in supporting collective argumentation is well established. This article seeks to explain differences in teachers’ support for argumentation by examining two student teachers’ beliefs about mathematics, teaching, and proof to see which beliefs are visible in their support for argumentation. Assisted by a framework for argumentation and a commitment to teachers’ beliefs and actions as sensible systems, we found that teachers’ beliefs about the role of the teacher, particularly with respect to giving explanations, were more visible in their support for collective argumentation than other beliefs about mathematics or proof.
ANALYSIS OF THE TECHNICAL EFFICIENCY OF MAJOR LATIN AMERICA AND THE CARIBBEAN PORTS USING BOOTSTRAP
Authors: GIL ROPERO ANTONIO , CERBÁN JIMÉNEZ MARIA DEL MAR , TURIAS DOMINGUEZ IGNACIO
Published: March 2021

ABSTRACT:
The aim of this paper is to analyze the Technical Efficiency of a sample of 13 container ports of Latin America and the Caribbean, which generated movements of more than one million TEUs in the period 2012-2018, according to the Economic Commission for Latin America and the Caribbean (ECLAC). In the first stage, Data Envelopment Analysis (DEA) has been used to obtain the Technical Efficiency, with an output-oriented option: Variable Return Scale (BCC). In a second stage, the bootstrap method has been applied in order to determine efficiency rankings of Latin America and the Caribbean container ports. The main contribution of this article is the application of DEA and Bootstrap models in the study of operational efficiency of the main container terminals in Latin America and the Caribbean. The techniques presented manage to determine, with a high degree of precision, the role played by the main container traffic variables in the operational efficiency of their terminals. They represent a valuable tool for the analysis of the dimensioning of the infrastructures of the ports studied. The models developed in this work have been evaluated through a database obtained from the public entities that manage these ports in Latin America and the Caribbean, but they can be applied in other ports of different countries and/or commercial areas that share the same typology of traffic and characteristics. The corrected efficiency results obtained by the Bootstrap BCC Output-oriented methodology denote some homogeneity in two large groups of ports. The ports with corrected efficiency values above 85%, and low differences between the values obtained in the two methodologies, should develop an analysis of their infrastructures in the short and medium-term. A second group consisting of Cartagena, Freeport, Lazaro Cardenas, San Antonio and Buenos Aires ports, obtain low efficiency values of less than 65% and therefore, should develop a traffic strategy analysis to attract new traffic in order to be efficient.

Keywords: Efficiency, Bootstrap, Data Envelopment Analysis, Terminal Containers
Captúrame, visualízame, compárteme: la revolución de las nuevas plataformas visuales colaborativas
Authors: Roig Antoni
Published: March 2021

La popularización de plataformas sociales como Pinterest, que permite compartir intereses de forma eminentemente visual, ha contribuido a situar en primer plano a la imagen como herramienta de expresión en las redes sociales. La imagen siempre ha formado una parte esencial de nuestros intercambios personales y sociales, pero la tendencia ha ido en aumento en paralelo a la mayor presencia de dispositivos móviles táctiles, como los smartphones o los tablets. El éxito de Pinterest y otras herramientas emergentes se encuentra en combinar una pasmosa facilidad de capturar contenido de la web y presentarlo gráficamente de una forma totalmente distinta. Y esto es sólo la punta del iceberg.
¿ISI lo quemamos todo?
Authors: Aranda Dani
Published: March 2021

Hemos transformando un sistema de comunicación y de intercambio de conocimiento académico como son, o eran, las revistas científicas en una simple herramienta de acreditación y en un negocio. Para muestra un botón.
Graphene Oxide Substrate Promotes Neurotrophic Factor Secretion and Survival of Human Schwann‐Like Adipose Mesenchymal Stromal Cells
Authors: Llewellyn Steffan H. , Faroni Alessandro , Iliut Maria , Bartlam Cian , Vijayaraghavan Aravind , Reid Adam J.
Published: March 2021

Mesenchymal stromal cells from adipose tissue (AD‐MSCs) exhibit favorable clinical traits for autologous transplantation and can develop ‘Schwann‐like’ phenotypes (sAD‐MSCs) to improve peripheral nerve regeneration, where severe injuries yield insufficient recovery. However, sAD‐MSCs regress without biochemical stimulation and detach from conduits under unfavorable transplant conditions, negating their paracrine effects. Graphene‐derived materials support AD‐MSC attachment, regulating cell adhesion and function through physiochemistry and topography. Graphene oxide (GO) is a suitable substrate for human sAD‐MSCs incubation toward severe peripheral nerve injuries by evaluating transcriptome changes, neurotrophic factor expression over a 7‐days period, and cell viability in apoptotic conditions is reported. Transcriptome changes from GO incubation across four patients are minor compared to biological variance. Nerve growth factor (NGF), brain‐derived neurotrophic factor (BDNF), and glial‐derived neurotrophic factor (GDNF) gene expression is unchanged from sAD‐MSCs on GO substrates, but NGF and GDNF protein secretion increase at day 3 and 7. Secretome changes do not improve dorsal root ganglia neuron axon regeneration in conditioned media culture models. Fewer sAD‐MSCs detach from GO substrates compared to glass following phosphate buffer saline exposure, which simulates apoptotic conditions. Overall, GO substrates are compatible with sAD‐MSC primed for peripheral nerve regeneration strategies and protect the cell population in harsh environments.
Investigation of Material Flow During Linear Flow Splitting Using Tracer Diffusion Experiments and Finite‐Element Simulations
Authors: Ahmels Laura , Dehtyriov Daniel , Bruder Enrico , Molotnikov Andrey
Published: March 2021

The deformation behavior and evolution of strain distributions of flat metal sheets subjected to the high‐strain forming process of linear flow splitting (LFS) are studied using experimental and numerical techniques. The new tracer gradient method for the mapping of material flow based on diffusional concentration gradients is proposed. The method is validated using theoretical predictions for rolling of a sheet and shown to overcome the limitations of previous techniques. A parametric finite‐element model for LFS of a HC800LA grade steel is developed and validated against the results of the tracer gradient method. A sensitivity study is undertaken to investigate the effects of strain‐hardening behavior and sheet thicknesses on the LFS process. A good agreement between experimental and numerical results is obtained, with the friction between rolls and sheet found to be a critical parameter in the modeling of the process. It is further observed that the formation of the characteristic steady state in the LFS process is linked to the material‐hardening behavior and not the geometry of the sheet.
Microbiota‐Host Immunity Communication in Neurodegenerative Disorders: Bioengineering Challenges for In Vitro Modeling
Authors: Boeri Lucia , Perottoni Simone , Izzo Luca , Giordano Carmen , Albani Diego
Published: March 2021

Human microbiota communicates with its host by secreting signaling metabolites, enzymes, or structural components. Its homeostasis strongly influences the modulation of human tissue barriers and immune system. Dysbiosis‐induced peripheral immunity response can propagate bacterial and pro‐inflammatory signals to the whole body, including the brain. This immune‐mediated communication may contribute to several neurodegenerative disorders, as Alzheimer's disease. In fact, neurodegeneration is associated with dysbiosis and neuroinflammation. The interplay between the microbial communities and the brain is complex and bidirectional, and a great deal of interest is emerging to define the exact mechanisms. This review focuses on microbiota‐immunity‐central nervous system (CNS) communication and shows how gut and oral microbiota populations trigger immune cells, propagating inflammation from the periphery to the cerebral parenchyma, thus contributing to the onset and progression of neurodegeneration. Moreover, an overview of the technological challenges with in vitro modeling of the microbiota‐immunity‐CNS axis, offering interesting technological hints about the most advanced solutions and current technologies is provided.
Improvements of Organic Light‐Emitting Diodes Using Graphene as an Emerging and Efficient Transparent Conducting Electrode Material
Authors: Adetayo Adeniji E. , Ahmed Tanjina N. , Zakhidov Alex , Beall Gary W.
Published: March 2021

Organic light emitting diodes (OLEDs) have received wide attention and progress in impacting the electronics market. The progress of OLEDs in the market over their inorganic counterpart is principally due to their cost savings, flexibility, and excellent performance. As a result of the rising demands for next‐generation electronic devices with increased efficiency, high flexibility, reduced cost, and stretchability, there is a need for improvements of OLEDs. In order to fulfill these requirements, it is necessity to replace the transparent conductive electrode (TCE) with a better alternative. The conventionally used TCE, indium tin oxide (ITO), suffers from the scarcity of indium, increased cost, instability, and brittleness. Graphene is recognized as a suitable alternative to ITO because of its excellent properties including high optical transmittance, outstanding electrical conductivity, stability, and great mechanical flexibility. However, the performance of graphene as the TCE material in OLEDs is limited. Several efforts have been made to improve graphene's performance through electrode modifications. This review covers a summary of fabrication techniques for graphene‐based TCEs and their improvements. Finally, the application and performance of graphene‐based TCEs in OLED devices and the performance of such OLEDs are discussed.
Carbon‐Based Composite Phase Change Materials for Thermal Energy Storage, Transfer, and Conversion
Authors: Chen Xiao , Cheng Piao , Tang Zhaodi , Xu Xiaoliang , Gao Hongyi , Wang Ge
Published: March 2021

Phase change materials (PCMs) can alleviate concerns over energy to some extent by reversibly storing a tremendous amount of renewable and sustainable thermal energy. However, the low thermal conductivity, low electrical conductivity, and weak photoabsorption of pure PCMs hinder their wider applicability and development. To overcome these deficiencies and improve the utilization efficiency of thermal energy, versatile carbon materials have been increasingly considered as supporting materials to construct shape‐stabilized composite PCMs. Despite some carbon‐based composite PCMs reviews regarding thermal conductivity enhancement, a comprehensive review of carbon‐based composite PCMs does not exist. Herein, a systematic overview of recent carbon‐based composite PCMs for thermal storage, transfer, conversion (solar‐to‐thermal, electro‐to‐thermal and magnetic‐to‐thermal), and advanced multifunctional applications, including novel metal organic framework (MOF)‐derived carbon materials are provided. The current challenges and future opportunities are also highlighted. The authors hope this review can provide in‐depth insights and serve as a useful guide for the targeted design of high‐performance carbon‐based composite PCMs.
An Investigation of Active Sites for electrochemical CO2 Reduction Reactions: From In Situ Characterization to Rational Design
Authors: Zou Yuqin , Wang Shuangyin
Published: March 2021

The electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) is among the most promising approaches used to transform greenhouse gas into useful fuels and chemicals. However, the reaction suffers from low selectivity, high overpotential, and low reaction rate. Active site identification in the CO2RR is vital for the understanding of the reaction mechanism and the rational development of new electrocatalysts with both high selectivity and stability. Herein, in situ characterization monitoring of active sites during the reaction is summarized and a general understanding of active sites on the various catalysts in the CO2RR, including metal‐based catalysts, carbon‐based catalysts, and metal‐organic frameworks‐based electrocatalysts is updated. For each type of electrocatalysts, the reaction pathway and real active sites are proposed based on in situ characterization techniques and theoretical calculations. Finally, the key limitations and challenges observed for the electrochemical fixation of CO2 is presented. It is expected that this review will provide new insights and directions into further scientific development and practical applicability of CO2 electroreduction.
Long‐term effects of straw mulching coupled with N application on soil organic carbon sequestration and soil aggregation in a winter wheat monoculture system
Authors: Li Xiushuang , Qu Chunyan , Li Yunuo , Liang Zhiying , Tian Xiaohong , Shi Jianglan , Ning Peng , Wei Gehong
Published: March 2021

Straw mulching can be affected by N fertilization rate with regard to improving soil organic carbon (SOC) lability, which modifies the net accumulation of SOC and soil aggregation. We conducted a 14‐yr field experiment to determine how straw mulching coupled with N application rates affects crop yield, SOC sequestration as a net gain of SOC, and soil aggregation in a winter wheat (Triticum aestivum L.) monoculture system. Six combinations of two cultivation practices, conventional cultivation (CC) and straw mulching (SM), and three N application rates (0, 120, and 240 kg N ha–1) were compared. Results revealed that SM did not affect wheat yield throughout the 14 yr of cultivation, but increased the SOC stock, SOC lability, and the carbon management index (CMI) in surface soil (0–20 cm). Instead, N application, N120 and N240, increased the wheat production almost equally, and followed a trend for increasing SOC stock: N240 > N120 > N0; however, a different trend for increasing SOC lability and soil CMI (N120 > N240 > N0). Soil macro‐aggregation was increased by SM but decreased with increasing N application. Principal component analysis (PCA) indicated that organic C input was the key to improving SOC sequestration, SOC lability, and soil macro‐aggregation rather than N input, especially high N input (N240) reduced SOC lability and soil aggregation in soil. Consequently, medium N application (N120) may be expected to couple with straw direct‐returning for improving soil productivity and quality in this agro‐system.
Cerebral amyloid‐β load is associated with neurodegeneration and gliosis: Mediation by p‐tau and interactions with risk factors early in the Alzheimer'scontinuum
Authors: Salvadó Gemma , Milà‐Alomà Marta , Shekari Mahnaz , Minguillon Carolina , Fauria Karine , Niñerola‐Baizán Aida , Perissinotti Andrés , Kollmorgen Gwendlyn , Buckley Christopher , Farrar Gill , Zetterberg Henrik , Blennow Kaj , Suárez‐Calvet Marc , Molinuevo José Luis , Gispert Juan Domingo ,   for the ALFA study
Published: March 2021

Introduction

The association between cerebral amyloid‐β accumulation and downstream CSF biomarkers is not fully understood, particularly in asymptomatic stages.

Methods

In 318 cognitively unimpaired participants, we assessed the association between amyloid‐β PET (Centiloid), and cerebrospinal fluid (CSF) biomarkers of several pathophysiological pathways. Interactions by Alzheimer's disease risk factors (age, sex andAPOE‐ε4), and the mediation effect of tau and neurodegeneration were also investigated.

Results

Centiloids were positively associated with CSF biomarkers of tau pathology (p‐tau), neurodegeneration (t‐tau, NfL), synaptic dysfunction (neurogranin) and neuroinflammation (YKL‐40, GFAP, sTREM2), presenting interactions with age (p‐tau, t‐tau, neurogranin) and sex (sTREM2, NfL). Most of these associations were mediated by p‐tau, except for NfL. The interaction between sex and amyloid‐β on sTREM2 and NfL was also tau‐independent.

Discussion

Early amyloid‐β accumulation has a tau‐independent effect on neurodegeneration and a tau‐dependent effect on neuroinflammation. Besides, sex has a modifier effect on these associations independent of tau.
Deep Learning Accelerated Determination of Hydride Locations in Metal Nanoclusters
Authors: Wang Song , Wu Zili , Dai Sheng , Jiang De‐en
Published: March 2021

Although the coordinates of the metal atoms can be accurately determined by X‐ray crystallography, locations of hydrides in metal nanoclusters are challenging to determine. In principle, neutron crystallography can be employed to pinpoint the hydride positions, but it requires a large crystal and a neutron source, which prevents its routine use. Here, we present a deep‐learning approach that can accelerate determination of hydride locations in single‐crystal X‐ray structure of metal nanoclusters of different sizes. We demonstrate the efficiency of our method in predicting the most probable hydride sites and their combinations to determine the total structure for two recently reported copper nanoclusters, [Cu25H10(SPhCl2)18]3− and [Cu61(StBu)26S6Cl6H14]+ whose hydride locations have not been determined by neutron diffraction. Our method can be generalized and applied to other metal systems, thereby eliminating a bottleneck in atomically precise metal hydride nanochemistry.
Spatial–temporal variations in biosonar activity of Yangtze finless porpoise in the lower reaches of the Yangtze River and its correlation with underwater noise: Are quieter non‐shipping branches the remaining shelters?
Authors: Zhou Lu , Chen Xu , Duan Peng‐Xiang , Wang Ding , Wang Zhi‐Tao , Wang Ke‐Xiong
Published: March 2021

Yangtze finless porpoise (YFP) is Critically Endangered, It relies on its biological sonar sensing system for important life activities. The rapid development of the Yangtze valley has brought busy shipping, which has resulted in increased noise.

Two locations on the shipping channel and non‐shipping branch were selected. Passive acoustic monitoring was used to record the biosonar signals of porpoises and underwater noise. The number of click trains, echolocation encounters, buzzes and buzz ratios were counted and the root mean square sound pressure level of noise was calculated in five diel phases.

A non‐parametric test was used to analyse the differences among different phases and between different locations. The aim of the study was to detect the spatial and temporal variations in the biosonar activity of YFPs and underwater noise between non‐shipping and shipping channels, and to provide scientific advice for YFP conservation.

Significant spatial and temporal patterns were observed both in biosonar activity and noise. Average biosonar activity, including click trains, buzzes, buzz ratio and echolocation encounters, was higher in the non‐shipping channel than in the shipping channel, whereas the noise level was higher in the shipping channel than in the non‐shipping channel.

In the non‐shipping channel, the buzz numbers and buzz ratios, indicators of porpoise feeding activity, were higher at night than during the day while the noise level was higher during the day than at night.

These findings may be associated with the noise avoidance strategies of YFPs to adapt to the busy shipping on the Yangtze River. Maintaining the non‐shipping status of some branches of the Yangtze River can provide more shelters for the YFPs. Strengthening the measures for banning navigation at night or reducing the vessel speed at night throughout the entire year would improve the YFPs’ feeding success.
Identification of an MGST2 gene and analysis of its function in antioxidant processes in Apis cerana cerana
Authors: Zhao Guangdong , Zhao Wenchun , Cui Xuepei , Xu Baohua , Liu Qingxin , Li Han , Guo Xingqi
Published: March 2021

MGST2 is a member of the MAPEG superfamily, which participates in LTC4 synthesis and plays important roles in the regulation of the oxidative stress pathway and some diseases. Here, we isolated a previously uncharacterized gene in Apis cerana cerana named AccMGST2 by reverse transcription‐polymerase chain reaction. The biological characteristics of AccMGST2 were analyzed by bioinformatics. The amino acid sequence similarity between AccMGST2 and AmMGST2 of Apis mellifera reached 96.08%. The expression characteristics of AccMGST2 were explored in several tissues. The quantitative real‐time polymerase chain reaction results showed that the AccMGST2 gene was highly expressed in the head and muscle and that AccMGST2 expression responded to oxidative stress caused by different abiotic stresses. AccMGST2 was silenced using RNA interference, which decreased the expression levels of some MAPK and antioxidant genes. Therefore, we conclude that AccMGST2 is involved in the regulation of oxidative stress in A. cerana cerana.
Late‐Stage Alkylation of Heterocycles Using N‐(Acyloxy)phthalimides
Authors: Parida Sushanta Kumar , Hota Sudhir Kumar , Kumar Raushan , Murarka Sandip
Published: March 2021

Synthetic methods enabling late‐stage modification of heterocycles hold tremendous importance in the pharmaceutical and agrochemical industry and drug discovery. Accordingly, efficient, functional group tolerant and selective late‐stage alkylation of valuable molecular entities is of enormous significance and well‐acknowledged in medicinal chemistry. Radical alkylation of heteroarenes employing carboxylic acids as the alkyl radical precursor represents one of the most direct ways of C−H functionalizations of heterocycles. Recently, the field has undergone a revolutionary development especially with regard to the generation of alkyl radicals under much milder conditions. In this regard N‐(acyloxy)phthalimides (NHPI esters) have emerged as a suitable precursor of a diverse set of alkyl radicals allowing formal C−H alkylation of not only N‐heteroarenes but a diverse set of non‐aromatic heterocycles under visible light photocatalysis or electrochemical conditions. This review delineates all these discoveries and provides readers a comprehensive overview of this rapidly expanding field.
Design and application of a tire slip energy control scheme based on optimal guaranteed cost theory for four‐in‐wheel drive electric vehicles
Authors: Li Hewei , Zhao Bin , Yu WeiBo , Xu Nan , Guo KongHui
Published: March 2021

In this paper, vehicle stability with time‐varying tire cornering stiffness and tire slip energy torque distribution is investigated for four‐in‐wheel motor drive electric vehicles thanks to the control flexibility. On the issue of tire slip energy, a scheme of “semi‐empirical tire slip energy model” is proposed and analyzed. In this scheme, the hierarchical control method is used to reduce tire slip energy and improve vehicle stability. In the outer loop controller, cost control is designed based on optimal guaranteed cost theory, which is compared with the traditional linear quadratic regulator. The integrated control method of active front steering and direct yaw moment control is evaluated and studied from the cost perspective by norm‐bounded uncertainty. Finally, the simulation results verify that the control framework considering time‐varying uncertainty has significant advantages under the condition of high‐friction coefficient single‐lane change and low‐friction coefficient slalom change. Compared with the linear quadratic regulator and the minimization of tire slip energy control, the control framework with optimal guaranteed cost can achieve smaller sideslip angle; meanwhile, it can save more tire slip energy.
A life‐table analysis of the intrauterine fate of malformed human embryos and fetuses
Authors: Shiota Kohei
Published: March 2021

Background

Various malformations are frequently encountered in spontaneously aborted embryos and fetuses. Thus, spontaneous abortion appears to be a screening device for abnormal conceptuses (“teratothanasia”). However, the prevalence rate of abnormal conceptuses at each gestational stage is unknown and the true picture of prenatal natural selection remains to be elucidated.

Methods

An in utero life‐table of normal and malformed human conceptuses was constructed utilizing the data for human embryos and fetuses procured after therapeutic abortion and kept in the Kyoto Collection of Human Embryos (N = 21,798).

Results

The prevalence of external major malformations was estimated to be 9.6% at the start of the fifth week after fertilization and drop to 9.2, 8.5, and 7.5% during the following weeks. The malformation rate decreased to 5.3% by the end of the embryonic period (the eighth week), 2.8% by the 13th week and 1% at term. The prenatal mortality rate of externally malformed conceptuses between the fifth week of gestation and term was 92.8%, whereas the corresponding rate for externally normal embryos was 24.9%. The prenatal mortality rates of embryos with neural tube defects and holoprosencephaly were 96.0 and 99.7%, respectively.

Conclusions

Abnormal development occurs frequently early in development and many of the malformed embryos/fetuses die in utero to end in spontaneous abortion. Natural prenatal screening of abnormal conceptuses most likely contributes to reducing the birth of malformed infants.
Vergussbeton – Innovation in der Betoninstandsetzung
Authors: von Daake Henning , Schäffel Patrick
Published: March 2021

Vergussbetone und ‐mörtel werden bereits seit vielen Jahren sehr erfolgreich im Betonbau eingesetzt. In den vergangenen Jahren hat sich ihr Einsatz vom anfänglichen Vergießen dünner Schichten unter Brückenlagern und Maschinen bis auf den Bereich der Betoninstandsetzung unter schwierigen Randbedingungen erweitert. Aktuelles Regelwerk ist die Vergussbetonrichtlinie des DAfStb 2011 [1], die 2019 [2] aktualisiert wurde. Diese Überarbeitung wurde nun in die Musterverwaltungsvorschrift Technische Baubestimmung aufgenommen und wird in den kommenden Monaten in die Verwaltungsvorschriften Technische Baubestimmungen der Bundesländer übernommen.

Der vorliegende Beitrag gibt einen Überblick zur Entwicklung von zementgebundenem Vergussbeton und ‐mörtel. Anschließend wird auf Besonderheiten der Produkte im Vergleich zu herkömmlichem Normalbeton und Mörtel eingegangen. Die folgenden Kapitel beschäftigen sich mit den Aspekten der praktischen Anwendung und innovativen Möglichkeiten der Betoninstandsetzung.
Recent applications of microextraction sample preparation techniques in biological samples analysis
Authors: Daryanavard Seyed Mosayeb , Zolfaghari Hesane , Abdel‐Rehim Abbi , Abdel‐Rehim Mohamed
Published: March 2021

Analysis of biological samples is affected by interfering substances with chemical properties similar to those of the target analytes, such as drugs. Biological samples such as whole blood, plasma, serum, urine and saliva must be properly processed for separation, purification, enrichment and chemical modification to meet the requirements of the analytical instruments. This causes the sample preparation stage to be of undeniable importance in the analysis of such samples through methods such as microextraction techniques. The scope of this review will cover a comprehensive summary of available literature data on microextraction techniques playing a key role for analytical purposes, methods of their implementation in common biological samples, and finally, the most recent examples of application of microextraction techniques in preconcentration of analytes from urine, blood and saliva samples. The objectives and merits of each microextration technique are carefully described in detail with respect to the nature of the biological samples. This review presents the most recent and innovative work published on microextraction application in common biological samples, mostly focused on original studies reported from 2017 to date. The main sections of this review comprise an introduction to the microextraction techniques supported by recent application studies involving quantitative and qualitative results and summaries of the most significant, recently published applications of microextracion methods in biological samples. This article considers recent applications of several microextraction techniques in the field of sample preparation for biological samples including urine, blood and saliva, with consideration for extraction techniques, sample preparation and instrumental detection systems.
Capillary electrophoresis‐based methodology for screening of oligonucleotide aptamers
Authors: Guo Xin , Chen Guan‐Hua
Published: March 2021

As a new molecular recognition element, oligonucleotide aptamer not only has higher affinity and specificity to target molecules, but also has the advantages of wide recognition range, in vitro synthesis and chemical stability compared with conventional antibodies. Since a kind of screening method termed systematic evolution of ligands by exponential enrichment (SELEX) was reported, scientists have extensively researched the methodology of how to highly and efficiently screen out aptamers from a library consisting of a large number of random oligonucleotides. Certainly capillary electrophoresis‐based screening methodologies, including nonequilibrium capillary electrophoresis of equilibrium mixtures, equilibrium capillary electrophoresis of equilibrium mixtures, non‐SELEX, ideal‐filter capillary electrophoresis, capillary transient isotachophoresis, etc., are revolutionary. Compared with conventional SELEX, these capillary electrophoresis‐based methodologies show incomparable advantages such as the single‐round screening of aptamers and increased successful screening rate. Methodology studies on the screening process of aptamers are comprehensively reviewed.
Successful pembrolizumab treatment of microsatellite instability‐high intrahepatic cholangiocarcinoma: A case report
Authors: Ikeda Yuki , Ono Michihiro , Ohmori Ginji , Ameda Saki , Yamada Michiko , Abe Tomoyuki , Fujii Shigeyuki , Fujita Miri , Maeda Masahiro
Published: March 2021

Key Clinical Message

The tumor reduction effect of pembrolizumab is extremely high compared to standard chemotherapy and might show prolonged survival. Therefore, the MSI status should be examined in patients with cholangiocarcinoma.
Cashew – von der großen Mühe um einen kleinen Kern, der keine Nuss ist
Authors: Sicker Dieter
Published: March 2021

Reisen Sie gern? Oft hat man dabei unerwartete Erlebnisse, die irgendwie mit Chemie zu tun haben und chemisches Lehrbuchwissen wird ungeahnt erweitert. Es verknüpft sich mit Geschichte und Geschichten, unbekannten Anwendungen, praktischen Handgriffen und dem realen Leben anderer Menschen. Man staunt über etwas, in dem man gar nichts Staunenswertes vermutete. Über solche kleinen Wunder soll diese Serie berichten. Mehr als sonst wollen wir dazu Fotos benutzen. Diesmal schauen wir uns in Indien an, wie Cashew‐Kerne aus der Frucht gewonnen werden.
CFD analysis of blade coating from a reservoir onto a horizontal substrate using a homogeneous two‐phase model
Authors: Singh Arpan R. , Ormiston Scott J.
Published: March 2021

A two‐phase numerical analysis is performed of two‐dimensional, laminar, liquid flow from a reservoir onto a horizontal, rigid, moving substrate. The homogeneous two‐phase model in commercial CFD code CFX is used to model the liquid plus a region containing both liquid and air near the phase interface and downstream of the blade region. Slow convergence due to surface tension modelling required initialization from intermediate results omitting surface tension. Comparisons made with two previous numerical analyses demonstrate the performance of this approach. For a particular upstream reservoir geometry, the effects of changing the substrate speed and the liquid properties from a Newtonian fluid to a Carreau‐Yasuda non‐Newtonian fluid on the pressure field and the downstream film height are studied. The details of the liquid recirculation in the reservoir and the overall pressure distribution are discussed. New results are presented for the meniscus position and contact angle, which are fully predicted by the two‐phase approach. The meniscus position was strongly influenced by substrate speed and liquid properties, whereas the contact angle did not change significantly with changes in substrate speed and dynamic viscosity for the Newtonian fluid nor with changes in the functional parameters for the non‐Newtonian fluid.
F‐18 FDG PET‐CT for response evaluation in head and neck malignancy: Experience from a tertiary level hospital in south India
Authors: Benjamin Justin , Hephzibah Julie , Shanthly Nylla , Oommen Regi , Mathew David , Pavamani Simon , Rajnikanth Janakiraman
Published: March 2021

Background

Head and neck squamous cell carcinoma (HNSCC) accounts for 90% of head and neck cancers. There has been no established qualitative system of interpretation for therapy response assessment using PET‐CT for HNSCC.

Aim

To assess response evaluation of nodal status in post‐treatment PET‐CT scans in HNSCC using a 5‐point Likert scale (Deauville score [DS]).

Methods and Results

Retro‐prospective analysis was performed of the nodal status of pre and post‐RT PET‐CT in patients diagnosed with HNSCC (n = 43) from May 2013 to March 2018. All eligible patients underwent a pre‐RT PET‐CT scan before the start of RT. Another post‐RT PET‐CT scan was performed 12 weeks after the completion of RT. The median time from completion of radiotherapy (RT) to post‐RT PET‐CT was 92 days; 80% of the patients had their post‐RT PET‐CT scan between 77 and 147 days after therapy. Of 43 patients (M/33, F/10, age range 18 to 80 years (median 54 years) selected for the study, good concordance was noted between DS and clinical response in these patients. The change in SUV from pre‐RT PET to post‐RT PET was analyzed using a paired t‐test. The P‐value was found to be statistically significant while comparing pre and post‐RT SUVmax levels showing that RT had significantly reduced the SUVmax levels of the nodes in DS 2‐3 groups whereas the number of patients was too small to allow a reliable calculation in DS 4‐5 groups. It was found that 36/39 patients with DS 1‐3 had no nodal recurrence showing a high NPV of 92.3%. Of the four patients with DS 4‐5, all had active disease showing PPV of 100%. Applying Fisher's exact test, the P‐value was found to be .004.

Conclusion

DS seems to satisfy the requirements for a simple qualitative method of interpreting PET scans and for identifying patients requiring neck dissection. Consensus regarding qualitative assessment would facilitate standardization of PET reporting in clinical practice and enable comparative multicentric studies
Predicting chemotherapy‐induced menopause using baseline and post‐chemotherapy anti‐Müllerian hormone levels: Results of a pilot study
Authors: Martin Hilary Laura , Ullah Shahid , Abbas Nazim , Scott‐Hoy Alex , Kichenadasse Ganessan , Karapetis Christos Stelios , Roy Amitesh , Sukumaran Shawgi , Ross David M , Khattak Muhammad Adnan , Koczwara Bogda
Published: March 2021

Background

Chemotherapy can cause premature menopause which may result in adverse effects such as fertility loss, osteoporosis, cardiovascular disease and menopausal symptoms. It is thus very important that women are provided with accurate information regarding their risk of premature menopause as a consequence of proposed chemotherapy. Unfortunately, at present there are no reliable tools which can be applied in clinical practice to estimate the risk of premature menopause in women undergoing chemotherapy, beyond age of the patient and form of chemotherapy utilized.

Aim

This was a pilot study to determine whether AMH levels pre and during chemotherapy are able to predict for chemotherapy induced menopause, and to assess quality of life and menopausal symptoms.

Methods and results

Premenopausal women between 18 to 45 who were planned to undergo gonadotoxic chemotherapy with curative intent for either breast cancer or haematologic malignancy were recruited from a single centre. AMH, FSH, LH and oestradiol levels were recorded prior to commencement of therapy, during and following completion of chemotherapy. Menstrual status, menopausal symptoms and quality of life data were collected at baseline and during follow‐up. Twenty two women were recruited. The baseline AMH was higher in women who regained menses post‐chemotherapy (median 23.1 vs 9.9 pM (P = .06). Menopausal symptoms were significantly higher at 1 year post diagnosis than at baseline however quality of life was similar.

Conclusion

AMH may be useful for predicting chemotherapy induced menopause. Further research is still required to determine the place of such testing for patient counselling and management.
Oral and oropharyngeal cancer: Knowledge, attitude and practices among medical and dental practitioners
Authors: Algudaibi Latifa Yousef , AlMeaigel Shahad , AlQahtani Nouf , Shaheen Naila A. , Aboalela Ali
Published: March 2021

Background

Oral and oropharyngeal cancer are significant health problems. They are both life‐threatening conditions usually diagnosed at an advanced stage causing survival rates to decline.

Aim

To assess and compare practices, knowledge and attitude regarding oral and oropharyngeal cancer between dental and medical practitioners.

Methods

A cross‐sectional study was conducted to assess knowledge, attitude and practices of oral and oropharyngeal cancer among dental and medical practitioners at King Abdulaziz Medical City, Riyadh, Saudi Arabia. 360 participants were included in the study using a convenient sampling technique. Participants were approached in their clinics and printed self‐administered questionnaire were handed over to them after signing a written consent form. Frequency distribution and Chi‐Square test were used for the statistical analysis and the level of significance was set at P value of .05 or less.

Results

A total of 174 participants responded. Assessment of oral and oropharyngeal cancer knowledge between dental practitioners and medical practitioners showed comparable results. Regarding practices, a significant difference was seen between medical practitioners and dental practitioners in determining the duration of intra‐oral ulcer to consider urgent referral (P = .006) and in number of referrals made in relation to suspicious oral lesions (P = .002). Moreover, a significant difference (P = .006) was seen between medical practitioners and dental practitioners in determining the duration of intra‐oral ulcer to consider urgent referral.

Conclusion

Medical and dental practitioners showed areas of differences in practice, attitude and knowledge of oral and oropharyngeal cancer that when addressed would lead to improved survival rates.
The meaning of colors in food packaging: A study of industrialized products sold in Brazil
Authors: Pereira Carla
Published: March 2021

Currently, packaging needs to communicate material and immaterial qualities of food, linked to the satisfaction of nutritional, psychological and cultural needs of consumers. For this, the design builds complex discourses, associating verbal and visual language. In Brazil, with the standardization of packaging formats and the growing variety of products, the importance of color in visual communication has expanded. This research aims to explain the system of color meanings in food packaging sold in Brazil, and demonstrate that the color of designs reflects ideological and cultural concepts of contemporary society. An empirical study was conducted, with a qualitative approach, in which the colors of 612 food packages were analyzed. The analysis tools come from semiology/semiotics. The results show that colors played three semiotic functions: (1) showing the color of the food (iconic function), (2) signaling objective characteristics of the products (indicative function), and (3) representing psychological and cultural qualities (symbolic function). It was found that the system of color meanings in the food packaging is organized based on color attributes (hue, lightness and chroma), through differences and oppositions. It is concluded that, in Brazil, the colors of food packaging reflect the heterogeneity of the consumption groups—such as white for the “healthy” people, black for the “refined”, pink for “women”, green for the “ecological”—and, in this sense, they work as identity markers.
Effect of Moderate Hepatic Impairment on the Pharmacokinetics of Vadadustat, an Oral Hypoxia‐Inducible Factor Prolyl Hydroxylase Inhibitor
Authors: Chavan Ajit , Burke Leontia , Sawant Rishikesh , Navarro‐Gonzales Pamela , Vargo Dennis , Paulson Susan K.
Published: March 2021

Vadadustat is a hypoxia‐inducible factor prolyl hydroxylase inhibitor in development for the treatment of anemia of chronic kidney disease. This phase 1, open‐label, parallel‐group, single‐dose study evaluated the pharmacokinetics of 450‐mg vadadustat in adults with moderate hepatic impairment (Child‐Pugh class B) vs those with normal hepatic function. Primary end points were area under the plasma concentration–time curve (AUC) from dosing to last concentration and to infinity, as well as maximum concentration (Cmax); additional pharmacokinetic parameters included time to Cmax (Tmax) and half‐life. Safety and tolerability were also assessed. All enrolled participants (n = 16) completed the study. Demographics were similar in both groups (overall, 100% White; 62.5% female; mean age, 59.2 years). Vadadustat plasma exposure was higher in the moderate hepatic impairment group, whereas maximum concentration was similar between groups. Point estimates of the hepatic impairment : normal geometric mean ratios (90% confidence interval) for AUC from dosing to last concentration, AUC from dosing to infinity, and Cmax were 1.05 (0.82‐1.35), 1.06 (0.82‐1.36), and 1.02 (0.79‐1.32), respectively. Mean elimination half‐life was 5.8 and 7.8 hours in the normal and hepatic impairment groups, respectively. Treatment‐emergent adverse events were mostly mild in severity, and vadadustat was generally well tolerated. In conclusion, moderate hepatic impairment did not significantly impact vadadustat systemic exposure, and mild hepatic impairment is unlikely to alter vadadustat exposure.
Comparison among nine alfalfa breeding schemes based on actual biomass yield gains
Authors: Annicchiarico Paolo , Pecetti Luciano
Published: March 2021

The definition of efficient selection methods for biomass yield of alfalfa and other open‐pollinated forage crops has lagged behind, despite its crucial importance for breeders. This study, performed in northern Italy, aimed to compare nine breeding schemes encompassing the evaluation of replicated clones and half‐sib (HS), first selfing generation (S1) or second selfing generation (S2) families without or with within‐family selection. The comparison was based on actual gains for dry‐matter yield over 43 mo and final plant survival across irrigated and rainfed cropping of advanced generation synthetics (Syn‐3) built from 12 selected parents. The study envisaged biomass yield selection over 31 mo under dense planting among 125 S0 plants and/or their progenies, after a stage of stratified mass selection which acted as a benchmark for genetic gains and whose genetic progress over the original genetic base was concurrently assessed. Half‐sib progeny‐based selection exhibited highest genetic gains with respect to unit time and return on yearly investment for direct costs for both biomass yield and crop persistence. Among‐and‐within‐HS family selection ranked second, and S1 progeny‐based selection ranked third, for yield gains, whereas three schemes implying two selfing generations were valuable for improving persistence but not yield. The initial stage of stratified mass selection was time‐ and cost‐efficient for improving yield but not persistence. We provided information also on self‐fertility and inbreeding depression variation across selfing generations, genetic variation of clonal, HS, S1 and S2 material, and consistency of S0 parent value across different types of material. Our results may have implications for field‐based and genomic selection.
H2‐free Plastic Conversion: Converting PET back to BTX by Unlocking Hidden Hydrogen
Authors: Lu Shenglu , Jing Yaxuan , Feng Bo , Guo Yong , Liu Xiaohui , Wang Yanqin
Published: March 2021

The strong desire for a circular economy makes obtaining fuels and chemicals via plastic degradation an important research topic in the 21st century. Here, the first example of the H2‐free polyethylene terephthalate (PET) conversion to BTX (benzene, toluene and xylene) was achieved by unlocking hidden hydrogen in the ethylene glycol part over Ru/Nb2O5 catalyst. Among the whole process (hydrolysis, reforming and hydrogenolysis/decarboxylation), the parallel hydrogenolysis and decarboxylation were competing and the rate‐determining step. Ru/Nb2O5 exhibited superior hydrogenolysis and poorer decarboxylation performance in direct comparison with Ru/NiAl2O4, accordingly contributing to the distinct selectivity to alkyl aromatics among BTX. Ru species on Nb2O5, unlike those on NiAl2O4, showed more Ruδ+ species owing to the strong interaction between Ru and Nb2O5, restricting the undesired decarboxylation. Along with NbOx species for C−O bond activation, excellent reactivity towards the H2‐free conversion of PET back to BTX with alkyl aromatics as dominant species was achieved. This H2‐free system was also capable of converting common real PET plastics back to BTX, adding new options in the circular economy of PET.
Green Hydrothermal Synthesis of Fluorescent 2,3‐Diarylquinoxalines and Large‐Scale Computational Comparison to Existing Alternatives
Authors: Amaya‐García Fabián , Caldera Michael , Koren Anna , Kubicek Stefan , Menche Jörg , Unterlass Miriam M.
Published: March 2021

Here, the hydrothermal synthesis (HTS) of 2,3‐diarylquinoxalines from 1,2‐diketones and o‐phenylendiamines (o‐PDAs) was achieved. The synthesis is simple, fast, and generates high yields, without requiring any organic solvents, strong acids or toxic catalysts. Reaction times down to <10 min without decrease in yield could be achieved through adding acetic acid as promoter, even for highly apolar biquinoxalines (yield >90 % in all cases). Moreover, it was shown that HTS has high compatibility: (i) hydrochlorides, a standard commercial form of amines, could be used directly as combined amine source and acidic catalyst, and (ii) Boc‐diprotected o‐PDA could be directly employed as substrate that underwent HT deprotection. A systematic large‐scale computational comparison of all reported syntheses of the presented quinoxalines from the same starting compounds showed that this method is more environmentally friendly and less toxic than all existing methods and revealed generic synthetic routes for improving reaction yields. Finally, the application of the synthesized compounds as fluorescent dyes for cell staining was explored.