Slow conformational changes of blue light sensor BLUF proteins in milliseconds

BLUF (blue light sensor using flavin) proteins consist of flavin-binding BLUF domains and functional domains. Upon blue light excitation, the hydrogen bond network around the flavin chromophore changes, and the absorption spectrum in the visible region exhibits red-shift. Ultimately, the light information received in the BLUF domain is transmitted to the functional region. It has been believed that this red-shift is complete within nanoseconds. Contrary to this commonly accepted scheme, in this study, slow reaction kinetics were discovered in milliseconds (τ1- and τ2-phase) for all the BLUF proteins examined (AppA, OaPAC, BlrP1, YcgF, PapB, SyPixD, and TePixD). Despite extensive reports on BLUF, this is the first clear observation of the BLUF protein absorption change with the duration in the millisecond time region. From the measurements of some domain-deleted mutants of OaPAC and two chimeric mutants of PixD proteins, it was found that the slower dynamics (τ2-phase) are strongly affected by the size and nature of the C-terminal region adjacent to the BLUF domain. Hence, this millisecond reaction is a significant indicator of conformational changes in the C-terminal region, which is essential for the biological functions. On the other hand, the τ1-phase commonly exists in all BLUF proteins, including any mutants. The origin of the slow dynamics was studied using site-specific mutants. These results clearly show the importance of Trp in the BLUF domain. Based on this, a reaction scheme for the BLUF reaction is proposed.

On the use of light sensors on CubeSat nanosatellites

The paper focuses on the usage of the TCS34725 light sensor in the motion control system of the SamSat-Science nanosatellite platform. The sensor is designed to determine the angle between the sensor normal and the direction to the light emitter center. We developed a technique for calibrating light sensors, carried out a series of experiments, verified the nominal characteristic of the light sensor, and found the dependency of mean squared deviation (MSD) of the sensor values on the angle of incidence of the light flux. Three layouts of light sensors on the lateral faces of the nanosatellite are considered: on a plane; on the faces of a quadrangular pyramid with an inclination angle of 45°; on the faces of a truncated quadrangular pyramid with an angle of inclination of 45°. We have chosen a circuit that provides measurements with minimum noise.

RANCANG BANGUN ALAT PENDETEKSI KONDISI TELUR AYAM BERBASIS MIKROKONTROLER ATMEGA 32 DENGAN SENSOR CAHAYA

When consumers buy eggs, consumers should be more careful choosing the egg because there are some eggs that the quality has been decreased or the eggs are damaged and cannot be consumed anymore. This is caused by the length of egg storage time and didn’t have a tool that capable to detect the condition of the egg. People or egg breeders / entrepreneurs habit on looking the quality of eggs still use manual way, as a result it takes a long time because it must select the eggs condition one by one. The purpose of this research is to design and make the detection tool of chicken egg condition with ATmega 32 microcontroller using light sensor, so that the time efficiency and the result of egg selection becomes faster. . The use of tools is very easy and simple so that consumers or breeders / entrepreneurs can use it. Then to simplify and speed up the selection time of chicken eggs breeder or entrepreneur to distinguish good and damaged egg condition.

The Device for Houseplants Caring

The article is devoted to the development of an automated device for plant care at home. The main factors influencing plant development are considered. A comparative analysis of existing devices was made. The growth of plants is influenced by many factors: the level of light, soil moisture, room temperature, carbon dioxide level. When plants are growing indoors, the most important thing is timely watering and access to light. The required amount of light for most plants is 12-18 hours per day. Our country is in the temperate climate zone, so we have 15 hours of light in summer, 13 hours in autumn and spring, and 9 hours in winter. The amount of light in summer is normal, in autumn and spring - within normal limits, but in winter there is a certain lack of light. The lack of natural insolation in winter leads to light starvation of houseplants and reduced intensity of photosynthesis. Therefore, the decrease of the amount of natural light is compensated by artificial light sources. Analysis of the devices on the market has shown that devices that can solve such problems exist, but there is no device with all functions simultaneously. Lighting devices illuminate on a timer, regardless of natural light. Irrigation devices are intended for industrial, not for domestic use. Existing technological solutions for home cultivation have only a warning function: sound or light, which can bring some inconvenience. Looking on these problems, a device is created to maintain the required soil moisture and the required amount of light. The control unit is based on a microcontroller that analyses the data obtained from the sensors and sends the appropriate signals to the climate control devices. The device is equipped with a soil moisture sensor, a light sensor, a real - time sensor, an LED lamp, a water pump, an LED lamp driver, and a control key of water pump. To control soil moisture, a capacitive humidity sensor is used, the advantages of it is the absence of corrosion of metal parts of the sensors that touch the ground. A light meter based on the BH1750 chip is used as a light sensor. This sensor has a wide measuring range, measuring accuracy - 1 lux, small dimensions and the ability to connect to a microcontroller via I2C interface. The DS3231 chip is used as a real-time clock that required to maintain a circadian rhythm close to the natural one for a given plant. An LED strip with red and blue LEDs is used for lighting. The ratio of blue / red LEDs depends on the stage of growth and the type of plant, but it is usually from 1/3 to 1/5. The key that controls the LED strip and the water pump are the MOS transistors. They are silent and allow you to adjust the brightness of the LED strip.