THE BASIS OF CARRYING OUT OF SAFE LOCAL ANESTHETIC IN OUTPATIENT DENTAL PRACTICE

On the basis of clinical and functional studies, a protocol for conducting safe local anesthesia in outpatient dental practice has been developed. The essence of the protocol is anesthesia with the treatment and removal of teeth in the upper jaw and lower jaw in the frontal section using a 4% articaine solution with a vasoconstrictor of 1: 200,000 under the infiltration method of anesthesia with an efficiency of 97.3 ± 1.3%, duration 29.2 ± 2.48 minutes and an MPA of 96.3 ± 1.23% and an injection rate of 1 ml / min; in anesthesia of the molars in the lower jaw using the conductive method at the mandibular orifice with the obligatory aspiration test with 4% articaine with epinephrine 1: 200000 with an efficiency up to 92.54% ± 1.3 and a duration of 35.2 ± 2.43 minutes with a speed drug administration - 1 ml / min. Improving the effectiveness of anesthesia to 95.54 ± 0.3% is achieved by the periodontal method of introducing a 4% solution of articaine with a vasoconstrictor of 1: 200,000.

Influence of Different Instrument Carrying Systems on the Kinematics of the Spine of Saxophonists

AIMS: Back strain is a common musculoskeletal complaint affecting musicians, which may be related to unsuitable playing positions causing fatigue and muscle tension. In this study, three saxophone-carrying systems (neck-strap, shoulder-strap, and Saxholder) were examined for their effects on spinal column kinematics. METHODS: The influence of saxophone-carrying systems was investigated in 14 physically healthy alto saxophonists using ultrasound topometry. Additional tests were performed on 1 subject to examine the influence of the different weights of alto, tenor, and baritone saxophones with the three different carrying systems. RESULTS: The clearest difference between two systems (shoulder-strap vs Saxholder) was found in the angle at which the player’s head bows forward while playing (3.35°; 95% CI 0.44, 6.26; p=0.0272). The use of the Saxholder resulted in a physiologically favorable axial position of the head. The head posture to ankle distance showed that the shoulder-strap and Saxholder, compared to the neck-strap, allowed a sagittal straightening and therefore advantageous axially balanced body position, although the differences were not statistically significant. The Saxholder also enabled a stabilization in the frontal section of the shoulders. In additional tests on 1 subject, the coefficient of variation showed that the instruments’ weights had a larger influence on the physiologically favorable balanced body position than the different carrying systems. CONCLUSION: This pilot study was able to show that the technique of sonometric examination (Zebris) is an effective way to investigate the influence of instrument-carrying systems on the kinematics of the spine. The Saxholder may be physiologically advantageous, but further research with a larger sample is needed to verify the findings.

THE PARTIAL TRANSPLANTATION OF DESCEMET’S MEMBRANE WITH ENDOTHELIUM (½ AND ¼ DMEK)

The lamellar keratoplasty is the first operation of choice under selective pathology of cornea. In view of satisfactory results of endothelium surgery similar operations are implemented at more earlier stages that increases need in donor tissue. The life-span of population increases hence number of patients in need of cornea transplantation also increases and number of intact cadaver corneas decreases because of stable increasing of number of surgical interventions at the frontal section of eye. The purpose of study is to analyze operations of partial transplantation of Descemet's membrane with endothelium (½ DMEK and ¼ DMEK). Material and methods. The analysis was applied to the results of 10 operations ½ DMEK (semi-DMEK, hemi-DMEK) and 10 operations ¼ DMEK, implemented at eyes of 20 patients with primary endothelium dystrophy. The average age of patients made up to 64,9±10,4 years. The average visual acuity prior to implementation of partial DMEK amounted to 0,14 ± 0,08, average central thickness of cornea, according data of optical coherent tomography, made up to 669 ± 91 мкм. Results. In 16 out of 20 cases of partial DMEK, restoration of transparency of cornea, resorption of edema and increasing of visual acuity was achieved. In other 4 cases, during one week after partial DMEK, a subtotal DMEK was implemented. In 16 cases, average visual acuity increased up to 0,8 ± 0,3 three months later after operation. Conclusion. The techniques of partial transplantation of Descemet's membrane with endothelium (¼ DMEK и ½ DMEK) are efficient for treatment of primary endothelium pathology of cornea and permit to apply donor's material as much as possible rationally.

ASYNCHRONOUS MOTOR WITH A HOLLOW PERFORATED ROTOR

The paper presents a brief analysis of the conducted researches of the asynchronous executive motors and the induction motor, as well as the design of the asynchronous executive motor with a hollow perforated rotor. The basic relationships for determining the geometry of the rotor that directly influences the energy performance of the electric machine are also presented. The calculations to determine the geometry of the windows, located within a part of the active length of the stator package in the zone adjacent to the solid frontal area of the surface of the barrel from the side of its end face that is opposite to the bottom of the rotor barrel. In an asynchronous motor with a hollow perforated rotor improvement of energy performance (increase of maximum torque, efficiency and cosj of the engine) is achieved. These advantages are provided by the fact that the windows in the hollow rotor barrel are located within the part of the active length of the stator package in the zone adjacent to the solid frontal section of the rotor barrel surface on its end face that is opposite to the bottom of the barrel. In accordance with the design of the hollow rotor, the bottom of the barrel of one of the ends acts as superconducting short-circulating ring, therefore the ratio of increase in resistance (caused by the transverse edge effect) depends on the distribution of the rotor currents in the area adjacent to the solid frontal portion of the surface of the barrel on end that is opposite to the bottom of the barrel. In the analysis of current density distribution in a hollow rotor with the axial length L', all electric constant and geometric dimensions that are taken into account in the calculation are known values. Arbitrarily set constants are the primary currents and the rotational frequency of the rotor. With the rotation speed increase, due to the presence of the windows on one end face of the rotor and to the impact of the bottom of the barrel on the other one, the elementary currents of the rotor within the active length of the machine boring would be directed mainly in the axial direction, including the cases of comparatively small slippage that corresponds to the small frequency of the alternating magnetization of the rotor material. I. e. a certain part of the active surface of the rotor on the end that is opposite to the bottom of its barrel would not function as the frontal part of the winding while reducing the frequency of currents in the rotor material. This provides an increase in the active component of the rotor current that is proportional to the electromagnetic torque of the motor. Correspondingly, the frontal parts of equivalent winding of the hollow rotor (through which the currents do not generate torque) would not be spread at high rotational speeds to the area of the active length of the machine.

A GENERALIZED METHOD FOR PREDICTING CONTACT STRENGTH, WEAR, AND THE LIFE OF INVOLUTE CONICAL SPUR AND HELICAL GEARS: PART 1. SPUR GEARS

The paper presents the results of research undertaken to determine maximum contact pressures, wear, and the life of involute conical spur gear, taking into account gear height correction, tooth engagement, and weargenerated changes in the curvature of their involute profile. Moreover, we have established the following: (a) the initial contact pressures are higher in the internal section with double-single-double tooth engagement; (b) the highest values can be observed at the entry of single tooth engagement; (c) the maximal tooth wear of the wheels in the frontal section will be less than half of that in the internal section; (d) profile shift coefficients have an optimum at which the highest gear life is possible; and (e) gear life in the internal section will be less than half of that the frontal section. The calculations were made for a reduced cylindrical gear using a method developed by the authors. The effect of applied conditions of tooth engagement in the frontal and internal sections of a cylindrical gear ring is shown graphically. In addition, optimal correction coefficients ensuring the longest possible gear life are determined.

A GENERALIZED METHOD FOR PREDICTING CONTACT STRENGTH, WEAR, AND THE LIFE OF INVOLUTE CONICAL SPUR AND HELICAL GEARS: PART 2. HELICAL GEARS

The paper presents the results of research undertaken to determine maximum contact pressures, wear, and the life of involute conical helical gear, taking account of gear height correction, tooth engagement, and weargenerated changes in the curvature of their involute profile. We have established the following: (a) initial maximal contact pressures will be almost the same at the engagement in external and internal segments; (b) their highest meanings occur in different points of engagement depending on the coefficients of displacement; (c) the maximal tooth wear of the rings in the internal section will be a little bit lower than in the external; (d) the coefficients of displacement have an optimum at which the highest gear life is possible; and, (e) the gear life in the frontal section will be 1.25 lower than in the internal section. The calculations were made for a reduced cylindrical gear using a method developed by the authors. The effect of applied conditions of tooth engagement in the frontal and internal sections of a cylindrical gear ring is shown graphically. In addition, optimal correction coefficients ensuring the longest possible gear life are determined.

Dynamic Energy Absorption Performances of Rain Forest Vehicle (RFV) under Frontal Impact

This paper treats the crash analysis and energy absorption response of Rain Forest Vehicle (RFV) subjected to frontal impact scenario namely impacting rigid wall and column. Dynamic computer simulation techniques validated by experimental testing are used to carry out a crash analysis of such vehicle. The study aims at quantifying the energy absorption capability of frontal section of RFV under impact loading, for variations in the load transfer paths and geometry of the crashworthy components. It is evident that the proposed design of the RFV frontal section are desirable as primary impact energy mitigation due to its ability to withstand and absorb impact loads effectively. Furthermore, it is found that the impact energy transmitted to the survival room may feasibly be minimized in these two impact events. The primary outcome of this study is design recommendation for enhancing the level of safety of the off-road vehicle where impact loading is expected.

Dynamic Energy Absorption Performances of Rain Forest Vehicle (RFV) under Frontal Impact

This paper treats the crash analysis and energy absorption response of Rain Forest Vehicle (RFV) subjected to frontal impact scenario namely impacting rigid wall and column. Dynamic computer simulation techniques validated by experimental testing are used to carry out a crash analysis of such vehicle. The study aims at quantifying the energy absorption capability of frontal section of RFV under impact loading, for variations in the load transfer paths and geometry of the crashworthy components. It is evident that the proposed design of the RFV frontal section are desirable as primary impact energy mitigation due to its ability to withstand and absorb impact loads effectively. Furthermore, it is found that the impact energy transmitted to the survival room may feasibly be minimized in these two impact events. The primary outcome of this study is design recommendation for enhancing the level of safety of the off-road vehicle where impact loading is expected.