In this paper, spherical gold nanoparticles (AuNPs), rod-shape AuNPs and triangular AuNPs were synthesized using CTAB as the coating reagent, and their bactericidal properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were studied. By the plate count method and turbidity method, the minimum bactericidal concentrations (MBC) and the minimum bacteriostasis concentrations (MIC) to the two kinds of bacteria were determined. The MIC of rod-shape AuNPs, triangular AuNPs and spherical AuNPs to E. coli were 0.65 μg/mL, 3.71 μg/mL, 21.21 μg/mL, and MBC were 1.30 μg/mL, 11.09 μg/mL, 21.21 μg/mL, respectively. The MIC to S. aureus were 0.26 μg/mL, 0.56 μg/mL, 2.65 μg/mL, while MBC were 0.52 μg/mL, 1.11 μg/mL, 2.65 μg/mL, respectively. The results showed that the bactericidal effect of rod-shape AuNPs on E. coli and S. aureus was higher than that of the other two forms, and the bactericidal effect of three different forms of AuNPs on S. aureus was better than that on E. coli.

The potential of nanotechnology to improve human health, optimize natural resource utilization, and reduce environmental pollution is remarkable. With the ever-growing advancement in dentistry, one of the breakthroughs is using nanotechnology. Nanotechnology in periodontics has touched every aspect of treatment modality, from non-surgical therapy to implant procedures, including regenerative procedures. Understanding their mechanism plays a pivotal role in more efficient usage of nanotechnology, better treatment procedures, and eventually better outcomes. In this paper, we review the application of nanotechnology in periodontal therapy. We performed the search for papers in Scopus using the key words and phrases as follows: “nanodentistry”; “dentistry and nanotechnology”; “dentistry and nanoparticles”; “dentistry and nanomedicine”; “dentistry and nanorobots”. There were found 530 papers in total. Some papers belonged to two and more categories. It is revealed that the number of papers versus year does not follow any specific pattern, but the cumulative amount of papers versus year is fitted with the exponential regression. There were also selected papers using certain inclusion/exclusion criteria. Only the selected papers were analyzed. Nanomedicine is subjected to intensive studies nowadays. There are some promising results that will likely be implemented into praxis soon in the fields of medical diagnostics and clinical therapeutics. The appearance of nanotechnology can have a considerable impact on the treatment of periodontal diseases.

We have studied the effect of the series resistance on the heating of the cathode, which is based on carbon nanotubes and serves to realize the field emission of electrons into the vacuum. The experiment was performed with the single multi-walled carbon nanotube (MCNT) that was separated from the array grown by CVD method with thin-film Ni-Ti catalyst (nickel 4 nm/Ti 10 nm). The heating of the cathode leads to the appearance of a current of the thermionic emission. The experimental voltage current characteristic exhibited the negative resistance region caused by thermal field emission. This current increases strongly with increasing voltage and contributes to the degradation of the cold emitter. The calculation of the temperature of the end of the cathode is made taking into account the effect of the phenomenon that warms up and cools the cathode. We have developed a method for processing of the emission volt-ampere characteristics of a cathode, which relies on a numerical calculation of the field emission current and the comparison of these calculations with experiments. The model of the volt-ampere characteristic takes into account the CNT’s geometry, properties, its contact with the catalyst, heating and simultaneous implementation of the thermionic and field emission. The calculation made it possible to determine a number of important parameters, including the voltage and current of the beginning of thermionic emission, the temperature distribution along the cathode and the resistance of the nanotube. The phenomenon of thermionic emission from CNTs was investigated experimentally and theoretically. The conditions of this type emission occurrence were defined. The results of the study could form the basis of theory of CNT emitter’s degradation.

In recent years, phytoremediation as a promising ecological restoration technique has emerged. Phytoremediation is a repair method that uses green plants to transfer, contain, or convert contaminants to the environment. Phytoremediation is a heavy metal, organic or radioactive element contaminated soil and water. The results show

that the use of plant absorption, volatilization, root filtration, degradation, stability and other effects, can purify soil

or water pollutants, to achieve the purpose of purifying the environment, so phytoremediation is a great potential, the development of the clean environment Pollution of green technology. The use of plants to repair contaminated soil is a cheap and durable bioremediation technique. The protection and management of Taihu Lake is an indispensable measure for the protection of Taihu Lake water, and the advantages of phytoremedry investment, low freight and

low leakage of pollutants show that its promotion has this unusual significance. This paper expounds the difference

of remediation soil between Taihu Lake Ecological Shelter Forest, and the comparison of the soil capacity of the

experimental tree species. Second, the correlation between the monitoring projects is discussed.

With modern society and the ever-increasing consumption of polymeric materials, the way we look at products has changed, and one of the main questions we have is about the negative impacts caused to the environment in the most diverse stages of the life cycle of these materials, whether in the acquisition of raw materials, in manufacturing, distribution, use or even in their final disposal. The main methodology currently used to assess the environmental impacts of products from their origin to their final disposal is known as Life Cycle Assessment (LCA). Thus, the objective of this work is to evaluate how much the biodegradable polymer contributes to the environment in relation to the conventional polymer considering the application of LCA in the production mode. This analysis is configured through the Systematic Literature Review (SLR) method. In this review, 28 studies were selected for evaluation, whose approaches encompass knowledge on LCA, green biopolymer (from a renewable but non-biodegradable source), conventional polymer (from a non-renewable source) and, mainly, the benefits of using biodegradable polymers produced from renewable sources, such as: corn, sugarcane, cellulose, chitin and others. Based on the surveys, a comparative analysis of LCA applications was made, whose studies considered evaluating quantitative results in the application of LCA, in biodegradable and conventional polymers. The results, based on comparisons between extraction and production of biodegradable polymers in relation to conventional polymers, indicate greater environmental benefits related to the use of biodegradable polymers.