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Unlike vertebrates, the number of toothed taxa in invertebrates is very few, with leeches being the only tooth-bearing organisms in the phylum Annelida. Copious studies have been conducted regarding vertebrate teeth; however, studies regarding the structure and function of invertebrate teeth are limited. In this study, the tooth structure of leeches, specifically Hirudo nipponia and Haemadipsa rjukjuana, was revealed, which showed sharp and pointed teeth along the apex of three jaws. Understanding conserved signaling regulations among analogous organs is crucial for uncovering the underlying mechanisms during organogenesis. Therefore, to shed light on the evolutionary perspective of odontogenesis to some extent, we conducted de novo transcriptome analyses using embryonic mouse tooth germs, Hirudo teeth, and Helobdella proboscises to identify conserved signaling molecules involved in tooth development. The selection criteria were particularly based on the presence of tooth-related genes in mice, Hirudo teeth, and Helobdella proboscis, wherein 4113 genes were commonly expressed in all three specimens. Furthermore, the chemical nature of leech teeth was also examined via TEM-EDS to compare the chemical composition with vertebrate teeth. The examination of tissue-specific genetic information and chemical nature between leeches and mice revealed chemical similarities between leech and mice teeth, as well as conserved signaling molecules involved in tooth formation, including Ptpro, Prickle2, and Wnt16. Based on our findings, we propose that leech teeth express signaling molecules conserved in mice and these conserved tooth-specific signaling for dental hard tissue formation in mice would corresponds to the structural formation of the toothed jaw in leeches.

Unlike vertebrates, the number of toothed taxa in invertebrates is very few, with leeches being the only tooth-bearing organisms in the phylum Annelida. Copious studies have been conducted regarding vertebrate teeth; however, studies regarding the structure and function of invertebrate teeth are limited. In this study, the tooth structure of leeches, specifically Hirudo nipponia and Haemadipsa rjukjuana, was revealed, which showed sharp and pointed teeth along the apex of three jaws. Understanding conserved signaling regulations among analogous organs is crucial for uncovering the underlying mechanisms during organogenesis. Therefore, to shed light on the evolutionary perspective of odontogenesis to some extent, we conducted de novo transcriptome analyses using embryonic mouse tooth germs, Hirudo teeth, and Helobdella proboscises to identify conserved signaling molecules involved in tooth development. The selection criteria were particularly based on the presence of tooth-related genes in mice, Hirudo teeth, and Helobdella proboscis, wherein 4113 genes were commonly expressed in all three specimens. Furthermore, the chemical nature of leech teeth was also examined via TEM-EDS to compare the chemical composition with vertebrate teeth. The examination of tissue-specific genetic information and chemical nature between leeches and mice revealed chemical similarities between leech and mice teeth, as well as conserved signaling molecules involved in tooth formation, including Ptpro, Prickle2, and Wnt16. Based on our findings, we propose that leech teeth express signaling molecules conserved in mice and these conserved tooth-specific signaling for dental hard tissue formation in mice would corresponds to the structural formation of the toothed jaw in leeches. [ABSTRACT FROM AUTHOR]

The purpose of the researches is to analyze the chemical nature of new commercial modified fatliquor materials obtained on the basis of sulfonated, sulfated, oxidized natural and synthetic fats, as well as to determine the features of interaction in the "collagen-fatliquor material" system, which will make it possible to predict the behavior of these materials during liquid finishing of leather. Methodology. To achieve this goal, spectral analysis and interpretation of the spectra of modified fatliquor materials were used. As the latter, new products from Smit & Zoon (Netherlands) were studied: Sulphirol EG 60 -- sulfited natural and synthetic fats; Synthol LC -- natural and synthetic fats, sulfated triglycerides, lecithin-containing mixture; Sulphirol C -- oxidized sulfited fats based on marine fish fats. The chemical nature of the analyzed fats and their interaction with gelatin as a collagen model was studied using infrared spectroscopy. The researches were carried out on an infrared spectrometer (FTIR), designed to obtain infrared transmission or reflection spectra of the objects under study. Findings. It has been experimentally established that, due to the presence of various functional groups and bonds, new modified fatliquor materials have a multifunctional nature and can interact with gelatin to form new (hydrogen, electrovalent, covalent, etc.) bonds in its structure. Based on a study of the relative optical density of chrome-plated gelatin films before and after treatment with modified fatliquor materials, it was revealed that sulfur- and phosphorus-containing groups of fats and nitrogen-containing (amine, imine, amide) groups of gelatin take the greatest part in this interaction, its oxygen-containing groups (hydroxyl and carbonyl) are less active) groups. Sulphirol EG 60 sulfited fat and sulfated lecithin-containing Synthol LC exhibit greater activity in interaction with gelatin among the studied fatliquor materials than Sulphirol C fatliquor material synthesized on the basis of oxidized and sulfited marine fish fats. The revealed ability of modified fatliquor materials to interact with gelatin, and therefore with collagen, will contribute to the prevention of their redistribution in the dermis or their removal from it, which will have a positive effect on the stability of the structure and properties of skin and leather products. Originality. The scientific novelty consists in determining the chemical nature of new modified fatliquor materials of various origins, intended for skin treatment, as well as the nature of their interaction with gelatin - a model of collagen, which is the main component of the dermis of the animal skin and natural leather, which is made from it. This will make it possible to explain the peculiarities of transformations in the "collagen-fatliquor material" system during liquid finishing, their influence on the formation of the structure and properties of the leather. Practical value. The results of the work will contribute to the expansion of the assortment and justified use of chemical reagents of the new generation in innovative technologies for the production of leather of the modern assortment. [ABSTRACT FROM AUTHOR]

In response to the enormous threat to human survival and development caused by the large number of viruses, it is necessary to strengthen the defense against and elimination of viruses. Metallic materials have been used against viruses for thousands of years due to their broad-spectrum antiviral properties, wide sources and excellent physicochemical properties; in particular, metal nanoparticles have advanced biomedical research. However, researchers in different fields hold dissimilar views on the antiviral mechanisms, which has slowed down the antiviral application of metal nanoparticles. As such, this review begins with an exhaustive compilation of previously published work on the antiviral capacity of metal nanoparticles and other materials. Afterwards, the discussion is centered on the antiviral mechanisms of metal nanoparticles at the biological and physicochemical levels. Emphasis is placed on the fact that the strong reducibility of metal nanoparticles may be the main reason for their efficient inactivation of viruses. We hope that this review will benefit the promotion of metal nanoparticles in the antiviral field and expedite the construction of a barrier between humans and viruses. [ABSTRACT FROM AUTHOR]

• The negative heat release in the post-flame zone and the overshoot of H2O is the main characteristics of SAFT for NH 3 /O 2 /N 2. • The relative lack of H radical in the main reaction zone is the important factors of SAFT. • The effects of initial conditions on SAFT have opposite trends at equivalence ratios of 1.2 and 1.6. The super adiabatic flame temperature (SAFT) phenomenon is important for understanding and controlling the flame stability, NO emission, reaction rate and other aspects of combustion. Therefore, a numerical study was conducted to study the SAFT phenomenon for NH 3 /O 2 /N 2 mixtures under different initial conditions. It was found that the main characteristics of SAFT for NH 3 /O 2 /N 2 mixture are the negative heat release in the post-flame zone and the overshoot of H2O. The chemical nature of SAFT was also analyzed and found that the reverse reaction of R4 (H2 + OH = H2O + H) in the post-flame zone, resulting in the overshoot of H2O concentration, is one of the reasons of SAFT. The study also found that H radical plays an important role in SAFT phenomenon, and the relative lack of H radical in the main reaction zone is another one of the important factors of SAFT phenomenon. In addition, the study found that the effects of initial temperatures, pressures and oxygen content on SAFT have opposite trends at different equivalence ratios. When the equivalence ratio is less than 1.6, the increase of initial temperatures and oxygen contents leads to the increase of SAFT; the increase of initial pressure leads to the decrease of SAFT. The opposite tendency occurs when the equivalence ratio exceeds 1.6. This is because the flame temperature and structure changes with the equivalence ratio increasing, and the chemical nature of SAFT changes accordingly. [ABSTRACT FROM AUTHOR]

To examine the critical role of electrically active defects and surface states in InGaN/GaN multiple quantum well (MQW) ultraviolet photodetectors (UV-PDs), the study of degradation mechanisms in such devices is very important. In this work, we have fabricated InGaN/GaN MQW UV-PDs with a thick passivation layer of Al 2 O 3 and studied their degradation behaviors by applying high current stress. The origin of degradation processes has been investigated intensively by employing different combined optical and electrical measurements. As a consequence of stress, we noticed that (i) the electroluminescence intensity decreases distinctly (∼ 48 %), suggesting that more of the charge carriers are captured by the newly induced defects in the active region; (ii) the open circuit voltage is mostly accountable for the degradation of photovoltaic properties in treated PDs; (iii) the parasitic current leakage paths increase significantly which in turn reduce the photocurrent generation process largely; (iv) within the temperature range of 100–440 K, the values of the ideality factor and barrier height are found to be always higher and lower in treated PDs, respectively, indicating the presence of generation-recombination centers caused by defects; (v) two major trap levels are identified in treated PDs via Laplace deep level transient spectroscopy analysis; and (vi) the responsivity in treated PDs decreases. The obtained results indicate that degradation is mainly associated with the newly generated defects, mostly Mg-related shallow acceptors, including Mg Ga and Mg-H 2 complexes, which can form the acceptor levels as a result of the breaking of Mg-H chemical complexes due to high heating levels during the stress treatment. [Display omitted] • Degradation characteristics of InGaN/GaN MQW UV photodetectors are studied. • Two major trap levels are detected in stressed PDs via Laplace deep level transient spectroscopy analysis. • Newly induced defects in the active region play an important role in worsening the device performances. • Degradation is mostly associated with Mg-related shallow acceptors, including Mg Ga and Mg-H 2 chemical complexes. [ABSTRACT FROM AUTHOR]