bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving properties of high volume fly ash binder by mechanical and chemical activation
Authors: Rakić Jelena , Baščarević Zvezdana
Published: January 2021

High volume fly ash (FA) binders are characterized by long setting times and low early strength. By applying mechanical and/or chemical activation methods, it is possible to increase the reactivity of FA and improve the properties of the binder. In this paper, influence of mechanical activation of FA on the properties of binders prepared with 70% FA and 30% Portland cement was investigated. Additionally, effect of chemical activation of the binder by using sodium sulfate as activator was evaluated. The binder obtained by combining mechanical and chemical activation had the highest early strength (up to 7 days) and the shortest setting times. However, the highest strength of the binder after 90 days was obtained by applying only mechanical activation of FA.
Rethinking success in software projects
Authors: Mitrović Zorica , Petrović Dejan , Mihić Marko
Published: January 2021

In recent years, one of the most important topics in the field of software development projects is rethinking success in context of increasing complexity and failure of software projects. Literature review shows that there is no clear line between success and failure, especially considering that a project can be both successful in one area and unsuccessful in another. In addition, the increasing complexity, context and broader conceptualization of projects, required both change in project and success definition. The aim of this paper is to perform literature review in field of software project success definition, as well as to propose a multidimensional construct that includes project management success, project success and strategic project success as three dimensions for measuring software's project success.
Proposal of the concept of smart cities development strategy in Montenegro
Authors: Buzdovan Ivana , Asanović Marko , Gospić Nataša
Published: January 2021

This study elaborates the elements which are important in the development of the smart city strategy, both at national and local level. They should provide a good foundation for the development of a longterm sustainable and comprehensive smart city concept. When developing the strategy itself, it is necessary to follow the examples of the smart cities in Europe, Region and based on their experience, to identify advantages and disadvantages in order to form clear goals and vision. This study also gives the proposal for defining the elements necessary for establishing the smart cities development strategy as a solution for improving the quality of life in cities, and therewith overall social and economic sustainable development of a country. Montenegro and the city of Budva have been developed as a case study. Montenegro is keeping pace with technological development and therewith the need to define a development strategy for its smart cities. This study emphasizes the role of state bodies, institutions and citizens themselves in that process.
Analysis of the voltage profile and power losses in distribution network with renewable energy sources using CONOPT solver
Authors: Rakočević Stevan , Ćalasan Martin , Konjić Tatjana
Published: January 2021

In this paper, CONOPT solver, embedded in program GAMS, is proposed for optimal power flow analysis in distribution network with renewable energy sources. CONOPT solver possibilities have been tested on IEEE 33 test system solving a problem o f minimizing active power losses in the network. Locations and sizes o f renewable energy sources were taken form available literature. The results obtained using CONOPT solver have been compared with results obtained by using metaheuristic and hybrid algorithms. It is shown that the CONOPT solver gives better results in terms o f minimum values o f active power losses.
Inclusive road infrastructure safety management in the settlement: An approach to improving the safety of vulnerable road users
Authors: Čabarkapa Milenko
Published: January 2021

In the last ten years, there has been a stabilization of traffic fatalities on the roads of the world. At the same time, the death toll of persons in the armor of vehicles was reduced, and the death toll of persons outside the armor of vehicles-vulnerable road users continued to grow. The most endangered are motorcyclists, then pedestrians and finally cyclists, both in developed countries of the European Union and in underdeveloped and developing countries. Lagging behind in reducing the fatalities of vulnerable road users requires innovation in research and the creation and implementation of new road safety management policies. In this aspect, inclusive road infrastructure safety management in the settlement can be a paradigm for the introduction and implementation of protection of vulnerable road users, persons with reduced mobility and persons with disabilities, through procedures to control road safety in the settlement, at all stages of the road life cycle: planning, design, construction and exploitation. The content of inclusive road infrastructure safety management in the settlement should include all areas of activity and all elements of the roads of the settlement, the improvement of which can raise the level of traffic safety of all users, so that the roads of the settlement are equally safe for all road users. At the same time, the risk of fatal traffic accidents on the roads of the settlement is indirectly exponentially related to the scope of the content of inclusive road infrastructure safety management in the settlement.
Performance appraisal and bonus calculation for warehouse employees
Authors: Novković Aleksandra , Andrejić Milan , Kilibarda Milorad
Published: January 2021

The development of global supply chains, market liberalization, and new business trends have contributed to creating more competition in the market and increasing demand. Logistics companies strive to generate revenue by providing services of a higher scope and level of quality, while cost minimization is often associated with a system of calculating salaries and employee benefits. The fluctuation of workers is one of the current problems faced by a large number of companies, so the development of a system that will improve conditions and motivate workers is very important. The paper proposes a model for evaluating work performance and calculating bonuses for employees in the warehouse. The model considers the main performance indicators that refer to work engagement in terms of the number of picked items and presence at the workplace. The sensitivity analysis of the model established the convenience and universality of the application.
“Bold Problem Solving”: A New Construct for Understanding Gender Differences in Mathematics
Authors: Lubienski Sarah Theule , Ganley Colleen M. , Makowski Martha B. , Miller Emily K. , Timmer Jennifer D.
Published: January 2021

Despite progress toward gender equity, troubling disparities in mathematical problem-solving performance and related outcomes persist. To investigate why, we build on recurrent findings in previous studies to introduce a new construct, “bold problem solving,” which involves approaching mathematics problems in inventive ways. We introduce a self-report survey of bold problem-solving orientation and find that it mediates gender differences in problem-solving performance for both high-achieving middle school students (n= 79) and a more diverse sample of high school students (n= 222). Confidence mediates the relation between gender and bold problem-solving orientation, with mixed results for mental rotation skills and teacher-pleasing tendencies as mediators. Overall, the new bold problem-solving construct appears promising for advancing our understanding of gender differences in mathematics.
Opioid-Free Recovery from Bunionectomy with HTX-011, a Dual-Acting Local Anesthetic Combining Bupivacaine and Meloxicam, as the Foundation of Non-Opioid Multimodal Analgesia
Authors: Pollak Richard , Cai Danlin , Gan Tong J.
Published: January 2021

Background

There is a need for postoperative pain control that minimizes or eliminates opioid use during the first 72 hours following surgery, when pain is most severe. HTX-011 is an extended-release, dual-acting local anesthetic that demonstrated superior 72-hour analgesia over standard of care bupivacaine hydrochloride (HCl) and saline placebo in a phase 3 bunionectomy study (EPOCH-1). Having shown HTX-011 monotherapy is superior to bupivacaine HCl in reducing postoperative pain intensity and opioid use, this follow-on study evaluated the safety and efficacy of HTX-011 as the foundation of a multimodal analgesia (MMA) regimen using over-the-counter medications recommended by practice guidelines for pain management.

Methods

Following regional anesthesia administered as a lidocaine block, patients underwent unilateral bunionectomy with osteotomy and internal fixation. Prior to closure, HTX-011 (up to 60 mg bupivacaine/1.8 mg meloxicam) was applied without a needle. Patients received scheduled postoperative MMA alternating ibuprofen (600 mg) and acetaminophen (1 g) every 3 hours for 72 hours. Efficacy was assessed based on pain intensity (numeric rating scale [NRS; 0–10]) and consumption of opioid rescue medication (intravenous morphine milligram equivalents [MME]). Adverse event and vital sign monitoring, plus laboratory and wound healing assessments, were used to determine safety.

Results

Over the 72-hour assessment period following bunionectomy, mean pain scores were mild in severity (NRS <4) and 22/31 patients (71%) experienced no severe pain (NRS ≥7) with HTX-011 as the foundation of scheduled, non-opioid MMA. Patients consumed an average of 1.61 MME total, with 24/31 (77%) requiring no opioid rescue medication (opioid-free). HTX-011 was well-tolerated and demonstrated no safety concerns with the inclusion of postoperative MMA.

Conclusions

HTX-011 as the foundation of an MMA regimen including scheduled ibuprofen and acetaminophen maintained mean postoperative pain scores in the mild range and enabled opioid-free recovery for 77% of bunionectomy patients through the 28-day recovery period.
Comparison of induced neurons reveals slower structural and functional maturation in humans than in apes
Authors: Schörnig Maria , Ju Xiangchun , Fast Luise , Ebert Sebastian , Weigert Anne , Kanton Sabina , Schaffer Theresa , Nadif Kasri Nael , Treutlein Barbara , Peter Benjamin Marco , Hevers Wulf , Taverna Elena
Published: January 2021

We generated induced excitatory neurons (iNeurons, iNs) from chimpanzee, bonobo, and human stem cells by expressing the transcription factor neurogenin-2 (NGN2). Single-cell RNA sequencing showed that genes involved in dendrite and synapse development are expressed earlier during iNs maturation in the chimpanzee and bonobo than the human cells. In accordance, during the first 2 weeks of differentiation, chimpanzee and bonobo iNs showed repetitive action potentials and more spontaneous excitatory activity than human iNs, and extended neurites of higher total length. However, the axons of human iNs were slightly longer at 5 weeks of differentiation. The timing of the establishment of neuronal polarity did not differ between the species. Chimpanzee, bonobo, and human neurites eventually reached the same level of structural complexity. Thus, human iNs develop slower than chimpanzee and bonobo iNs, and this difference in timing likely depends on functions downstream of NGN2.
The Arabidopsis active demethylase ROS1 cis-regulates defence genes by erasing DNA methylation at promoter-regulatory regions
Authors: Halter Thierry , Wang Jingyu , Amesefe Delase , Lastrucci Emmanuelle , Charvin Magali , Singla Rastogi Meenu , Navarro Lionel
Published: January 2021

Active DNA demethylation has emerged as an important regulatory process of plant and mammalian immunity. However, very little is known about the mechanisms by which active demethylation controls transcriptional immune reprogramming and disease resistance. Here, we first show that the Arabidopsis active demethylase ROS1 promotes basal resistance towards Pseudomonas syringae by antagonizing RNA-directed DNA methylation (RdDM). Furthermore, we demonstrate that ROS1 facilitates the flagellin-triggered induction of the disease resistance gene RMG1 by limiting RdDM at the 3' boundary of a transposable element (TE)-derived repeat embedded in its promoter. We further identify flagellin-responsive ROS1 putative primary targets and show that at a subset of promoters, ROS1 erases methylation at discrete regions exhibiting WRKY transcription factors (TFs) binding. In particular, we demonstrate that ROS1 removes methylation at the orphan immune receptor RLP43 promoter, to ensure DNA binding of WRKY TFs. Finally, we show that ROS1-directed demethylation of RMG1 and RLP43 promoters is causal for both flagellin responsiveness of these genes and for basal resistance. Overall, these findings significantly advance our understanding of how active demethylases shape transcriptional immune reprogramming to enable antibacterial resistance.
Offshore marine actinopterygian assemblages from the Maastrichtian–Paleogene of the Pindos Unit in Eurytania, Greece
Authors: Argyriou Thodoris , Davesne Donald
Published: January 2021

The fossil record of marine ray-finned fishes (Actinopterygii) from the time interval surrounding the Cretaceous–Paleogene (K–Pg) extinction is scarce at a global scale, hampering our understanding of the impact, patterns and processes of extinction and recovery in the marine realm, and its role in the evolution of modern marine ichthyofaunas. Recent fieldwork in the K–Pg interval of the Pindos Unit in Eurytania, continental Greece, shed new light on forgotten fossil assemblages and allowed for the collection of a diverse, but fragmentary sample of actinopterygians from both late Maastrichtian and Paleocene rocks. Late Maastrichtian assemblages are dominated by Aulopiformes (†Ichthyotringidae, †Enchodontidae), while †Dercetidae (also Aulopiformes), elopomorphs and additional, unidentified teleosts form minor components. Paleocene fossils include a clupeid, a stomiiform and some unidentified teleost remains. This study expands the poor record of body fossils from this critical time interval, especially for smaller sized taxa, while providing a rare, paleogeographically constrained, qualitative glimpse of open-water Tethyan ecosystems from both before and after the extinction event. Faunal similarities between the Maastrichtian of Eurytania and older Late Cretaceous faunas reveal a higher taxonomic continuum in offshore actinopterygian faunas and ecosystems spanning the entire Late Cretaceous of the Tethys. At the same time, the scarcity of Paleocene findings offers tentative clues for a depauperate state of Tethyan ichthyofaunas in the aftermath of the K–Pg Extinction.
Rubber Slippers and Environmental Effect in KCB School in Bhutan
Authors: Dorji Jigme
Published: January 2021

This paper reports the findings from the project implemented in one of the center schools in western district in Bhutan to enhance waste management behaviour among the students. It took the case of using rubber slippers which the Bhutan government provides to center school students for free as an object of focus for studying students’ awareness about the effect of rubber and plastic waste on health and environment. The baseline data were collected from grade 10 students (N=30) using questionnaire and semi-structured interviews. Based on the baseline findings, intervention activities were formulated and implemented for a month. Posters were distributed and online sessions were conducted. Besides, an alternative to rubber slipper was explored and experimented on 15 participants to draw comparison in terms of cost, comfort and durability. Post-intervention data were collected using the same tools used for baseline data. Data were analyzed employing descriptive analysis by counting frequency for quantitative data and content analysis technique for qualitative data. The project found that students’ perspective toward the rubber waste changed after the project intervention. And it can be concluded that this change is a positive sign that rubber slippers could be replaced by alternative footwear which would reduce waste production contributing to the health and environment significantly.
Cell Surface Functionalization with Heparin‐Conjugated Lipid to Suppress Blood Activation
Authors: Asawa Kenta , Ishihara Kazuhiko , Ekdahl Kristina N. , Nilsson Bo , Teramura Yuji
Published: January 2021

Organ transplantation leads to damage of the endothelial glycocalyx of the transplanted organ, and the activated endothelial surface induces thromboinflammation. The result is dysfunction of the transplanted organ, known as ischemia reperfusion injury (IRI). Long‐term graft survival strongly depends on the regulation of IRI. Here the aim is to reconstruct the glycocalyx to regulate blood activation during IRI. Heparin‐conjugated lipid (fHep‐lipid) is synthesized with 0.6, 1.8, 2.7, 4.5, or 8.0 fragmented heparins per lipid to compare their anticoagulation activity. First, liposome and cells are modified with each fHep‐lipid and the surface properties are evaluated. Then the hemocompatibility of the modified human mesenchymal stem cells (hMSCs) is examined in a loop model using human blood. The antithrombin‐binding capacity and anti‐factor Xa activity of the fHep‐lipids depend on the number of conjugated heparins, with efficacy increasing with increasing number of heparins. The modified liposomes are highly negatively charged and show strong anti‐factor Xa activity. In addition, the cell surfaces of human erythrocytes and hMSCs can be uniformly modified with fHep‐lipid. The whole blood studies reveal that fHep‐lipid on hMSCs can prevent generation of thrombin–antithrombin complexes, coagulation markers, and platelet aggregation, whereas unmodified hMSCs trigger activation of the platelet and coagulation systems.
Field‐Effect Transistors Based on Formamidinium Tin Triiodide Perovskite
Authors: Shao Shuyan , Talsma Wytse , Pitaro Matteo , Dong Jingjin , Kahmann Simon , Rommens Alexander Joseph , Portale Giuseppe , Loi Maria Antonietta
Published: January 2021

To date, there are no reports of 3D tin perovskite being used as a semiconducting channel in field‐effect transistors (FETs). This is probably due to the large amount of trap states and high p‐doping typical of this material. Here, the first top‐gate bottom‐contact FET using formamidinium tin triiodide perovskite films is reported as a semiconducting channel. These FET devices show a hole mobility of up to 0.21 cm2 V−1 s−1, an ION/OFF ratio of 104, and a relatively small threshold voltage (VTH) of 2.8 V. Besides the device geometry, the key factor explaining this performance is the reduced doping level of the active layer. In fact, by adding a small amount of the 2D material in the 3D tin perovskite, the crystallinity of FASnI3 is enhanced, and the trap density and hole carrier density are reduced by one order of magnitude. Importantly, these transistors show enhanced parameters after 20 months of storage in a N2 atmosphere.
Organoboron‐Containing Polymer Electrolytes for High‐Performance Lithium Batteries
Authors: Dai Kuan , Zheng Yuan , Wei Weifeng
Published: January 2021

Polymer electrolytes (PEs) have been deemed as a sought‐after candidate for next‐generation lithium batteries. Substantial effort has been dedicated to exploiting PEs with improved comprehensive performance. Organoboron compounds have aroused great interest in PEs due to their distinct characteristics such as high design diversity, excellent thermal stability, promoting lithium‐ion transportation, and raising Li+ transference number. Organoboron compounds also have unique functions that facilitate the development of a stable solid electrolyte interface on the electrode surface. Their diversified structures and multiple functions are fundamentally associated with boron's hybridization form that determines the electronic structure of boron as a central atom. Here, recent advancement in organoboron‐containing PEs is reviewed in the aspect of polymer matrixes with boron moieties and organoboron additives for PEs. This review aims to highlight the diverse roles and high application potentials of organoboron compounds utilized in PEs. It is anticipated to provide a clear perspective of organoboron‐containing PEs and to spur more research interests for the exploration of safe and efficient lithium batteries.
Template‐Free Self‐Caging Nanochemistry for Large‐Scale Synthesis of Sulfonated‐Graphene@Sulfur Nanocage for Long‐Life Lithium‐Sulfur Batteries
Authors: Yu Peng , Feng Lan‐Xiang , Ma Dai‐Chuan , Sun Xiao‐Rong , Pei Jing‐Ke , Zha Xiang‐Jun , Bao Rui‐Ying , Wang Yu , Yang Ming‐Bo , Guo Zai‐Ping , Yang Wei
Published: January 2021

Big volume changes, the shuttle effect, and poor conductivity are well‐known, critical issues of sulfur electrodes that prevent practical application of lithium‐sulfur batteries. The design of active materials with a conductive shell provides an effective solution. Traditional strategies have long been limited for practical applications; however, by low productivity and time/energy consuming template‐based methods. Here, a facile template‐free self‐caging nanotechnology for the scalable fabrication of graphene@sulfur nanocages with atomic‐scale shells is reported. To do that, a new sulfur‐graphene nanochemistry based on a reductive sulfur solution and oxidative sulfonated‐graphene dispersion is developed for the first time. With only the help of mechanical mixing, sulfur particles are successfully synthesized in situ and encapsulated into reaction‐induced self‐assembled sulfonated‐graphene nanocages. These unique nanocages not only provide accommodation of the big volume changes in the active materials, but also exhibit robust polysulfide trapping capability due to the synergistic effects from physical blocking and strong chemical absorption. As a result, the resultant sulfur cathodes deliver superior electrochemical performance and have shown an extremely slow capacity decay of 0.019% per cycle at 0.5 C for over 2000 cycles. This study introduces a new self‐caging nanochemistry for scalable synthesis of functional nanocages with significant applications beyond lithium‐sulfur batteries.
Chemically Stabilized and Functionalized 2D‐MXene with Deep Eutectic Solvents as Versatile Dispersion Medium
Authors: Kim Jeonghui , Yoon Yeoheung , Kim Seong K. , Park Seungyoung , Song Wooseok , Myung Sung , Jung Ha‐Kyun , Lee Sun Sook , Yoon Dae Ho , An Ki‐Seok
Published: January 2021

2D transition metal carbides and nitrides, namely MXenes, are normally synthesized in acidic solutions and are delaminated in basic solutions. This results in versatile materials with unique physical/chemical properties suitable for various practical applications. However, solution‐based chemical treatments can affect the chemical structures of MXenes, which accelerates the oxidation reactions and degrades their intrinsic properties. Here, long‐term stable Ti3C2Tx dispersion in deep eutectic solvents (DESs) that resisted oxidation degradation for up to 28 weeks is demonstrated. As an anti‐oxidative dispersion medium, DESs helped prevent oxidation of Ti3C2Tx layers due to hydrogen bond accepting and donating molecules passivated surface of the Ti3C2Tx. In addition, DES molecules in bulk solution can also be hydrated in the presence of water, which stabilizes reactive oxygen by forming stable DES‐water cluster. Therefore, the use of DESs enhanced the delamination of the Ti3C2Tx nanosheets, while preventing oxidation of the nanosheets in solution and even in their dried state. As a result, thick and thin films of Ti3C2Tx fabricated using DESs exhibited stable sheet resistance in comparison with pristine‐Ti3C2Tx. In addition, Ti3C2Tx dispersed in DESs can be applied as electrodes for electrochemical capacitors, in which they showed higher chemical stability and better performance than pristine Ti3C2Tx.
Efficient Electrical Doping of Organic Semiconductors Via an Orthogonal Liquid‐Liquid Contact
Authors: Sun Lulu , Yang Mengyuan , Dong Xinyun , Hu Lu , Hu Lin , Xie Cong , Liu Tiefeng , Qin Fei , Wang Wen , Jiang Youyu , Wu Mengying , Cao Wei , Larrain Felipe A. , Fuentes‐Hernandez Canek , Meng Ke , Kippelen Bernard , Müller‐Buschbaum Peter , Zhou Yinhua
Published: January 2021

Doping is an effective strategy to tune the electrical properties of organic semiconductors. Traditional solution‐processed doping methods, including “host‐dopant mixing‐doping” and “post‐fabrication doping” methods, present challenges for their use in applications in optoelectronic devices. This work reports about a novel method to prepare electrically doped films, the authors call orthogonal liquid‐liquid‐contact (OLLC) doping. In OLLC doping, dopant and polymer semiconductors are dissolved in water and an organic solvent, respectively, and electrical doping occurs during film formation at the orthogonal liquid‐liquid (aqueous‐organic) interface. A large free volume of polymer and dopant in their solutions enables diffusion for effective doping. Thanks to the high surface tension of water, nanometer‐thick polymer films form spontaneously on the aqueous surface and simultaneously get doped. The doped thin polymer films on the aqueous surface can be easily transferred to devices to facilitate hole collection/injection in organic photovoltaics and light‐emitting diodes with solution‐processed top electrodes.
Noble Metal Nanomaterials for NIR‐Triggered Photothermal Therapy in Cancer
Authors: Lv Zhuoqian , He Sijia , Wang Youfu , Zhu Xinyuan
Published: January 2021

It is of great significance to develop anticancer therapeutic agents or technologies with high degree of specificity and patient compliance, while low toxicity. The emerging photothermal therapy (PTT) has become a new and powerful therapeutic technology due to its noninvasiveness, high specificity, low side effects to normal tissues and strong anticancer efficacy. Noble metal nanomaterials possess strong surface plasmon resonance (SPR) effect and synthetic tunability, which make them facile and effective PTT agents with superior optical and photothermal characteristics, such as high absorption cross‐section, incomparable optical‐thermal conversion efficiency in the near infrared (NIR) region, as well as the potential of bioimaging. By incorporating with various functional reagents such as antibodies, peptides, biocompatible polymers, chemo‐drug and immune factors, noble metal nanomaterials have presented strong potential in multifunctional cancer therapy. Herein, the recent development regarding the application of noble metal nanomaterials for NIR‐triggered PTT in cancer treatment is summarized. A variety of studies with good therapeutic effects against cancer from impressive photothermal efficacy of noble metal nanomaterials are concluded. Intelligent nanoplatforms through ingenious fabrication showing potential of multifunctional PTT, combined with chemo‐therapy, immunotherapy, photodynamic therapy (PDT), as well as simultaneous imaging modality are also demonstrated.
In Situ Lignin Modification toward Photonic Wood
Authors: Xia Qinqin , Chen Chaoji , Yao Yonggang , He Shuaiming , Wang Xizheng , Li Jianguo , Gao Jinlong , Gan Wentao , Jiang Bo , Cui Mingjin , Hu Liangbing
Published: January 2021

Lignin serves as a binder that forms strong matrices of the cell walls of wood. However, it has many photolabile chromophore groups that create a monotonic brownish color and make wood susceptible to photodegradation. Herein, a new strategy is reported for modifying lignin using an in situ, rapid, and scalable process that involves the photocatalytic oxidation of native lignin in wood by H2O2 and UV light. The reaction selectively eliminates lignin's chromophores while leaving the aromatic skeleton intact, thus modulating the optical properties of wood. The resulting “photonic wood” retains ≈80% of its original lignin content, which continues to serve as a strong binder and water‐proofing agent. As a result, photonic wood features a much higher mechanical strength in a wet environment (20‐times higher tensile strength and 12‐times greater compression resistance), significant scalability (≈2 m long sample), and largely reduced processing times (1–6.5 h vs 4–14 h) compared with delignification methods. Additionally, this in situ lignin‐modified wood structure is easily patterned through a photocatalytic oxidation process. This photocatalytic production of photonic wood paves the way for the large‐scale manufacturing of sustainable biosourced functional materials for a range of applications, including energy‐efficient buildings, optical management, and fluidic, ionic, electronic, and optical devices.
Tuning the Selective Adsorption Site of Biomass on Co3O4 by Ir Single Atoms for Electrosynthesis
Authors: Lu Yuxuan , Liu Tianyang , Dong Chung‐Li , Huang Yu‐Cheng , Li Yafei , Chen Jun , Zou Yuqin , Wang Shuangyin
Published: January 2021

The electrosynthesis from 5‐hydroxymethylfurfural (HMF) is considered a green strategy to achieve biomass‐derived high‐value chemicals. As the molecular structure of HMF is relatively complicated, understanding the HMF adsorption/catalysis behavior on electrocatalysts is vital for biomass‐based electrosynthesis. The electrocatalysis behavior can be modulated by tuning the adsorption energy of the reactive molecules. In this work, the HMF adsorption behavior on spinel oxide, Co3O4 is discovered. Correspondingly, the adsorption energy of HMF on Co3O4 is successfully tuned by decorating with single‐atom Ir. It is observed that compared with bare Co3O4, single‐atom‐Ir‐loaded Co3O4 (Ir‐Co3O4) can enhance adsorption with the CC groups of HMF. The synergetic adsorption can enhance the overall conversion of HMF on electrocatalysts. With the modulated HMF adsorption, the as‐designed Ir‐Co3O4 exhibits a record performance (with an onset potential of 1.15 VRHE) for the electrosynthesis from HMF.
From Understanding Mechanical Behavior to Curvature Prediction of Humidity‐Triggered Bilayer Actuators
Authors: Dingler Carsten , Müller Henry , Wieland Matthias , Fauser Dominik , Steeb Holger , Ludwigs Sabine
Published: January 2021

Nature will always be an endless source of bioinspiration for man‐made smart materials and multifunctional devices. Impressively, even cutoff leaves from resurrection plants can autonomously and reproducibly change their shape upon humidity changes, which goes along with total recovery of their mechanical properties after being completely dried. In this work, simple bilayers are presented as autonomously moving, humidity‐triggered bending actuators. The bilayers—showing reproducible bending behavior with reversible kinematics and multiway behavior—are studied in terms of their mechanical behavior upon humidity changes. The active layer consists of a highly conducting polymer film based on poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with poly(dimethylsiloxane) (PDMS) as passive layer. The response to humidity is explored with dynamic mechanical thermal analysis and quartz crystal microbalance measurements. Introduction of a composite beam model allows to predict the curvature of the actuators with input from the rheological measurements. It is clearly demonstrated that volumetric strain and Young's modulus, both heavily influenced by the water uptake, dominate the bending behavior and therefore the curvature of the actuators. This loop of rheological characterization coupled with an analytical model allows to predict curvatures of in principle any complex geometry and material combination for moving parts in soft robotics.
Leidenfrost Motion of Water Microdroplets on Surface Substrate: Epitaxy of Gallium Oxide via Mist Chemical Vapor Deposition
Authors: Ha Minh‐Tan , Kim Kyoung‐Ho , Shin Yun‐Ji , Jeong Seong‐Min , Bae Si‐Young
Published: January 2021

It is hypothesized that gravity‐driven sedimentation and gliding of water microdroplets on a substrate surface due to the Leidenfrost effect explain the deposition behaviors of epilayers via mist chemical vapor deposition (mist CVD). The deposition rate, thickness uniformity, and surface morphology are dependent on the velocity, incident angle, incident probability, gliding distance, and the lifetime of the droplets on the surface of the substrate. Practically, the deposition of corundum structured gallium oxide (α‐Ga2O3) epilayers on a tilted 2‐inch c‐plane sapphire substrate validated the hypothesis. A high substrate tilt angle and a low mist stream velocity are favorable for a high deposition rate. In contrast, a low substrate tilt angle and a high mist stream velocity are suitable for high uniformity and stable deposition of the α‐Ga2O3 thin films via mist CVD.
High Contrast Ultrathin Light‐Field Camera Using Inverted Microlens Arrays with Metal–Insulator–Metal Optical Absorber
Authors: Bae Sang‐In , Kim Kisoo , Jang Kyung‐Won , Kim Hyun‐Kyung , Jeong Ki‐Hun
Published: January 2021

Light‐field imaging has attracted much attention in constructing 3D objects with a simple configuration and capturing all the spatial and directional data in a single photographic exposure. Here, an ultrathin light‐field camera (ULFC) for high contrast and high‐resolution light‐field imaging using a metal–insulator–metal optical absorber based inverted microlens arrays (MIM‐iMLA) is reported. A metal–insulator–metal based optical absorber (MIM‐OA) between microlenses exhibits high light absorption in the full visible region, thereby highly blocking microlens crosstalk. The MIM‐iMLA double the image contrast and improve MTF50 by up to 32%, compared to conventional light‐field image. In addition, the MIM‐iMLA substantially reduces an image plane distance and brings the objective lens position closer to the MLA. The ULFC exhibits a short total track length of 5.1 mm, demonstrating high contrast light‐field image acquisition and high accuracy 3D depth map estimation after light‐field rendering. This ultrathin and high contrast light‐field camera can provide a new platform for miniaturized 3D cameras in biomedical applications, biometrics, automated inspection, or mobile camera applications.
Broadband Achromatic Transmission–Reflection‐Integrated Metasurface Based on Frequency Multiplexing and Dispersion Engineering
Authors: Zhang Zuojun , Wang Jiangyu , Pu Mingbo , Ma Xiaoliang , Huang Cheng , Guo Yinghui , Luo Xiangang
Published: January 2021

Transmission–reflection‐integrated metasurfaces (TRIMs) provide an effective avenue to realize functionality integration and miniaturization of imaging and communication systems. However, most of the previous works suffer from large chromatic aberrations due to the intrinsic dispersive properties of the resonators constituting metasurfaces, which results in the meta‐devices working in a small operation bandwidth. Here, a broadband achromatic TRIM is proposed based on the frequency‐multiplexing scheme and dispersion engineering in transmission and reflection mode, respectively. As a proof of the scheme, 1D achromatic transmission–reflection‐integrated focusing metasurface and common‐caliber transmitarray and reflectarray flat plate antenna are demonstrated over a broad frequency range. The achromatic focusing in transmission mode and reflection mode with simulated focusing efficiencies of 13.12–17.21% and 14.57–20.86% are simultaneously realized at 12–18 and 19–24 GHz, respectively. The radiation gains increase by an average of 17.53 and 23.57 dB for the transmission mode and reflection mode relative to the bare standard rectangle waveguides. The scheme for achromatic and independent electromagnetic manipulation in transmission and reflection mode can also be applied to other frequency ranges and promise unprecedented progress for optical imaging and wireless telecommunication.
Extended Bound States in the Continuum with Symmetry‐Broken Terahertz Dielectric Metasurfaces
Authors: Han Song , Pitchappa Prakash , Wang Wenhao , Srivastava Yogesh Kumar , Rybin Mikhail V. , Singh Ranjan
Published: January 2021

Excitation of the non‐radiative eigenmodes in photonics and metamaterials above their light cone, that is, the bound states in the continuum (BICs), has drawn fundamental and technological interest. However, the current studies on photonic BICs are mainly restricted to the characterization of the eigenmodes with fixed point group. Here, a fourfold rotationally symmetric (C4v) array of silicon resonators in a square lattice is investigated that reveals the traditional symmetry‐protected (Γ‐state) and accidental (off‐Γ) BICs in the momentum space. Upon symmetry‐breaking, BICs at Γ‐state transform into quasi‐states with decaying quality factors that obey the inverse‐square law α−2 as a function of the structural asymmetry parameter α. Surprisingly, at larger asymmetries, multiple new states of extended BICs are observed beyond typical inverse‐square law behavior. The structural asymmetry of a resonator provides an important degree of freedom for exploring the Friedrich–Wintgen and new accidental BICs that are topologically protected by robust polarization vortices. The extended family of sharp BIC resonances in all‐dielectric silicon metasurfaces is extremely important for scalable applications in terahertz sensing, higher harmonic generation, and ultralow‐power switching.
Incorporating Electrochemical Halide Oxidation into Drift‐Diffusion Models to Explain Performance Losses in Perovskite Solar Cells under Prolonged Reverse Bias
Authors: Bertoluzzi Luca , Patel Jay B. , Bush Kevin A. , Boyd Caleb C. , Kerner Ross A. , O'Regan Brian C. , McGehee Michael D.
Published: January 2021

Partial shading of a solar module can induce a set of cells within the module to operate under reverse bias. Studies have shown that metal halide perovskite solar cells with a wide variety of compositions and contacts exhibit interesting behavior in reverse bias that includes both reversible performance loss and non‐reversible degradation. In this paper, an advanced drift‐diffusion approach incorporating an electrochemical term to explain the short‐circuit, open circuit and fill factor losses that are experimentally measured after prolonged reverse bias is used. It is shown that holes can tunnel into the perovskite due to sharp band bending near the contact, accumulate within the bulk of the perovskite absorber, and trigger the oxidation of halides to form neutral halogens. The density of neutral halogens is much higher in reverse bias because there are hardly any electrons available to reduce the iodine. The resulting halogens act as bulk recombination centers. While the interstitial halogen density does decay when the cell is operated in forward bias, permanent degradation can occur if the iodine diffuses out of the perovskite layer. Finally, the ways in which changing parameters such as the mobile ion density or the series resistance at the contact can influence device performance and stability are discussed.
Strategies and Challenges on Selectivity of Photocatalytic Oxidation of Organic Substances
Authors: Xiong Lunqiao , Tang Junwang
Published: January 2021

Most organic compounds are conventionally synthesized under high temperature and elevated pressure, resulting in significant energy consumption and wastage. Heterogeneous photocatalytic oxidation has the potential to provide a green route for the synthesis of the majority of industrially important chemicals. The major limiting factor affecting the efficiency of photocatalytic organic synthesis is the lack of high selectivity; therefore, substantial effort has been devoted to solving this problem. Responding to this fast‐moving progress, this review gives an overview of the fundamental understanding of the reactive oxygen species involved in photocatalytic organic oxidations and furthermore, the general mechanisms of a few crucial oxidation reactions. The focus of this critical review is on the discussion of diverse strategies to improve the selectivity of high value chemicals, including band engineering, metal loading, hybrid materials, and defect engineering, with the primary aim of highlighting the catalyst design protocols based on the reaction mechanism. Finally, the difficulties and challenges of developing highly selective oxidation photocatalysts are comprehensively discussed in order to help direct the focus of future research.
Construction of MXene‐Coupled Nitrogen‐Doped Porous Carbon Hybrid from a Conjugated Microporous Polymer for High‐Performance Supercapacitors
Authors: Seenath Jensheer Shamsudeen , Biswal Bishnu P.
Published: January 2021

MXene‐based organic material hybrids present huge potential for energy storage applications. However, the compatibility of hydrophilic MXenes with organic materials and their subsequent processing still remain elusive. Herein, a MXene‐based 2D sandwich‐like conjugated microporous polymer (MX‐CMP) manifesting high specific surface area and layered structure using a functionalized MXene as a 2D structure‐directing template is developed. The MX‐CMP is used as a robust organic precursor for preparing a MXene‐coupled nitrogen‐doped porous carbon (MX‐MC‐N) hybrid. The interconnected porous networks and large aspect ratio of MX‐MC‐N enhances the electrochemical active surface area and boosts the long‐distance charge transport. This leads to excellent performance for a three‐electrode, flexible all‐solid‐state supercapacitor (ASSC) and an asymmetric supercapacitor (ASC) with an expanded voltage window (1.6 V) and long‐term cyclability (>5000 cycles) compared to many state‐of‐the‐art analogous materials and hybrids. It is believed that the synthetic strategy presented for the MX‐MC‐N hybrid will indubitably pave a path for the development of novel MXenes and heteroatom‐doped porous hybrid materials for sustainable energy applications.
Functionalized Graphitic Carbon Nitrides for Environmental and Sensing Applications
Authors: Fidan Tuçe , Torabfam Milad , Saleem Qandeel , Wang Chao , Kurt Hasan , Yüce Meral , Tang Junwang , Bayazit Mustafa Kemal
Published: January 2021

Graphitic carbon nitride (g‐C3N4) is a metal‐free semiconductor that has been widely regarded as a promising candidate for sustainable energy production or storage. In recent years, g‐C3N4 has become the center of attention by virtue of its impressive properties, such as being inexpensive, easily fabricable, nontoxic, highly stable, and environment friendly. Herein, the recent research developments related to g‐C3N4 are outlined, which sheds light on its future prospective. Various synthetic methods and their impact on the properties of g‐C3N4 are detailed, along with discussion on frequently used characterization methods. Different approaches for g‐C3N4 surface functionalization, mainly categorized under covalent and noncovalent strategies, are outlined. Moreover, the processing methods of g‐C3N4, such as g‐C3N4‐based thin films, hierarchical, and hybrid structures, are explored. Next, compared with the extensively studied energy‐related applications of the modified g‐C3N4s, relatively less‐examined areas, such as environmental and sensing, are presented. By highlighting the strong potential of these materials and the existing research gaps, new researchers are encouraged to produce functional g‐C3N4‐based materials using diverse surface modification and processing routes.
Yield components of dryland winter wheat genotypes and response to seeding rate
Authors: Holman Johnathon D. , Haag Lucas A. , Schlegel Alan J. , Assefa Yared
Published: January 2021

Seeding at the optimum rate is among many decisions considered crucial for crop production. The main objective of this research was to evaluate seeding rate responses for popular dryland winter wheat (Triticum aestivum L.) varieties and determine if variety specific seeding rates were warranted. The study was conducted from 2015 through 2018 at Colby, Garden City, and Tribune, KS. The response of four winter wheat varieties Byrd, T158, TAM 111 or TAM 114, and Winterhawk at five seeding rates (34, 50, 67, 84, and 101 kg ha−1) were studied. The main effects of seeding rate and variety affected grain yield in all 12 environments with only one exception. The lowest yielding seeding rate was 34 kg ha−1 with seeding rates of 84 and 101 kg ha−1 producing the greatest yields in all years and locations. Averaged across site‐years, there was a 17% yield advantage from selecting seeding rates 67 kg ha−1 and greater compared with the lowest seeding rate (34 kg ha−1). A combination of two or more yield components was a good predictor for wheat yield response to increased seeding rate. Lower than optimum seeding rates reduced grain yield while no agronomic penalty was observed to seeding rates above the optimum. We concluded a seeding rate of 67 kg ha−1 or more and variety selection are important factors for dryland winter wheat yield in the central Great Plains region. Results of this study do not support the necessity of variety specific seeding rate for dryland wheat production in the central Great Plains.
Luminescent metal nanoclusters: Biosensing strategies and bioimaging applications
Authors: Xiao Yan , Wu Zhennan , Yao Qiaofeng , Xie Jianping
Published: January 2021

Metal nanoclusters (MNCs) are ultrasmall metal‐organic aggregates, composed of a metal core less than 2 nm and a protecting shell of metal‐organic ligand motifs. The controlled aggregation of metal atoms (in the cluster core) and metal‐organic ligand motifs (around the cluster core) renders MNCs with numerous molecule‐like properties, among which strong and bright luminescence has attracted extensive basic and applied interests. It has now known that aggregation‐induced emission is a feasible mechanism for controlling luminescence of MNCs, which makes it particularly useful in biosensing and bioimaging applications. Although the luminescence fundamentals and design principles largely determine the practicality and effectiveness of MNCs in biosensing and bioimaging applications, a systematic summary of this topic is lacking in the current literature. In this review, we aim to provide a concise discussion of the latest developments in biosensing and bioimaging applications of luminescent MNCs, highlighting their luminescence mechanisms, biosensing principles, and bioimaging strategies. Specifically, we first introduce the recent advances in the synthetic chemistry of MNCs, and then briefly discuss the luminescence fundamentals of MNCs. Then the design strategy and practicality of luminescent MNCs in biosensing and bioimaging applications are exemplified. We conclude the review with our perspectives on the further development of MNC‐based optical probes in biosensing and bioimaging applications. Our review is expected to provide guidance for the future practice of designing and synthesizing luminescent MNCs for biomedical and other applications.
Self‐assembled magnetic nanomaterials: Versatile theranostics nanoplatforms for cancer
Authors: Wang Shuren , Wang Zhiyi , Hou Yanglong
Published: January 2021

Self‐assembled magnetic nanomaterials (MNMs) are a class of promising biomaterials possessing excellent physiochemical and biological characteristics, making them highly attractive in biomedical applications. A myriad of magnetic nanosystems can be created by using self‐assembly as a synthetic tool. Favorable nano‐bio interfacial properties are shown in these promising self‐assembled magnetic nanosystems, while still retaining their physical/chemical functionalities. This review aims to provide a systematical overview of the self‐assembled MNMs. In addition, this review highlights their implementations in cancer theranostics in detail. Overall, this review points out the direction for the application of self‐assembled MNMs in biomedicine, and presents how clinical oncology could benefit from the self‐assembled nanotechnology.