Body temperature is an important indicator that may indicate the possibility of the existence of various pathological conditions and diseases. In the head and neck area, an infrared camera allows accurate temperature measurements of all regions of interest. The analysis of temperature characteristics of the region of interest of the head and neck in healthy subjects in terms of comparison of values in relation to the side of the face in the same person, and the comparison of values relative to the sex of the subjects is the topic of this research. These analyses are performed to create temperature maps of the face and determine physiological values. The research was conducted with the participation of 30 healthy people, 16 women and 14 men of different ages. Thermal imaging was performed in controlled conditions with infrared thermographic camera Varioscan 3021ST, while the software package IRBIS Professional 2.2 was used for thermogram analysis. Results show that the temperatures in female subjects at the submandibular region are significantly lower than in male subjects with an average temperature difference of 0.46?C, and the temperatures in female subjects at the supraorbital region are on average 0.5?C higher than in male subjects.

A new three-dimensional (3D) model of a high-power composite ultrasonic transducer is proposed and evaluated in this paper. This transducer comprises two active layers, each with at least two mechanically series-connected piezoelectric elements. A metal mass element is clamped between active layers with two bolts to create a sandwich structure comprising back and front metal radiation masses. The electromechanical equivalent circuit of the transducer, representing a general one-dimensional (1D) model, is first derived and presented in this paper. The general 1D model takes into account all existing transducer components, including both central bolts, in addition to the proposed 3D model. Additionally, when effects of the bolts are excluded, the resonance frequency equation was analytically derived based on the general 1D model. The composite transducer is designed and manufactured. For a large number of electrical connection combinations, transducer resonance frequencies are measured and compared with the results obtained from 3D and 1D models. The results indicate that the resonance frequencies obtained from 1D model are in line with the measured frequencies for the first thickness mode only. However, for all thickness and radial oscillation modes and their mutual coupling the analytically obtained frequencies from 3D model correspond well to the measured frequencies. In addition, the presented results in this paper contribute to a better understanding of the geometry and material properties of the composite piezoelectric transducer parts impact on transducer behavior.

A low-cost teslameter based on a Hall effect sensor MLX90242 is proposed in this paper. The proposed teslameter is built around a PIC18F4550 microcontroller and it can measure magnetic flux density in the range between -55 mT and 55 mT. Temperature stability of measurements originates from the MLX90242 sensor itself. In order for the proposed transducer to be accurate, it has undergone a calibration procedure using a highly accurate teslameter employed as reference instruments and high-quality variable-field electromagnet. The proposed teslameter can store measurements on a PC via built-in USB communication.

The root walls of immature permanent teeth are often weak, thin, and short, making regenerative endodontic treatment (RET) necessary. The goal of RET is to create a favorable environment for further root development. A biomimetic approach is essential for thorough disinfection, followed by the preservation and potential stimulation of stem cells from surrounding tissue to enable root regeneration and continued development. The objective of this study was to assess temperature changes on the external root surface, structural alterations in the internal root walls following irradiation with a 940 nm diode laser, and the biocompatibility of stem cells from the apical papilla (SCAPs). Irradiation was performed with varying output powers (0.5 W, 1 W, 1.5 W, and 2 W) in continuous mode for 5 s over four consecutive cycles. Thermographic measurements during irradiation, the micro-CT analysis of root samples, and mitochondrial activity of SCAPs were evaluated. The heating effect correlated directly with a higher output power and thinner root walls. A 1 W output power was found to be safe for immature teeth, particularly in the apical third of the root, while 1.5 W could be safely used for mature mandibular incisors. Diode laser irradiation at 1 W and 1.5 W significantly stimulated SCAPs’ mitochondrial activity within 24 h post-irradiation, indicating a potential photobiostimulatory effect. However, no significant changes were observed at lower (0.5 W) and higher (2 W) output powers. The area of open tubular space inside the root canal was significantly reduced after irradiation, regardless of the applied power. Additionally, irradiation contributed to the demineralization of the dentin on the inner root walls. Future studies should explore the impact of irrigants used between irradiation cycles, the potential benefits of conical laser tips for more even energy distribution, and a thorough analysis of how disinfection protocols affect both the dentin structure and stem cell viability.

Ultrasonic sandwich transducer is a half-wave resonant structure which oscillates in thickness direction. This paper presents a new Matlab/ Simulink model of a prestressed unsymmetrical ultrasonic sandwich transducer, which is modeled by applying three-dimensional (3D) Matlab/Simulink models of piezoceramic rings and metal endings derived from the piezoceramic ring model. With the cascade connection of the piezoceramic rings model with metal endings model, a complete model of ultrasonic transducer is obtained. Using this model one may determine any transducer transfer function, whereat is taken into the account the external medium influence, as well as the influence of the thickness and radial modes of each transducer component. The electromechanical equivalent circuit of the hammer transducer, which represents onedimensional (1D) model, is also derived and presented in this paper. The comparisons between experimental and theoretical results are quite good and validate the new analytical 3D design approach. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR33035]