bluuebunny/crossref_metadata_2025 huggingface dataset:
Delving Deeper: The Name Game: Exploring Random Permutations
Authors: Borkovitz Debra K.
Published: November 2020

To play the “Name Game,” students write their names on slips of paper and mix them up. They guess how many people will pick their own names when everyone picks a slip. After the students have played a few times, I ask them, “Would you expect more, fewer, or the same number of people to pick their own names if there were a thousand people in the class?” Since many more students would be picking names, some students expect that more students would pick a match. Other students reason that since the probability of any one individual picking his or her own name would be drastically lower, fewer people would pick matches.
Activities for Students: Transformations on Data Sets and Their Effects on Descriptive Statistics
Authors: Fox Thomas B.
Published: November 2020

The development of concepts in statistics and functions is an important part of the school mathematics curriculum. Also important is the formulation and verification of mathematical conjectures (National Council of Teachers of Mathematics 2000). This activity asks students to examine the effects on the descriptive statistics of a data set that has undergone either a translation or a scale change. They make conjectures relative to the effects on the statistics of a transformation on a data set. Students then defend their conjectures and deductively verify several of them.
The Tellem Weavers Meet the Graphing Calculator
Authors: Louise Gould S.
Published: November 2020

A hands-on activity that explores weaving patterns of the Tellem people. Students can look for patterns and discuss similarities and differences between their classmates' patterns. A graphing calculator program that simulates the weaving pattern is included.
Chinese Algebra: Using Historical Problems to Think About Current Curricula
Authors: Tillema Erik
Published: November 2020

Analyzing three problems from the Jiu Zhang Suanshu, a Chinese mathematics text from the first century BCE. Each problem examines how the Chinese generated equivalent expressions, an important concept in algebra today. Historical text is be adapted thereby algebraic thinking can be honed.
The Matrix Connection: Fibonacci and Inductive Proof
Authors: Veenstra Tamara B. , Miller Catherine M.
Published: November 2020

This article presents several activities (some involving graphing calculators) designed to guide students to discover several interesting properties of Fibonacci numbers. Then, we explore interesting connections between Fibonacci numbers and matrices; using this connection and induction we prove divisibility properties of Fibonacci numbers. Includes problems and samples of tasks used to help student discover patterns within the Fibonacci Sequence and connections to matrix algebra.
Delving Deeper: How Does One Know if a Number Is Divisible by 17?
Authors: Goldenberg E. Paul
Published: November 2020

How do you know if a number is divisible by 17?
Hands-On Perspective
Authors: Frantz Marc , Crannell Annalisa , Maki Dan , Hodgson Ted
Published: November 2020

The world of art offers rich applications of mathematics, and one of the most important of these applications is the notion of perspective. If an object is drawn in perspective, it is drawn as the eye sees it. We know, for example, that the height and width of the front face of the cube in figure 1 are the same as those of the back face. To the eye, however, the sides of the front face appear to be considerably longer than those of the back face. Moreover, the top, side, and bottom faces of the cube do not even appear to be squares.
Delving Deeper: Investigating Hypotheses with Inverse Functions and a Classical Geometry Problem
Authors: Lassak Marshall , Heller Brad , Siegel Steven
Published: November 2020

This month's “Delving Deeper” brings you two investigations.
Temperature and humidity monitoring to identify ideal periods for liquefaction on Earth and Mars – data from the High Andes
Authors: KERESZTURI Akos , PAL Bernadett , GYENIS Akos
Published: November 2020

During an almost two week-long field campaign in the Atacama Desert high altitude region of Ojos del Salado volcano, temperature (T) and relative humidity (RH) values were monitored on the surface and <1–5 cm sized rocks, focusing on the night-time values. The aim was to identify and evaluate potential temporal characteristics of daily T and RH changes, searching for ideal periods for deliquescence that has recently been proposed for Mars. Although the atmospheric pressure on Mars is much lower than on Earth, and the atmosphere is drier in general, the huge daily temperature fluctuation there could produce elevated humidity values at night-time; this aspect has thus been analysed on Earth at a desert location, where because of the high elevation night-time cooling is very strong, just like on Mars. Different nearby surface locations showed the same temporal T/RH characteristics, but evident variations were observed between different days. Strong fluctuations could be observed on 10–20 minute long temporal scales, that might influence the deliquescence process, and should be accounted for in future missions aiming to analyse this process on Mars. Night-time periods were favourable for deliquescence. Among the modelled Mars-relevant salts [CaCl2, Ca(ClO4)2, Mg(ClO4)2, NaCl] the longest durations of possible deliquescence were for CaCl2, Ca(ClO4)2 and Mg(ClO4)2, ~7–12 hours for one day. The duration for deliquescence showed some increase along with the rising elevation, due to the decreasing night-time temperature. Thus despite the low humidity on Mars, the cold nights may cause elevated RH towards deliquescence. The Atacama Desert locations analysed are a useful analogue of the deliquescence process on Mars. Fluctuation in RH was observed in night-time, suggesting that similar variability might be present on Mars, and that should be considered in the future, including in evaluating how fast the microscopic liquid formation progresses. Night-time slope winds expected on Mars might have a strong impact on the local T/RH conditions. A more detailed analysis in the future should focus on identifying and separating regions with and without much of the expected night-time fluctuation
Geochemistry and geochronology of the Jawornik granitoids, Orlica-Śnieżnik Dome, Sudetes, Poland
Authors: BIAŁEK Dawid
Published: November 2020

The Jawornik granitoids intrude, in vein-like form, a sequence of a polymetamorphic metavolcanic and metapelitic rocks of the Orlica-Śnieżnik Dome, Sudetes, Poland. This paper provides whole-rock geochemical data, sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon geochronological data as well as 40Ar-39Ar age determinations to constrain the genetic and temporal relationships of the different rock types forming these veins. Based on macroscopically visible features of the granitoids and their relationship with tectonic structures visible in the country rocks, four varieties of the Jawornik granitoids have been distinguished: amphibole- and biotite-bearing granites (HBG), biotite-bearing granites (BG), biotite- and muscovite-bearing granites (BMG) and muscovite-bearing granites (MG). The Jawornik granitoids as a whole show a limited but significant variation in major element chemical composition, with SiO2 ranging from 65 to 76 wt.% (average 69.16 wt.%, n = 24). They are subalkalic, peraluminous and calc-alkaline [average A/CNK = 1.07, average (Na2O + K2O) = 7.75, average (Fe2O3t/(Fe2O3t + MgO) = 0.59]. Close inspection of their geochemical parameters showed that the samples investigated can be subdivided into two groups. The first group, the HBG, BG, and BMG varieties, comprising most of the granitoids in the Złoty Stok-Skrzynka Tectonic Zone, were formed by melting of greywackes or/and amphibolites. The MG, belonging to the second group, were formed by partial melting of a more felsic source. The HBG yielded a zircon U-Pb age of 351 ±1.3 Ma and well-defined 40Ar-39Ar plateau ages for hornblende (351.1 ±3.9 Ma) and coexisting biotite (349.6 ±3.8 Ma), indicating probably the oldest magmatic event in this region. Zircons from the MG, the youngest rock variety on the basis of their relationship with the tectonic structures in the host rocks, yielded a U-Pb age of 336.3 ±2.4 Ma, though based on three points only. The biotites and muscovites from the BMG have 40Ar-39Ar plateau ages of 344.1 ±4.7 Ma and 344.6 ±3.8 Ma, respectively. These data, in combination with already published isotopic ages, suggest that the Jawornik granitoids intruded host rocks of the Orlica-Śnieżnik Dome in three stages, at ~350, ~344 and ~335 Ma.
ON THE SUPERSONIC MOTION OF CHAPLYGIN GAS
Authors: CHUANG FENG-KAN
Published: November 2020

In this paper the approximation which was originally introduced by Chaplygin in his famous paper "on gas jet" for the treatment of subsonic flow is extended to the supersonic motion. Four typical initial value problems are solved using hodograph variables, and the analytical forms of the solutions are obtained. The approximate solutions of supersonic flow given by Christianovich is extended in this paper to slightly supersonic flow. Finally the relation between the Christianovich's approximate method and the general treatment presented here is studied.
A SIMPLE ELECTRONIC TIMER
Authors: TZE YUNC-KWEI  , SCHAW TA-CHEN
Published: November 2020

A new type of simple electronic timer and its operational principle are described. The method and circuits of calibration are explained. The experimental results are tabulated and plotted in comparison with calculated values. Finally, discussions on the circuit, its accuracy, range of operation and applications are presented.
Effect of functional groups on crumpling behavior and structure of graphene oxide
Authors: Chen Chao , Duan Fang-Li ,   State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing 400030, China
Published: November 2020

Graphene has a wide range of applications in the fields of electricity, chemistry, biomedicine, and lubrication. But the strong van der Waals interaction between graphene sheets makes it easy to aggregate in preparation process, difficult to produce and put into practical applcation on a large-scale. There are many methods to prevent the graphene sheets from aggregating, such as reducing the size of sheets, adjusting the interaction between solvent and graphene, and using dispersant. Another possible method is to turn the sheet graphene into a three-dimensional structure like the crumpled paper. Compared with sheet graphene, the crumpled graphene ball has excellent aggregation-resistant. The current research on crumpled graphene ball mainly focuses on the effect of the initial structure of graphene sheet on the structure stability of the crumpled ball, but rarely involves the effect of functional groups. In this paper, ReaxFF molecular dynamics is used to simulate the crumpling process of graphene oxide sheet. The effect of functional groups (hydroxyl, epoxy) on the crumpling behavior and the stability of the crumpled ball of graphene oxide are studied. Graphene sheet oxidized by hydroxyl exhibits a push-up crumpling behavior. Graphene sheet oxidized by epoxy exhibits a layer-to-layer fitted crumpling behavior. Different crumpling behavior will lead to the difference in final crumpled ball structure. By analyzing the relationship between the atomic level potential energy incremental distribution and the distribution of broken and formed C—C bonds, we find that the broken and formed C—C bonds mainly occur in areas with a large degree of deformation, and the epoxy group has a stronger weakening effect on the C—C bond connected to it than the hydroxyl group. The release process of graphene oxide crumpled ball is simulated to study its structural stability. The stability of graphene oxide crumpled ball depends on the number of the broken and formed C—C bonds, that is, the more the number of broken and formed C—C bonds, the more stable the structure is, and under the same oxidation rate, the stability of the crumpled ball structure increases with the proportion of epoxy groups increasing. This study shows that the stability of graphene oxide crumpled ball structure can be controlled by changing the relative proportion of functional groups.
Influenza virus and coronavirus: Cellular binding and internalization
Authors: Bao Mei-Mei , Yang Kai , Yuan Bing ,   Center for Soft Condensed Matter Physics and Intersectional Research, Soochow University, Suzhou 215006, China
Published: November 2020

Viruses are acellular organisms that must be parasitized in living cells and proliferated by replication. Although different viruses invade cells in different ways, they mainly initiate the invasion process through binding to specific receptor proteins or lipid structures on the cell surface for the following cellular internalization. Thus revealing the interaction process and underlying mechanism between viruses and cell membranes will be helpful in developing targeted drugs or vaccines from the source. In this review, the influenza virus and coronavirus are taken for example. We will first discuss the structure of influenza viruses, their binding modes with cell membranes, the way of realizing cell endocytosis and the cytokines involved in this process. After that, recent research progress of coronavirus especially the novel coronavirus SARS-CoV-2, including its structural characteristics, its binding with cell receptor ACE2 and the following cellular internalization, is briefly introduced.
Characterization and evaluation of the photocatalytic activity of oxides based on TiO2 synthesized by hydrolysis controlled by the use of water/acetone mixtures
Authors: Machado Werick A. , da Hora Machado Antonio Eduardo
Published: November 2020

New photocatalysts based on TiO2 were synthesized and characterized. The synthesis involved the controlled hydrolysis of titanium tetraisopropoxide using water containing different proportions of acetone. X-ray diffraction analyses combined with Raman spectroscopy revealed crystalline oxides characterized by the coexistence of the anatase and brookite phases. The Rietveld refinement of diffractograms showed that the presence of acetone in the synthesis process influenced the composition of these crystalline phases, with the proportion of brookite growing from 13% to 22% with the addition of this solvent in the synthesis process. The BET isotherms revealed that these materials are mesoporous with surface area approximately 12% higher than that of the oxide prepared from hydrolysis using pure water. The photocatalytic potential of these oxides was evaluated by means degradation tests using the dyes Ponceau 4R and Reactive Red 120 as oxidizable substrates. The values achieved using the most efficient photocatalyst among the synthesized oxides were, respectively, 83% and 79% for mineralization, and 100% for discoloration of these dyes. This same oxide loaded with 0.5% of platinum and suspended in a 5:1 v/v water/methanol mixture, produced 56 mmol of gaseous hydrogen in 5 h of reaction, a specific hydrogen production rate of 138.5 mmol h−1g−1, a value 60% higher than that achieved using TiO2 P25 under similar conditions.
Changes and sex- and age-related differences in the expression of drug metabolizing enzymes in a KRAS-mutant mouse model of lung cancer
Authors: Li Xiaoyan , Lu Yiyan , Ou Xiaojun , Zeng Sijing , Wang Ying , Qi Xiaoxiao , Zhu Lijun , Liu Zhongqiu
Published: November 2020

Background

This study aimed to systematically profile the alterations and sex- and age-related differences in the drug metabolizing enzymes (DMEs) in a KRAS-mutant mouse model of lung cancer (KRAS mice).

Methodology

In this study, the LC-MS/MS approach and a probe substrate method were used to detect the alterations in 21 isoforms of DMEs, as well as the enzymatic activities of five isoforms, respectively. Western blotting was applied to study the protein expression of four related receptors.

Results

The proteins contents of CYP2C29 and CYP3A11, were significantly downregulated in the livers of male KRAS mice at 26 weeks (3.7- and 4.4-fold, respectively, p < 0.05). SULT1A1 and SULT1D1 were upregulated by 1.8- to 7.0- fold at 20 (p = 0.015 and 0.017, respectively) and 26 weeks (p = 0.055 and 0.031, respectively). There were positive correlations between protein expression and enzyme activity for CYP2E1, UGT1A9, SULT1A1 and SULT1D1 (r2 ≥ 0.5, p < 0.001). Western blotting analysis revealed the downregulation of AHR, FXR and PPARα protein expression in male KRAS mice at 26 weeks. For sex-related differences, CYP2E1 was male-predominant and UGT1A2 was female-predominant in the kidney. UGT1A1 and UGT1A5 expression was female-predominant, whereas UGT2B1 exhibited male-predominant expression in liver tissue. For the tissue distribution of DMEs, 21 subtypes of DMEs were all expressed in liver tissue. In the intestine, the expression levels of CYP2C29, CYP27A1, UGT1A2, 1A5, 1A6a, 1A9, 2B1, 2B5 and 2B36 were under the limitation of quantification. The subtypes of CYP7A1, 1B1, 2E1 and UGT1A1, 2A3, 2B34 were detected in kidney tissue.

Conclusions

This study, for the first time, unveils the variations and sex- and age-related differences in DMEs in C57 BL/6 (WT) mice and KRAS mice.
Stem cell imaging through convolutional neural networks: current issues and future directions in artificial intelligence technology
Authors: Ramakrishna Ramanaesh Rao , Abd Hamid Zariyantey , Wan Zaki Wan Mimi Diyana , Huddin Aqilah Baseri , Mathialagan Ramya
Published: November 2020

Stem cells are primitive and precursor cells with the potential to reproduce into diverse mature and functional cell types in the body throughout the developmental stages of life. Their remarkable potential has led to numerous medical discoveries and breakthroughs in science. As a result, stem cell–based therapy has emerged as a new subspecialty in medicine. One promising stem cell being investigated is the induced pluripotent stem cell (iPSC), which is obtained by genetically reprogramming mature cells to convert them into embryonic-like stem cells. These iPSCs are used to study the onset of disease, drug development, and medical therapies. However, functional studies on iPSCs involve the analysis of iPSC-derived colonies through manual identification, which is time-consuming, error-prone, and training-dependent. Thus, an automated instrument for the analysis of iPSC colonies is needed. Recently, artificial intelligence (AI) has emerged as a novel technology to tackle this challenge. In particular, deep learning, a subfield of AI, offers an automated platform for analyzing iPSC colonies and other colony-forming stem cells. Deep learning rectifies data features using a convolutional neural network (CNN), a type of multi-layered neural network that can play an innovative role in image recognition. CNNs are able to distinguish cells with high accuracy based on morphologic and textural changes. Therefore, CNNs have the potential to create a future field of deep learning tasks aimed at solving various challenges in stem cell studies. This review discusses the progress and future of CNNs in stem cell imaging for therapy and research.
Two-phase MHD Flow through Porous Medium with Heat Transfer in a Horizontal Channel
Authors: Kumar Devendra , Satyanarayana B. , Kumar Rajesh , Singh Bholey , Shrivastava R. K.
Published: November 2020

The present study deals with two layered MHD immiscible fluid flow through porous medium in presence of heat transfer through parallel plate channel. The fluids are incompressible, and flow is fully developed. The fluids are of different viscosities and thermal conductivities so flowing without mixing each other. Two different phases are accounted for study and are electrically conducting. Temperature of the walls of parallel plate channel is constant. Rheological properties of the immiscible fluids are constant in nature. The flow is governed by coupled partial differential equations which are converted to ordinary differential equations and exact solutions are obtained. The velocity profile and temperature distribution are evaluated and solved numerically for different heights and viscosity ratios for the two immiscible fluids. The effect of magnetic field parameter M and porosity parameter K is discussed for velocity profile and temperature distribution. Combined effects of porous medium and magnetic fields are accelerating the flow which, can be helpful in draining oil from oil wells.
Sensorial and Functional Properties of Nutri-Cereal Bran Enriched Muffins and Buns
Authors: Mrunal D. Barbhai , Hymavathi T. V. , Kuna Aparna , Sreedhar M. , Rani V. Sudha
Published: November 2020

Bran is waste generated during primary processing of cereal grains. These brans are rich source of dietary fiber, nutrients, phytonutrients especially phenols and flavonoids contributing to their antioxidant properties. Thus, bran is gaining lot of attention as functional ingredient in bakery industry due to their nutritional properties. Millets are tiny grains that are highly nutritious hence termed as nutri-cereals but their primary processing is tedious given its small size. This leads to loss of major portion of grain generating huge amount of bran and bran-rich fractions that are usually discarded or used as animal feed. Utilization of millet brans in value addition of bakery products still remains understudied. Thus, present study was designed to evaluate functional properties of minor millet bran (proso and barnyard) enriched flour (0 – 30%) and formulate bakery products viz. buns and muffins. It was evident from results that water absorption capacity of flour increased with addition of bran but water solubility index, oil absorption and foaming capacity decreased. The sensory scores of muffins and buns reduced with increased bran incorporation and control scored highest. Study concluded that muffins with 30% and buns with 20% proso and barnyard bran showed better acceptability.
Zirconia Fiber Containing TRIP‐Matrix Composites Prepared via Paper‐Manufacturing Technology
Authors: Heuer Claudia , Brachhold Nora , Aneziris Christos G.
Published: November 2020

Herein, the continuous further development of metal matrix composites prepared by the paper‐manufacturing technology is in focus. The composites are based on metastable austenitic stainless steel with the addition of magnesia partially stabilized zirconia particles or yttria‐stabilized zirconia fibers. The sintering conditions are profoundly investigated, to study and subsequently inhibit the formation of carbides, which deteriorates the mechanical performance of the paper‐derived materials in the past. The cellulose pulp fiber content as well as the filler particle content is adjusted with the aim to improve the mechanical performance of the paper‐derived materials during tensile load testing. In addition, the cellulose pulp fibers are partially replaced by yttria‐stabilized zirconia fibers. The improved composites that contain 3 and 6 vol% of yttria‐stabilized zirconia fibers exhibit the ultimate tensile strengths of 264 and 322 MPa. The tensile strain of the improved TRIP‐matrix composites as well as of the reference material is significantly increased (up to 10%) as compared with our previous study, where all materials show brittle fracture behavior. This can certainly be attributed to the improvements in the sintering process and the corresponding prevention of carbide formation during heat treatment upon cooling.
Pulsed Gate Switching of MoS2 Field‐Effect Transistor Based on Flexible Polyimide Substrate for Ultrasonic Detectors
Authors: Naqi Muhammad , Kim Bosung , Kim Sang‐Woo , Kim Sunkook
Published: November 2020

Molybdenum disulfide (MoS2) semiconductors have closely been studied for potential applications in detectors, optoelectronics, and flexible electronics due to its high electrical and robust mechanical performance. Herein, the first experimental study of the high‐speed ultrasound wave detection by the combinational structure of flexible MoS2 field‐effect transistor (FET) and piezoelectric device based on polyvinylidene fluoride trifluoro ethylene P(VDF‐TrFE) is reported. The proposed flexible MoS2 based FET device exhibits maximum mobility of 18.12 cm2 Vs−1, high on/off current ratio of ≈105, high robustness over mechanical tests, and excellent gate‐pulsed switching behavior at different frequencies (10, 100, and 500 kHz), thus, utilized as supporting electronics to detect ultrasound wave at high‐speed. The ultrasound waves are applied to the self‐assembled piezoelectric device under different power scales (0 ≈ 1.5 W cm−2) and the transfer curve of the proposed FET is analyzed. The results show a clear detection of ultrasound waves with high stability and excellent linearity in terms of threshold voltage (Vth) shift and drain current (Ids) under different power levels. Also, the pulsed gate‐switching behavior is analyzed and the ultrasound detection with high stability is observed at high‐speed switching, thus, enabling the development of applications in high‐speed electronic devices and biomedical imaging tools.
Halohydrin Dehalogenases and Their Potential in Industrial Application – A Viewpoint of Enzyme Reaction Engineering
Authors: Findrik Blažević Zvjezdana , Milčić Nevena , Sudar Martina , Majerić Elenkov Maja
Published: November 2020

At the moment, there are approx. 100 published papers investigating halohydrin dehalogenases from different aspects; enzymology, molecular biology and reactions they can catalyse. Unquestionably, these enzymes are of great importance and hold an immense potential due to the wide spectrum of different compounds that can be synthesized by their action. These compounds, such as chiral epoxides, β‐substituted alcohols, oxazolidinones etc., significantly enrich the chemist's toolbox and, moreover, open the possibility for the synthesis of even more complex compounds. Still, there are many unknowns, and it is the purpose of this work to demonstrate the possibilities and bottlenecks, in scientific sense, that could further help in broadening the applicative potential of these fascinating enzymes.

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Pd(II)‐catalyzed, Picolinamide‐aided sp2 γ−C−H Functionalization of Phenylglycinol: Access to γ−C−H Arylated, Alkylated and Halogenated Phenylglycinol Scaffolds
Authors: Singh Prabhakar , Arulananda Babu Srinivasarao , Aggarwal Yashika , Patel Pooja
Published: November 2020

We report the Pd(II)‐catalyzed picolinamide‐aided ortho‐C−H arylation‐, alkylation‐, and halogenation (sp2 γ−C−H functionalization) of phenylglycinol substrates. Phenylglycinols are remarkable building blocks and have found different applications in synthetic organic and medicinal chemistry. This work is a contribution towards the expansion of the library of phenylglycinol scaffolds and also substrate scope development by using the Pd(II)‐catalyzed bidentate directing group picolinamide‐aided C−H activation tactic.
Environmental Control of Single‐Molecule Junction Evolution and Conductance: A Case Study of Expanded Pyridinium Wiring
Authors: Nováková Lachmanová Štěpánka , Kolivoška Viliam , Šebera Jakub , Gasior Jindřich , Mészáros Gábor , Dupeyre Grégory , Lainé Philippe P. , Hromadová Magdaléna
Published: November 2020

Environmental control of single‐molecule junction evolution and conductance was demonstrated for expanded pyridinium molecules by scanning tunneling microscopy break junction method and interpreted by quantum transport calculations including solvent molecules explicitly. Fully extended and highly conducting molecular junctions prevail in water environment as opposed to short and less conducting junctions formed in non‐solvating mesitylene. A theoretical approach correctly models single‐molecule conductance values considering the experimental junction length. Most pronounced difference in the molecular junction formation and conductance was identified for a molecule with the highest stabilization energy on the gold substrate confirming the importance of molecule–electrode interactions. Presented concept of tuning conductance through molecule–electrode interactions in the solvent‐driven junctions can be used in the development of new molecular electronic devices.
Unveiling the Activity Origin of Iron Nitride as Catalytic Material for Efficient Hydrogenation of CO2 to C2+ Hydrocarbons
Authors: Zhao Bohang , Sun Mengyao , Chen Fanpeng , Shi Yanmei , Yu Yifu , Li Xingang , Zhang Bin
Published: November 2020

Developing efficient catalytic materials and unveiling the active species are significant for selective hydrogenation of CO2 to C2+ hydrocarbons. Fe2N@C nanoparticles were reported to exhibit outstanding performance toward selective CO2 hydrogenation to C2+ hydrocarbons (C2+ selectivity: 53.96 %; C2‐C4= selectivity, 31.03 %), outperforming corresponding Fe@C. In situ X‐ray diffraction, ex situ Mössbauer and X‐ray photoelectron spectra revealed that iron nitrides were in situ converted to highly active iron carbides, which acted as the real active species. Moreover, the combined results of in situ diffuse reflectance infrared Fourier transform spectroscopy and control experiments suggested an in situ formed carbonyl iron‐mediated conversion mechanism from iron nitrides to iron carbides.
Azide Radical Initiated Ring Opening of Cyclopropenes Leading to Alkenyl Nitriles and Polycyclic Aromatic Compounds
Authors: Muriel Bastian , Waser Jerome
Published: November 2020

We report herein a radical‐mediated amination of cyclopropenes. The transformation proceeds through a cleavage of the three‐membered ring after the addition of an azide radical on the strained double bond and leads to tetrasubstituted alkenyl nitrile derivatives upon loss of N2. With 1,2‐diaryl substituted cyclopropenes, this methodology could be extended to a one‐pot synthesis of highly functionalized polycyclic aromatic compounds (PACs). This transformation allows the synthesis of nitrile‐substituted alkenes and aromatic compounds from rapidly accessed cyclopropenes using only commercially available reagents.
Synthesis of Indanones and Spiroindanones by Diastereoselective Annulation Based on a Hydrogen Autotransfer Strategy
Authors: Chen Yate , Ding Zhengtian , Wang Yiming , Liu Wenfeng , Kong Wangqing
Published: November 2020

An unprecedented nickel‐catalyzed domino reductive cyclization of alkynes and o‐bromoaryl aldehydes is described. The reaction features broad substrate scope and is tolerant of a variety of functional groups, providing straightforward access to biologically significant indanones and spiroindanone pyrrolidine derivatives in good yields with excellent regio‐ and diastereoselectivity. Preliminary mechanistic studies have shown that indanones are formed by the cyclization of o‐bromoaryl aldehydes and alkynes to form indenol intermediates, followed by hydrogen autotransfer.
Self‐Supported Mesoporous Iron Phosphide with High Active‐Site Density for Electrocatalytic Hydrogen Evolution in Acidic and Alkaline Media
Authors: Huang Guoqing , Zhang Cong , Liu Zhipeng , Yuan Shisheng , Yang Guohua , Wang Kaiwen , Li Xiaotian , Li Nan , Jing Shubo
Published: November 2020

Developing low‐cost and highly active electrocatalysts for the hydrogen evolution reaction (HER) is urgently desired. We fabricated a mesoporous FeP self‐supported electrode (meso‐FeP/CC) through a facile and mild sol‐gel method. The mesoporous FeP self‐supported electrode displays superior HER electrocatalytic activity, requiring low overpotentials of 57 and 84 mV to drive 10 mA cm−2 in acidic and alkaline electrolyte, respectively. Meanwhile, the as‐prepared electrode exhibits fast kinetics with a small Tafel slope (acidic media: 42 mV dec−1 and alkaline media: 60 mV dec−1). The excellent catalytic performance of the electrode benefits from mesoporous framework with a large surface area (74.1 m2 g−1) and highly conductive self‐supported structure. The former endows the catalyst with a large active‐site density (3.5×1018 site per mg) and substantial accessible mesopores, and the latter accelerates reaction kinetics. This work offers a new avenue for rational designing high‐efficiency FeP HER electrocatalysts.
Chemodivergence between Electrophiles in Cross‐Coupling Reactions
Authors: Reeves Emily K. , Entz Emily D. , Neufeldt Sharon R.
Published: November 2020

Chemodivergent cross‐couplings are those in which either one of two (or more) potentially reactive functional groups can be made to react based on choice of conditions. In particular, this review focuses on cross‐couplings involving two different (pseudo)halides that can compete for the role of the electrophilic coupling partner. The discussion is primarily organized by pairs of electrophiles including chloride vs. triflate, bromide vs. triflate, chloride vs. tosylate, and halide vs. halide. Some common themes emerge regarding the origin of selectivity control. These include catalyst ligation state and solvent polarity or coordinating ability. However, in many cases, further systematic studies will be necessary to deconvolute the influences of metal identity, ligand, solvent, additives, nucleophilic coupling partner, and other factors on chemoselectivity.
Synthesis of Acrylonitriles via Mild Base Promoted Tandem Nucleophilic Substitution‐Isomerization of α‐Cyanohydrin Methanesulfonates
Authors: Liu Shiwen , Meng Lingling , Zeng Xiaojun , Hammond Gerald B. , Xu Bo
Published: November 2020

Main observation and conclusion

We have developed an efficient synthesis of acrylonitriles via mild base promoted tandem nucleophilic substitution‐isomerization of α‐cyanohydrin methanesulfonates with alkenylboronic acids. This transition metal‐free protocol works under simple and mild conditions and offers good chemical yields for a wide range of substrates and demonstrates good functional group tolerance.

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Effects of blood parasite infections on spatiotemporal migration patterns and activity budgets in a long‐distance migratory passerine
Authors: Emmenegger Tamara , Bensch Staffan , Hahn Steffen , Kishkinev Dmitry , Procházka Petr , Zehtindjiev Pavel , Bauer Silke
Published: November 2020

How blood parasite infections influence the migration of hosts remains a lively debated issue as past studies found negative, positive, or no response to infections. This particularly applies to small birds, for which monitoring of detailed migration behavior over a whole annual cycle has been technically unachievable so far. Here, we investigate how bird migration is influenced by parasite infections. To this end, we tracked great reed warblers (Acrocephalus arundinaceus) with multisensor loggers, characterized general migration patterns as well as detailed flight bout durations, resting times and flight heights, and related these to the genus and intensity of their avian haemosporidian infections. We found migration distances to be shorter and the onset of autumn migration to be delayed with increasing intensity of blood parasite infection, in particular for birds with Plasmodium and mixed‐genus infections. Additionally, the durations of migratory flight bout were prolonged for infected compared to uninfected birds. But since severely infected birds and particularly birds with mixed‐genus infections had shorter resting times, initial delays seemed to be compensated for and the timing in other periods of the annual cycle was not compromised by infection. Overall, our multisensor logger approach revealed that avian blood parasites have mostly subtle effects on migratory performance and that effects can occur in specific periods of the year only.
Ras Homolog Family Member F, Filopodia Associated Promotes Hepatocellular Carcinoma Metastasis by Altering the Metabolic Status of Cancer Cells Through RAB3D
Authors: Li Shi , Liu Yu , Bai Yifeng , Chen Min , Cheng Donghui , Wu Mengwan , Xia Jianling
Published: November 2020

Background and Aims

The mechanism by which tumor cells resist metabolic stress remains unclear, but many oncogenes are known to regulate this process. Accordingly, metabolic stress is closely associated with tumor metastasis. In this study, gene chip technology showed that Ras homolog family member F, filopodia associated (RHOF), a member of the Rho guanosine triphosphatase family, is an oncogene that is significantly related to hepatocellular carcinoma (HCC) metastasis; however, it has rarely been reported in tumors. Our aim was to determine the clinicopathological significance and role of RHOF in HCC progression and investigate the associated mechanisms.

Approach and Results

The results showed that compared to expression in adjacent noncancerous tissues, RHOF was frequently up‐regulated in HCC tumor samples and elevated under conditions of glucose deprivation. RHOF expression was associated with tumor–node–metastasis stage, T grade, metastasis status, recurrence, and survival in HCC. RHOF also affected cell morphology and promoted migration, invasion, and epithelial–mesenchymal transition (EMT) of HCC cell lines. Analysis of the underlying mechanism showed that RHOF promoted the Warburg effect by up‐regulating the expression and function of several glycolytic enzymes in HCC cells. This metabolic shift enhanced HCC cell migration and invasion. Specifically, RHOF exerted a tumor‐promoting effect by directly interacting with AMP‐activated protein kinase (AMPK) and increasing the phosphorylation of AMPK. This subsequently affected RAB3D mRNA stability and led to elevated RAB3D expression, thereby amplifying the Warburg effect and malignant biological behaviors of HCC cells.

Conclusions

RHOF helps tumor cells resist metabolic stress through modulating the Warburg effect and plays a critical role in promoting HCC cell migration, invasion, and EMT, highlighting its important role in remodeling the metastatic microenvironment and regulating tumor metastasis. RHOF shows potential as a therapeutic target and prognostic biomarker for HCC.
Effects of different autophagy inhibitors on sensitizing KG‐1 and HL‐60 leukemia cells to chemotherapy
Authors: Haghi Atousa , Salemi Mahdieh , Fakhimahmadi Aila , Mohammadi Kian Mahnaz , Yousefi Hassan , Rahmati Marveh , Mohammadi Saeed , Ghavamzadeh Ardeshir , Moosavi Mohammad Amin , Nikbakht Mohsen
Published: November 2020

A little number of current autophagy inhibitors may have beneficial effects on the acute myeloid leukemia (AML) patients. However, there is a strong need to figure out which settings should be activated or inhibited in autophagy pathway to prevail drug resistance and also to improve current treatment options in leukemia. Therefore, this study aimed to compare the effects of well‐known inhibitors of autophagy (as 3‐MA, BafA1, and HCQ) in leukemia KG‐1 and HL‐60 cells exposed to arsenic trioxide (ATO) and/or all‐trans retinoic acid (ATRA). Cell proliferation and cytotoxicity of cells were examined by MTT assay. Autophagy was studied by evaluating the development of acidic vesicular organelles, and the autophagosomes formation was investigated by acridine orange staining and transmission electron microscopy. Moreover, the gene and protein expressions levels of autophagy markers (ATGs, p62/SQSTM1, and LC‐3B) were also performed by qPCR and western blotting, respectively. The rate of apoptosis and cell cycle were evaluated using flow cytometry. We compared the cytotoxic and apoptotic effects of ATO and/or ATRA in both cell lines and demonstrated that some autophagy markers upregulated in this context. Also, it was shown that autophagy blockers HCQ and/or BafA1 could potentiate the cytotoxic effects of ATO/ATRA, which were more pronounced in KG‐1 cells compared to HL‐60 cell line. This study showed the involvement of autophagy during the treatment of KG‐1 and HL‐60 cells by ATO/ATRA. This study proposed that therapy of ATO/ATRA in combination with HCQ can be considered as a more effective strategy for targeting leukemic KG‐1 cells.
Novel fully human anti‐CD47 antibodies stimulate phagocytosis and promote elimination of AML cells
Authors: Wang Chaoyu , Sun Chengtao , Li Mengzhen , Xia Bing , Wang Yi , Zhang Li , Zhang Yanyan , Wang Juan , Sun Feifei , Lu Suying , Zhu Jia , Huang Junting , Zhang Yizhuo
Published: November 2020

Although most patients with acute myeloid leukemia (AML) enter remission after induction chemotherapy, the risk of relapse remains considerable. Therefore, some novel therapeutic strategies are still required. This study found that the overexpression of CD47 on AML cells was at least twofold more than that on normal bone marrow (NBM) cells in 81% (17/21) of the investigated patients; no patients had lower expression level of CD47 compared with healthy donors. The study also demonstrated that blocking the CD47/SIRPα (signal regulatory protein α) signal with the established novel fully human anti‐CD47 monoclonal antibodies increased the phagocytosis of AML cells by macrophages in vitro. Furthermore, in vivo experiments showed that the novel fully human anti‐CD47 monoclonal antibodies could significantly prolong the survival time of mice. Overall, the novel fully human anti‐CD47 antibodies could block CD47/SIRPα interaction, increase macrophage‐mediated phagocytosis, and enhance the elimination of AML cells.
3D Oxygen‐Enhanced MRI at 3T MR System: Comparison With Thin‐Section CT of Quantitative Capability for Pulmonary Functional Loss Assessment and Clinical Stage Classification of COPD in Smokers
Authors: Ohno Yoshiharu , Yui Masao , Yoshikawa Takeshi , Seki Shinichiro , Takenaka Daisuke , Kassai Yoshimori , Hattori Hidekazu , Murayama Kazuhiro , Toyama Hiroshi
Published: November 2020

Background

Oxygen (O2)‐enhanced MRI is mainly performed by a 2D sequence using 1.5T MR systems but trying to be obtained by a 3D sequence using a 3T MR system.

Purpose

To compare the capability of 3D O2‐enhanced MRI and that of thin‐section computed tomography (CT) for pulmonary functional loss assessment and clinical stage classification of chronic obstructive pulmonary disease (COPD) in smokers.

Study Type

Prospective study.

Population

Fifty six smokers were included.

Field Strength/ Sequence

3T, 3D O2‐enhanced MRIs were performed with a 3D T1‐weighted fast field echo pulse sequence using the multiple flip angles.

Assessments

Smokers were classified into four stages (“Without COPD,” “Mild COPD,” “Moderate COPD,” “Severe or very severe COPD”). Maps of regional changes in T1 values were generated from O2‐enhanced MR data. Regions of interest (ROIs) were then placed over the lung on all slices and averaged to determine mean T1 value change (ΔT1). Quantitative CT used the percentage of low attenuation areas within the entire lung (LAA%).

Statistical Tests

ΔT1 and LAA% were correlated with pulmonary functional parameters, and compared for four stages using Tukey's Honestly Significant Difference test. Discrimination analyses were performed and McNemar's test was used for a comparison of the accuracy of the indexes.

Results

There were significantly higher correlations between ΔT1 and pulmonary functional parameters (–0.83 ≤ r ≤ –0.71, P < 0.05) than between LAA% and the same pulmonary functional parameters (–0.76 ≤ r ≤ –0.69, P < 0.05). ΔT1 and LAA% of the “Mild COPD” and “Moderate COPD” groups were significantly different from those of the “Severe or Very Severe COPD” group (P < 0.05). Discriminatory accuracy of ΔT1 (62.5%) and ΔT1 with LAA% (67.9%) was significantly greater than that of LAA% (48.2%, P < 0.05).

Data Conclusion

Compared with thin‐section CT, 3D O2‐enhanced MRI has a similar capability for pulmonary functional assessment but better potential for clinical stage classification in smokers.

Level of Evidence

2

Technical Efficacy Stage

1
Bayesian Time‐Series Models in Single Case Experimental Designs: A Tutorial for Trauma Researchers
Authors: Natesan Batley Prathiba , Contractor Ateka A. , Caldas Stephanie V.
Published: November 2020

Single‐case experimental designs (SCEDs) involve obtaining repeated measures from one or a few participants before, during, and, sometimes, after treatment implementation. Because they are cost‐, time‐, and resource‐efficient and can provide robust causal evidence for more large‐scale research, SCEDs are gaining popularity in trauma treatment research. However, sophisticated techniques to analyze SCED data remain underutilized. Herein, we discuss the utility of SCED data for trauma research, provide recommendations for addressing challenges specific to SCED approaches, and introduce a tutorial for two Bayesian models—the Bayesian interrupted time‐series (BITS) model and the Bayesian unknown change‐point (BUCP) model—that can be used to analyze the typically small sample, autocorrelated, SCED data. Software codes are provided for the ease of guiding readers in estimating these models. Analyses of a dataset from a published article as well as a trauma‐specific simulated dataset are used to illustrate the models and demonstrate the interpretation of the results. We further discuss the implications of using such small‐sample data‐analytic techniques for SCEDs specific to trauma research.
Predictive factors of PNE success in a contemporary series: A single institution experience
Authors: Kocher Neil J. , Derisavifard Samir , Rueb Jessica , Goldman Howard B.
Published: November 2020

Purpose

Peripheral nerve evaluation (PNE) permits a trial of sacral neuromodulation to determine candidates for single stage implant. Before routine fluoroscopy, PNE success rates were 40%–50% compared to approximately 77% with staged procedures. There are limited data on PNE success rates with the use of fluoroscopy and improved techniques. We evaluated a contemporary series of PNE patients to determine predictors of PNE success and persistent functional response following permanent implantation.

Methods

A retrospective review of PNE patients at a large academic center from 2015 to 2019 was performed. Patients with urgency‐frequency, urge incontinence, and/or fecal incontinence (FI) were included. Rates of permanent implant after successful PNE trial and continued improvement at ≥1 month were reviewed. Multivariable logistic regression determined predictors of PNE success and continued response at follow‐up.

Results

A total of 102 PNE patients were included. A total of 78 patients (76.5%) were PNE responders. Predictors of PNE success included younger age (p = .014), urgency incontinence (p = .021), FI (p = .017), absence of a neurologic diagnosis (p = .04), presence of bellows and toe responses (p = .038), and perineal sensation (p = .027). A total of 68 of 78 PNE responders (87.2%) maintained optimal responses at ≥1 month. Absence of a neurologic diagnosis was predictive of persistent success at follow‐up (p = .013).

Conclusions

This contemporary PNE series revealed screening success equivalent to a two‐staged approach. A small proportion of patients demonstrate suboptimal responses following permanent implant. Conversion from testing to permanent implant may not be the ideal outcome as it may overestimate success, and evaluation for persistent improvement should be investigated further as a more reliable indicator of successful screening.