scholarly journals Naturally occurring van der Waals materials

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Riccardo Frisenda ◽  
Yue Niu ◽  
Patricia Gant ◽  
Manuel Muñoz ◽  
Andres Castellanos-Gomez
Keyword(s):  
Crystal Structures ◽  
Scientific Community ◽  
2D Materials ◽  
Van Der Waals ◽  
Chemical Compositions ◽  
Naturally Occurring ◽  
Wide Range ◽  
The Family ◽  
Materials Research ◽  
Van Der Waals Materials

Abstract The exfoliation of two naturally occurring van der Waals minerals, graphite and molybdenite, arouse an unprecedented level of interest by the scientific community and shaped a whole new field of research: 2D materials research. Several years later, the family of van der Waals materials that can be exfoliated to isolate 2D materials keeps growing, but most of them are synthetic. Interestingly, in nature, plenty of naturally occurring van der Waals minerals can be found with a wide range of chemical compositions and crystal structures whose properties are mostly unexplored so far. This Perspective aims to provide an overview of different families of van der Waals minerals to stimulate their exploration in the 2D limit.

Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

2018 ◽  
Author(s):  
Sherif Tawfik ◽  
Olexandr Isayev ◽  
Catherine Stampfl ◽  
Joseph Shapter ◽  
David Winkler ◽  
...  
Keyword(s):  
Machine Learning ◽  
Band Gap ◽  
Density Functional ◽  
2D Materials ◽  
Van Der Waals ◽  
Building Blocks ◽  
Machine Learning Techniques ◽  
Interlayer Distance ◽  
Computational Screening ◽  
Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

scholarly journals Polarization-dependent optical responses in natural 2D layered mineral teallite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ravi P. N. Tripathi ◽  
Xiaodong Yang ◽  
Jie Gao
Keyword(s):  
Optical Sensors ◽  
Linear Dichroism ◽  
Layered Materials ◽  
Sulfide Mineral ◽  
Nonlinear Susceptibility ◽  
Chemical Compositions ◽  
Optical Responses ◽  
Naturally Occurring ◽  
Wide Range ◽  
Raman Modes

AbstractMulti-element layered materials enable the use of stoichiometric variation to engineer their optical responses at subwavelength scale. In this regard, naturally occurring van der Waals minerals allow us to harness a wide range of chemical compositions, crystal structures and lattice symmetries for layered materials under atomically thin limit. Recently, one type of naturally occurring sulfide mineral, ternary teallite has attained significant interest in the context of thermoelectric, optoelectronic, and photovoltaic applications, but understanding of light-matter interactions in such ternary teallite crystals is scarcely available. Herein, polarization-dependent linear and nonlinear optical responses in mechanically exfoliated teallite crystals are investigated including anisotropic Raman modes, wavelength-dependent linear dichroism, optical band gap evolution, and anisotropic third-harmonic generation (THG). Furthermore, the third-order nonlinear susceptibility of teallite crystal is estimated using the thickness-dependent THG emission process. We anticipate that our findings will open the avenue to a better understanding of the tailored light-matter interactions in complex multi-element layered materials and their implications in optical sensors, frequency modulators, integrated photonic circuits, and other nonlinear signal processing applications.

Turmeric

2020 ◽  
pp. 163-172
Author(s):  
Mazia Ahmed ◽  
Urvashi Srivastava ◽  
Chitra Gupta
Keyword(s):  
Biological Activities ◽  
Curcuma Longa ◽  
Healthy Food ◽  
Natural Food ◽  
Food Ingredient ◽  
Tropical Regions ◽  
Naturally Occurring ◽  
Diverse Field ◽  
Wide Range ◽  
The Family

Turmeric (Curcuma longa) is a rhizomatous crop found in tropical regions and belongs to the family Zingiberaceae. It was used in the form of a spice, flavoring substance, coloring agent, and as a therapeutic agent for the treatment of several human ailments for centuries. Turmeric, along with its extracts, has a very broad and diverse field of application. It is an exclusive and versatile naturally occurring plant product having properties of not only a spice but also food colorant, medicine or drug, and cosmetics. In ethnic delicacies, turmeric is a commonly used flavoring ingredient. It is also a popularly used natural food color. It exhibits several biological activities such as having antioxidant, anti-inflammatory, anticarcinogenic, antimutagenic, antimicrobial, antiviral, and antiparasitic properties. It is well known as a skincare product and a healthy food ingredient. It is found to have the capability to prevent or retard a wide range of ailments.

scholarly journals Phylogenetic evidence for homologous recombination within the family Birnaviridae

2008 ◽  
Vol 89 (12) ◽  
pp. 3156-3164 ◽  
Author(s):  
Chung-Chau Hon ◽  
Tommy Tsan-Yuk Lam ◽  
Chi-Wai Yip ◽  
Raymond Tsz-Yeung Wong ◽  
Mang Shi ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Live Attenuated Vaccine ◽  
Double Stranded Rna ◽  
Live Vaccines ◽  
Naturally Occurring ◽  
Wide Range ◽  
The Family ◽  
Bursal Disease ◽  
Comprehensive Survey ◽  
Dsrna Viruses

Birnaviruses are bi-segmented double-stranded RNA (dsRNA) viruses infecting insects, avian species and a wide range of aquatic species. Although homologous recombination is a common phenomenon in positive-sense RNA viruses, recombination in dsRNA viruses is rarely reported. Here we performed a comprehensive survey on homologous recombination in all available sequences (>1800) of the family Birnaviridae based on phylogenetic incongruence. Although inter-species recombination was not evident, potential intra-species recombination events were detected in aquabirnaviruses and infectious bursal disease virus (IBDV). Eight potential recombination events were identified and the possibility that these events were non-naturally occurring was assessed case by case. Five of the eight events were identified in IBDVs and all of these five events involved live attenuated vaccine strains. This finding suggests that homologous recombination between vaccine and wild-type IBDV strains may have occurred; the potential risk of mass vaccination using live vaccines is discussed. This is the first report of evidence for homologous recombination within the family Birnaviridae.

Transition Metal Dichalcogenide-Decorated MXenes: Promising Hybrid Electrodes for Energy Storage and Conversion Applications

2021 ◽  
Author(s):  
Hemanth N R ◽  
Taekyung Kim ◽  
Byeongyoon Kim ◽  
Arvind H. Jadhav ◽  
Kwangyeol Lee ◽  
...  
Keyword(s):  
Energy Storage ◽  
Energy Harvesting ◽  
Transition Metal ◽  
2D Materials ◽  
Energy Storage And Conversion ◽  
Transition Metal Dichalcogenide ◽  
Two Dimensional ◽  
Unique Structure ◽  
Wide Range ◽  
The Family

Various two-dimensional (2D) materials have demonstrated unique structure-dependent characteristics that are conducive to energy-harvesting applications. Among them, the family of layered MXenes has found a wide range of applications in...

scholarly journals Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

2018 ◽  
Author(s):  
Sherif Tawfik ◽  
Olexandr Isayev ◽  
Catherine Stampfl ◽  
Joseph Shapter ◽  
David Winkler ◽  
...  
Keyword(s):  
Machine Learning ◽  
Band Gap ◽  
Density Functional ◽  
2D Materials ◽  
Van Der Waals ◽  
Building Blocks ◽  
Machine Learning Techniques ◽  
Interlayer Distance ◽  
Computational Screening ◽  
Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

Quantitative and Qualitative Methods of Studying the Processes of Socialization of a Modern Teenager

2020 ◽  
pp. 102-109
Author(s):  
Svetlana Alekseevna Raschetina ◽  
Keyword(s):  
Research Methods ◽  
Interpersonal Relations ◽  
Internet Communication ◽  
Socialization Process ◽  
Wide Range ◽  
The Family ◽  
Modern Family ◽  
Making Friends ◽  
Main Support

Relevance and problem statement. Modern unstable society is characterized by narrowing the boundaries of controlled socialization and expanding the boundaries of spontaneous socialization of a teenager based on his immersion in the question arises about the importance of the family in the process of socialization of a teenager in the conditions of expanding the space of socialization. There is a need to study the role of the family in this process, to search, develop and test research methods that allow us to reveal the phenomenon of socialization from the side of its value characteristics. The purpose and methodology of the study: to identify the possibilities of a systematic and anthropological methodology for studying the role of the family in the process of socialization of adolescents in modern conditions, testing research methods: photo research on the topic “Ego – I” (author of the German sociologist H. Abels), profile update reflexive processes (by S. A. Raschetina). Materials and results of the study. The study showed that for all the problems that exist in the family of the perestroika era and in the modern family, it acts for a teenager as a value and the first (main) support in the processes of socialization. The positions well known in psychology about the importance of interpersonal relations in adolescence for the formation of attitudes towards oneself as the basis of socialization are confirmed. Today, the frontiers of making friends have expanded enormously on the basis of Internet communication. The types of activities of interest to a teenager (traditional and new ones related to digitalization) are the third pillar of socialization. Conclusion. The “Ego – I” method of photo research has a wide range of possibilities for quantitative and qualitative analysis of the socialization process to identify the value Pillars of this process.

THE VALUE OF LOVE IN THE SYSTEM OF FORMATION OF THE PROFESSIONAL MATURITY OF THE EDUCATOR

2020 ◽  
Vol 1 (10(79)) ◽  
pp. 12-18
Author(s):  
G. Bubyreva
Keyword(s):  
Russian Federation ◽  
The State ◽  
Educational Process ◽  
Wide Range ◽  
The Family ◽  
The Russian Federation ◽  
The Government ◽  
The Individual ◽  
The Right

The existing legislation determines the education as "an integral and focused process of teaching and upbringing, which represents a socially important value and shall be implemented so as to meet the interests of the individual, the family, the society and the state". However, even in this part, the meaning of the notion ‘socially significant benefit is not specified and allows for a wide range of interpretation [2]. Yet the more inconcrete is the answer to the question – "who and how should determine the interests of the individual, the family and even the state?" The national doctrine of education in the Russian Federation, which determined the goals of teaching and upbringing, the ways to attain them by means of the state policy regulating the field of education, the target achievements of the development of the educational system for the period up to 2025, approved by the Decree of the Government of the Russian Federation of October 4, 2000 #751, was abrogated by the Decree of the Government of the Russian Federation of March 29, 2014 #245 [7]. The new doctrine has not been developed so far. The RAE Academician A.B. Khutorsky believes that the absence of the national doctrine of education presents a threat to national security and a violation of the right of citizens to quality education. Accordingly, the teacher has to solve the problem of achieving the harmony of interests of the individual, the family, the society and the government on their own, which, however, judging by the officially published results, is the task that exceeds the abilities of the participants of the educational process.  The particular concern about the results of the patriotic upbringing served as a basis for the legislative initiative of the RF President V. V. Putin, who introduced the project of an amendment to the Law of RF "About Education of the Russian Federation" to the State Duma in 2020, regarding the quality of patriotic upbringing [3]. Patriotism, considered by the President of RF V. V. Putin as the only possible idea to unite the nation is "THE FEELING OF LOVE OF THE MOTHERLAND" and the readiness for every sacrifice and heroic deed for the sake of the interests of your Motherland. However, the practicing educators experience shortfalls in efficient methodologies of patriotic upbringing, which should let them bring up citizens, loving their Motherland more than themselves. The article is dedicated to solution to this problem based on the Value-sense paradigm of upbringing educational dynasty of the Kurbatovs [15].

Heterocycle Compounds with Antimicrobial Activity

2020 ◽  
Vol 26 (8) ◽  
pp. 867-904 ◽  
Author(s):  
Maria Fesatidou ◽  
Anthi Petrou ◽  
Geronikaki Athina
Keyword(s):  
Heterocyclic Compounds ◽  
Bacterial Infections ◽  
Scientific Community ◽  
Antimicrobial Agents ◽  
Fungal Infections ◽  
Biological Activities ◽  
Literature Survey ◽  
New Findings ◽  
Wide Range ◽  
Number Of Microorganisms

Background: Bacterial infections are a growing problem worldwide causing morbidity and mortality mainly in developing countries. Moreover, the increased number of microorganisms, developing multiple resistances to known drugs, due to abuse of antibiotics, is another serious problem. This problem becomes more serious for immunocompromised patients and those who are often disposed to opportunistic fungal infections. Objective: The objective of this manuscript is to give an overview of new findings in the field of antimicrobial agents among five-membered heterocyclic compounds. These heterocyclic compounds especially five-membered attracted the interest of the scientific community not only for their occurrence in nature but also due to their wide range of biological activities. Method: To reach our goal, a literature survey that covers the last decade was performed. Results: As a result, recent data on the biological activity of thiazole, thiazolidinone, benzothiazole and thiadiazole derivatives are mentioned. Conclusion: It should be mentioned that despite the progress in the development of new antimicrobial agents, there is still room for new findings. Thus, research still continues.

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