bluuebunny/crossref_metadata_2025 huggingface dataset:
The assessment of house construction situation and investments in housing development in the regions of Volga Federal District
Authors: Bushkova-Shiklina Elvira , Starikova Mariya Mikhailovna
Published: February 2021

This article is dedicated to the assessment of socioeconomic and house construction situation, as well as investments of local authorities and household sector in the development of housing facilities and infrastructure in Volga Federal District. The situation is described on the example of three regions different in the level of socioeconomic development – the Republic of Tatarstan, Nizhny Novgorod Oblast and Kirov Oblast. Analysis is conducted on such parameters as housing quantity, possibility of residential mortgage, strategies for improvement housing conditions, and planned investment volume in housing on the part of population, etc. The research is based on the analysis of the official statistical data on socioeconomic situation, as well as housing and utilities policy in the regions of Volga Federal District; survey that involved population of three cities – Kazan, Nizhny Novgorod and Kirov (total of 1560 respondents); and expert interview with 25 realtors from the indicated cities. The acquired results allow determining three clusters of the regions in accordance with socioeconomic indexes and characteristics of housing policy: regions-leaders, regions-drivers", and regions-anchors. A more detailed comparative characteristics of the official statistics in three regions – the Republic of Tatarstan, Nizhny Novgorod and Kirov regions, confirmed the results of clusterization. The population polling of the cities of Kazan, Nizhny Novgorod and Kirov complemented the picture with specific details on citizens’ perception of their living conditions and readiness to improve them. Interview with the realtors revealed the typical trends in development of house construction and residential property market in the aforementioned cities.
On the need to reform the Institution of undesirability of stay (residence) of foreign citizens in Russia in the conditions of digitalization
Authors: Paukova Yuliya Viktorovna
Published: February 2021

The subject of this research is the legislative provisions on undesirability stay (residence) of foreign citizens and stateless persons in Russia, as well as the established law enforcement practice. The object this research is the social relations developed in the process of rendering decisions by the federal executive authorities on undesirability of stay (residence) and their enforcement. The goal of this work consists in formulation of recommendations on reforming the institution of undesirability of stay (residence) of foreign citizens and stateless persons in Russia in the conditions of digitalization of the government actions. The article examines the grounds for making decisions on undesirability of stay (residence) of foreign citizens in Russia, the powers of the departments, and the consequences of decisions made on foreign citizens and stateless persons. Substantiation is made on the need for changes in the grounds for decision-making on undesirability of stay (residence) of foreign citizens in Russia. The author proposes the development and implementation of the “Automated System of Migration Control” using the advanced computer technologies based on the “rating” of a foreign citizen or stateless person. Such system will determine the period for restricting entry with consideration of all circumstances pertaining to the individual and crimes they committed. It is recommended to legislate the possibility of annulment of a decision on undesirability of stay (if the grounds thereof no longer exist) or suspension (if, for example, a stateless person has been issued a “temporary identification document of a stateless person”).
Model of decision support system in educational process of a university on the basis of learning analytics
Authors: Buldaev Alexander Alexandrovich , Naykhanova Larisa Vladimirovna , Evdokimova Inga Sergeevna
Published: February 2021

In recent decades, the potential of analytics and data mining – the methodologies that extract valuable information from big data, transformed multiple fields of scientific research. Analytics has become a trend. With regards to education, these methodologies are called the learning analytics (LA) and educational data mining (EDM). Latterly, the use of learning analytics has proliferated due to four main factors: a significant increase in data quantity, improved data formats, achievements in the area of computer science, and higher complexity of available analytical tools. This article is dedicated to the description of building the model of decision support system (DSS) of a university based on educational data acquired from digital information and educational environment. The subject of this research is the development of DSS with application of learning analytics methods. The article provides a conceptual model of decision-making system in the educational process, as well as a conceptual model of the components of DSS component – forecasting subsystem. The peculiarity of forecasting subsystem model implies usage of learning analytics methods with regards to data sets of a higher educational institution, which contain the results of work of the digital information and educational environment, and include the characteristics of student activity. The main results of the conducted research is the examined and selected methods of clusterization and classification (KNN), the testing of which demonstrated palatable results. The author examined various methods of clusterization, among which k-prototypes method showed best results. The conclusion is made on favorable potential of application of the methods of learning analytics in Russian universities.
The available methods of computer modeling of biofilms and their development trends
Authors: Konov Evgenii Aleksandrovich , Sorokoumov Petr Sergeevich
Published: February 2021

The object of this research is the available means of computer modeling of bacterial communities-biofilms. Such communities include the majority (95-99%) of bacteria and are ubiquitous. Biofilms are much more resistant than single bacteria to antibiotics and other antibacterial means due to weak permeability of intercellular environment and moderation of metabolism of some specimen of the community. Examination of influence techniques on biofilms is an important problem of biology; its solution requires various computer modeling tools that allow achieving significant scientific results. The subject of this research is the mathematical models used in modern techniques of biofilm modeling, and as well as the software for their implementation. The conclusion is made that the available methods of biofilm modeling are capable of successful reproduction of multiple behavioral aspects of these bacteria communities, including growth, destruction, and self-regulation; however, certain relevant problems are yet to be resolved. This is associated with the fact that the development of modern software for two-dimensional and three-dimensional agent modeling of biofilms – BSim, iDynoMiCS, CellModeller, require competent programmers for describing the interactions between simulated objects. Most promising direction in further development of this software implies a more active usage of tools for describing behavior and interaction of agents applied in the sphere of artificial intelligence, for example, fin-state automaton or production rules systems, with mandatory preservation of biological content of the models.
Ultrafast dynamics of electron excited states of phenylacetylene
Authors: Xiang Mei , Ling Feng-Zi , Deng Xu-Lan , Wei Jie , Bumaliya Abulimiti , Zhang Bing ,   College of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, China,   State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
Published: February 2021

Interaction of light with matter has always been important in the field of natural science. Particularly, the ultrafast radiationless relaxation induced by UV light of molecular electronic excited states accompanied by ultrafast energy transfer plays an important role in the natural photophysical, photochemical and biological reactions. Generally, the molecular electronic excited state can be deactivated through a variety of decay channels, including dissociation, isomerization, internal conversion, intersysterm crossing, vibrational energy redistribution, and autoionization. This complexity of relaxation channels brings about a wide variety of deactivation mechanisms. The ultrafast nonadibatic relaxation dynamics of the excited state of phenylacetylene is studied by using femtosecond time-resolved photoelectron imaging and femtosecond time-resolved mass spectrometry. The first excited state S2 of phenylacetylene is excited by 235 nm pump light, and the excited state deactivation process is detected by 400 nm probe light. The time-dependent curves of parent ions include two exponential curves. One is the fast component with a time constant of 116 fs, and the other is the slow component with a time constant of 106 ps. The time-resolved photoelectron kinetic energy distribution is obtained from the time-resolved photoelectron images. Combined with the time-resolved photoelectron spectroscopy data, the fast component with a time constant of 116 fs is found to reflect the internal conversion process from S2 state to S1 state. The experimental results also show that S1 state is arranged by internal conversion, and the inter system jump process to T1 state is an important attenuation channel. This work provides a clearer physical picture for S1 state nonadibatic relaxation dynamics of phenylacetylene.
Integration of IL-2 and IL-4 signals coordinates divergent regulatory T cell responses and drives therapeutic efficacy
Authors: Zhou Julie Y , Alvarez Carlos A , Cobb Brian A
Published: February 2021

Cells exist within complex milieus of communicating factors, such as cytokines, that combine to generate context-specific responses, yet nearly all knowledge about the function of each cytokine and the signaling propagated downstream of their recognition is based on the response to individual cytokines. Here, we found that regulatory T cells (Tregs) integrate concurrent signaling initiated by IL-2 and IL-4 to generate a response divergent from the sum of the two pathways in isolation. IL-4 stimulation of STAT6 phosphorylation was blocked by IL-2, while IL-2 and IL-4 synergized to enhance STAT5 phosphorylation, IL-10 production, and the selective proliferation of IL-10-producing Tregs, leading to increased inhibition of conventional T cell activation and the reversal of asthma and multiple sclerosis in mice. These data define a mechanism of combinatorial cytokine signaling and lay the foundation upon which to better understand the origins of cytokine pleiotropy while informing improved the clinical use of cytokines.
March Mammal Madness and the power of narrative in science outreach
Authors: Hinde Katie , Amorim Carlos Eduardo G , Brokaw Alyson F , Burt Nicole , Casillas Mary C , Chen Albert , Chestnut Tara , Connors Patrice K , Dasari Mauna , Ditelberg Connor Fox , Dietrick Jeanne , Drew Josh , Durgavich Lara , Easterling Brian , Henning Charon , Hilborn Anne , Karlsson Elinor K , Kissel Marc , Kobylecky Jennifer , Krell Jason , Lee Danielle N , Lesciotto Kate M , Lewton Kristi L , Light Jessica E , Martin Jessica , Murphy Asia , Nickley William , Núñez-de la Mora Alejandra , Pellicer Olivia , Pellicer Valeria , Perry Anali Maughan , Schuttler Stephanie G , Stone Anne C , Tanis Brian , Weber Jesse , Wilson Melissa , Willcocks Emma , Anderson Christopher N
Published: February 2021

March Mammal Madness is a science outreach project that, over the course of several weeks in March, reaches hundreds of thousands of people in the United States every year. We combine four approaches to science outreach – gamification, social media platforms, community event(s), and creative products – to run a simulated tournament in which 64 animals compete to become the tournament champion. While the encounters between the animals are hypothetical, the outcomes rely on empirical evidence from the scientific literature. Players select their favored combatants beforehand, and during the tournament scientists translate the academic literature into gripping “play-by-play” narration on social media. To date ~1100 scholarly works, covering almost 400 taxa, have been transformed into science stories. March Mammal Madness is most typically used by high-school educators teaching life sciences, and we estimate that our materials reached ~1% of high-school students in the United States in 2019. Here we document the intentional design, public engagement, and magnitude of reach of the project. We further explain how human psychological and cognitive adaptations for shared experiences, social learning, narrative, and imagery contribute to the widespread use of March Mammal Madness.
Refining the marine reptile turnover at the Early–Middle Jurassic transition
Authors: Fischer Valentin , Weis Robert , Thuy Ben
Published: February 2021

Even though a handful of long-lived reptilian clades dominated Mesozoic marine ecosystems, several biotic turnovers drastically changed the taxonomic composition of these communities. A seemingly slow paced, within-geological period turnover took place across the Early–Middle Jurassic transition. This turnover saw the demise of early neoichthyosaurians, rhomaleosaurid plesiosaurians and early plesiosauroids in favour of ophthalmosaurid ichthyosaurians and cryptoclidid and pliosaurid plesiosaurians, clades that will dominate the Late Jurassic and, for two of them, the entire Early Cretaceous as well. The fossil record of this turnover is however extremely poor and this change of dominance appears to be spread across the entire middle Toarcian–Bathonian interval. We describe a series of ichthyosaurian and plesiosaurian specimens from successive geological formations in Luxembourg and Belgium that detail the evolution of marine reptile assemblages across the Early–Middle Jurassic transition within a single area, the Belgo–Luxembourgian sub-basin. These fossils reveal the continuing dominance of large rhomaleosaurid plesiosaurians, microcleidid plesiosaurians andTemnodontosaurus-like ichthyosaurians up to the latest Toarcian, indicating that the structuration of the upper tier of Western Europe marine ecosystems remained essentially constant up to the very end of the Early Jurassic. These fossils also suddenly record ophthalmosaurid ichthyosaurians and cryptoclidid plesiosaurians by the early Bajocian. These results from a geographically-restricted area provide a clearer picture of the shape of the marine reptile turnover occurring at the early–Middle Jurassic transition. This event appears restricted to the sole Aalenian stage, reducing the uncertainty of its duration, at least for ichthyosaurians and plesiosaurians, to 4 instead of 14 million years.
The Existence and Uniqueness of the Solution of a Diusive Predator-Prey Model with Omnivory and General Nonlinear Functional Response
Authors: Yang Wensheng
Published: February 2021

In this work, we consider a three species modified Lesie-Gower food web model with general  nonlinear functional response and omnivory which is defined as feeding on more than one trophic level. The carrying capacity of the model is proportional to the population size of the biotic resource plus a const. The main objective of this paper is to investigate the existence and  uniqueness of the solution of this model. It is shown that the omnivory has important influence on the existence and uniqueness of the solution of the model.
Mechanical Modeling Study on the Impact of Pick-and-Place Design on Die Attach Voids
Authors: Talledo Jefferson
Published: February 2021

Pick-and-place (PnP) rubber tip is used for the die attach process in semiconductor packaging. During the die attach process involving a very thin integrated circuit (IC) die, voids in the die attach film (DAF) adhesive were observed. This paper presents the modeling study conducted to understand the impact of PnP rubber tip design on the occurrence of DAF voids. Mechanical modeling was done to simulate the deformation of the very thin die when it is picked using the PnP rubber tip. Different PnP rubber tip designs were modeled. The results revealed that the die deforms during the die pick up process because of the vacuum force, and rubber tip design affects the amount of deformation. It was also found out that more DAF voids occur when the resulting die deformation is larger.
Stress Modeling Study on Package Crack Due to Debris
Authors: Talledo Jefferson
Published: February 2021

Very thin semiconductor package is very prone to package crack. This paper discusses the stress modeling study conducted to understand the package crack problem in a specific smart card package. Finite element analysis (FEA) was used to analyze the maximum package stress level and corresponding location to find out if the presence of debris during the package assembly punching process could cause such problem and how it would happen. Based on the stress results, it was confirmed that even with a 60μm-thick piece of debris under the package, crack at the top is possible due to package bending and mold stress exceeding the flexural strength of the package mold material. The stress increases as the debris location is moved closer to the area where force is applied during the punching process. The study shows that the presence of debris should not be taken for granted though how small the debris may seem because significantly high bending stress could still be induced especially for very thin packages. Eliminating any source of debris in the package assembly process.is very important to prevent package crack.
Using 3D Printing for Pre-planning of Orthopedic Surgeries, a Review
Authors: Mosleh Hamidreza , Nazeri Shahab Aldin , Mehdizadeh Mehdi , Moradi Fatemeh , Mosleh Hoda , Shabani Ronak , Sajjadi Mohammadreza Miniator
Published: February 2021

Background: Recent developments in 3D printing have gave orthopedic surgeons among a novel technology that has the ability to revolutionize preoperative planning. The appearance of 3D printing technology (3DPT) enables the digital preoperative plan & simulation to move from the virtual phase to the reality phase. Numerous fields of medicine are lately benefiting from the operate of 3D printing, including the arising part of 3D printing in orthopedic surgery.

Methods: We searched on PubMed and Google Scholar databases in January 2020 to find papers and studies about using 3D printing in orthopedy for aim of preplanning. The key words for search were (“3D printing” OR “3D-printed Model” OR “three-dimensional Printer”) AND (“Orthopedy” OR “Orthopedics” OR “Orthopedics”) AND (“Surgery” OR “Operation”) AND (“Pre-planning” OR “Plan”) AND (“Fracture” OR “Trauma”) that we used compound. We exclude the papers which their titles or abstracts were not relevant. At last, we select the most related papers to use in this article.

Results: The search on PubMed found 80 Papers and on Google Scholar found 104 papers. After excluding similar and unrelated papers, 44 papers were selected for this review article.

Conclusion: Almost all studies have shown us that using a 3D model can have a very positive effect on the surgical process and its outcomes, as well as patient and surgeon satisfaction. Therefore, we anticipate that this technology will be used in many orthopedic surgeries in the near future.
Deadly dormmate: A case study on Bungarus candidus living among a student dormitory with implications for human safety
Authors: Hodges Cameron Wesley , Barnes Curt Hrad , Patungtaro Porramin , Strine Colin Thomas
Published: February 2021

1. Snakebite, which was reclassified as a neglected tropical disease by the World Health Organization in 2017, afflicts at least 1.8–2.7 million people worldwide each year. Understanding the habits of medically significant snakes can help us better construct preventative measures which reduce snake–human conflicts and snakebite.

2. As a case study, using radio‐telemetry, we monitored a single focal Bungarus candidus individual for 102 days within a suburban landscape (a university dormitory complex) in Nakhon Ratchasima, Thailand.

3. Daily location checks revealed the telemetered snake sheltered within human settlement habitat 75% of the time it was tracked, where we also documented active foraging, a predation event and interactions with humans.

4. Despite being captured and relocated to an adjacent forest on two occasions, the focal animal promptly returned to the dormitories. Translocation as a management tool requires meaningful discussion at the local level and further study, considering the costs and potential limitations for effectiveness.

5. This case study provides brief insight into the ecology and behaviour of one of Asia's most medically significant snake species and highlights challenges current conflict management practices face locally. Our observations appear to lend credibility to preventative measures such as increasing awareness, encouraging the use of flashlights and carefully maintaining buildings so that snakes cannot enter through crevices or plumbing. Snake–human conflict prevention and mitigation techniques require further evaluation to determine the effectiveness of prescribed management methods.
Successful weaning from mechanical ventilation in a patient with SMA type 1 treated with nusinersen
Authors: Lee Jiwon , Park Se Eun , Lee Dajeong , Song Joo Young , Lee Jeehun
Published: February 2021

SMA type 1 is the most severe type, characterized by early onset at <6 months of age, and rapid progression resulting in permanent assisted ventilation before 2 years of life. Supportive care was the only treatment until the approval of nusinersen, an antisense oligonucleotide drug that increases functional SMN protein levels. We present a case of successful weaning from permanent ventilation via tracheostomy with nusinersen in an infant who had been diagnosed with SMA type 1 at the age of one month and had become ventilator‐dependent from the age of 3 months.
A meta‐analysis of the global impact of the COVID‐19 pandemic on stroke care & the Houston Experience
Authors: Reddy Sujan T. , Satani Nikunj , Beauchamp Jennifer E. S. , Selvaraj Sudhakar , Rajan Suja S. , Rahbar Mohammad H. , Tahanan Amirali , Kim Sori , Holder Travis , Jiang Xiaoqian , Chen Luyao , Kamal Haris , Indupuru Hari Kishan R. , Wu Tzu‐Ching , Savitz Sean I.
Published: February 2021

Objective

To review the global impact of the COVID‐19 pandemic on stroke care‐metrics and report data from a health system in Houston.

Methods

We performed a meta‐analysis of the published literature reporting stroke admissions, intracerebral hemorrhage (ICH) cases, number of thrombolysis (tPA) and thrombectomy (MT) cases, and time metrics (door to needle, DTN; and door to groin time, DTG) during the pandemic compared to prepandemic period. Within our hospital system, between January–June 2019 and January–June 2020, we compared the proportion of stroke admissions and door to tPA and MT times.

Results

A total of 32,640 stroke admissions from 29 studies were assessed. Compared to prepandemic period, the mean ratio of stroke admissions during the pandemic was 70.78% [95% CI, 65.02%, 76.54%], ICH cases was 83.10% [95% CI, 71.01%, 95.17%], tPA cases was 81.74% [95% CI, 72.33%, 91.16%], and MT cases was 88.63% [95% CI, 74.12%, 103.13%], whereas DTN time was 104.48% [95% CI, 95.52%, 113.44%] and DTG was 104.30% [95% CI, 81.99%, 126.61%].

In Houston, a total of 4808 cases were assessed. There was an initial drop of ~30% in cases at the pandemic onset. Compared to 2019, there was a significant reduction in mild strokes (NIHSS 1‐5) [N (%), 891 (43) vs 635 (40), P = 0.02]. There were similar mean (SD) (mins) DTN [44 (17) vs 42 (17), P = 0.14] but significantly prolonged DTG times [94 (15) vs 85 (20), P = 0.005] in 2020.

Interpretation

The COVID‐19 pandemic led to a global reduction in stroke admissions and treatment interventions and prolonged treatment time metrics.
Carbon Nanoparticles as Versatile Auxiliary Components of Perovskite‐Based Optoelectronic Devices
Authors: Litvin Aleksandr P. , Zhang Xiaoyu , Ushakova Elena V. , Rogach Andrey L.
Published: February 2021

Metal halide perovskite‐based optoelectronics has experienced an unprecedented development in the last decade, while further improvements of efficiency, stability, and economic gains of such devices require novel engineering concepts. The use of carbon nanoparticles as versatile auxiliary components of perovskite‐based optoelectronic devices is one strategy that offers several advantages in this respect. In this review, first, a brief introduction is offered on metal halide perovskites and on the major performance characteristics of related optoelectronic devices. Then, the versatility and merits of different kinds of carbon nanoparticles, such as graphene quantum dots and carbon dots, are discussed. The tunability of their electronic properties is focused upon, their interactions with perovskite components are analyzed, and different strategies of their implementation in optoelectronic devices are introduced, which include solar cells, light‐emitting diodes, luminescent solar concentrators, and photodetectors. It is shown how carbon nanoparticles influence charge carriers extraction and transport, promote perovskite crystallization, allow for efficient passivation, block ion migration, suppress hysteresis, enhance their environmental stability, and thus improve the performance of perovskite‐based optoelectronic devices.
Liquid Alloy Enabled Solid‐State Batteries for Conformal Electrode–Electrolyte Interfaces
Authors: Guo Xuelin , Bae Jiwoong , Ding Yu , Zhang Xiao , Yu Guihua
Published: February 2021

Recent research efforts on solid‐state alkali‐metal batteries are pushing the limit of energy density to a higher level. However, the development of solid‐state batteries is still hindered by many intrinsic limitations, among which the incompatibility between the solid electrolyte and the metal anode is a critical issue attracting massive research attention. A Na–K liquid alloy electrode is designed to form a conformal electrode–electrolyte interface with a solid electrolyte. Much enhanced electrode–electrolyte interfacial contact electrically and physically is observed with liquid metal anodes than solid alkali metals on solid electrolytes. Symmetric cells of the liquid metal electrolytes show much lower overpotential as well as better cyclability than the alkali‐metal electrodes. Excellent cyclability over 500 cycles with reasonable capacity decay and good rate performance of full cells with the sodium rhodizonate and a ferricyanide potassium‐ion cathode are both achieved. By adjusting salt and filler species in the polymer electrolyte, the wettability of liquid metal on the electrolyte can be further improved, and the raised ionic conductivity can further improve the battery performance of such a design.
Volatile Ultrafast Switching at Multilevel Nonvolatile States of Phase Change Material for Active Flexible Terahertz Metadevices
Authors: Pitchappa Prakash , Kumar Abhishek , Prakash Saurav , Jani Hariom , Medwal Rohit , Mishra Mayank , Rawat Rajdeep Singh , Venkatesan Thirumalai , Wang Nan , Singh Ranjan
Published: February 2021

Phase change materials provide unique reconfigurable properties for photonic applications that mainly arise from their exotic characteristic to reversibly switch between the amorphous and crystalline nonvolatile phases. Optical pulse based reversible switching of nonvolatile phases is exploited in various nanophotonic devices. However, large area reversible switching is extremely challenging and has hindered its translation into a technologically significant terahertz spectral domain. Here, this limitation is circumvented by exploiting the semiconducting nature of germanium antimony telluride (GST) to achieve dynamic terahertz control at picosecond timescales. It is also shown that the ultrafast response can be actively altered by changing the crystallographic phase of GST.  The ease of fabrication of phase change materials allows for the realization of a variable ultrafast terahertz modulator on a flexible platform. The rich properties of phase change materials combined with the diverse functionalities of metamaterials and all‐optical ultrafast control enables an ideal platform for design of efficient terahertz communication devices, terahertz neuromorphic photonics, and smart sensor systems.
Co and Pt Dual‐Single‐Atoms with Oxygen‐Coordinated Co–O–Pt Dimer Sites for Ultrahigh Photocatalytic Hydrogen Evolution Efficiency
Authors: Wang Cong , Wang Kaiwen , Feng Yibo , Li Chong , Zhou Xiaoyuan , Gan Liyong , Feng Yajie , Zhou Hanjun , Zhang Bin , Qu Xianlin , Li Hui , Li Jieyuan , Li Ang , Sun Yiyang , Zhang Shengbai , Yang Guo , Guo Yizhong , Yang Shize , Zhou Tianhua , Dong Fan , Zheng Kun , Wang Lihua , Huang Jun , Zhang Ze , Han Xiaodong
Published: February 2021

The platinum single‐atom‐catalyst is verified as a very successful route to approach the size limit of Pt catalysts, while how to further improve the catalytic efficiency of Pt is a fundamental scientific question and is challenging because the size issue of Pt is approached at the ultimate ceiling as single atoms. Here, a new route for further improving Pt catalytic efficiency by cobalt (Co) and Pt dual‐single‐atoms on titanium dioxide (TiO2) surfaces, which contains a fraction of nonbonding oxygen‐coordinated Co–O–Pt dimers, is reported. These Co–Pt dimer sites originate from loading high‐density Pt single‐atoms and Co single‐atoms, with them anchoring randomly on the TiO2 substrate. This dual‐single‐atom catalyst yields 13.4% dimer sites and exhibits an ultrahigh and stable photocatalytic activity with a rate of 43.467 mmol g−1 h−1 and external quantum efficiency of ≈83.4% at 365 nm. This activity far exceeds those of equal amounts of Pt single‐atom and typical Pt clustered catalysts by 1.92 and 1.64 times, respectively. The enhancement mechanism relies on the oxygen‐coordinated Co–O–Pt dimer coupling, which can mutually optimize the electronic states of both Pt and Co sites to weaken H* binding. Namely, the “mute” Co single‐atom is activated by Pt single‐atom and the activity of the Pt atom is further enhanced through the dimer interaction. This strategy of nonbonding interactive dimer sites and the oxygen‐mediated catalytic mechanisms provide emerging rich opportunities for greatly improving the catalytic efficiency and developing novel catalysts with creating new electronic states.
Stacking Relations and Substrate Interaction of Graphene on Copper Foil
Authors: Schädlich Philip , Speck Florian , Bouhafs Chamseddine , Mishra Neeraj , Forti Stiven , Coletti Camilla , Seyller Thomas
Published: February 2021

The crystallinity of graphene flakes and their orientation with respect to the Cu(111) substrate are investigated by means of low‐energy electron microscopy (LEEM). The interplay between graphene and the metal substrate during chemical vapor deposition (CVD) introduces a restructuring of the metal surface into surface facets, which undergo a step bunching process during the growth of additional layers. Moreover, the surface facets introduce strain between the successively nucleated layers that follow the topography in a carpet‐like fashion. The strain leads to dislocations in between domains of relaxed Bernal stacking. After the transfer onto an epitaxial buffer layer, the imprinted rippled structure of even monolayer graphene as well as the stacking dislocations are preserved. A similar behavior might also be expected for other CVD grown 2D materials such as hexagonal boron nitride or transition metal dichalcogenides, where stacking relations after transfer on a target substrate or heterostructure could become important in future experiments.
Formation and Activity Enhancement of Surface Hydrides by the Metal–Oxide Interface
Authors: Wang Beibei , Zhang Lunjia , Cai Jun , Peng Zheng , Cheng Peihong , Li Xiaobao , Zhang Hui , Yang Fan , Liu Zhi
Published: February 2021

The observation of hydride species in reduced ceria has triggered recent interest because the formation of hydrides in solid catalysts is limited although hydrides are widely explored in homogeneous catalysis as active species for hydrogenation reactions. Here, a strategy is proposed to enhance the formation and activity of surface hydrides on oxide‐based catalysts via the construction of metal–oxide interface. Specifically, during the reaction with H2, Cu supported on CeO2 nanorods (NRs) is found to enhance the formation of hydride species, with the capacity more than an order of magnitude higher than that of CeO2 NRs. Moreover, sub‐nanometer clusters (sub‐NCs) of Cu supported on CeO2 NRs can enhance the formation and activity of surface hydrides, much more superior to that of Cu nanoparticles on CeO2 NRs. A combination of ambient‐pressure photoelectron spectroscopy techniques has enabled in situ measurements of hydrogen interaction and as such to directly correlate the electronic structures of solid catalysts with their activity. A strong metal–support interaction between undersaturated Cu clusters with CeO2 is found to account for the enhanced stability and reactivity of surface hydrides at the (sub‐NCs) Cu–CeO2 interface, which provides insight for the design of highly efficient catalysts for catalytic hydrogenation reactions.
Coherent Networks of Si Nanocrystals: Tunable Collective Resonances with Narrow Spectral Widths
Authors: Sadeghi Seyed M. , Gutha Rithvik R.
Published: February 2021

The ultralong coherent networks of Si nanocrystals (NCs) via lattice‐enhanced dipole–dipole coupling and the formation of disordered arrays of phase‐correlated field hotspots are studied. Such arrays occur in structures consisting of Si NCs randomly positioned inside long strips that are periodically repeated. The theoretical results predict the formation of all‐dielectric coherent networks of Si NCs, formed via in‐phase coupling of the resonances generated by diffraction of light. Such networks are extended along the lengths of the strips while supporting high field enhancement associated with the phase‐correlated chains of field hotspots between the nanocrystals. It is shown that these phenomena occur at the wavelengths where the Rayleigh anomaly condition is satisfied. Under this condition the electric field is squeezed between two field‐impenetrable regions, causing efficient concentration of electromagnetic energy along the disordered arrays of Si NCs in each strip. The results show that these arrays act as coherently assembled units that are efficiently coupled with the lattice modes, forming highly tunable collective resonances with spectral widths less than 5 nm. These results pave the way for all‐dielectric‐tunable optical filters with very small losses and near‐perfect reflectivity and laser systems based on Si NCs.
Light‐Powered Microrobots: Challenges and Opportunities for Hard and Soft Responsive Microswimmers
Authors: Bunea Ada‐Ioana , Martella Daniele , Nocentini Sara , Parmeggiani Camilla , Taboryski Rafael , Wiersma Diederik S.
Published: February 2021

Worldwide research in microrobotics has exploded in the past two decades, leading to the development of microrobots propelled in various manners. Despite significant advances in the field and successful demonstration of a wide range of applications, microrobots have yet to become the preferred choice outside a laboratory environment. After introducing available microrobotic propulsion and control mechanisms, microrobots that are manufactured and powered by light are focused herein. Referring to pioneering works and recent interesting examples, light is presented not only as a fabrication tool, by means of two‐photon polymerization direct laser writing, but also as an actuator for microrobots in both hard and soft stimuli–responsive polymers. In this scenario, a number of challenges that yet prevent polymeric light‐powered microrobots from reaching their full potential are identified, whereas potential solutions to overcome said challenges are suggested. As an outlook, a number of real‐world applications that light‐powered microrobots should be particularly suited for are mentioned, together with the advances needed for them to achieve such purposes. An interdisciplinary approach combining materials science, microfabrication, photonics, and data science should be conducive to the next generation of microrobots and will ultimately foster the translation of microrobotic applications into the real world.
Nanoparticulate Systems for Bioactive Agent Delivery: What Is the Missing Link in Research for Real Applications?
Authors: Lai Wing-Fu , Wong Wing-Tak
Published: February 2021

Diverse nanoparticulate systems, ranging from polymeric nanoparticles to liposomes, have been exploited as carriers of bioactive agents in recent years; however, the use of these systems has been confined largely to the laboratory context till now. Systems that can successfully be adopted for bioactive agent delivery in practice are few. Herein, such low efficiency in clinical translation is partly due to the lack of awareness of the similar nature between a carrier and a real drug. To rectify this situation, it is important to treat a carrier as an ordinary drug despite its absence of therapeutic effects. The current situation in prevalent bioactive agent delivery research, as well as those routine research practices that should be changed to enhance clinical translation, will be discussed here.
Cadmium Selenide Quantum Dots for Solar Cell Applications: A Review
Authors: Rahman Mohammad Mominur , Karim Mohammad Rezaul , Alharbi Hamad F. , Aldokhayel Belal , Uzzaman Tauriq , Zahir Hasan
Published: February 2021

Quantum dot‐sensitized solar cells (QDSSCs) are significant energy‐producing devices due to their remarkable capability to growing sunshine and produce many electrons/holes pairs, easy manufacturing, and low cost. However, their power conversion efficiency (4%) is usually worse than that of dye‐sensitized solar cells (≤12%); this is mainly due to their narrow absorption areas and the charge recombination happening at the quantum dot/electrolyte and Ti
/electrolyte interfaces. Thus, to raise the power conversion efficiency of QDSSC, new counter electrodes, working electrodes, sensitizers, and electrolytes are required. CdSe thin films have shown great potential for use in photodetectors, solar cells, biosensors, light‐emitting diodes, and biomedical imaging systems. This article reviews the CdSe nanomaterials that have been recently used in QDSSCs as sensitizers. Their size, design, morphology, and density all noticeably influence the electron injection efficiency and light‐harvesting capacity of these devices. A detailed overview of the development of QDSSCs is presented, including their basic principles, the synthesis methods for their CdSe quantum dots, and the device fabrication processes. Finally, the challenges and opportunities of realizing high‐performance CdSe QDSSCs are discussed and some future directions are suggested.
On the critical endpoint and the first‐order phase transition in the extended Polyakov Nambu Jona‐Lasinio Lagrangian
Authors: Aichelin Jörg , Fuseau David , Torres‐Rincon Juan
Published: February 2021

The (Polyakov) Nambu‐ Jona‐Lasinio (PNJL) approach is an effective theory for low energies which shares with Quantumchromodynamics (QCD) the global symmetries. This approach is easy to handle and allows for analytical results for many of the observables which are of interest for the studies of ultrarelativistic heavy‐ion collisions but also for the merger and collisions of neutron stars. It allows in particular to study the density and temperature dependence of quark masses and of the masses of mesons and baryons as well as the chiral phase transition. In recent times, this transition came in the focus of interest because it is expected that the upcoming experiments at the Fair (Germany) and NICA (Russia) facilities will observe a Quark‐Gluon‐Plasma (QGP) at finite baryon chemical potential. In this contribution, we show that the extended PNJL model is able to describe the properties of symmetric matter at vanishing chemical potential, as determined by lQCD calculations.
Mechanochemical Synthesis of CD‐MOFs and Application as a Cosmetic Ingredient
Authors: Kang Hye Ji , Choi Yong Han , Joo Il Woo , Lee Ji Ean
Published: February 2021

The cyclodextrins (CDs) are widely used in food, pharmaceutical, textile, and cosmetic industries. The CD macrocycles can be applied in various fields by coordinating with metals to synthesize coordination polymers. In this study, cyclodextrin‐metal–organic frameworks (CD‐MOFs) were successfully synthesized using two different methods for the reaction between cyclodextrin and potassium. The structural identities of the CD‐MOF‐a and CD‐MOF‐b synthesized by two methods were confirmed through 1H NMR, powder X‐ray diffraction, and FTIR measurements. In addition, substances, such as ferulic acid, salicylic acid, and so on, that were difficult to use as cosmetic ingredients due to their water insolubility, were easily encapsulated within CD‐MOFs, and the resulting amounts of loading were determined using 1H NMR, FT‐IR, and HPLC analyses.
Giant hepatic cyst causing lower extremity edema and scoliosis
Authors: Hirayama Ichiro , Inokuchi Ryota , Fukue Masataka , Doi Kent
Published: February 2021

Hepatic cysts usually do not cause symptoms and may be detected incidentally on abdominal imaging. However, a giant hepatic cyst can rarely compress the inferior vena cava, right lung, and spine, leading to edema of lower extremities and scoliosis.
Eclampsia and postpartum onset of subarachnoid hemorrhage in dual setting of cerebral venous thrombosis and posterior reversible encephalopathy syndrome: A case report
Authors: Tshering Sangay , Youden Sonam , Pema Dechen
Published: February 2021

Subarachnoid hemorrhage (SAH) can be an initial presentation of cerebral venous thrombosis. Eclampsia and postpartum onset of SAH should prompt physicians to identify possible causes and institute prompt management to avert irreversible cerebrovascular sequelae.
Three‐dimensional Porous Co Doped VN Nanosheet Arrays as Cathode Electrode for Alkaline Water Electrolysis
Authors: Xu Haitao , Du Peng , Zhang Xiaofan , Qiu Hua‐Jun
Published: February 2021

Alkaline anion exchange membrane (AEM) water electrolysis is currently the most promising hydrogen production technology, and the development of non‐precious metal‐based hydrogen evolution reaction (HER) electrocatalysts with high performance and low price is one of the greatest challenges for large‐scale AEM. Although the reaction mechanism of HER under alkaline conditions is very different from acidic conditions, many researchers still believe that the HER activity is determined by Gibbs free energy for hydrogen absorption (ΔGH*) in all pH environments. In the meantime, vanadium‐based nitrides are rarely reported as alkaline HER catalysts due to the large density unoccupied orbitals of V cause high ΔGH* value. Herein, we prepare nanoporous VN sheet arrays (NSAs) with high specific surface by hydrothermal‐nitriding treatment, and then optimize its electronic structure via varying the doping amount of Co. As a result, the Co doped VN NSAs display an outstanding HER performance (overpotential of 37 mV at 10 mA cm−2 and Tafel slope of 41 mV dec−1), which is even close to the commercial Pt/C catalyst under alkaline conditions. Moreover, by combining theoretical calculations and HER performances under acid and basic conditions, we find that the adsorption/desorption of hydrogen on activity sites could not fully revealed by ΔGH*. This work opens up a new door to understand the mechanism of alkaline HER reaction and the development of HER electrocatalysts.
Molten Salt Derived Nb2CTx MXene Anode for Li‐ion Batteries
Authors: Dong Hanyu , Xiao Peng , Jin Na , Wang Binbin , Liu Ying , Lin Zifeng
Published: February 2021

2D MXenes, are receiving increasing attention thanks to their outstanding performance for electrochemical energy‐storage applications. So far, Ti3C2 is the most studied MXene, while less effort is dedicated to investigating many other MXenes. In this paper, we report the preparation of Nb2CTx MXene by Lewis acidic etching in molten salts. The achieved Nb2CTx MXene is able to deliver a maximum lithium storage capacity up to 330 mAh g−1 at 0.05 A g−1, outperforming the maximum capacity (205 mAh g−1) achieved by molten salt derived Ti3C2Tx MXene. The high‐rate performance is also obtained with a capacity of 80 mAh g−1 at 10 A g−1 (100 C). This work highlights the promising potential of Nb‐based MXenes to be explored as high‐rate lithium storage electrodes.
Air‐Steam Etched Construction of Hierarchically Porous Metal‐Organic Frameworks
Authors: Huang Hongliang , Sun Yuxiu , Jia Xuemeng , Xue Wenjuan , Geng Chenxu , Zhao Xin , Mei Donghai , Zhong Chongli
Published: February 2021

Main observation and conclusion

The introduction of mesoporosity into the microporous metal‐organic frameworks (MOFs) is expected to expand their applications. Herein, we report a green and facile method to obtain hierarchically porous MOF structures by using an air‐steam etching process. By virtue of the protonation reaction between the imidazole moiety and water vapor, the protonated imidazole related linkers leave the framework, resulting in the formation of mesopores in the zeolitic imidazolate frameworks (ZIFs), as exemplified by ZIF‐8. Given the mild etching process, the materials’ structural integrity and crystallinity are well maintained. Accordingly, the hierarchical porous ZIF‐8 exhibited enhanced performance in the dye removal as well as CO2 cycloaddition reaction with epichlorohydrin in comparison with microporous ZIF‐8, owing to the accelerated mass transfer arising from mesoporous structures. Remarkably, the proposed steam etching approach is generally applicable, which can be readily extended to other ZIFs, such as ZIF‐14, ZIF‐69, and ZIF‐71, thus representing a powerful strategy to construct hierarchically porous MOF materials.
Adaptive banding covariance estimation for high‐dimensional multivariate longitudinal data
Authors: Qian Fang , Zhang Weiping , Chen Yu
Published: February 2021

Modelling the covariance matrix of multiple responses in longitudinal data plays a vital role. It is more challenging than its univariate counterpart due to the presence of correlations among multiple responses. Using the modified Cholesky block decomposition, we impose an adaptive block‐banded structure on the Cholesky factor and sparsity on the innovation variance matrices via a novel convex hierarchical penalty and lasso penalty, respectively. The resulting adaptive block‐banding regularized estimator is fully data‐driven and has more flexibility than regular banding estimators. We develop an efficient alternative convex optimization algorithm using the Alternating Direction Method of Multipliers (ADMM) algorithm. The resulting estimators converge optimally in the Frobenius norm. We establish row‐specific support recovery for the precision matrix. Simulations and real data analysis show that the proposed estimator is better able to reveal banding sparsity patterns in data.