The effectiveness of red light therapy (RLT) on cellular activity is important in determining if its usage is suitable for the treatment of various health conditions. In order to better understand the molecular and metabolic mechanisms related to RLT, our preliminary study of the effect of LED light sources 660 nm and 850 nm on the proliferation of human lymphocyte cells was further extended to analyze its effect on the synthesis of cellular enzymes. Using the Bradford method, the total concentration of proteins in lymphocytes was monitored for different time parameters and conditions of exposure and in relation to the untreated (non-irradiated) control cells. Our results show a higher protein concentration for all irradiated samples when compared to the unirradiated samples and it was especially increased for multiple exposures to red/infrared light. Since the used method cannot answer whether the increased protein concentration has positive or negative connotations, it is important to continue the research and include additional methods that test oxidative stress and the structure of chromosomes on a larger number of samples in order to gain additional understanding of the beneficial impact of RLT on lymphocyte cells.

In order to complete the analysis of the water vapor diffusion problem, as well as the conditions for the appearance of mold, the paper investigates the cases when condensation occurs in the layer inside the structure while considering the increase in the humidity of the material in relation to its natural humidity. Additionally, the level of the average monthly humidity in relation to the critical relative humidity, as well as the temperature factor are investigated. The analysis was done on two materials that are most often used in our region – lightweight concrete (Siporex) block and normal concrete, in situations when thermal insulation is laid on the outside or on the inside of the structure. The calculation showed that for certain situations, already after a couple of years, the total humidity of the material exceeds the permitted values for the materials in question. It was also observed that in the case when moisture diffusion occurred adjacent to the insulating material, the total amount of condensed moisture exceeded the permitted value for which the appearance of mold is avoided.

The applications of light emitting diodes (LED) as a red light therapy (RLT) source for the management of various conditions such as wound treatment, control of inflammation and pain have been growing continually. Despite its extensive medical application, the effects of RLT on living cells are still highly contested. This study is conducted to test the effects of RLT using combined LED source with 660 nm (red) and 850 nm (near infrared) light on cultured human lymphocytes in vitro. To analyze the effect of RLT on human peripheral blood lymphocyte’s proliferation, the mitotic index (cytostatic effect) is monitored under different irradiation exposure time parameters and conditions. This value indicates how a particular treatment affected cell division, either proliferatively, inhibitory, or had no effect at all. The interpretation of the results of the mitotic index is done in relation to the mitotic index of the untreated (unirradiated) control cells. Our data shows higher lymphocyte proliferation for all of the irradiated samples, and is particularly enhanced by multiple exposures to red light. The effectiveness of RLT on cell activity is of importance in determination of suitable treatment for diseases related to the immune system. To better understand the molecular and metabolic mechanisms involved in red LED-induced photobiomodulation, the study will be extended to investigate the RLT effect on cell protein synthesis.

This paper presents the health chatbot application created on the Chatfuel platform. This application allows people to interact with the health chatbot in the same way as they do with other people. The health chatbot identifies their symptoms through a series of queries and guides them to decide whether or not to go to doctor. Such application can be of great benefit to people who are not sure whether their symptoms are transients or require a response to a doctor for detailed tests. It also offers advice to users on minor illnesses, and in that way, encourages people to take appropriate measures to stay healthy, which is a great example of promoting a healthy life. For the purpose of this research, an end-user survey was created and conducted with aim to collect the users’ opinion regarding the acceptance and usage motivation of health chatbot. The results showed good acceptance and usage motivation of health chatbot.

Under normal conditions it may take years to gather failure data on the life cycle of new LED products. Through accelerated life testing the product life of HP LED is simulated by increasing the stress levels of the ambient temperature to higher than normal. A lifetime acceleration estimate is made using the Arrhenius model. The value of activation energy is not assumed, but is experimentally determined by performing tests at multiple temperatures and plotting the results. The acceleration factor is obtained by the ratio of the reaction rates at the tested temperatures and the declared temperature. Using the correct value of the activation energy is important because it represents the dominating reason for degradation and small change in its value will have an effect on the acceleration factor.Under normal conditions it may take years to gather failure data on the life cycle of new LED products. Through accelerated life testing the product life of HP LED is simulated by increasing the stress levels of the ambient temperature to higher than normal. A lifetime acceleration estimate is made using the Arrhenius model. The value of activation energy is not assumed, but is experimentally determined by performing tests at multiple temperatures and plotting the results. The acceleration factor is obtained by the ratio of the reaction rates at the tested temperatures and the declared temperature. Using the correct value of the activation energy is important because it represents the dominating reason for degradation and small change in its value will have an effect on the acceleration factor.

The performed evaluation consisted of two phases: measurement of the illumination levels of (new) LED system and carrying out the public opinion poll on the subjective visual performance of LED in traffic lights. The results of the measured levels of illumination show that deposition of dirt considerably affects its values. The survey results confirm an overall positive impression on LED performances in traffic lights.

High power light emitting diodes (HP LED) are energy efficient light sources that have been developing at great speed. Aging process was performed at increased pin temperatures, with approximate values of 80°C, 90°C and 100°C and constant current. The conditions in chambers are simultaneously monitored for approximately 5000 hours. The change in HP LED's SPD was small and for the second test group was within the narrower wavelength interval than for the first. This interval corresponds to the phosphor emission region and indicates that important factor of white LED's SPD stability is the choice of type of phosphor used.