bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonwoven Scaffolds Under Tension: In Situ High‐Resolution Ultrasound Observation of Microstructure Evolution in the Volume
Authors: Morokov Egor , Zykova Anna , Tyubaeva Polina
Published: February 2021

Fibrous scaffolds represent the basic material for tissue engineering, where creation of matrices with predictable properties is an important issue. Typically, the assessment of scaffold characteristics, including the mechanical behavior, is conducted in the air environment that is far from the natural physiological conditions in a living organism, despite possible differences in the properties obtained in dry and water‐filled specimens. The studies of the mechanical behavior of scaffolds in the wet environment are limited by the properties of visualization methods. The optimal method for studying fibrous objects in the wet environment is ultrasonic techniques, for which water immersion is a prerequisite for the experiment. Herein, a high‐frequency (200 MHz) acoustic microscopy is combined with a horizontal mechanical testing machine for in situ visualization of microstructural transformation in the volume of elastic and rigid electrospun scaffolds under tension. For the first time, the results show that in situ ultrasound monitoring provides high‐resolution imaging of the internal microstructure in water‐filled specimens. This work provides the foundation for future experimental setups for characterization of tissue‐engineered constructs in the conditions close to those in a living organism.
Effect of Microsegregation on High‐Temperature Microstructure Evolution in Rapid Solidification Processed Nb‐Rich Ni Superalloys
Authors: Enrique Pablo Daniel , Keshavarzkermani Ali , Zhou Norman Y.
Published: February 2021

Rapid solidification processes are used for coating, repairing, and manufacturing of metal alloy components in numerous industries. However, many alloys experience microsegregation of elements at subgrain boundaries at the termination of solidification, which have potential consequences for phase transformations at elevated temperatures if used without homogenization heat treatments. Herein, the effect of this microsegregation and solidification microstructure on the coarsening kinetics of the δ phase in a Nb‐rich Ni superalloy is evaluated. Microsegregation in rapid solidification processed (RSP) alloy 718 results in a greater availability of nucleation sites for the precipitation of the δ phase, resulting in smaller precipitate sizes. Coarsening of the δ phase is found to follow a Lifshitz–Slyozov–Wagner model, which is used to determine that Nb diffusion is the limiting factor in δ phase coarsening. With the formation of the δ phase, and the concurrent coarsening and dissolution of the γ″ strengthening phase, a decrease in both tensile strength and microhardness is observed. An improved understanding of the influence of microsegregation on phase transformations allows for a more informed application of non‐homogenized, RSP alloys in industry.
Concentration Gradients in Material Sciences: Methods to Design and Biomedical Applications
Authors: Hua Dawei , Xiong Ranhua , Braeckmans Kevin , Scheid Benoit , Huang Chaobo , Sauvage Félix , De Smedt Stefaan C.
Published: February 2021

Concentration gradients are at the basis of many natural phenomena and hold great importance in human and plant biology. This basic phenomenon has inspired many material scientists to confer novel and original properties to materials with numerous biomedical and pharmaceutical applications such as drug discovery, controlled release of drugs, tissue engineering, orthopedic implants and time–temperature indicators, amongst others. While the generation of gradients in solution is well described, their incorporation in solid materials remains challenging. This study reviews concepts and methods reported to generate gradients in respective solutions and (at the surface or in) solid materials like polymer scaffolds and matrices. This article also discusses how innovative materials possessing such gradients may be applied in biomedicine and pharmacy.
Effect of Palladium‐Tetrakis(Triphenylphosphine) Catalyst Traces on Charge Recombination and Extraction in Non‐Fullerene‐based Organic Solar Cells
Authors: Schopp Nora , Brus Viktor V. , Lee Jaewon , Dixon Alana , Karki Akchheta , Liu Tuo , Peng Zhengxing , Graham Kenneth R. , Ade Harald , Bazan Guillermo C. , Nguyen Thuc‐Quyen
Published: February 2021

The effect of the cross‐coupling catalyst tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4) on the performance of a model organic bulk‐heterojunction solar cell composed of a blend of poly([2,6′‐4,8‐di(5‐ethylhexylthienyl)benzo[1,2‐b;3,3‐b]dithiophene]{3‐fluoro‐2[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl}) (PTB7‐Th) donor and 3,9‐bis(2‐methylene‐((3‐(1,1‐dicyanomethylene)‐6,7‐difluoro)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene (IOTIC‐4F) non‐fullerene acceptor is investigated. The effect of intentional addition of different amounts of Pd(PPh3)4 on morphology, free charge carrier generation, non‐geminate bulk trap‐ and surface trap‐assisted recombination as well as bimolecular recombination and charge extraction is quantified. This work shows that free charge carrier generation is affected significantly, while the impact of Pd(PPh3)4 on non‐geminate recombination processes is limited because the catalyst does not facilitate efficient trap‐assisted recombination. The studied system shows substantial robustness towards the addition of Pd(PPh3)4 in small amounts.
Encapsulating Sulfides into Tridymite/Carbon Reactors Enables Stable Sodium Ion Conversion/Alloying Anode with High Initial Coulombic Efficiency Over 89%
Authors: Liu Yani , Li Linpo , Zhan Renming , Xu Maowen , Jiang Jian , Liu Jinping
Published: February 2021

Electrode dissolution/collapses and interfacial reactions pose challenges to batteries, leading to pronounced capacity loss particularly during the initial few cycles. As high‐capacity conversion/alloying anodes for sodium storage, metal sulfides generally show unsatisfactory performances like poor initial Coulombic efficiency (ICE; mostly <70% in the usual electrolyte) and inferior cyclic stability due to thick solid‐electrolyte interface (SEI) layer formation and ubiquitous volume/phase changes. Using SnS2 as an example, here, sulfides are elaborately encapsulated into functionalized amorphous tridymite/carbon reactors to address the above issues. The outer tridymite/carbon manifests good ionic permeability and superb electrochemical/mechanical tolerance against destructive Na+ insertion. Confining actives into tailored reactors endows SnS2 full of nanoboundaries with an ultrahigh ICE of ≈89.13% and remarkable electrochemical attributes including large initial capacity (Max. 733.24 mAh g−1), prominent stability in subsequent cycles, and excellent rate capability. Detailed investigation unveils that thin and steady SEI condition on tridymite/carbon rather than SnS2 is key to achieving outstanding ICE. Engineered reactors always keep intact and free of valence‐state changes, guaranteeing capacities running at a high level without an evident downtrend. Their peculiar functions on enlisting Na+ diffusion/transport and inhibiting sulfides’ release are also discussed. Packed full‐cell Na‐ion batteries with less irreversibility may show great potential in practical utilizations.
Oriented Perovskite Growth Regulation Enables Sensitive Broadband Detection and Imaging of Polarized Photons Covering 300–1050 nm
Authors: Han Zeyao , Fu Weifei , Zou Yousheng , Gu Yu , Liu Jiaxin , Huang Bo , Yu Dejian , Cao Fei , Li Xiaoming , Xu Xiaobao , Zeng Haibo
Published: February 2021

Photodetectors selective to the polarization empower breakthroughs in sensing technology for target identification. However, the realization of polarization‐sensitive photodetectors based on intrinsically anisotropic crystal structure or extrinsically anisotropic device pattern requires complicated epitaxy and etching processes, which limit scalable production and application. Here, solution‐processed PEA2MA4(Sn0.5Pb0.5)5I16 (PEA= phenylethylammonium, MA= methylammonium) polycrystalline film is probed as photoactive layer toward sensing polarized photon from 300 to 1050 nm. The growth of the PEA2MA4(Sn0.5Pb0.5)5I16 crystal occurs in confined crystallographic orientation of the (202) facet upon the assistance of NH4SCN and NH4Cl, enhancing anisotropic photoelectric properties. Therefore, the photodetector achieves a polarization ratio of 0.41 and dichroism ratio (Imax/Imin) of 2.4 at 900 nm. At 520 nm, the Imax/Imin even surpasses the one of the perovskite crystalline films, 1.8 and ≈1.2, respectively. It is worth noting that the superior figure‐of‐merits possess a response width of 900 kHz, Ion/Ioff ratio of ≈3 × 108, linear dynamic range from 0.15 nW to 12 mW, noise current of 8.28 × 10−13 A × Hz−0.5, and specific detectivity of 1.53 × 1012 Jones, which demonstrate high resolution and high speed for weak signal sensing and imaging. The proof of concept in polarized imaging confirms that the polarization‐sensitive photodetector meets the requirements for practical application in target recognition.
Increasing the Hot‐Electron Driven Hydrogen Evolution Reaction Rate on a Metal‐Free Graphene Electrode
Authors: Chae Hyun Uk , Ahsan Ragib , Tao Jun , Cronin Stephen B. , Kapadia Rehan
Published: February 2021

Recently, it has been shown that a semiconductor–insulator–graphene device can drive the hydrogen evolution reaction (HER) at the graphene surface with a reduced onset potential by injecting hot electrons into graphene. However, the catalytic properties of graphene are limited by the large hydrogen adsorption energy and lack of electrochemically active sites. To address these limitations, a n‐silicon/insulator/plasma etched graphene device is investigated, where a dry etch process is used to increase the number of active sites on the graphene by creating a greater number of active edge sites, increasing hydrogen adsorption at a given potential. This has been shown to improve the properties of devices with cold electrons. However, here it is shown that this approach can improve the HER rate with hot electrons. The electrons injected into the graphene from the silicon shift the onset potential of HER by as high as ≈0.8 V reaching a current density of 90 mA cm−2 at an overpotential of ‐0.5 V versus RHE. Furthermore, the comparison between device with pristine graphene shows a ≈2X improvement in current density at high overpotentials. This result shows that hot‐electron devices can be improved by modifying the catalytically active sites without metal catalysts.
Antisolvent‐Induced Fastly Grown All‐Inorganic Perovskite CsPbCl3 Microcrystal Films for High‐Sensitive UV Photodetectors
Authors: Zhu Zhihao , Deng Wen , Li Wen , Chun Fengjun , Luo Chao , Xie Meilin , Pu Ben , Lin Na , Gao Bo , Yang Weiqing
Published: February 2021

CsPbCl3‐based inorganic perovskite ultraviolet photodetectors (UV‐PDs) have a great promise for the wide application prospects due to the desirably UV‐matched energy band and the excellent intrinsic optoelectronic properties. However, the traditional high‐temperature Bridgman method (near 600 °C) and complexly time‐consuming vapor preparation (several days) of high‐quality CsPbCl3 crystals have badly restricted its commercial applications to date. Herein, an antisolvent‐induced crystallization kinetics (ACK) strategy is demonstrated for the quick lower‐temperature fabrication (50 °C, tens of minutes) of excellent continuous highly crystalline CsPbCl3 microcrystal films (MCFs) with low trap density (1.42 × 1012 cm−3). Further, the as‐developed CsPbCl3 MCF‐based UV‐PDs present a high detectivity of 5.6 × 1012 Jones, a superior responsivity of 2.11 A W−1, and robust stability. Evidently, this work provides a rapid and simple method to prepare high‐quality perovskite MCFs, greatly promoting the commercial development of perovskite‐based photodetectors.
Rapid Fabrication of Alcohol Responsive Photonic Prints with Changeable Color Contrasts for Anti‐Counterfeiting Application
Authors: Yang Dongpeng , Ouyang Cheng , Zhang Yuqi , Ma Dekun , Huang Shaoming
Published: February 2021

Efficient fabrication of responsive photonic prints (RPPs) with specific functionalities is imminently desired owing to its applications in display, anti‐photobleaching, and anti‐counterfeiting. Here, RPPs with changeable color contrasts are fabricated through the region selective swelling of the swellable photonic crystals paper with 2‐hydroxyethyl methacrylate (HEMA) as ink followed by fixing the structures of the swelled regions by photopolymerization. The fabrication process is considerable simple, fast, and efficient, and multicolor RPPs with any desired patterns can be generated within 6 min. Different from the dual/triple color contrasts of conventional RPPs, the as‐prepared RPPs can instantly and reversibly show five color contrasts [(blue/transparent/green/yellow/red)‐red] in the alcohol solution owing to the asymmetric swelling behavior between the background and pattern. The similar solubility parameter between the photonic paper and HEMA/ethanol is the key for the fast fabrication process and abundant color contrasts of RPPs in solvents. The simple and rapid fabrications as well as the responsive properties will extend the applications of RPPs in color display, information storage, and anti‐counterfeiting.
Laser‐Induced Reversible and Irreversible Surface Nanostructuring
Authors: Li Hui , Qin Junling , Cao Zhiguang , Su Zixue
Published: February 2021

Harnessing the 4D transmission electron microscopy (4D‐TEM) technique capable of in situ study of light‐material interactions with high spatiotemporal resolution, the authors are able to demonstrate the formation of a reversible laser‐induced periodic surface structure (RLIPSS) on the top few‐nanometer surface of free‐standing amorphous thin films of silicon nitride and silicon dioxide. Compared with commonly reported permanent laser‐induced periodic surface structures (LIPSS) grown on thermal ablation of materials, highly ordered RLIPSS here develop in a nonthermal manner by femtosecond laser irradiation with unprecedented low intensity down to 10 000 times lower than their reported ablation thresholds. This reversible structure can undergo a transition to permanent structure with increasing laser intensity and number of laser shots. The orientation of the RLIPSS exhibits an unexpected memory of laser polarization, making it a potential candidate for future ultrafast rewritable photo‐image recording. These experimental results exclude the widely accepted formation mechanism of LIPSS based on the interference between the incident light with the surface scattering waves or the surface plasmon polaritons, and suggest a novel mechanism for surface laser micromachining, relevant to the laser‐induced production of charged point defects and the polarization‐dependent generation of tensile stress induced by electrostatic repulsion.
Turning Trash into Treasure: MXene with Intrinsic LiF Solid Electrolyte Interfaces Performs Better and Better during Battery Cycling
Authors: Xu Hao , Zhu Wen , Sun Fengzhan , Qi Hu , Zou Jianxin , Laine Richard , Ding Wenjiang
Published: February 2021

Commercialization of lithium ion batteries has accelerated dramatically over the last few decades. Single‐layered Ti3C2 (s‐Ti3C2) is effectively prepared by etching Ti3AlC2 via simple treatment with HCl and LiF, producing inevitably sediments always discarded after etching. This study explores the effect of LiF doping of multilayered Ti3C2 to form m‐Ti3C2/LiF consisting essentially of the sediments. Simple half‐cells assembled with m‐Ti3C2/LiF sediments suggest that LiF suppresses electrode volume expansion and surface cracking during cycling promoting Li+ intercalation/deintercalation. The data also suggest that LiF promotes formation of stable artificial solid electrolyte interfaces to prevent electrolyte and electrode degradation. The capacity of m‐Ti3C2/LiF sediments derived cells maintains 136 mAh g−1 after 1500 cycles at 300 mA g−1 while s‐Ti3C2 from supernatants physically mixed with 20 wt% LiF shows a capacity of 335 mAh g−1 (100th cycle) at 100 mA g−1 with an initial coulombic efficiency of 83%. Half‐cell anodes made of Ti3C2 etched by HF, commercial TiO2, and Sn powder mixed physically with 20 wt% LiF exhibit improved performance with cycling. These results indicate that the always discarded sediments can be directly used in LIBs and simple doping with LiF obviously improves the electrochemical performance of materials.
Avalanche Effect and High External Quantum Efficiency in MgZnO/Au/ZnO Sandwich Structure Photodetector
Authors: Zhao Xinjing , Jiang Dayong , Zhao Man , Duan Yuhan
Published: February 2021

The metal–semiconductor–metal (MSM) structure is widely applied in photodetectors (PDs) owing to its simple preparation method and a more effective light collecting area. However, the realization of weak light detection remains a daunting challenge, attributed to the low external quantum efficiency (EQE) in MSM‐based PDs. Herein, sandwich structure PD (SSPD), a new structure of PD based on MSM structure, is presented to solve the problem of low gain in MSM PDs. Herein, the high‐EQE MgZnO/Au/ZnO SSPD with avalanche effect is reported for the first time. The avalanche effect is realized by changing the position of electronic transmission through energy band engineering between MgZnO and ZnO in the sandwich structure. The SSPD exhibits high EQE when photogenerated carriers get transported at the interface of ZnO and MgZnO. Under 275 nm illumination, the MgZnO/Au/ZnO SSPD achieves avalanche multiplication at 63 V and shows EQE of up to 502780% at 90 V. These results reveal that a high EQE originates from the special sandwich structure existing in MgZnO/Au/ZnO SSPD. This study presents possible guidance for high‐performance ZnO‐based avalanche PD for applications in telecommunications, sensing, and single‐photon detection.
High Efficiency Green‐Emitting LuAG:Ce Ceramic Phosphors for Laser Diode Lighting
Authors: Ding Hui , Liu Zehua , Hu Pan , Liu Yongfu , Sun Peng , Luo Zhaohua , Chen Xipao , Jiang Haochuan , Jiang Jun
Published: February 2021

Lu3Al5O12:Ce3+ (LuAG:Ce3+) ceramic phosphors (CPs) are regarded as the most promising green color converter and play a key role in high quality white light in the next‐generation laser diode (LD) lighting. High efficient LuAG:Ce3+ CPs are still urgent for high luminous efficacy (LE) LD lighting devices. By designing the Ba2+–Si4+ pair to keep charge balance and annealing in air to remove oxygen vacancy defects, the luminescent properties of LuAG:Ce CPs are greatly enhanced. The LE is promoted to 216.9 lm W−1, which is the best performance of LuAG:Ce in LD lighting so far. Strategies for optimizing LuAG:Ce3+ CPs are detailed. It is believed that this work makes a big step and the proposed strategies will inspire more researchers to approach high performance of Al‐based garnet CPs and accelerate the development of LD lighting.
Controlled Nucleation and Growth of Carbon Nitride Films on CNT Fiber Fabric for Photoelectrochemical Applications
Authors: Karjule Neeta , Rana Moumita , Shalom Menny , Barrio Jesús , Vilatela Juan José
Published: February 2021

The controlled growth of carbon nitride (CN) films with tailored electronic properties and surface area is quite challenging due to the solid‐state reaction and the lack of efficient interaction between CN monomers and substrates. Herein, controlled growth of CN films over robust carbon nanotubes (CNT) fiber fabric is reported, which is obtained by either direct calcination of melamine on their surface, that yields a bulk material, or by its chemical vapor deposition resulting in hybrid films. These materials are effective electrodes consisting of high surface‐area CN containing CNT fiber fabrics acting as a scaffold and a highly conducting built‐in current collector. The results confirm that CNTs act as nucleation centers for the formation of CN films, forming close contact at the CN/CNT interphase, and resulting in efficient charge transfer upon illumination and enhanced electrochemical surface area.
Flexophotovoltaic Effect in Potassium Sodium Niobate/Poly(Vinylidene Fluoride‐Trifluoroethylene) Nanocomposite
Authors: Wang Chenchen , Zhang Yang , Zhang Bowen , Wang Bo , Zhang Jinxi , Chen Long‐Qing , Zhang Qiming , Wang Zhong Lin , Ren Kailiang
Published: February 2021

Flexoelectricity is an electromechanical coupling effect in which electric polarization is generated by a strain gradient. In this
investigation, a potassium sodium niobite/poly(vinylidene fluoride‐trifluoroethylene) (KNN/PVDF‐TrFE)‐based nanocomposite is fabricated, and the flexoelectric effect is used to enhance the photovoltaic current (Ipv) in the nanocomposite. It is found that both a pyroelectric current and photovoltaic current can be generated simultaneously in a light illumination process. However, the photovoltaic current (Ipv) in this process contributes ≈85% of the total current. When assessing the effect of flexoelectricity with a curvature of 1/20, the Ipv of the curved KNN/PVDF‐TrFE (20%) (K/P‐20) composite increased by ≈13.9% compared to that of the flat K/P‐20 nanocomposite. Similarly, at a curvature of 1/20, the Ipv of the K/P‐20 nanocomposite is 71.6% higher than that of the PVDF‐TrFE film. However, the photovoltaic effect induced by flexoelectricity is much higher than the increased polarization from flexoelectricity, so this effect is called as the flexophotovoltaic effect. Furthermore, the calculated energy conversion efficiency of the K/P‐20 film is 0.017%, which is comparable to the previous research result. This investigation shows great promise for PVDF‐based nanocomposites in ferroelectric memory device applications.
Use of craniometric data to facilitate migrant identifications at the United States/Mexico border
Authors: Spradley M. Katherine
Published: February 2021

Objectives

Thousands of migrants have died along the United States/Mexico border and many remain unidentified. The purpose of this research is to test whether estimations of population affinity, derived from craniometric data, can facilitate identification of migrant remains and provide a geographic region of origin rather than the broad label Hispanic. The appropriateness of current forensic reference data will also be assessed.

Methods

A case study combined with craniometric data from positively identified and unidentified migrants from the Pima County Office of the Medical Examiner (n = 489) in Arizona and operation identification (n = 201) in Texas were compared to skeletal data representing Guatemalan (n = 87) and Mexican (n = 65) Mayans. Biological distance and discriminant function analyses were used to assess overall population relationships and classificatory models for forensic anthropological application.

Results

The majority of evidence indicates that estimations of population affinity can assist in the facilitation identification of migrant remains, even when a broad classification is used. Biological distances among the groups suggest that positively identified Guatemalan and Mexican migrants are similar to one another but differ from Guatemalan and Mexican Mayans.

Conclusions

Population affinity estimations can aid migrant identification, and current reference data used in forensic anthropological practice should be replaced with data from positive identifications. Estimates of geographic origin may be more useful than the broad generic term Hispanic for narrowing down the search for a missing person, but more data and research is needed to achieve this goal. Although, the utility of geographic origin estimates relies on transnational data centralization and sharing, which is not always the case.
Intramolecular Stereoselective Stetter Reaction Catalyzed by Benzaldehyde Lyase
Authors: Chen Xiaoyang , Wang Zhiguo , Lou Yujiao , Peng Yongzhen , Zhu Qiaoyan , Xu Jian , Wu Qi
Published: February 2021

The reliable design and prediction of enzyme promiscuity to access transformations not observed in nature remains a long‐standing challenge. Herein, we present the first example of an intramolecular stereoselective Stetter reaction catalyzed by benzaldehyde lyase, guided by the rational structure screening of various ThDP‐dependent enzymes using molecular dynamics (MD) simulations. After optimization, high productivity (up to 99 %) and stereoselectivity (up to 99:1 e.r.) for this novel enzyme function was achieved.
Enhanced Photoelectrocatalytic Activities for CH3OH‐to‐HCHO Conversion on Fe2O3/MoO3: Fe‐O‐Mo Covalency Dominates the Intrinsic Activity
Authors: Huang Sheng , Ouyang Ting , Zheng Bang‐Feng , Dan Meng , Liu Zhao‐Qing
Published: February 2021

The catalytic conversion of alcohols under mild conditions is a great challenge because it is constrained by low selectivity and low activity. Herein, we demonstrate a hollow nanotube Fe2O3/MoO3heterojunction (FeMo‐2) for the photoelectrocatalytic conversion of small‐molecule alcohols. Experimental and theoretical analyses reveal that the optical carrier transfer rate is enhanced by constructing interfacial internal electric fields and Fe‐O‐Mo charge transfer channels. For the formox process, heterojunctions possess superior HCHO‐selective reaction paths and free energy transitions, optimizing the selectivity of HCHO and enhancing the reactivity. FeMo‐2 shows a greatly improved performance compared to single Fe2O3; the photocurrent density of FeMo‐2 reaches 0.66 mA cm−2, which is 3.88 times that of Fe2O3(0.17 mA cm−2), and the Faraday efficiency of the CH3OH‐to‐HCHO conversion is 95.7 %. This work may deepen our understanding of interfacial charge separation and has potential for the production of HCHO and for conversion reactions of other small‐molecule alcohols at cryogenic temperatures.
Tungstic acid (H4WO5) immobilized on magnetic‐based zirconium amino acid metal–organic framework: An efficient heterogeneous Brønsted acid catalyst for l‐(4‐phenyl)‐2,4‐dihydropyrano[2,3c]pyrazole derivatives preparation
Authors: Khademi Shima , Zahmatkesh Saeed , Aghili Alireza , Badri Rashid
Published: February 2021

A new magnetic nanocatalyst based on the immobilization of tungstic acid onto new design robust, cost‐effective, green, and scalable zirconium‐L‐aspartate amino acid metal–organic framework (MOF)‐grafted L‐(+)‐tartaric acid stabilized magnetite nanoparticles (Fe3O4/tart‐NPs) was synthesized by two successive solvo (hydro)‐thermal methods. This catalyst was characterized by Fourier‐transform infrared (FT‐IR), energy‐dispersive X‐ray spectroscopy (EDS), X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH), zeta potential, Thermogravimetry Analysis‐Differential Thermal Analysis (TGA–DTA), and vibrating sample magnetometer (VSM) analyses. This catalyst is outstanding to prepare l‐(4‐phenyl)‐2,4‐dihydropyrano[2,3‐c] pyrazole derivatives in aqueous media due to the open metal sites, high and steady proton conductivity in the zirconium‐MOF, MIP‐202(Zr), and MOF and also due to Brønsted acid properties of tungstic acid. This acidic catalyst can easily be extracted by an outward magnetic field after completion of the reaction without any deactivation or selectivity loss. The products were characterized by spectroscopic analysis (FT‐IR,1H‐NMR, and13C‐NMR). The optimized reaction conditions and a possible reaction mechanism are outlined.
Reactive organophosphorus flame retardant for transparency, low‐flammability, and mechanical reinforcement epoxy resin
Authors: Wang Junjie , Tang Hao , Yu Xuejun , Xu Jin , Pan Zhiquan , Zhou Hong
Published: February 2021

To maintain transparency and improve flame retardancy and mechanical properties of epoxy resin, a reactive organophosphorus flame retardant (DPDDM) was designed and synthesized, which was derived from 3,4‐dihydroxybenzaldehyde, 4, 4′‐ diamino diphenylmethane and 9,10‐dihydro‐9‐oxa –10‐ phosphaphenanthrene‐10‐oxidein two steps. Compared with neat epoxy resin (EP), the tensile strength and flexural strength of the EP with 5% DPDDM increased by 28.6% and 42.8%, respectively, indicating that DPDDM can significantly improve the mechanical properties of EP materials. Meanwhile, the DPDDM modified EP materials have good transparency and the EP with 5% DPDDM passed the V‐0 rating and had the limiting oxygen index as high as 34%. Cone calorimeter test results showed that the heat release and smoke generation of the modified materials were significantly lower than the unmodified materials, which were reduced by 32.6% and 64.6%, respectively, indicating that the modified materials can greatly improve the safety of fire prevention. This work provides a new approach to prepare transparent epoxy resin with good mechanical properties and excellent flame retardancy.
Preparation, characterization, and antibacterial activity of chitosan/silicone rubber filled zeolite, silver, and copper nanocomposites againstPseudomonas aeruginosaand methicillin‐resistantStaphylococcus aureus
Authors: Rezazadeh Nader , Kianvash Abbas
Published: February 2021

The ongoing emergence of antibiotic‐resistant bacteria has become one of the biggest threats to global health and development today.Pseudomonas aeruginosaand methicillin‐resistantStaphylococcus aureus(MRSA) are important antibiotic‐resistant bacteria due to their increasing resistance to a broad array of antimicrobial agents. Herein, we developed a novel antibacterial nanocomposite based on chitosan and liquid silicone rubber filled zeolite‐A, Ag, and Cu nanoparticles with remarkable antibacterial activity againstP. aeruginosaand MRSA. The antibacterial activity of the nanocomposite was studied by disc diffusion and broth culture methods. Besides, the mechanical properties, wetting behavior, and chemical structure of the present nanocomposite were also investigated. The results exhibited that the inhibition zone diameter of the nanocomposite forP. aeruginosaand MRSA were 40 and 27 mm, respectively. It also took approximately 1 h to inhibit the growth of the tested bacteria. The nanocomposite sample with a thickness of around 1 mm showed an elastic elongation of nearly 49% and a contact angle of roughly 120°. Thus, the present nanocomposite was found to be useful in killing and inhibiting the growth ofP. aeruginosaand MRSA, and it could also be qualified as a superior elastic and hydrophobic material.
Nonstationarity of the link between the Tropics and the summer East Atlantic pattern
Authors: Rieke Ole , Greatbatch Richard J. , Gollan Gereon
Published: February 2021

A 700‐year pre‐industrial control run with the MPI‐ESM‐LR model is used to investigate the link between the summer East Atlantic (SEA) pattern and the Pacific‐Caribbean rainfall dipole (PCD), a link that has previously been shown using ERA‐Interim reanalysis data. In the model, it is found that the link between the SEA and PCD is present in some multidecadal epochs but not in others. A simple statistical model reproduces this behaviour. In the statistical model, the SEA is represented by a white noise process plus a weak influence from the PCD based on the full 700 years of the model run. The statistical model is relevant to other extratropical modes of variability, for example, the winter North Atlantic Oscillation (NAO), that are weakly influenced by the Tropics. It follows that the link between the Tropics and the winter NAO is likely to undergo modulation on multidecadal time scales, as found in some previous studies. The results suggest that any predictability of the SEA, and by implication the NAO, based on tropical rainfall may not be robust and may, in fact, be modulated on multidecadal time scales, with implications for seasonal and decadal prediction systems.
Real‐world data of chronic myelomonocytic leukemia: A chinese single‐center retrospective study
Authors: Ma Liya , Jiang Lingxu , Yang Wenli , Luo Yingwan , Mei Chen , Zhou Xinping , Xu Gaixiang , Xu Weilai , Ye Li , Ren Yanlin , Lu Chenxi , Lin Peipei , Jin Jie , Tong Hongyan
Published: February 2021

Chronic myelomonocytic leukemia (CMML) is a rare disease of elderly people characterized by the presence of sustained peripheral blood monocytosis, overlapping features of myeloproliferation, and myelodysplasia. We present a large retrospective study of 156 CMML patients in China. Mean age at diagnosis was 68 years old (range 23‐91). According to the CMML‐specific prognostic scoring system (CPSS), 10 patients (8.3%) were low risk, 27 patients (22.5%) were intermediate‐1 risk, 72 patients (60%) were intermediate‐2 risk, and 11 patients (9.2%) were high risk. A total of 90 patients (57.7%) received hypomethylating agents (HMAs) treatment, 19 patients (12.2%) received chemotherapy and 47 patients (30.1%) received the best supportive care. Seventeen patients (10.9%) underwent allogeneic hematopoietic stem cell transplantation (allo‐SCT) after HMAs treatment or chemotherapy. With a median follow‐up of 35.3 months, overall response rate (ORR) was 69.5% in the HMAs ± chemotherapy group, 79.5% in the HMAs monotherapy group, 60.0% in the HMAs + chemotherapy group, and 37.5% in the chemotherapy group. HMAs monotherapy group had prolonged OS compared with the chemotherapy group (23.57 months vs. 11.73 months; p = 0.035). Patients who achieved ORR had prolonged OS (25.83 months vs. 8.00 months; p < 0.001) and LFS (20.53 months vs. 6.80 months; p < 0.001) compared with those not achieved ORR in the HMA ± chemotherapy group. By univariate analysis, only higher hemoglobulin (≥80 g/L) and lower serum LDH levels (<300 U/L) predicted for better OS and LFS. By multivariate analysis, only Hb ≥ 80 g/L predicted for prolonged OS, Hb ≥ 80 g/L, and monocytes < 3 × 109/L predicted for prolonged LFS. In summary, our study highlights the benefit of HMAs therapy in CMML, but we still need to develop novel therapeutics to achieve better outcomes.
β‐Resorcylic Acid Derivatives, with Their Phytotoxic Activities, from the Endophytic Fungus Lasiodiplodia theobromae in the Mangrove Plant Xylocarpus granatum
Authors: Sato Shiho , Sofian Ferry Ferdiansyah , Suehiro Wataru , Harneti Desi , Maharani Rani , Supratman Unang , Abdullah Fajar Fauzi , Salam Supriatno , Koseki Takuya , Shiono Yoshihito
Published: February 2021

Nine new β‐resorcylic acid derivatives, (15S)‐de‐O‐methyllasiodiplodin (1), (13S,15S)‐13‐hydroxy‐de‐O‐methyllasiodiplodin (2), (14S,15S)‐14‐hydroxy‐de‐O‐methyllasiodiplodin (3), (13R,14S,15S)‐13,14‐dihydroxy‐de‐O‐methyllasiodiplodin (4), ethyl (S)‐2,4‐dihydroxy‐6‐(8‐hydroxynonyl)benzoate (5), ethyl 2,4‐dihydroxy‐6‐(8‐hydroxyheptyl)benzoate (6), ethyl 2,4‐dihydroxy‐6‐(4‐methoxycarbonylbutyl)benzoate (7), 3‐(2‐ethoxycarbonyl‐3,5‐dihydroxyphenyl)propionic acid (8), and isobutyl (S)‐2,4‐dihydroxy‐6‐(8‐hydroxynonyl)benzoate (9), together with a known ethyl 2,4‐dihydroxy‐6‐(8‐oxononyl)benzoate (10) were obtained from Lasiodiplodia theobromae GC‐22. The structures of these compounds were elucidated by extensive spectroscopic analyses. Compounds 1, 3, and 6 showed growth inhibitory effects against Digitaria ciliaris. Conversely, treatment with compounds 5, 6, 7, 9, and 10 stimulated elongation activity toward the root of Lactuca sativa. These data expand the repertoire of new β‐resorcylic acid derivatives that may function as lead compounds in the synthesis of new agrochemical agents.
Baseline characteristics of participants in the LANDMARC trial: A 3‐year, pan‐india, prospective, longitudinal study to assess management and real‐world outcomes of diabetes mellitus
Authors: Das Ashok K. , Mithal Ambrish , Joshi Shashank , Kumar K. M. Prasanna , Kalra Sanjay , Unnikrishnan A. G. , Thacker Hemant , Sethi Bipin , Ghosh Romik , Kanade Vaishali , Nair Arjun , Mohanasundaram Senthilnathan , Menon Shalini K. , Chodankar Deepa , Salvi Vaibhav , Trivedi Chirag , Chatterjee Godhuli , Chowdhury Subhankar , Rais Nadeem , Wangnoo Subhash K. , Zargar Abdul H.
Published: February 2021

Introduction

Longitudinal data on progression, complications, and management of type 2 diabetes mellitus (T2DM) across India are scarce. LANDMARC (CTRI/2017/05/008452), the first pan‐India, longitudinal, prospective, observational study, aims to understand the management and real‐world outcomes of T2DM over 3 years.

Methods

Adults (≥25 to ≤60 years old at T2DM diagnosis; diabetes duration ≥2 years at enrollment; controlled/uncontrolled on ≥2 anti‐diabetic agents) were enrolled. Baseline characteristics were analyzed using descriptive statistics.

Results

Of the 6279 recruited participants, 6236 were eligible for baseline assessment (56.6% [n/N = 3528/6236] men; mean ± SD age: 52.1 ± 9.2 years, diabetes duration: 8.6 ± 5.6 years). mean ± SD HbA1c, fasting plasma glucose, and postprandial glucose values were 64 ± 17 mmol/mol (8.1 ± 1.6%), 142.8 ± 50.4 mg/dl, and 205.7 ± 72.3 mg/dl, respectively. Only 25.1% (n/N = 1122/6236) participants had controlled glycemia (HbA1c < 53 mmol/mol, <7%). Macrovascular and microvascular complications were prevalent in 2.3% (n/N = 145/6236) and 14.5% (n/N = 902/6236) participants, respectively. Among those with complications, non‐fatal myocardial infarction (n/N = 74/145, 51.0%) and neuropathy (n/N = 737/902, 81.7%) were the most reported macrovascular and microvascular complication, respectively. Hypertension (n/N = 2566/3281, 78.2%) and dyslipidemia (n/N = 1635/3281, 49.8%) were the most reported cardiovascular risks. Majority (74.5%; n/N = 4643/6236) were taking oral anti‐diabetic drugs (OADs) only, while 24.4% (n/N = 1522/6236) participants were taking OADs+insulin. Biguanides (n/N = 5796/6236, 92.9%) and sulfonylureas (n/N = 4757/6236, 76.3%) were the most reported OADs. Basal (n/N = 837/6236, 13.4%) and premix (n/N = 684/6236, 11.0%) insulins were the most reported insulins.

Conclusions

Baseline data from LANDMARC help understand the clinical/medical profile of study participants and underscore the extent of suboptimal glycemic control and prevalence of associated complications in a vast majority of Indians with T2DM.
The effects of key rock layer fracturing on gas extraction during coal mining over a large height
Authors: Xiao Peng , Han Kai , Shuang Haiqing , Ding Yang , Kong Xiangguo , Lin Haifei
Published: February 2021

To prevent outbursts and extract the gas, it is necessary to investigate the structure of the key layer and the evolution of cracks during coal mining over a large height. A physical similarity model with a geometric similarity ratio of 1:100 and a strike length of 2 m was established on the basis of prevailing geological and mining conditions. Stress sensors and microseismic equipment were adopted to monitor the collapse characteristics of different key layers through variations in stress and energy. The research results showed that: The displacement of the overlying strata exhibited group motion characteristics marked by the key layer and there was zone of rapidly increasing stress in the goaf behind the working face before and after the fracture of the key layer. Through the analysis of microseismic events, fissure density, and fractal dimension, we found that: before and after the primary key layer fractured, the energy loss in the microseismic event accounted for 27% of the total, the fissure density also changed abruptly from 8 cracks/m to 10 cracks/m and the slope of the fractal dimension curves changed from 0.00243 to 9.94801 × 10−4. Then a gas drainage model suitable for this condition was constructed. When the primary key layer had not fractured, the cracks below fully developed to form a gas migration channel and a gas enrichment area, and gas boreholes could be arranged therein. After the primary key layer had been fractured, the rate of crack development decreased, the permeability would increase, and the gas concentration would increase. The boreholes could still be arranged in the gas migration channel. This study elucidated the control role of the primary key layer from multiple angles and provided experimental guidance for gas drainage over large‐mining heights and during complex key layer mining.
Impact of textural patterns on modeled rock weathering rates and size distribution of weathered grains
Authors: Israeli Yoni , Salhov Eyal , Emmanuel Simon
Published: February 2021

Rock texture has a critical influence on the way rocks weather. The most important textural factors affecting weathering are grain size and the presence of cracks and stylolites. These discontinuities operate as planes of mechanical weakness at which chemical weathering is enhanced. However, it is unclear how different rock textures impact weathering rates and the size of weathered grains. Here, we use a numerical model to simulate weathering of rocks possessing grain boundaries, cracks, and stylolites. We ran simulations with either synthetic or natural patterns of discontinuities. We found that for all patterns, weathering rates increase with discontinuity density. When the density was <~25%, the weathering rate of synthetic patterns followed the order: grid > honeycomb > Voronoi > brick wall. For higher values, all weathering rates were similar. We also found that weathering rates decreased as the tortuosity of the pattern increased. Moreover, we show that textural patterns strongly impact the size distributions of detached grains. Rocks with an initial monomodal grain size distribution produce weathered fragments that are normally distributed. In contrast, rocks with an initial log‐normal size distribution produce weathered grains that are log‐normally distributed. For the natural patterns, weathering produced lower modality distributions.
Human behavioral ecology and niche construction
Authors: Ready Elspeth , Price Michael Holton
Published: February 2021

We examine the relationship between niche construction theory (NCT) and human behavioral ecology (HBE), two branches of evolutionary science that are important sources of theory in archeology. We distinguish between formal models of niche construction as an evolutionary process, and uses of niche construction to refer to a kind of human behavior. Formal models from NCT examine how environmental modification can change the selection pressures that organisms face. In contrast, formal models from HBE predict behavior assuming people behave adaptively in their local setting, and can be used to predict when and why people engage in niche construction. We emphasize that HBE as a field is much broader than foraging theory and can incorporate social and cultural influences on decision‐making. We demonstrate how these approaches can be formally incorporated in a multi‐inheritance framework for evolutionary research, and argue that archeologists can best contribute to evolutionary theory by building and testing models that flexibly incorporate HBE and NCT elements.
A ratiometric electrochemical aptasensor for ochratoxin A detection
Authors: Liang Xiujun , Zhao Fengjuan , Xiao Chengui , Yue Shuang , Huang Yawei , Wei Min
Published: February 2021

With the superiority of providing a more accurate signal through their self‐referencing capability and reducing the environmental influence, a ratiometric electrochemical aptasensor was proposed for ochratoxin A (OTA) detection using methylene blue (MB) and ferrocene (Fc) as signal probes. The magnetic beads were used for the immobilization of OTA aptamer (Apt). When OTA and MB‐labeled complementary DNA (cDNA‐MB) were added, OTA combined with Apt, whereas cDNA‐MB released and existed in the supernatant after magnetic separation. By dropping the supernatant onto the electrode modified with HP‐Fc, the hairpin structure of HP‐Fc was opened by the hybridization between cDNA‐MB and HP‐Fc. As a result, MB was close to the electrode surface, whereas Fc was away from the electrode surface. Based on the value of IMB/IFc, OTA was detected sensitively and specifically. Under the optimal conditions, a linear relationship in the range of 0.005–50 ng/ml was obtained with the detection limit of 2.35 pg/ml. The aptasensor showed high anti‐interference toward AFB1, FB1, ZEN, and OTB. The aptasensor was applied to detect OTA in spiked corn samples, and the recoveries were 93–102%. This method provides a great potential for the development of sensitive biosensing platform for food safety.
Ischemic Stroke Increased Gadolinium Deposition in the Brain and Aggravated Astrocyte Injury After Gadolinium‐Based Contrast Agent Administration: Linear Versus Macrocyclic Agents
Authors: Huang Xin‐Xin , Jiang Run‐Hao , Xu Xiao‐Quan , Zu Qing‐Quan , Wu Fei‐Yun , Liu Sheng , Shi Hai‐Bin
Published: February 2021

Background

Gadolinium (Gd)‐based contrast agents (GBCAs) have been widely used in MRI. However, several studies have reported Gd deposition in the brain, which has raised concerns about safety.

Purpose

To investigate the effects of ischemic stroke on Gd deposition in the brain after repeated administration of linear or macrocyclic GBCAs and to determine whether GBCAs aggravate astrocyte injury after stroke.

Study Type

Animal study.

Animal Model

Twenty‐seven male Sprague–Dawley rats were randomized to an exposure group (n = 24) and a healthy control group (n = 3). Half of the exposure group (n = 12) underwent transient middle cerebral artery occlusion (tMCAO) and half (n = 12) had a sham procedure. In each subgroup (tMCAO or sham), the rats had repeated gadopentetate (n = 6) or gadobutrol (n = 6) injections. Oxygen–glucose deprivation and reoxygenation (OGD/R) was used as an in vitro model of stroke.

Assessment

On day 3 and day 28 after the last injection (p.i.), the Gd concentration in the cerebrum was quantified by inductively coupled plasma mass spectrometry. Cell viability, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were analyzed in vitro.

Statistical Tests

One‐way analysis of variance and two‐sample t‐tests were performed.

Results

The Gd concentration in the ipsilateral hemisphere homogenates of tMCAO group was significantly higher than that in the brain homogenates of the sham group on day 3 p.i. of either gadobutrol (0.065 ± 0.006 vs. 0.042 ± 0.007 μg/g, P < 0.05) or gadopentetate (0.093 ± 0.010 vs. 0.069 ± 0.008 μg/g, P < 0.05). Increased Gd deposition was also found in the ipsilateral hemisphere homogenates of the tMCAO group compared with the brain homogenates of the sham group on day 28 p.i. of gadopentetate (0.075 ± 0.012 vs. 0.044 ± 0.003 μg/g, P < 0.05), but not gadobutrol (0.012 ± 0.007 vs. 0.010 ± 0.001 μg/g, P = 0.80). The Gd concentration in the ipsilateral hemisphere in the tMCAO group was significantly higher for gadopentetate than gadobutrol on both day 3 p.i. (0.085 ± 0.006 vs. 0.049 ± 0.005 μg/g, P < 0.05) and day 28 p.i (0.075 ± 0.012 vs. 0.012 ± 0.007 μg/g, P < 0.05). Additionally, compared with gadobutrol, gadopentetate decreased viability, increased ROS accumulation, and decreased MMP in OGD/R‐induced astrocytes (all P < 0.05).

Data Conclusion

Administration of GBCAs after an animal model of ischemic stroke increased Gd deposition in the brain and aggravated astrocyte injury. The effect of gadopentetate appeared to be more pronounced than that of gadobutrol.