bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering Cell‐Derived Matrices: From 3D Models to Advanced Personalized Therapies
Authors: Rubi‐Sans Gerard , Castaño Oscar , Cano Irene , Mateos‐Timoneda Miguel A. , Perez‐Amodio Soledad , Engel Elisabeth
Published: July 2020

Regenerative medicine and disease models have evolved in recent years from two to three dimensions, providing in vitro constructs that are more similar to in vivo tissues. By mimicking native tissues, cell‐derived matrices (CDMs) have emerged as new modifiable extracellular matrices for a variety of tissues, allowing researchers to study basic cellular processes in tissue‐like structures, test tissue regeneration approaches, and model disease development. In this review, different fabrication techniques and characterization methods of CDMs are presented and examples of their application in cell behavior studies, tissue regeneration, and disease models are provided. In addition, future guidelines and perspectives in the field of CDMs are discussed.
Thermal Shrinkage Behavior of Metal–Organic Frameworks
Authors: Pan Ting , Shen Yu , Wu Peng , Gu Zhida , Zheng Bing , Wu Jiansheng , Li Sheng , Fu Yu , Zhang Weina , Huo Fengwei
Published: July 2020

Thermal treatment of metal–organic frameworks (MOFs) as a post‐treatment approach has grown in popularity and resulted in various MOF‐derived materials. However, the widely used extreme thermolytic conditions (usually above 500 °C) lead to degradation in the well‐defined MOFs intrinsic properties. This work demonstrates that MIL‐101 calcined at medium‐temperature range (200–280 °C) partially breaks the coordination bonds that can introduce more accessible active sites, exhibiting a 10‐fold increase in oxidation activity while retaining its intrinsic structure and porosity. Another fascinating feature of MIL‐101 calcined in this temperature range is their temperature‐dependent shrinkage behavior, which is also found in many other types of MOFs. Based on different shrinkage ratios of various MOFs, yolk–shell MOFs@MOFs structures can be constructed through nonsacrificial template method. Overall, the structural and morphological evolution process of MOFs treated in the medium‐temperature range can open new horizons to develop efficient MOFs catalysts and design complex structures.
Molybdenum and Phosphorous Dual Doping in Cobalt Monolayer Interfacial Assembled Cobalt Nanowires for Efficient Overall Water Splitting
Authors: Hoa Van Hien , Tran Duy Thanh , Nguyen Dinh Chuong , Kim Do Hwan , Kim Nam Hoon , Lee Joong Hee
Published: July 2020

The necessity for better water splitting requires speedy development of efficient catalysts with high activity, long‐term stability, and cost effectiveness. In this work, a bifunctional catalyst originating from the interfacial assembly of a thin Mo,P‐codoped Co layer (≈50 nm) shelled Co nanowire (Co‐Mo‐P/CoNWs) network is fabricated via a facile approach. The catalyst exhibits low overpotentials of 0.08 and 0.27 V to reach a current response of 20 mA cm−2 for the hydrogen evolution reaction and oxygen evolution reaction, respectively, together with long‐term stability in 1.0 m KOH medium. The outstanding performance is further demonstrated by a Co‐Mo‐P/CoNWs‐based electrolyzer, which enables a cell voltage of only 1.495 V to reach 10 mA cm−2, superior to one derived from commercial (Pt/C + RuO2/C) as well as to various reports recently published elsewhere. It is recognized that the formation of multiactive centers together with the increased active site number caused by Mo and P dual doping synergistically promote both hydrogen and oxygen evolution performance. Such a hybrid material opens a new approach for developing efficient and cost‐effective catalysts for water splitting application.
Light Out‐Coupling Management in Perovskite LEDs—What Can We Learn from the Past?
Authors: Zhang Qianpeng , Zhang Daquan , Fu Yu , Poddar Swapnadeep , Shu Lei , Mo Xiaoliang , Fan Zhiyong
Published: July 2020

The research on perovskite light‐emitting diodes (PeLEDs) has experienced an exponential growth in the past six years. The highest external quantum efficiencies (EQEs) have surpassed 20%, 20%, and 10% for red, green, and blue colored LEDs, respectively. Considering the internal quantum efficiency is already approaching unity owing to the high material quality, the limiting factor for further improving the EQE is mainly the poor light out‐coupling efficiencies. Here, by reviewing the progress on the light out‐coupling studies for PeLEDs, organic LEDs (OLEDs), conventional semiconductor LEDs, and other special LEDs, the rational design guidelines are summarized for enhancing PeLED out‐coupling. Briefly, these design guidelines include: 1) introducing nanostructures into the active layer or tuning the thickness of it to couple out the waveguide modes, 2) adding nanostructures between the active layer and transparent electrodes to couple the waveguide modes to substrate modes, 3) adding nanostructures such as nanowires to the glass substrate to couple the substrate mode to air. Essentially, these guidelines indicate that implementing nanophotonic engineering on PeLEDs is a highly promising direction to explore, so as to substantially enhance the device performance.
Direct Growth of Pyramid‐Textured Perovskite Single Crystals: A New Strategy for Enhanced Optoelectronic Performance
Authors: Zhang Yunxia , Liu Yucheng , Yang Zhou , Chen Ming , Liu Shengzhong (Frank)
Published: July 2020

Even though there have been a few reports of substrate surface texturing of thin film perovskite solar cells to enhance their light trapping, there has been no direct texturing of the perovskite material, let alone perovskite single crystals (SCs). Herein, a method to prepare a pyramid‐structured perovskite CH3NH3PbX3 (CH3NH3+ = MA, X = I, Br) SC surface with minimized light reflection and maximized incident light harvesting is reported. Specifically, a hard template is used to directly transfer the pyramidal texture onto the MAPbX3 SC during its growth. A well‐shaped pyramidal texture is formed on the single‐crystal surface leading to improved light trapping. The textured MAPbBr3 SC shows good crystallinity, prolonged carrier lifetime, and improved carrier mobility. Furthermore, the photodetector made from the textured SC shows enhanced responsivity of 321 A W−1 and external quantum efficiency of 7191%, about two times higher than that of a control device. This method may be used to directly fabricate desired textures on general single crystal surfaces.
A New Scalable Preparation of Metal Nanosheets: Potential Applications for Aqueous Zn‐Ion Batteries Anode
Authors: Wu Chen , Tan Huiteng , Huang Wenjing , Li Weixin , Dinh Khang Ngoc , Yan Chunshuang , Wei Weifeng , Chen Libao , Yan Qingyu
Published: July 2020

2D metal nanosheets are attractive for various applications stemming from the intriguing characteristics related with their dimensionality; however, their effective and scalable preparation remains a great challenge. Herein, a scalable preparation process of relatively active metal nanosheets (e.g., Zn, Al, and Cu) with the thickness down to several nanometers at low cost is demonstrated, which involves an initial self‐folding‐rolling step followed by the subsequent ultrasonication to exfoliate them without any etching step. The native oxide on the surface of the metals, which acts as a barrier between the adjacent metal layers, plays a special role in enabling the successful preparation of 2D metal nanosheets. As a demonstration for their practicability, a hierarchical Zn anode, which is constructed by the Zn microsheets coated with carbon (Zn MS@C) via in situ carbonization of carboxymethylcellulose (CMC) binder, is successfully implemented as anode for rechargeable aqueous Zn‐ion batteries. When applied in symmetrical battery, the Zn MS@C delivers a long lifespan of over 800 h at 0.2 mA cm−2 with a capacity of 0.1 mA h cm−2. Importantly, the full battery of MnO2 || Zn MS@C also performs a high discharge capacity of 217.4 mA h g−1 after 140 cycles at 300 mA g−1.
Smart Thermally Actuating Textiles
Authors: Sanchez Vanessa , Payne Christopher J. , Preston Daniel J. , Alvarez Jonathan T. , Weaver James C. , Atalay Asli T. , Boyvat Mustafa , Vogt Daniel M. , Wood Robert J. , Whitesides George M. , Walsh Conor J.
Published: July 2020

Soft robots have attracted attention for biomedical and consumer devices. However, most of these robots are pneumatically actuated, requiring a tether and thus limiting wearable applications that require multiple controlled actuators. By pairing liquid‐vapor phase change actuation with a textile‐based laminated manufacturing method, smart thermally actuating textiles (STATs) eliminate the need for a pneumatic tether. STATs are lightweight and unobtrusive for wearable applications and exploit a facile manufacturing approach that supports arbitrary customization of the form factor and easy creation of connected arrays of individual robotic modules. Through integrated sensing and heating elements, STATs demonstrate closed‐loop feedback that enables dynamic pressure control in the presence of environmental temperature fluctuations.
Rhodium(III)‐Catalyzed C−H Benzylation of Indole's C3 Position with Aza‐o‐Quinone Methides
Authors: Liu Ruixing , Wei Yin , Shi Min
Published: July 2020

In this paper, we report an example of indole's site selective C3 benzylation process through a rhodium(III)‐catalyzed indole's C2 activation relay using aza‐o‐QM as a functionalization reagent, affording the desired products in good yields under mild conditions. The plausible reaction mechanism is proposed on the basis of control and deuterium labeling experiments and the further transformation has been also described.

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Charge Recombination in Polaron Pairs: A Key Factor for Operational Stability of Blue‐Phosphorescent Light‐Emitting Devices
Authors: Odinokov Alexey , Osipov Alexey , Oh Juwon , Moon Yu Kyung , Ihn Soo‐Ghang , Lee Hasup , Kim Inkoo , Son Won‐Joon , Kim Sangmo , Kravchuk Dmitry , Kim Jong Soo , Kim Joonghyuk , Choi Hyeonho , Kim Sunghan , Kim Wook , Lee Namheon , Kang Seongsoo , Kim Dongho , You Youngmin , Yakubovich Alexander
Published: July 2020

Irreversible chemical reactions are responsible for limited operational lifetime of organic light‐emitting devices (OLEDs). These reactions are triggered by highly reactive polaron pairs present in the emissive layer of OLEDs. Fast recombination of the polaron pairs is, therefore, crucial for slow degradation and high stability of OLED materials. Here, a study of the formation and annihilation of close polaron pairs in binary mixtures of wide bandgap hosts and a series of blue‐phosphorescent Ir(III) complex dopants, including two novel compounds, is reported. OLED devices containing doped light‐emitting layer are fabricated, and their operational lifetimes are estimated. Although inaccessible in solid films, charge recombination kinetics inside the polaron pairs is measured in liquid solutions using nanosecond laser flash photolysis. Multiscale computer simulations are applied to connect experimental results in different media and predict recombination rates in the device, with proper account taken of the inner‐ and outersphere reorganization in nonpolar materials. Predicted rates correlate with measured operational lifetimes, which demonstrates the key role of polaron pairs in the OLED degradation process. The developed methodology is useful for the rational design of novel OLED materials with higher efficiency and stability.
WB5−x: Synthesis, Properties, and Crystal Structure—New Insights into the Long‐Debated Compound
Authors: Kvashnin Alexander G. , Rybkovskiy Dmitry V. , Filonenko Vladimir P. , Bugakov Vasilii I. , Zibrov Igor P. , Brazhkin Vadim V. , Oganov Artem R. , Osiptsov Andrey A. , Zakirov Artem Ya
Published: July 2020

The recent theoretical prediction of a new compound, WB5, has spurred the interest in tungsten borides and their possible implementation in industry. In this research, the experimental synthesis and structural description of a boron‐rich tungsten boride and measurements of its mechanical properties are performed. The ab initio calculations of the structural energies corresponding to different local structures make it possible to formulate the rules determining the likely local motifs in the disordered versions of the WB5 structure, all of which involve boron deficit. The generated disordered WB4.18 and WB4.86 models both perfectly match the experimental data, but the former is the most energetically preferable. The precise crystal structure, elastic constants, hardness, and fracture toughness of this phase are calculated, and these results agree with the experimental findings. Because of the compositional and structural similarity with predicted WB5, this phase is denoted as WB5−x. Previously incorrectly referred to as “WB4,” it is distinct from earlier theoretically suggested WB4, a phase with a different crystal structure that has not yet been synthesized and is predicted to be thermodynamically stable at pressures above 1 GPa. Mild synthesis conditions (enabling a scalable synthesis) and excellent mechanical properties make WB5−x a very promising material for drilling technology.
Oxytocin Differentially Modulates Amygdala Responses during Top‐Down and Bottom‐Up Aversive Anticipation
Authors: Xin Fei , Zhou Xinqi , Dong Debo , Zhao Zhongbo , Yang Xi , Wang Qianqian , Gu Yan , Kendrick Keith M. , Chen Antao , Becker Benjamin
Published: July 2020

The ability to successfully regulate negative emotions such as fear and anxiety is vital for mental health. Intranasal administration of the neuropeptide oxytocin (OXT) has been shown to reduce amygdala activity but to increase amygdala–prefrontal cortex connectivity during exposure to threatening stimuli suggesting that it may act as an important modulator of emotion regulation. The present randomized, between‐subject, placebo‐controlled pharmacological study combines the intranasal administration of OXT with functional magnetic resonance imaging (fMRI) during an explicit emotion regulation paradigm in 65 healthy male participants to investigate the modulatory effects of OXT on both bottom‐up and top‐down emotion regulation. OXT attenuates the activation in the posterior insular cortex and amygdala during anticipation of top‐down regulation of predictable threat stimuli in participants with high trait anxiety. In contrast, OXT enhances amygdala activity during the bottom‐up anticipation of unpredictable threat stimuli in participants with low trait anxiety. OXT may facilitate top‐down goal‐directed attention by attenuating amygdala activity in high anxiety individuals, while promoting bottom‐up attention/vigilance to unexpected threats by enhancing amygdala activity in low anxiety individuals. OXT may thus have the potential to promote an adaptive balance between bottom‐up and top‐down attention systems depending on an individual's trait anxiety level.
Molten‐Salt‐Assisted Chemical Vapor Deposition Process for Substitutional Doping of Monolayer MoS2 and Effectively Altering the Electronic Structure and Phononic Properties
Authors: Li Wei , Huang Jianqi , Han Bo , Xie Chunyu , Huang Xiaoxiao , Tian Kesong , Zeng Yi , Zhao Zijing , Gao Peng , Zhang Yanfeng , Yang Teng , Zhang Zhidong , Sun Shengnan , Hou Yanglong
Published: July 2020

Substitutional doping of layered transition metal dichalcogenides (TMDs) has been proved to be an effective route to alter their intrinsic properties and achieve tunable bandgap, electrical conductivity and magnetism, thus greatly broadening their applications. However, achieving valid substitutional doping of TMDs remains a great challenge to date. Herein, a distinctive molten‐salt‐assisted chemical vapor deposition (MACVD) method is developed to match the volatilization of the dopants perfectly with the growth process of monolayer MoS2, realizing the substitutional doping of transition metal Fe, Co, and Mn. This doping strategy effectively alters the electronic structure and phononic properties of the pristine MoS2. In addition, a temperature‐dependent Raman spectrum is employed to explore the effect of dopants on the lattice dynamics and first‐order temperature coefficient of monolayer MoS2, and this doping effect is illustrated in depth combined with the theoretical calculation. This work provides an intriguing and powerful doping strategy for TMDs through employing molten salt in the CVD system, paving the way for exploring new properties of 2D TMDs and extending their applications into spintronics, catalytic chemistry and photoelectric devices.
Structural and Thermodynamic Understandings in Mn‐Based Sodium Layered Oxides during Anionic Redox
Authors: Kang Seok Mun , Kim Duho , Lee Kug‐Seung , Kim Min‐Seob , Jin Aihua , Park Jae‐Hyuk , Ahn Chi‐Yeong , Jeon Tae‐Yeol , Jung Young Hwa , Yu Seung‐Ho , Mun Junyoung , Sung Yung‐Eun
Published: July 2020

A breakthrough utilizing an anionic redox reaction (O2−/On−) for charge compensation has led to the development of high‐energy cathode materials in sodium‐ion batteries. However, its reaction results in a large voltage hysteresis due to the structural degradation arising from an oxygen loss. Herein, an interesting P2‐type Mn‐based compound exhibits a distinct two‐phase behavior preserving a high‐potential anionic redox (≈4.2 V vs Na+/Na) even during the subsequent cycling. Through a systematic series of experimental characterizations and theoretical calculations, the anionic redox reaction originating from O 2p‐electron and the reversible unmixing of Na‐rich and Na‐poor phases are confirmed in detail. In light of the combined study, a critical role of the anion‐redox‐induced two‐phase reaction in the positive‐negative point of view is demonstrated, suggesting a rational design principle considering the phase separation and lattice mismatch. Furthermore, these results provide an exciting approach for utilizing the high‐voltage feature in Mn‐based layered cathode materials that are charge‐compensated by an anionic redox reaction.
Chirally Reversed Graphene Oxide Liquid Crystals
Authors: Liu Yanjun , Wu Peiyi
Published: July 2020

Colloidal liquid crystals (LCs) formed by nanoparticles hold great promise for creating new structures and topologies. However, achieving highly ordered hierarchical architectures and stable topological configurations is extremely challenging, mainly due to the liquid‐like fluidity of colloidal LCs in nature. Herein, an innovative synchronous nanofluidic rectification (SNR) technique for generating ultralong graphene oxide (GO) liquid crystal (GOLC) fibers with hierarchical core‐skin architectures is presented, in which the GO sheet assemblies and hydrogel skin formation are synchronous. The SNR technique conceptually follows two design principles: horizontal polymer‐flow promotes the rapid planar alignment of GO sheets and drives the chiral‐reversing of cholesteric GOLCs, and in situ formed hydrogel skin affords some protection against environmental impact to maintain stable topological configurations. Importantly, the dried fibers retain the smooth surface and ordered internal structures, achieving high mechanical strength and flexibility. The linear and circular polarization potential of GOLC fibers are demonstrated for optical sensing and recognition. This work may open an avenue toward the scalable manufacture of uniform and robust, yet highly anisotropic, fiber‐shaped functional materials with complex internal architectures.
Converting to Connect: A Rapid RE‐AIM Evaluation of the Digital Conversion of a Clerkship Curriculum in the Age of COVID‐19
Authors: Nagji Alim , Yilmaz Yusuf , Zhang Peter , Dida Joana , Cook‐Chaimowitz Lauren , Dong Junghwan Kevin , Colpitts Lorraine , Beecroft James , Chan Teresa M.
Published: July 2020

Background

With the advent of the 2019 coronavirus pandemic, a decision was made to remove medical students from clinical rotations for their own safety. This forced students on a core emergency medicine (EM) rotation at McMaster University to immediately cease all in‐person activities. An urgent need for a virtual curriculum emerged.

Methods

A virtual curriculum consisting of asynchronous case‐based learning on Slack, ask‐me‐anything webinars, and online e‐modules was created to fill the need. We describe a program evaluation using the RE‐AIM framework and a social networking analysis of participants.

Results

Medical students (n = 23) and 11 facilitators (five residents, six faculty members) participated in this pilot study. Faculty members sent a mean (±SD) of 115 (±117) messages (n = 6), and mean (±SD) message counts for students and residents were 49.96 (±25; n = 23) and 39 (±38; n = 5), respectively. A total of 62,237 words were written by the participants, with a mean of 1,831 per person. Each message consisted of a mean (±SD) of 25 words (±29). Students rapidly acquitted themselves to digital technology. Using the RE‐AIM framework we highlight the feasibility of a virtual curriculum, discuss demands on faculty time, and reflect on strategies to engage learners.

Conclusions

The use of asynchronous digital curricula creates opportunities for faculty–resident interaction and engagement. We report the successful deployment of a viable model for undergraduate EM training for senior medical students in the COVID‐19 era of physical distancing.
Establishing Consensus‐based Objectives for the Creation of an Opioid Overdose Curriculum for Emergency Medical Services Clinicians
Authors: Trebach Joshua D. , Levy Matthew , Ali Fahad , Beauchamp Gillian , Biary Rana , Everett Christopher , Margolis Asa , Nawrocki Philip Stuart , Wendell Jonathan C. , Zour John , Stolbach Andrew
Published: July 2020

Objectives

Emergency medical services (EMS) clinicians are on the front lines of the opioid epidemic and are often the first health care personnel system to contact patients experiencing opioid toxicity. Although national educational guidelines include opioid toxicity, no specific standardized prehospital educational objectives or competencies exist. The goal of this project was to identify objectives for an EMS opioid toxicity curriculum that could be used for EMS training.

Methods

A list of preliminary educational objectives from U.S. EMS training programs was compiled and reviewed by a group of experts. The Delphi method was used to attain consensus on a final list of objectives for an EMS opioid curriculum.

Results

A total of 107 opioid‐related preliminary objectives were identified and then narrowed down to 81 preliminary objectives after accounting for redundancy. After four successive rounds of evaluating/accepting/rejecting objectives, 18 final objectives were identified and unanimously approved by the expert panel.

Conclusion

We identified 18 objectives to serve as a framework for an opioid toxicity curriculum for EMS clinicians. These objectives can serve as a basis for creating a standardized didactic training program for EMS training programs nationwide. Further evaluation will be needed to explore the best means for educational program delivery.
Quantum Thermalization and Vanishing Thermal Entanglement in the Open Jaynes–Cummings Model
Authors: Fan Li‐Bao , Zhou Yue‐Hui , Zou Fen , Guo Huan , Huang Jin‐Feng , Liao Jie‐Qiao
Published: July 2020

The quantum thermalization of the Jaynes–Cummings (JC) model in both equilibrium and non‐equilibrium open‐system cases is studied, in which the two subsystems, a two‐level system and a single‐mode bosonic field, are in contact with either two individual heat baths or a common heat bath. It is found that in the individual heat‐bath case, the JC model can only be thermalized when either the two heat baths have the same temperature or the coupling of the JC system to one of the two baths is turned off. In the common heat‐bath case, the JC system can be thermalized irrespective of the bath temperature and the system–bath coupling strengths. The thermal entanglement in this system is also studied. A counterintuitive phenomenon of vanishing thermal entanglement in the JC system is found and proved.
Ruthenium tetrazene complexes bearing glucose moieties on their periphery: Synthesis, characterization, and in vitro cytotoxicity
Authors: Hamala Vojtěch , Martišová Andrea , Červenková Šťastná Lucie , Karban Jindřich , Dančo Andrej , Šimarek Adam , Lamač Martin , Horáček Michal , Kolářová Tamara , Hrstka Roman , Gyepes Róbert , Pinkas Jiří
Published: July 2020

Ruthenium tetrazene complexes with general formula [Cp*RuCl(1,4‐R2N4)] (Cp* = η5‐C5Me5), where R = benzyl (1), 2‐fluorobenzyl (2), β‐d‐glucopyranosyl‐unprotected (3a) and acyl‐protected (3b–d), 2‐acetamido‐β‐d‐glucopyranosyl‐unprotected (4a) and acyl‐protected (4b–d), propyl‐β‐d‐glucopyranoside‐unprotected (5a), and O‐acetylated (5b), were synthesized and characterized using nuclear magnetic resonance and electrospray ionization–mass spectrometry. In addition, the molecular structure of 3b was determined using X‐ray crystallography. The cytotoxicity of complexes against ovarian (A2780, SK‐OV‐3) and breast (MDA‐MB‐231) cancer cell lines and noncancerous cell line HEK‐293 was evaluated and compared to cisplatin activity. The carbohydrate‐modified complexes bearing acyl‐protecting groups exhibited higher efficacy (in low micromolar range) than unprotected ones, where the most active 4d was superior to cisplatin up to five times against all investigated cancer cell lines; however, no significant selectivity was achieved. The complex induced apoptotic cell death at low micromolar concentrations (0.5 μM for A2780 and HEK293; 2 μM for SK‐OV‐3 and MDA‐MB‐231).
Development of Industrially Scalable Method for Phospholipids and Branch‐Chain Fatty Acids of Dairy by‐Product
Authors: Price Nathan , Wan Zifan , Fei Tao , Clark Stephanie , Wang Tong
Published: July 2020

Dairy phospholipids (PL) is of interest due to their health benefits and functional properties. Solvent fractionation of PL has not been commonly used in the dairy industry to fractionate milk fat to obtain or concentrate the PL. The total lipid extracted from the β stream, a waste by‐product of dairy processing, was used in this study to investigate suitable solvent and conditions to separate the neutral lipid from PL. A fixed lipid solvent ratio (1:10 g/v) was used at various fractionation temperatures (−20, 2, 15, 23, 40, and 60 °C) depending on the solvents. The use of acetone at 23 °C, not at the lower temperatures, led to a dairy lecithin product with high PL content, such as 71.5%. The more aqueous ethanol, i.e. at 70% concentration compared to 95%, was able to preferentially extract PL to form products with up to 74.7% PL, but the PL yield was much lower (26.3%) compared to acetone precipitation (97.9%). The enrichment of branch chain fatty acids proved to be very challenging due to the overlapping melting points with other fatty acids. The composition of the major fatty acids of polar and neutral lipids also showed interesting patterns that may indicate different nutritional and oxidative properties of the fractionated products.
The bottom‐up synthesis for aramid nanofibers: The influence of copolymerization
Authors: Shi Yifei , Qiu Teng , Tuo Xinlin
Published: July 2020

Aramid based on poly (p‐phenylene terephthalamide) (PPTA) is widely concerned as high‐performance materials. Herein, copolymerized aramid nanofibers (CANFs) were prepared for the first time by a direct bottom‐up polymerization method without additives. Three kinds of third monomers of m‐phenylenediamine, 4,4′‐diaminodiphenyl ether, and 2,5‐dichloro‐1,4‐phenylenediamine were separately copolymerized in PPTA and transformed into nanofiber dispersions in water medium. The characterization results revealed the relationship between the morphology of products and the structure as well as dosages of the different kinds of monomers, which was explained by the influence on conjugate regularities of the PPTA molecules. Furthermore, CANFs were used to build aramid paper blended in pure PPTA nanofibers, and the mechanical and insulation properties of composite paper were improved significantly, which would be of potential use as the new building block for aramid composite materials.
Effects of ammonium polyphosphate microencapsulated on flame retardant and mechanical properties of the rigid polyurethane foam
Authors: Cheng Jiaji , Niu Shaoshuai , Ma Dan , Zhou Yue , Zhang Feng , Qu Wenjuan , Wang Dong , Li Shaoxiang , Zhang Xinlong , Chen Xianqun
Published: July 2020

In this article, a flame retardant microcapsule ammonium polyphosphate microencapsulated by polyurea (POAPP) was successfully synthesized by interfacial polymerization method using ammonium polyphosphate (APP) as core and polyurea as shell. The microencapsulation is observed by scanning electron microscopy and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and hydroscopicity test, which prove the success in synthesizing microencapsulation. When the POAPP is added into rigid polyurethane foam (RPUF), the flame retardant and mechanical properties are investigated using cone calorimeter, limited oxygen index test, and compressive strength test. The PHRR of RPUF‐POAPP20 decreased from 336.52 kW/m2 (Ref. RPUF) to 203.84 kW/m2 and the THR of RPUF‐POAPP20 was only 7.6 MJ/m2, which is 33.9% lower than that of Ref. RPUF. Furthermore, the limiting oxygen index of RPUF‐POAPP20 reaches 24.8%, which increased by 36.3% compared to Ref. RPUF. Whereas the maximum compressive strength of RPUF‐POAPP5 was 7.46 MPa, which is higher than that of RPUF‐APP5.
Nonlinear decentralized load frequency control of multi‐machine power systems with exponential stability and low L2 gain against load disturbance
Authors: Wang Wei , Liu Kang‐Zhi
Published: July 2020

This paper proposes a novel nonlinear decentralized control method for a class of multi‐machine power systems. The aim is to construct a suitable decentralized feedback control law so as to guarantee that the large‐scale interconnected power system is exponentially stable and robust against load fluctuations. To this end, we propose a novel design algorithm based on the backstepping, which involves five steps and actively utilizes the locally measurable part of the tie‐line power to improve the performance. The effectiveness of the proposed control scheme is demonstrated through extensive simulation studies.
Adaptive Fractional High‐order Terminal Sliding Mode Control for Nonlinear Robotic Manipulator under Alternating Loads
Authors: Ahmed Saim , Wang Haoping , Tian Yang
Published: July 2020

In this study, trajectory tracking of robotic manipulators under varying loads with uncertainties and external disturbances is obtained by proposing model‐independent adaptive fractional high‐order terminal sliding mode control (AFO‐HoTSMC). The proposed AFO‐HoTSMC method is composed of an adaptive high‐order terminal sliding mode control integrated with fractional‐order (FO) control. An adaptive tuning control is utilised to evaluate the uncertain unknown dynamics of the system without relying on the prior knowledge of the upper bounds. FO control and HoTSMC are used to achieve the fast finite‐time convergence, chatter‐free control inputs, better tracking performance and robustness. The finite‐time stability of the overall system is investigated and derived from the Lyapunov stability criterion. Finally, to validate the effectiveness and robustness of the developed control method, comparative simulations with H∞‐Adaptive control, intelligent PD (iPD), intelligent PID (iPID) and adaptive third‐order SMC (ATOSMC) are realized to demonstrate the performance of AFO‐HoTSMC.
The Truth About Water Efficiency in the United States
Authors: DeOreo William B.
Published: July 2020

Key Takeaways

In December 2019, US president Donald Trump questioned the value of water‐efficient toilets, saying the need for excessive flushing eliminated any potential water savings.

Research reports published in 1999 and 2016 demonstrate that water‐efficient fixtures—primarily toilets and clothes washers—led to significant savings in residential water use.

The 1993 Energy Policy Act and the voluntary WaterSense program, which provide guidelines for residential plumbing fixtures, have been successful in helping US residents conserve water.
Exploring the binding mode of donepezil with calf thymus DNA using spectroscopic and molecular docking methods
Authors: Guo Hui , Xie Jiawen , Liao Tancong , Tuo Xun
Published: July 2020

Donepezil (DNP) is one of approved drugs to treat Alzheimer's disease (AD). However, the potential effect of DNP on DNA is still unclear. Therefore, the interaction of DNP with calf thymus DNA (DNA) was studied in vitro using spectroscopic and molecular docking methods. Steady‐state and transient fluorescence experiments showed that there was a clear binding interaction between DNP and DNA, resulting from DNP fluorescence being quenched using DNA. DNP and DNA have one binding site between them, and the binding constant (Kb) was 0.78 × 104 L·mol−1 at 298 K. In this binding process, hydrophobic force was the main interaction force, because enthalpy change (ΔH) and entropy change (ΔS) of DNP–DNA were 67.92 kJ·mol−1 and 302.96 J·mol−1·K−1, respectively. DNP bound to DNA in a groove‐binding mode, which was verified using a competition displacement study and other typical spectroscopic methods. Fourier transform infrared (FTIR) spectrum results showed that DNP interacted with guanine (G) and cytosine (C) bases of DNA. The molecular docking results further supported the results of spectroscopic experiments, and suggested that both Pi‐Sigma force and Pi‐Alkyl force were the major hydrophobic force functioning between DNP and DNA.
Patient-reported chronic pain after open inguinal hernia repair with lightweight or heavyweight mesh: a prospective, patient-reported outcomes study
Authors: Melkemichel M , Bringman S , Nilsson H , Widhe B
Published: July 2020

Background

Chronic pain after groin hernia repair is a significant problem, and it is unclear whether or not lightweight meshes help. This national register-based study investigated whether patients who underwent open anterior mesh inguinal hernia repair with lightweight mesh had less chronic pain than those who had hernia repair with heavyweight mesh.

Methods

All patients registered in the Swedish Hernia Register between September 2012 and October 2016 were asked to complete a questionnaire assessing patient-reported outcome measures 1 year after surgery. The present study examined open anterior repair with mesh sutured in place with non-absorbable sutures in male patients only. The primary endpoint, chronic pain, was defined as pain present in the past week that could not be ignored and interfered with concentration (on chores) and daily activities.

Results

In total, 23 259 male patients provided data for analysis (response rate 70·6 per cent). Rates of chronic pain after repairs using regular polypropylene lightweight mesh, composite (poliglecaprone-25) polypropylene lightweight mesh and polypropylene heavyweight mesh were 15·8, 15·6 and 16·2 per cent respectively. Adjusted multiple logistic regression analysis showed no significant differences between regular (odds ratio (OR) 0·98, 95 per cent c.i. 0·90 to 1·06) or composite (OR 0·95, 0·86 to 1·04) lightweight mesh versus heavyweight mesh. The most striking risk factor for chronic pain was young age; 19·4 per cent of patients aged less than 50 years experienced pain 1 year after hernia repair (OR 1·43, 1·29 to 1·60).

Conclusion

Patient-reported chronic pain 1 year after open mesh repair of inguinal hernia was common, particularly in young men. The risk of developing chronic pain was not influenced by the type of mesh.
Activities and assessment solutions for students in advanced molecular genetics and biochemistry to direct and engage with public communication in an online environment
Authors: Kanapeckas Métris Kimberly L.
Published: July 2020

Apart from classroom presentations to their instructors and peer groups, STEM students have limited opportunities or encouragement to engage in guided communication of scientific concepts to others (family, friends, or the general public). A critical need exists for accurate, comprehensible science to be disseminated to these groups. To develop student proficiency in communication of complex biomolecular concepts impacting diverse audiences, I introduce learning approaches and assessments easily adapted to fit the needs of individual instructors and any molecular biology or biochemistry laboratory or lecture course in a remote/online environment. To help students develop an appreciation of the needs of different audiences and the nuanced drivers of clear communication, I provided them the choice of projects of similar length: Option (1) Create a scientific news release and short podcast or video clip newscast describing a recent advancement in understanding the molecular/biochemical basis of a disease; or Option (2) Create a lesson plan and mini‐video designed to teach a simple biochemical or molecular mechanism of disease with learning objectives, a brief activity, and appropriate assessment mechanisms. Students who chose the scientific news release/newscast activity distilled complex biomolecular concepts using the 5 W's of journalism—who, what, where, why, when—and learned to accurately communicate the relevance of advanced scientific discoveries and recent events for a broader audience. Students who chose the lesson plan designed activities centered on biomolecular science concepts that build upon what their audience already knows, revealing possibilities for undergraduates to contribute to educational outreach to secondary school teachers and classes.
Novel methodology to perform incurred sample reanalysis on dried blood spot cards: Experimental data using darolutamide and filgotinib
Authors: Kiran Vinay , Dixit Abhishek , Gabani Bhavesh Babulal , Srinivas Nuggehally R. , Mullangi Ramesh
Published: July 2020

Different options on performing incurred sample reanalysis (ISR) on dried blood spot (DBS) cards were investigated using drugs belonging to various therapeutic areas: (a) darolutamide (to treat prostate cancer) and (b) filgotinib (to treat rheumatoid arthritis). The proposed novel methodology included the generation of half‐DBS and quarter‐DBS discs after initial blood collection using the full‐DBS discs. Accordingly, blood collection via DBS was performed in male BALB/c mice following intravenous and oral dosing of darolutamide; in male Sprague Dawley rats following intravenous and oral dosing of filgotinib. The ISR data generated from the full‐DBS disc, half‐DBS disc and quarter‐DBS disc were compared for the assessment of the proposed methodology. Quantification of darolutamide and filgotinib was accomplished using liquid chromatography‐electrospray ionization/tandem mass spectrometry methods. Darolutamide and filgotinib ISR samples, which were collected and prepared using full‐, half‐ and quarter‐DBS discs, met the acceptance criteria for ISR analysis. In conclusion, this is the first report showing a viable tool for the performance of ISR on DBS cards. The use of quarter‐ or half‐DBS discs would aid in not only ISR but also in long‐term storage experiments of analytes because it would avoid the need for additional blood sampling in patients.
Computational thinking in higher education: A review of the literature
Authors: Lyon Joseph A. , J. Magana Alejandra
Published: July 2020

Computational thinking is of growing interest to the science, technology, engineering, and mathematics (STEM) education research community. Calls from national agencies look to increase computation in STEM education. This review identifies key areas for future study by reviewing recent empirical studies that investigate computational thinking in teaching and learning contexts within higher education. Using a systematic process, this review identified four different databases for peer‐reviewed research articles using keywords. Results were evaluated against inclusion and exclusion criteria. Studies were analyzed for types of methods, target population, the role of computational thinking, pedagogical designs used, and significant findings of the study. This process resulted in a final set of 13 studies. The results indicate that computational thinking research in higher education is growing, yet there are opportunities for more research. The findings of this study highlight the need for more concrete definitions and implementations of computational thinking within higher education spaces.
Epidemiology and practice patterns for male breast cancer compared with female breast cancer in Japan
Authors: Ishii Taisuke , Nakano Eriko , Watanabe Tomone , Higashi Takahiro
Published: July 2020

Background

The incidence of male breast cancer (MBC), although rare, has shown an increase. However, the current epidemiology of and practice patterns for MBC remain unclear. This study evaluated the characteristics and care patterns for MBC compared with female breast cancer (FBC) in Japan.

Methods

Using the National Database of Hospital‐Based Cancer Registries (HBCR) linked to the Diagnosis Procedure Combination data, we analyzed newly diagnosed breast cancer cases between January 2012 and December 2015 at participating hospitals in a large quality‐of‐care monitoring project. We employed logistic regression models to assess cancer treatment differences between MBC and FBC in patients who were indicated for adjuvant radiation therapy and neo‐adjuvant/adjuvant chemotherapy.

Results

Of 142,636 breast cancer patients, 870 (0.61%) were MBC patients. At diagnosis, the mean age of MBC patients was 10 years older than FBC patients (70 vs 60 years; P < .001). Advanced‐stage cancer was more frequently observed in MBC than in FBC (stage III/IV 18.9%/6.1% vs 10.6%/5.2%). Despite this, MBC patients were less likely to receive adjuvant radiation therapy and neo‐adjuvant/adjuvant chemotherapy. Gender was an independent treatment determinant factor for chemotherapy decisions.

Conclusion

MBC patients were older and had higher stages of cancer than FBC patients at diagnosis, but received suboptimal treatment.
Reexamination of the Ergothioneine Biosynthetic Methyltransferase EgtD from Mycobacterium tuberculosis as a Protein Kinase Substrate
Authors: Maurer Alice , Seebeck Florian P.
Published: July 2020

Ergothioneine has emerged as a crucial cytoprotectant in the pathogenic lifestyle of Mycobacterium tuberculosis. Production of this antioxidant from primary metabolites may be regulated by phosphorylation of Thr213 in the active site of the methyltransferase EgtD. The structure of mycobacterial EgtD suggests that this post‐translational modification would require a large‐scale change in conformation to make the active‐site residue accessible to a protein kinase. In this report, we show that, under in vitro conditions, EgtD is not a substrate of protein kinase PknD.
Structural modification of phenoxyimine titanium complexes and activation studies with alkylaluminum compounds
Authors: Yang Huaqin , van Ingen Yara , Blom Burgert , Rastogi Sanjay , Romano Dario
Published: July 2020

The synthesis and characterization of three complexes of the type (N‐(3‐tert‐butylsalicylidene)‐R)2TiCl2 [R=2,6‐difluorophenyl 1, R=2,6‐dimethylphenyl 2, R=phenyl 3] is reported and compared with the highly active R=2,3,4,5,6,–pentafluorophenyl 4. The complexes were tested for ethylene polymerization when activated with different co‐catalysts, giving high catalytic activity when activated with methylaluminoxane for complexes 3 and 4. Complex 3 is the only catalyst to be inactive when activated with diethylaluminum chloride. Unexpectedly, for complexes 1 and 2, no catalytic activity is recorded when butylated hydroxytoluene in methylaluminoxane is used to remove the trimethylaluminum, while the catalytic activity for complex 3 is retained. NMR study on the activation of the four complexes in the presence of common alkyl aluminum co‐catalysts suggests the formation of Ti(III) species in the presence of tri‐iso‐butylaluminum, and also the formation of NR−CH2 (R: −Al(CH2CH(CH3)2)2) bond from the N=C−H bond of the ligand explaining the absence of catalytic activity. Density functional theory calculations using B3LYP and a combination of basis sets (6‐31+G and cc‐pVTZ) were performed on the catalyst precursors and the activated species showing insights into the frontier orbitals, localizing the LUMO on the imino bond elucidating their reactivity. Mulliken charges are also reported and an unexpected relationship between the nitrogen on the ligands and the molecular weight is observed.
Capturing Lacunary Iron–Oxo Keggin Clusters and Insight Into the Keggin‐Fe13 Cluster Rotational Isomerization
Authors: Zheng Xiu‐Ying , Chen Man‐Ting , Du Ming‐Hao , Wei Rong‐Jia , Kong Xiang‐Jian , Long La‐Sheng , Zheng Lan‐Sun
Published: July 2020

The formation mechanism of ferrihydrite is the key to understand its treatment of pollutants in waste water and purification of surface water and groundwater. Although emerging evidence suggests that formation of the ferrihydrite occurs through the aggregation of prenucleation clusters, rather than classical atom‐by‐atom growth, its formation mechanism remains unclear. Herein, an iron–oxo anionic cluster of [Fe22(μ4‐O)8(μ3‐OH)20(μ2‐OH)18(CH3COO)16(H2O)2]4− viewed as a dimer of bivacant β‐Keggin‐Fe13 clusters was for the first time obtained by using lanthanide ions as stabilizers. Upon dissolution in a mixed solution of isopropanol and water, the lacunary β‐Keggin‐Fe13 cluster can transform into an α‐Keggin‐Fe13 cluster, distinctly demonstrating that the Keggin‐Fe13 cluster rotational isomerization can be realized through the vacant Keggin‐Fe13 cluster.
S‐shaped para‐Quinodimethane‐Embedded Double [6]Helicene and Its Charged Species Showing Open‐Shell Diradical Character
Authors: Jiang Qing , Han Yi , Zou Ya , Phan Hoa , Yuan Liu , Herng Tun Seng , Ding Jun , Chi Chunyan
Published: July 2020

Helicenes and extended helical π‐conjugated compounds have been widely studied, but most of the systems contain only aromatic benzene or heterocyclic rings, showing local aromatic character. Herein, new S‐shaped double [6]helicene 1, which has two embedded para‐quinodimethane (p‐QDM) units, is reported. Due to the existence of a proaromatic quinoidal substructure, it has open‐shell diradical character. Its model compound, C‐shaped single [6]helicene 2 containing one p‐QDM unit, was also synthesized and compared. Their ground‐state structures and electronic properties were systematically studied by a combination of various experimental methods assisted by theoretical calculations. Compound 1 has a double‐helical structure in the crystal, with the two terminal [6]helicene units bent in opposite directions (i.e., anti form). However, an anti/syn isomerization process with a moderate interconversion energy barrier was observed on the NMR timescale. Compound 1 shows amphoteric redox behavior. It also exhibits open‐shell diradical character (y0=12.1 %) and a small singlet–triplet gap. On the other hand, compound 2 has a typical closed‐shell nature. The dication and dianion of 1 also show open‐shell diradical character. The dianion of 2 and the tetraanion of 1 exhibit similar electronic structures to their respective isoelectronic structures, that is, [6]helicene and a double [6]helicene. This work provides some insights into the design and synthesis of stable helical π systems with open‐shell diradical character and magnetic activity.