scholarly journals Mechanochromic Fluorescent Polymers with Aggregation-Induced Emission Features

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4969 ◽  
Author(s):  
Andrea Pucci

Mechanochromic polymers are defined as materials that are able to detect a mechanical stress through an optical output. This feature has evoked a growing interest in the last decades, thanks to the progress of chromogenic molecules whose optical characteristics and chemical functionalities allow their effective insertion in many thermoplastic and thermoset matrices. Among the different types of fluorogenic probes able to detect mechanical solicitations, those with aggregation-induced emission (i.e., AIEgens) have attracted tremendous interest since their discovery in 2001. In the present review, the main principles behind the AIEgens working behavior are introduced along with the current state of knowledge concerning the design and preparation of the derived mechanochromic fluorescent polymers. Examples are provided concerning the most ingenious solution for the preparation of chromogenic materials, starting from different types of commodity plastics or synthetic polymers and combined with the latest AIE technology to provide the most sensitive response to mechanical stress.

2019 ◽  
Vol 21 (15) ◽  
pp. 7717-7731 ◽  
Author(s):  
Anatoly S. Buchelnikov ◽  
Vladislav P. Evstigneev ◽  
Maxim P. Evstigneev

The present review discusses the current state-of-the-art in building models enabling the description of non-covalent equilibrium complexation of different types of molecules in solution, which results in the formation of supramolecular structures different in length and composition (hetero-association or supramolecular multicomponent co-polymerisation).


Author(s):  
Parisa Dehghani ◽  
Monireh Esameili Rad ◽  
Atefeh Zarepour ◽  
Ponnurengam Malliappan Sivakumar ◽  
Ali Zarrabi

: Diabetes mellitus (DM) is a type of chronic metabolic disease that has affected millions of people worldwide and is known with a defect in the amount of insulin secretion, insulin functions, or both. This deficiency leads to an increase in the amounts of glucose, which could be accompanied by long-term damages to other organs such as eyes, kidneys, heart, and nervous system. Thus, introducing an appropriate approach for diagnosis and treatment of different types of DM is the aim of several researches. By the emergence of nanotechnology and its application in medicine, new approaches were presented for these purposes. The object of this review article is to introduce different types of polymeric nanoparticles (PNPs), as one of the most important classes of nanoparticles, for diabetic management. To achieve this goal, at first, some of the conventional therapeutic and diagnostic methods of DM will be reviewed. Then, different types of PNPs, in two forms of natural and synthetic polymers with different properties, as a new method for DM treatment and diagnosis will be introduced. In the next section, the transport mechanisms of these types of nano-carriers across the epithelium, via paracellular and transcellular pathways will be explained. Finally, the clinical use of PNPs in the treatment and diagnosis of DM will be summarized. Based on the results of this literature review, PNPs could be considered one of the most promising methods for DM management.


2021 ◽  
Vol 37 (2) ◽  
pp. 3-19
Author(s):  
A.A. Gagarina

The present review describes the concept of probiotics for plants and analyzes the prospects for using actinomycetes as producers of these drugs. The minimum requirements for plant probiotic microorganisms are proposed, similar to those for human probiotic microorganisms. These are utility, efficiency and safety for plants, as well as mandatory isolation from plant samples. It is noted that these requirements are usually met by endophytic and rhizosphere microorganisms that stimulate plant growth and provide them with protection from phytopathogens. Evidence is given for the possibility of attributing actinomycetes to probiotic plant bacteria, due to the close relationship of these microorganisms with plants, their wide distribution in populations of endophytic and rhizosphere microorganisms, and the presence of phytoregulatory activity. The review provides examples of genera and species of actinomycetes that are promising producers of probiotics for agronomically important crops. The most studied and commercialized of them are representatives of the Streptomyces genus. The current state, prospects and problems in commercialization of probiotics based on actinomycetes are discussed. probiotic microorganisms of plants, associative actinomycetes, endophytes, rhizosphere, biological preparations


Author(s):  
Santiago García

With the rapid development of smart phones, tablets and their operative systems, many positioning enabled sensors have been built into these devices. Users can now accurately fix their location according to the function of GPS receivers. For indoor environments, as in the case we are studying, WiFi based positioning is preferred to GPS due to the attenuation or obstruction of signals. This paper deals with the automatic classification of customers in a Sports Shop Center on the basis of their movements around the shop's premises. To achieve this goal, we start by collecting (x,y) coordinates from customers while they visit the store. Consequently, any costumer's path through the shop is formed by a list of coordinates, obtained with a frequency of one measurement per minute. Then, a guess about the full trajectory is constructed and a number of parameters about these trajectories is calculated before performing an Unsupervised Learning Clustering Process. As a result, we can identify several types of customers, and the dynamics of their behavior inside the shop. This information is of great value to the company, to be used both in the long term and also in short periods of time, monitoring the current state of the shop at any moment, identifying different types of situation appearing during restricted periods, or predicting customer flow conditions


2020 ◽  
Vol 92 (4) ◽  
pp. 91-97
Author(s):  
A. S. Tokareva ◽  
N. Yu. Borovkova

A present review is devoted to the current state of the problem of blood pressure variability (BPV) in hemodialysis patients. The BPV classification and clinical significance of BPV metrics are discussed. The results of cohort and randomized studies on the high BPV influence on outcomes in hemodialysis patients, as well as on the possibilities of antihypertensive drugs in the treatment of high BPV in dialysis patients, are presented.


2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Adrián Fuentes-Luque ◽  
Pabsi Livmar González-Irizarry

Even though Audiovisual Translation (AVT) is growing and flourishing throughout the world, it is practically unheard-of in the Caribbean, where accessibility faces an even bleaker existence. The circumstances of the deaf and hard of hearing (also referred to as D/deaf) are no less alarming: social barriers and exclusion are widespread. This paper emphasizes the need to make subtitles accessible in the Spanish-speaking Caribbean, specifically on the islands of Puerto Rico, Cuba, and the Dominican Republic, and underscores the challenges faced by the D/deaf communities on each island. Our research focuses on issues like AVT laws and regulations, the habits of viewers of audiovisual (AV) products, and literacy and limitations on each island. This paper also examines the different types of D/deaf audiovisual consumers in the Spanish-speaking Caribbean and the difficulties each community faces when accessing media and entertainment. Our research reveals the current state of AVT accessibility in this region and provides a foundation for influencing legislators to begin enforcing AVT regulations and drafting SDH guidelines.


2021 ◽  
Author(s):  
Hai Zhou ◽  
Haiping Wu ◽  
Jian Xu ◽  
Hongbin Fang

Abstract Origami-inspired structures and materials have shown remarkable properties and performances originating from the intricate geometries of folding. Origami folding could be a dynamic process and origami structures could possess rich dynamic characteristics under external excitations. However, the current state of dynamics of origami has mostly focused on the dynamics of a single cell. This research has performed numerical simulations on multi-stable dual-cell series Miura-Ori structures with different types of inter-cell connections based on a dynamic model that does not neglect in-plane mass. We introduce a concept of equivalent constraint stiffness k* to distinguish different types of inter-cell connections. Results of numerical simulations reveal the multi-stable dual-cell structure will exhibit a variety of complex nonlinear dynamic responses with the increasing of connection stiffness because of the deeper energy well it has. The connection stiffness has a strong effect on the steady-state dynamic responses under different excitation amplitudes and a variety of initial conditions. This effect makes us able to adjust the dynamic behaviors of dual-cell series Miura-Ori structure to our needs in a complex environment. Furthermore, the results of this research could provide us a theoretical basis for the dynamics of origami folding and serve as guidelines for designing dynamic applications of origami metastructures and metamaterials.


Author(s):  
Santosh Tiwari ◽  
Georges Fadel ◽  
Vladimir Gantovnik

In this paper, we investigate the current state-of-the-art in packing algorithms. The focus of this survey is on the different types of encoding schemes and associated placement techniques used to represent the layout of a set of objects. The encoding schemes are investigated with respect to their suitability to different types of packing problems, specific scenarios where a given representation may outperform others and their limitations. The different types of placement algorithms that can be used with a given encoding are described. Some common desirable characteristics that an encoding scheme should follow are also discussed. Finally a qualitative comparison of the various encoding schemes is presented to help in selecting a specific representation based on a set of criteria.


Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3851
Author(s):  
Efficient N. Ncube ◽  
Lucia Steenkamp ◽  
Ian A. Dubery

Ambergris, an excretion product of sperm whales, has been a valued agent in the formulation of perfumes. The composition of ambergris consists of two major components: 40–46% cholestanol type steroids and approximately 25–45% of a triterpenoid known as ambrein. Ambergris undergoes oxidative decomposition in the environment to result in odorous compounds, such as ambraoxide, methylambraoxide, and ambracetal. Its oxidized form, ambrafuran (IUPAC name: 3a,6,6,9a-tetramethyl-2,4,5,5a,7,8,9,9b-octahydro-1H-benzo[e][1]benzofuran), is a terpene furan with a pleasant odor and unique olfactive and fixative properties. The current state of the fragrance industry uses ambrafuran materials entirely from synthetic or semisynthetic sources. However, natural compounds with the potential to be converted to ambergris-like odorants have been extracted from several different types of plants. Here we review plant terpenoids suitable as starting materials for the semisyntheses of ambrafuran or intermediates, such as ambradiol, that can be used in biocatalytic transformations to yield ambrafuran.


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