Influence Of Chemical Factors Research Articles

Squamous cell carcinoma around a subperiosteal implant in the maxilla and the association of chronic mechanical irritation and peri-implantitis: a case report

BackgroundAs carcinogenic risk factors, environmental factors can be classified into physical, biological, and chemical factors. Subperiosteal implants (SIs) are associated with complications, such as framework exposure, infection, and fistula formation. A current hypothesis suggests that chronic mechanical irritation could be a co-factor in carcinogenesis, while peri-implantitis might be an initiating or promoting agent in the development of oral mucosal cancer. Herein, we report a case of squamous cell carcinoma (SCC) around a maxillary SI associated with chronic mechanical irritation and peri-implantitis as physical and biological factors, respectively.Case presentationA 74-year-old male patient presented with severe mobility of the SI and an undermined ulcer with induration, accompanied by a palatal fistula and the exposure of the metal framework. The SI had been placed on the maxilla for the occlusal reconstruction of the molar area 20 years ago. An incisional biopsy of the ulcer revealed SCC (cT4aN2cM0). Neoadjuvant chemotherapy was initiated, followed by bilateral neck dissection and partial resection of the maxilla with SI removal. Energy-dispersive X-ray analysis suggested that the SI was fabricated using pure titanium, and titanium was absent in the specimen. Scanning electron microscopy of the SI in contact with the SCC showed a few microcracks, suggesting pitting corrosion.DiscussionChronic mechanical irritation due to the mobility of an improperly designed SI can be a physical factor, and prolonged peri-implantitis without regular maintenance can be a biological factor in carcinogenesis. Improperly designed main struts and a large masticatory force in the molar area resulted in deterioration of the retention and mobility of the SI. The screw and framework frequently moved on mastication and came in direct contact with the ulcer as chronic mechanical irritation. Bacterial invasion into the subperiosteal space expanded by the mobility of the metal framework led to peri-implantitis. The influence of chemical factors was considered relatively small in this case since the patient had no history of smoking or drinking, and titanium was absent in the specimen. Therefore, it is conceivable that SCC can arise owing to persistent inflammation caused by chronic mechanical irritation and peri-implantitis as physical and biological factors, respectively.

Change in the coherence of light scattering from the surface of apples and their transpiration during storage

The potential possibility of using coherent optics for non-destructive testing to modify the microstructure of the surface of apples under the influence of chemical factors was studied. The model objects included solar and shade sides of fruits of Antonovka Common variety, untreated (control) and treated with diphenylamine (DPA). The amplitude-phase parameters of laser radiation reflected from the fruit surface were evaluated using a polarization shearing interferometer. It was experimentally shown that by the intensity and degree of coherence of the reflected laser radiation of the surface of apples, it is possible to register the anatomical and morphological characteristics of their tissues. It was revealed that after two months of storage, the spatial coherence of light scattering of the shadow side of an apple is higher than that of the solar, and the surface of apples treated with diphenylamine has a higher coherence of light scattering of the surface of both the solar and shadow sides. It was shown that the transpiration of apples treated with diphenylamine exceeds the transpiration of control apples.

The influence of chemical factors on the metal-binding capacity of non-starch polysaccharides

The article considers not only the possibility of non-starch polysaccharides to bind heavy metal ions, but the factors affecting this ability are determined. The ability of some non-starch polysaccharides to form complexes with heavy metal ions significantly depends on the structure, structure and external chemical factors. Considered polysaccharides are: pectin, chitosan and sodium alginate. Considered factors: temperature and pH.

THE USE OF MOLECULAR AND BIOCHEMICAL MARKERS OF BONE METABOLISM FOR SCREENING OF DENTAL HEALTH OF THE POPULATION

At present, the research interests of both dentists and clinical laboratory diagnosticians lie in the field of using oral fluid as an object of diagnostic estimation of molecular and biochemical markers in oral cavity diseases. It is commonly known that oral fluid has both organic and non-organic components. Non-organic components of saliva are represented by macro- and microelements that can be parts of various compounds or stay in the ionized form. Organic components are represented by proteins, carbohydrates, lipids, essential nitrogenous compounds (urea and uric acid), vitamins, hormones, organic and nucleic acids.
 Compared with the traditional method of blood testing, the identification of markers in the oral fluid has several advantages. They are non-invasiveness, atraumatic character for the patient, the absence of stress typical of venipuncture; simpler conditions of storage and transportation due to the liquid state (unlike whole blood, which tends to coagulate); being able to take biological material an unlimited number of times; no need for qualified personnel and special equipment when taking oral fluid.
 The introduction of biological markers into the complex of dental checkups is one of the topical tasks of modern dentistry and clinical laboratory diagnostics. This is particularly important for those dental patients whose living or working conditions are accompanied by harmful chemical factors.
 The authors have performed complex research of lactoferrin, cathelicidin, and MMP8 present in the oral fluid of 50 patients who worked under harmful conditions (group 1), and of other 50 patients whose work is not associated with the harmful influence of chemical factors (group 2). The oral fluid was collected on an empty stomach in the morning by spitting into a sterile glass tube. The biomass was centrifuged and stored at 300C, and the amount of lactoferrin (Hycto Biotech, the Netherlands), cathelicidin (Hycult Biotech, the Netherlands), and MMP8 (Matrix Metalloproteinase-8) was determined in the test samples. The analysis was performed by enzyme-linked immunosorbent assay based on the use of a "sandwich" variant of solid-phase enzyme-linked immunosorbent assay. The procedure was performed on the enzyme-linked immunosorbent assay ImmunoChem-2100 (USA). The analysis was performed in 96-well microplates, the bottom of the wells was covered with monoclonal antibodies to the corresponding molecular marker.
 The analysis of the oral cavity condition in patients of both groups demonstrated the presence of caries (100 % of group 1 patients, 80% of group 2 patients) and partial adentia (75% of group 1 patients, 60% of group 2 patients). Secondary to the above-mentioned abnormalities, group 1 and 2 patients had periodontal diseases. Such abnormalities were registered in 87% of group 1 patients; in group 2 patients, such changes were less explicit and were present in 67% of the patients. On the contrary, it was established that the patients of both groups presented with a statistically significant increase of lactoferrin in the oral fluid (on average, 81% and 40% higher, respectively, in groups 1 and 2) and MMP8 (64% and 24% higher), as well as a decrease in cathelicidin concentration (87% and 42% lower) in comparison with the patients of group 3.
 The established pathological biochemical changes indicate pathological processes in the oral cavities of the research groups of patients.
 In modern practice, Lf is used as an organ-specific marker of the activation of a pathological process to diagnose and predict the course of mucosal and periodontal diseases. At the same time, the decrease in oral cathelicidin LL37 reflects the suppression of local immunity in the oral cavity and is regarded as a pathogenic chain in the progression of diseases of the mucosa, periodontium, including dental caries in patients. Similar dynamics of cathelicidin in group 1 patients, in our opinion, explains the intensity of oral disease development in this category of patients. Thus, neutrophils and macrophages die under the action of aggressive chemical factors, as a result of which the pool of antimicrobial peptides, including cathelicidin, decreases.
 The present markers determine the topicality and great potential of further research of the given molecular markers for both fundamental investigations and understanding the pathogenesis of oral cavity diseases in this category of patients. Besides, these indices can be used as independent markers for diagnosis, screening, and effective treatment of oral cavity diseases.

MODERN METHODS of PROPHYLAXIS AND RESEARCH ofPROFESSIONAL DISEASES, TRAUMATISM are With HEAVYCONSEQUENCES In AGRICULTURAL PRODUCTION

In all countries of the world, as well as in Ukraine, occupational injuries are an urgent problem of modern society. The analysis of accidents at Ukrainian enterprises showed that there is a problem of developing modern methods of preventing injuries and occupational diseases prevention. The main objective of prevention of occupational diseases at enterprises in Ukraine is to create safe and healthy working conditions, and to preserve the health of workers. At each enterprise, the workers are constantly exposed to harmful and dangerous production factors. These factors negatively affect human health, which leads to a decrease in their ability to work. At the present time, there are accidents with fatal consequences on the Ukrainian factories, which indicates the unsatisfactory state of preventive work. The owner of an enterprise should objectively identify the real causes of an accident. This will provide a real opportunity for an effective search for ways to intensify preventive work and reduce injuries. Dangerous factors often lead to injuries, and harmful factors - to the disease. 80% of accidents at home and at work are observed for organizational reasons. In all countries of the world in the system of measures for the prevention of injuries, a significant role is devoted to the development and implementation of integrated approaches to labor safety. According to statistics from the International Labor Organization, more than 500 deaths in agriculture, industry and services are recorded worldwide every day. Annually more than 300 thousand workers receive occupational injuries and occupational diseases. Every three minutes, one worker dies as a result of an accident, and every four workers receive a work injury every second. Economic losses associated with occupational injuries around the world make up about 1% of the world's gross national product. One of the most traumatic industries is the agro-industrial complex, where mortal injuries are in percentage terms in crop production - 24% of the total number of injuries, livestock - 21%. The article presents the structure and frequency of the main forms of the diseases associated with the respiratory tract pathology in general in Ukraine, as well as diseases that arise under the influence of chemical factors, an analysis of occupational diseases at enterprises, depending on working conditions.

The mixed impact of chemical and physical factors on reproductive system of rats in conditions of cold stress.

The results of experimental investigations on studying features of gonadotoxic effect of nitrobenzene (NB), methyl tertiary butyl e the r (MTBE) and electromagnetic radiation (EMR) both in conditions of cold stress and in conditions of thermal acceptability are given. The investigations were carried out on laboratory animals, in 30-fold intragastric administration of NB or MTBE in a dose of 1/10 LD 50 and exposition of animals in two different thermal regimens – 4 hours a day, 5 times a week. Effect of EMR was simulated in 70 kHz frequency, 600 V/m voltage. The features of gonadotoxic effect of NB and MTBE were studied by the indices of spermatozoa functional state, general histological analysis of the state of testicle tissues, supplemented with morphometric values, was carried out,. The analysis of results of experimental research proves that morpho-functional changes of reproductive system in laboratory animals during the influence of chemical factors (NB and MTBE), physical factors (EMR) in two different thermal regimens are similar provided that there is the increase of gonadotoxic effect in mixed effect of mentioned factors and decreased temperature.

Influence of Relative Humidity and Ozone on the Sampling of Volatile Organic Compounds on Carbotrap/Carbosieve Adsorbents

By using a dynamic dilution system, the atmospheric measurement of 11 selected toxics VOCs (ethylene, acetylene, propene, 1-butene, 1,3-butadiene, 1-pentene, 1-hexene, benzene, toluene, ethylbenzene, m+p-xylene) from the list WHO of 1996 and TO-14 method of US EPA by preconcentration by thermal desorption (TD), analysis by gas chromatography (GC), identification and quantification with a flame ionisation detector (FID) was developed and validated in term of metrology, especially the techniques of sampling of these VOCs with adsorbents cartridges "Air Toxics" when used with an "UMEG sampler" equipped in the inlet with a nafion membrane. In particular the influence of climatic conditions (temperature and relative humidity) and the influence of chemical factors like ozone, on the representativity of sampling were studied. Experiments made with various humidities showed that the addition of a nafion membrane in the inlet of the sampling system was required. Without this membrane, losses of compounds were observed for RH >50%. With this membrane, storage for 2 weeks in a refrigerator, as for canisters, did not induce a loss of compounds. No significative decrease of concentrations of the studied VOCs after 14 days storage, which are known to react with ozone, were observed with an ozone concentrations of 55 ppb. One explanation is that nafion membrane, placed in the inlet of the sampler, will neutralize ozone before entering the sampling tubes. This observation is in accordance with literature which states that the sampling of VOCs on Carbotrap cartridges without ozone scrubber induce a loss of compounds.

On the influence of chemical factors of low intensity upon growing organism

On the influence of chemical factors of low intensity upon growing organism

On the Influence of Chemical Factors of Low Intensity Upon Growing Organism

On the Influence of Chemical Factors of Low Intensity Upon Growing Organism

Trivalent metal ions in the prevention of calcification in glutaraldehyde treated biological tissues. Is there a chemical correlation?

The influence of chemical factors on trivalent metal ions in the prevention of calcification of glutaraldehyde treated biological tissue has been explored. The results indicate that the chemical link lies in the hard character of the trivalent metal ions. Metal ions with the hardest character appear to have the best chance of reacting with oxygen atoms of the phosphate groups at nucleation sites of hydroxyapatite. This disrupts the nucleation and thus prevents calcification in glutaraldehyde treated biological tissue.

Influence of Chemical Factors on Palatability of Forage to Voles

Laboratory-feeding trials were used to test the palatability of 15 plant species to two species of voles (Microtus pennsylvanicus and M. ochrogaster) in central Illinois. The intake of different plant species was compared to the chemical composition of plants, as measured by nitrogen, water, fiber, alkaloid, and phenolics, and to selectivity for plants by voles in the field. Palatability of plants varied greatly; some species were ignored but others were consumed heavily. The most palatable plant species in our laboratory trials were those previously reported as species selected for in the field. The relative payabilities of plants were similar for both vole species. Multiple-regression analyses incorporating chemical characteristics for all the plants explained a maximum of 29% of the variance in consumption. However, when only consumed plants were considered, as much as 73% of the variance was explained by nitrogen level and substances that reduce digestibility (fiber and protein-binding phenolics). Plants not eaten by either vole species are known to contain toxic compounds. These results support the hypothesis that food selection by generalist herbivores is a two-step process: plant characteristics that determine which plant species are avoided may differ from characteristics that determine the level of consumption of those eaten.

The influence of chemical factors on the selectivity of Pinus resinosa stumps for Fomes annosus

AbstractCompounds such as resins or phenols produced by the host in response to wounding or fungal penetration may play an important role as factors of resistance against Fomes annosus. By extracting stem sections, that were kept for different intervals in a closed chamber, with different organic solvents chloroform produced the most inhibitory extractives against F. annosus. This may explain at least partially the decreasing stump selectivity for F. annosus.Three compounds were isolated from the neutral fractions of chloroform extractives from 24 days wounded wood discs which were found to be different from the compounds in normal and 12 days fractions. Spectrophotometric analyses reveal some characteristics of these isolated compounds, whereas their chemical formula and structure need further investigation.

The influence of chemical factors on the selectivity of Pinus resinosa stumps for Fomes annosus.

Fresh pine stump surfaces act selectively for primary invaders such as Fomes annosus that competes successfully against other microorganisms. However, a series of chemical reactions on the stump surface due to aeriation and the hosts response to wounding may be implicated in the selectivity of the host for certain microorganisms. The theory of stump selectivity of coniferous trees for F. annosus as well as the theory of wound reaction and protection wood are discussed. The sequence of events after wounding is complicated and the present investigation concentrates on the processes associated with the host response to wounding.

The influence of chemical factors on the crystallization of hornblende in igneous rocks

It is now more than sixty years since Tschermak first published his classical paper on the relationship between the pyroxenes and amphiboles, but, in spite of our greatly increased knowledge of these important rock-forming minerals, many of the problems concerning their constitution and genesis remain unsolved. In particular, the nature of the conditions which determine whether a pyroxene or an amphibole will separate from a crystallizing magma are imperfectly understood, although the point is one of very considerable petrological significance. Much fuller information is necessary, particularly with regard to the relationship between the composition of the ferromagnesian minerals and the rocks in which they occur. The present paper merely represents a preliminary attempt to correlate the available chemical evidence and to determine what other possible factors might influence the character of the ferromagnesian crystallization.

The influence of chemical factors on the coronary circulation

The influence of chemical factors on the coronary circulation