Modeling indicates degradation of mRNA and protein as a potential regulation mechanisms during cold acclimation

Plants are constantly exposed to temperature fluctuations, which have direct effects on all cellular reactions because temperature influences reaction likelihood and speed. Chloroplasts are crucial to temperature acclimation responses of plants, due to their photosynthetic reactions whose products play a central role in plant metabolism. Consequently, chloroplasts serve as sensors of temperature changes and are simultaneously major targets of temperature acclimation. The core subunits of the complexes involved in the light reactions of photosynthesis are encoded in the chloroplast. As a result, it is assumed that temperature acclimation in plants requires regulatory responses in chloroplast gene expression and protein turnover. We conducted western blot experiments to assess changes in the accumulation of two photosynthetic complexes (PSII, and Cytb6f complex) and the ATP synthase in tobacco plants over two days of acclimation to low temperature. Surprisingly, the concentration of proteins within the chloroplast varied negligibly compared to controls. To explain this observation, we used a simplified Ordinary Differential Equation (ODE) model of transcription, translation, mRNA degradation and protein degradation to explain how the protein concentration can be kept constant. This model takes into account temperature effects on these processes. Through simulations of the ODE model, we show that mRNA and protein degradation are possible targets for control during temperature acclimation. Our model provides a basis for future directions in research and the analysis of future results.

Possibilities of measuring the local density of seawater in probe instruments

In modern expeditionary research carried out on research vessels, the local density of seawater is not measured, but calculated using the TEOS-10 thermodynamic equation of state based on cumulative measurements of pressure, temperature and electrical conductivity or speed of sound. The equation of state with satisfactory accuracy is valid only for oceanological waters, and is used with corrections for the waters of the marginal and inland seas. These corrections are permanently refined and will be refined in the future. It is desirable to have direct measurements of the local density of any waters directly in the environment with sufficient accuracy, which is now 4·10-6. Laboratory measurements made by various methods and with different devices, not always automated, give accuracy ~ . Attempts to automate these measurements and introduce them into sounding devices have been made several times. Experimental samples of vibration, refractometric and hydrostatic devices have been created and tested, none of which have been introduced into the practice of expeditionary work for various reasons. However, scientific and technological progress makes possible technical solutions previously difficult to implement. This also applies to modifications of the hydrostatic method for measuring the local density, which have recently attracted the interest of developers. The paper analyzes the possibilities of implementing the hydrostatic method using multi-element resistor distributed pressure and temperature sensors, resistance profilers of these sensors and determining the spatial pressure drop on a given base by measuring and subtracting sensor resistances, taking into account temperature correction. The use of three such sensors, mounted on three rods, oriented downward along the axes of a rectangular coordinate system, provides the possibility of measuring the local density with an arbitrary orientation of the probe relative to the vertical. The analysis shows the possibility of measuring the local density of seawater by the hydrostatic method with the required accuracy in probe instruments.

Digital Model of Boiler Furnace Processes

The normative method (NM) of thermal boiler calculation, which has been confirmed and refined multiple times, contains the structure of ideas and methods retained and adapted during the transition to digital technologies. As applied to the analysis of thermal processes in the boiler furnace with flare furnaces, this required the transformation of a large array of initial and reference data, which cannot be used unchanged in digital technologies, including computer-assisted. This applies to graphical and tabular data, which occupy up to 80% of the NM volume. The main regulatory elements of the digital model in this case are the temperature of adiabatic combustion of the fuel, the coefficient of attenuation of radiation by the combustion medium, the degree of emissivity of the furnace taking into account the size of the radiating layer, the coefficient of thermal efficiency of the furnace wall pipings, the resulting Boltzmann number and the final calculated value of the gas temperature at the exit from the furnace. The use of specific data for a boiler with D = 400 t/h made it possible to clarify the structure of analytical dependencies, as well as the magnitude of deviations from the standard values in the final temperature values. The paper presents a developed transition to dependencies accounting for the thermal power of the boiler and the type of fuel. The digital model adaptation to the boiler conditions with all types of fuel in use made it possible to determine the average deviations of the final parameters. Quantitatively, the entire material corresponds to the normative data, is presented digitally and corresponds methodically to the Mathcad-15 package. In contrast to acclaimed works in this area, all factors affecting the heat balance are represented by approximations taking into account temperature variability.

Investigation of atomic mixing during adsorption of iron film on silver substrate

The results of calculations of the energy and magnetic characteristics of the activated adsorption of a monolayer ferromagnetic iron film on the silver surface are presented. The studies were carried out using two approaches: the variational method of the spin density functional taking into account temperature effects and inhomogeneous distribution of magnetization and the ab initio one, implemented using the VASP software package. Calculations were made of the total and interfacial energies, magnetic moment and adsorption energy of the Fe / Ag system, depending on the orientation of the substrate face, the coating parameter Θ and the fraction of adatoms in the film. The strong influence of mixing and the energetic advantage of the formation of a "sandwich" system have been revealed. A continuous Fe film will not form on the close-packed Ag face, which is confirmed by experimental studies.

Calculation Of Fire Resistance Of Compressed Reinforced Concrete Elements Taking Into Account The Heat And Technical Characteristics Of Reinforcement

The calculation of fire resistance of reinforced concrete elements depends on the accuracy of the thermal calculation. When performing this calculation, the distribution of the temperature field over the cross section of the element and the strength characteristics that depend on it are determined. The temperature distribution over the section of the structure depends on such parameters as the heat capacity and thermal conductivity of the section parts, and its humidity. The article considers an approach to solving the problem of taking into account the actual temperature field when calculating the fire resistance of reinforced concrete and steel-reinforced concrete elements. Fire resistance calculations were performed for temperature fields that do not take into account the inclusion of reinforcement (concrete section), as well as for temperature fields that take into account temperature inclusions. For the section under consideration, additional coefficients are calculated, which are entered into the calculation of fire resistance when using the method STO 36554501-006-2006 "Rules for ensuring the fire resistance and fire safety of reinforced concrete structures". According to the results of this work, an increase in the bearing capacity of rectangular and square sections was noted when calculating with regard to the thermal characteristics of the reinforcement.

Advanced Exergetic Analysis of a Double-Effect Series Flow Absorption Refrigeration System

This paper contains theoretical results of an advanced exergy study of a double-effect series flow absorption refrigeration cycle. Traditional second law of thermodynamics analysis was performed and revealed the absorber as the component with the highest exergy destruction of the system. In the evaporator, ≈49.34% of the exergy destruction is avoidable and almost in it’s entirety, ≈99.12% is of endogenous nature. The highest potential for improvement of the high-pressure generator is its design and manufacture because ≈67.47% of the endogenous exergy destruction is avoidable. A parametric study was presented to discuss the sensitivity of splitting exergy destruction concepts taking into account temperature variations in the absorber and condenser temperatures and the heat source temperature.

Mass of dusty clumps with temperature and density structure

We consider a dusty clump in two cases of spherical and cylindrical symmetry to investigate the effect of temperature and density gradients on the observed flux density. Conversely, we evaluate how the presence of these gradients affects the calculation of the clump mass from the observed flux. We provide approximate expressions relating flux density and mass in the optically thick and thin limits and in the Rayleigh-Jeans regime, and we discuss the reliability of these expressions by comparing them to the outcome of a numerical code. Finally, we present the application of our calculations to three examples taken from the literature, which shows how the correction introduced after taking into account temperature and density gradients may affect our conclusions on the stability of the clumps.