New technological solutions for restoring the inner surface of hydraulic cylinders

Relevance. Agricultural machines widely use hydraulic cylinders for various auxiliary and working movements. Operation in harsh field conditions leads to the failure of the hydraulic cylinder mirror and, as a result, to the loss of force on the cylinder rod. The development of technological solutions for the restoration of the inner surface as a more appropriate solution in repair production is relevant.Methods. Studies of the heat flow using the “Fluke Ti32” thermal imager and ofthe influence of gas-dynamic spraying (GDS) modes on the adhesive and cohesive strength when using a new design of the nozzle part of the GDS equipment were carried out.Results. The suitability of usage of new nozzle design for GDS in order to restore the inner surface of the hydraulic cylinder body has been established. The elongated and curved nozzle for installations of the “Dimet” type practically does not change the temperature regime of spraying. The adhesive and cohesive strength of the coatings obtained with the new nozzle design is sufficient to operate under conditions characteristic of the inner surface of the hydraulic cylinder body.

EXPERIMENTAL RESEARCH AND CFD MODELING OF MODULAR POULTRY BREEDING

For high-quality and simultaneous breeding of different ages of poultry a modular keeping is proposed. The heating system of the module is a panel infrared heater. It is intended for local heating of technological area. Design dimensions of the module were determined for reasons of qualitative course of technological process, namely the stocking density of poultry. Experimental studies of the temperature regime of poultry breeding area were carried out. Body temperature of the poultry was within acceptable limits, up to 41.5ºC. In addition, the surface temperature of the feathers did not exceed 29.1ºC, which fully complies with sanitary and hygienic standards. For a better representation of temperature regime in the module, CFD modeling was performed. Fields of velocities, pressures and temperatures were obtained. The air temperature near poultry in the module reached 18.6ºC, and the average velocity did not exceed 0.75m/s.

Variance of Voltages in a Lattice Coulomb Gas

We study the behavior of the variance of the difference of energies for putting an additional electric unit charge at two different locations in the two-dimensional lattice Coulomb gas in the high-temperature regime. For this, we exploit the duality between this model and a discrete Gaussian model. Our estimates follow from a spontaneous symmetry breaking in the latter model.

An experience of obtaining mature eggs of the Siberian sturgeon (Acipenser baerii (Brandt, 1869)) in non-traditional period

Purpose. To investigate the peculiarities of obtaining ovulated eggs of the Siberian sturgeon in hatchery conditions in non-traditional (winter) period and determine major features of brood fish used for the experiments. Methodology. The material for the study were age-10+ Siberian sturgeon females with body weights of 6.20-8.24 kg grown in conditions of floating cages in a water body with natural temperature regime of the forest-steppe zone of Ukraine. The experiments were conducted with a regulated water temperature regime in the third decade of January with the use of natural gonadotropic drugs for the stimulation of egg maturation in fish. Brood fish were prepared for the experiment in the recirculating aquaculture system. Measurement of fisheries parameters and study of physicochemical factors of the aquatic medium were performed according to generally accepted methods. Experiment results were assessed statistically using standard software. Findings. With water temperature of 14-15оС, depending on the dosage of the gonadotropic drug, different efficiencies of gonad maturation in experimental groups of fish were detected. More than 85% of females matured after dosing of gonadotropic drugs 3.5 and 4.5 mg / kg. In the version with a minimum dose of gonadotropic substance 2.5 mg / kg responded positively to hormonal stimulation 57% of females. The average weight of eggs obtained in some groups of brood fish was 819.5-1079.0 g. Average working fecundity and relative working fecundity in experimental groups of the Siberian sturgeon females varied within 47.95-52.64 thousand eggs and 6.93-7.17 thousand eggs/kg of fish body weight, respectively. The duration of maturation after the second (resolving) administration of the gonadotropic drug until the moment of the occurrence of the ovulation process varied mainly within 15-20 hours. Originality. The peculiarities of obtaining mature eggs of the Siberian sturgeon with the use of methods of industrial reproduction of sturgeons, which are new for the aquaculture of Ukraine, were studied. Practical value. The study results are of interest for the development of modern methods of sturgeon aquaculture in conditions of fish farms of industrial type. Key words: brood Siberian sturgeon, industrial aquaculture, non-traditional technologies, eggs, ovulation, fisheries parameters.

Prolonged subfebrile condition, pyretic fever and febrile attacks of unknown genesis: new approach to diagnosis and treatment. Part 1. Clinical picture

Background. The study was aimed to establish the true etiological cause of such pathological conditions as prolonged low-grade fever, fever of unknown genesis, and cases of rapid short-term febrile increase of temperature of unknown origin. Materials and methods. The design of the study was clinical-diagnostic and included the search for ways to diagnose and treat such pathological conditions as prolonged subfebrile fever, fever of unknown genesis, and cases of rapid short-term febrile increase of temperature of unknown origin. The studies were prospective-retrospective and were longitudinal with long-term periodic follow-up of a certain part of the same patients during 1–10 years after diagnosis of CBIS (chronic bacterial intoxication syndrome) and appropriate treatment. According to the effectiveness of the obtained results, the study was direct, because it undoubtedly led to the recovery of the patient with the improvement of his/her state and life. All patients (infants and adults aged till 80 years) who went to the hospital during 2009–2020 with complaints about violation of the temperature regime (subfebrile or febrile increase). Results. During 2009–2020, 3999 patients (adults — 2047/3999, 51.2 %, children — 1952/3999, 48.8 %) with a fever of unknown origin, namely 1578/2047 (77.1 %) adults and 1206/1952 (61.8 %) children with prolonged subfebrile fever, 70/2047 (3.4 %) and 25/1952 (1.3 %), respectively — with febrile fever and 399/2047 (19.5 %) and 721/1952 (36.9 %) — with febrile attacks (FA), were observed by the authors. In all 3999 (100 %) patients, there was detected a focus of chronic bacterial infection in the kidneys. Herewith in more than 2/3 cases (2780/3999 patients, 69.5 %), there was diagnosed the locally asymptomatic nephrodysbacteriosis without clinical, general laboratory (inclu­ding almost normal general analysis of urine) and instrumental signs of the inflammatory process in the kidneys. In 960/3999 (24.0 %) ca­ses, there was first established the latent form of delayed clinically asymptomatic chronic pyelonephritis. 259/3999 (6.5 %) patients were diagnosed with chronic pyelonephritis at the stage of clinical exacerbation. As a consequence of the formation of a focus of chronic bacterial infection in the kidneys, the patients developed monosymptomatic (only with temperature increase) or full-symptom CBIS, namely: 2024/2784 (72.7 %) children and adults with prolonged subfebrile fever there presented with typical clinical manifestations of CBIS in various combinations, but in 760/2784 (27.3 %) cases, the subfebrile temperature was monosymptoma­tic without other complaints and clinical symptoms. The diagnosis was confirmed by bacteriological examination of warm urine (three times, for three days running) and toxicological blood examination using the diagnostic system Toxicon. Urine cultures of various bacteria were isolated from urine in all 3999 (100 %) patients. Herewith in 2205/3999 (55.1 %) cases, there were isolated one culture of bacteria in each case, in 1608/3999 (40.2 %) patients — simultaneously two cultures of different bacteria, i.e. another 3216 strains, in 186/3999 (4,7 %) — three cultures (558 strains). That is, in general, there were isolated 5979 strains of different bacteria, which were considered as diagnostic confirmation of the presence of a focus of chronic bacterial infection in the kidneys in all 3999 patients with prolonged subfebrile fever, fever of unknown genesis, or febrile attacks. The main factors of the occurrence of temperature regime disorders on the background of CBIS were Enterococci (2471/3999 strains from 61.8 % of patients), Escherichia coli — 1495/3999 strains (from 37.4 % of patients) and Staphylococci (Staphylococcus aureus and Staphylococcus haemolyticus) and Streptococci (Streptococcus pyogenes): a total of 696/3999 strains (from 17.4 % of patients). In 818 (100 %) patients who were examined using the Toxi­con system, all, without exception, the indicators of cytolytic activity of toxic proteomes, which were tested, significantly exceeded the norm (p < 0.001). In the vast majority of patients (in 664/818 or 81.17 % of cases), there was detected severe toxemia, in 140/818 (17.11 %) — moderate and only in 14 (1.71 %) — mild. All 3999 patients with prolonged subfebrile fever, fever of unknown genesis, and FA were treated with bacterial autovaccines made from strains, isolated during the bacteriological examination. One cycle consisted of 2–3 courses of immunization with bacterial vaccines. One course included 10 or 12 subcutaneous injections in increasing dosage during 19–21 days. Between courses, there was maintained an interval of 3 to 4 weeks. The treatment cycle generally lasted from 70 to 110 days, depending on the number of courses. Intervals between treatment cycles were usually maintained for 3 months. The effectiveness of such treatment was 71.2 % after the first cycle, 92.8 % — after the second, and 99.2 % — after the third with full recovery of the ability to work, lost during the illness, and the emotional level of personal life. Conclusions. It has been established that the etiological cause of the occurrence of prolonged subfebrile fever, febrile fevers of unknown genesis, and febrile attacks is such a clinically and nosologically separate disease as chronic bacterial intoxication syndrome, which develops on the background of a chronic bacterial focus, usually locally asymptomatic infection in the kidneys, called nephrodysbacteriosis, and is usually associated with severe bacterial endotoxicosis that was confirmed by appropriate toxicological examination of the blood. The use of bacterial autovaccines was proved to be an effective method of treatment (up to 99.2 %) of patients with increased temperature of bacterial-toxic origin.

Prolonged subfebrile condition, pyretic fever and febrile attacks of unknown genesis: new approach to diagnosis and treatment. Part 2. Diagnostics and treatment

Background. The study was aimed to establish the true etiological cause of such pathological conditions as prolonged low-grade fever, fever of unknown genesis, and cases of rapid short-term febrile increase of temperature of unknown origin. Materials and methods. The design of the study was clinical-diagnostic and included the search for ways to diagnose and treat such pathological conditions as prolonged subfebrile fever, fever of unknown genesis, and cases of rapid short-term febrile increase of temperature of unknown origin. The studies were prospective-retrospective and were longitudinal with long-term periodic follow-up of a certain part of the same patients during 1–10 years after diagnosis of CBIS (chronic bacterial intoxication syndrome) and appropriate treatment. According to the effectiveness of the obtained results, the study was direct, because it undoubtedly led to the recovery of the patient with the improvement of his/her state and life. All patients (infants and adults aged till 80 years) who went to the hospital during 2009–2020 with complaints about violation of the temperature regime (subfebrile or febrile increase). Results. During 2009–2020, 3999 patients (adults — 2047/3999, 51.2 %, children — 1952/3999, 48.8 %) with a fever of unknown origin, namely 1578/2047 (77.1 %) adults and 1206/1952 (61.8 %) children with prolonged subfebrile fever, 70/2047 (3.4 %) and 25/1952 (1.3 %), respectively — with febrile fever and 399/2047 (19.5 %) and 721/1952 (36.9 %) — with febrile attacks (FA), were observed by the authors. In all 3999 (100 %) patients, there was detected a focus of chronic bacterial infection in the kidneys. Herewith in more than 2/3 cases (2780/3999 patients, 69.5 %), there was diagnosed the locally asymptomatic nephrodysbacteriosis without clinical, general laboratory (inclu­ding almost normal general analysis of urine) and instrumental signs of the inflammatory process in the kidneys. In 960/3999 (24.0 %) ca­ses, there was first established the latent form of delayed clinically asymptomatic chronic pyelonephritis. 259/3999 (6.5 %) patients were diagnosed with chronic pyelonephritis at the stage of clinical exacerbation. As a consequence of the formation of a focus of chronic bacterial infection in the kidneys, the patients developed monosymptomatic (only with temperature increase) or full-symptom CBIS, namely: 2024/2784 (72.7 %) children and adults with prolonged subfebrile fever there presented with typical clinical manifestations of CBIS in various combinations, but in 760/2784 (27.3 %) cases, the subfebrile temperature was monosymptoma­tic without other complaints and clinical symptoms. The diagnosis was confirmed by bacteriological examination of warm urine (three times, for three days running) and toxicological blood examination using the diagnostic system Toxicon. Urine cultures of various bacteria were isolated from urine in all 3999 (100 %) patients. Herewith in 2205/3999 (55.1 %) cases, there were isolated one culture of bacteria in each case, in 1608/3999 (40.2 %) patients — simultaneously two cultures of different bacteria, i.e. another 3216 strains, in 186/3999 (4,7 %) — three cultures (558 strains). That is, in general, there were isolated 5979 strains of different bacteria, which were considered as diagnostic confirmation of the presence of a focus of chronic bacterial infection in the kidneys in all 3999 patients with prolonged subfebrile fever, fever of unknown genesis, or febrile attacks. The main factors of the occurrence of temperature regime disorders on the background of CBIS were Enterococci (2471/3999 strains from 61.8 % of patients), Escherichia coli — 1495/3999 strains (from 37.4 % of patients) and Staphylococci (Staphylococcus aureus and Staphylococcus haemolyticus) and Streptococci (Streptococcus pyogenes): a total of 696/3999 strains (from 17.4 % of patients). In 818 (100 %) patients who were examined using the Toxi­con system, all, without exception, the indicators of cytolytic activity of toxic proteomes, which were tested, significantly exceeded the norm (p < 0.001). In the vast majority of patients (in 664/818 or 81.17 % of cases), there was detected severe toxemia, in 140/818 (17.11 %) — moderate and only in 14 (1.71 %) — mild. All 3999 patients with prolonged subfebrile fever, fever of unknown genesis, and FA were treated with bacterial autovaccines made from strains, isolated during the bacteriological examination. One cycle consisted of 2–3 courses of immunization with bacterial vaccines. One course included 10 or 12 subcutaneous injections in increasing dosage during 19–21 days. Between courses, there was maintained an interval of 3 to 4 weeks. The treatment cycle generally lasted from 70 to 110 days, depending on the number of courses. Intervals between treatment cycles were usually maintained for 3 months. The effectiveness of such treatment was 71.2 % after the first cycle, 92.8 % — after the second, and 99.2 % — after the third with full recovery of the ability to work, lost during the illness, and the emotional level of personal life. Conclusions. It has been established that the etiological cause of the occurrence of prolonged subfebrile fever, febrile fevers of unknown genesis, and febrile attacks is such a clinically and nosologically separate disease as chronic bacterial intoxication syndrome, which develops on the background of a chronic bacterial focus, usually locally asymptomatic infection in the kidneys, called nephrodysbacteriosis, and is usually associated with severe bacterial endotoxicosis that was confirmed by appropriate toxicological examination of the blood. The use of bacterial autovaccines was proved to be an effective method of treatment (up to 99.2 %) of patients with increased temperature of bacterial-toxic origin.