cpSRP43 is both highly flexible and stable: Structural insights using a combined experimental and computational approach

The novel multidomain protein, cpSRP43, is a unique subunit of the post-translational chloroplast signal recognition particle (cpSRP) targeting pathway in higher plants. The cpSRP pathway is responsible for targeting and insertion of light-harvesting chlorophyll a/b binding proteins (LHCPs) to the thylakoid membrane. Nuclear-encoded LHCPs are synthesized in the cytoplasm then imported into the chloroplast. Upon emergence into the stroma, LHCPs form a soluble transit complex with the cpSRP heterodimer, which is composed of cpSRP43 and cpSRP54, a 54 kDa subunit homologous to the universally conserved GTPase in cytosolic SRP pathways. cpSRP43 is irreplaceable as a chaperone to LHCPs in their translocation to the thylakoid membrane and remarkable in its ability to dissolve aggregates of LHCPs without the need for external energy input. In previous studies, cpSRP43 has demonstrated significant flexibility and interdomain dynamics. However, the high flexibility and structural dynamics of cpSRP43 is yet unexplained by current crystal structures of cpSRP43. This is due, in part, to the fact that free full length cpSRP43 is so flexible that it is unable to crystalize. In this study, we explore the structural stability of cpSRP43 under different conditions using various biophysical techniques and find that this protein is concurrently highly stable and flexible. This conclusion is interesting considering that stable proteins typically possess a non-dynamic structure. Molecular dynamics (MD) simulations which correlated with data from biophysical experimentation were used to explain the basis of the extraordinary stability of cpSRP43. This combination of biophysical data and microsecond-level MD simulations allows us to obtain a detailed perspective of the conformational landscape of these proteins.

The irreducible mass of Christodoulou–Ruffini–Hawking mass formula

We reveal three new discoveries in black hole physics previously unexplored in the Hawking era. These results are based on the remarkable 1971 discovery of the irreducible mass of the black hole by Christodoulou and Ruffini, and subsequently confirmed by Hawking. (1) The Horizon Mass Theorem states that the mass at the event horizon of any black hole — neutral, charged, or rotating — is always twice its irreducible mass observed at infinity. (2) The External Energy Theorem asserts that the rotational energy of a Kerr black hole exists completely outside the horizon. This is due to the fact that the irreducible mass does not contain rotational energy. (3) The Moment of Inertia Theorem shows that every black hole has a moment of inertia. When the rotation stops, the irreducible mass of a Kerr black hole becomes the moment of inertia of a Schwarzschild black hole. This is recognized as the rotational equivalent of the rest mass of a moving body in relativity. Thus after 50 years, the irreducible mass has gained a new and profound significance. No longer is it a limiting value in rotation, it determines black hole dynamics and structure. What is believed to be a black hole is a mechanical body with an extended structure. Astrophysical black holes are likely to be massive compact objects from which light cannot escape.

ANSYS CFX STUDY OF AERODYNAMIC CHARACTERISTICS DURING BLADE PROFILE ROTATION

Currently, wind energy is one of the most developing areas, which is primarily due to the absence of emissions of harmful substances into the atmosphere. Wind power allows providing electricity to remote areas, where fuel delivery, as well as the construction of thermal power plants is laborious and expensive. The effective development of wind turbines should solve the following tasks: the creation of the necessary driving force and the possibility of using a high coefficient of wind energy, which does not contradict the maintenance of the ecological balance of the territory. An electric generator for a household wind turbine must provide electricity in a wide range of rotation speeds and be able to work independently without automation and external energy sources. The study of the numerical implementation of the method of aerodynamic analysis of the wind turbine blade in rotational motion in the ANSYS CFD software package is by far the most promising and dynamically developing direction in the field of aerodynamics calculations. The results of approbation of the mixed calculation method using a dynamically variable and stationary finite-volume mesh are presented. The use of a mixed design scheme allows for calculations of wind turbines inside the building, while it becomes possible to minimize the required power for the study.

Kinetic Solar Envelope: Performance Assessment of a Shape Memory Alloy-Based Autoreactive Façade System for Urban Heat Island Mitigation in Athens, Greece

The paper explores the potentials of shape memory alloys (SMAs) for the design of autoreactive façade systems without using additional external energy. The exploration is conducted and assessed through the design of a façade concept for the city of Athens in Greece, aiming to improve both the indoor and outdoor environment by means of a kinetic autoreactive system featuring a dual-seasonal function, with a focus on the building’s direct and indirect impact on the urban heat island (UHI) effect. The paper covers a demonstration of the methodology followed, using a feedback-loop logic informed by environmental and energy performance evaluation studies in Grasshopper to optimize the geometry and movement of the shading component. During the façade design process, a comprehensive and systematic computational toolset is being developed, targeted on the abovementioned performance evaluation studies. Through the development and assessment of the façade concept, the objective is to explore the potentials and limitations for the application of autoreactive envelopes in the façade design. At the same time, the aim is to exploit the possibilities and optimization potentials offered through the developed iterative computational workflows, by showcasing the methodology and interoperability logic of the digital tools used for the data interchange.

Energy at Origins: Favorable Thermodynamics of Biosynthetic Reactions in the Last Universal Common Ancestor (LUCA)

Though all theories for the origin of life require a source of energy to promote primordial chemical reactions, the nature of energy that drove the emergence of metabolism at origins is still debated. We reasoned that evidence for the nature of energy at origins should be preserved in the biochemical reactions of life itself, whereby changes in free energy, ΔG, which determine whether a reaction can go forward or not, should help specify the source. By calculating values of ΔG across the conserved and universal core of 402 individual reactions that synthesize amino acids, nucleotides and cofactors from H2, CO2, NH3, H2S and phosphate in modern cells, we find that 95–97% of these reactions are exergonic (ΔG ≤ 0 kJ⋅mol−1) at pH 7-10 and 80-100°C under nonequilibrium conditions with H2 replacing biochemical reductants. While 23% of the core’s reactions involve ATP hydrolysis, 77% are ATP-independent, thermodynamically driven by ΔG of reactions involving carbon bonds. We identified 174 reactions that are exergonic by –20 to –300 kJ⋅mol−1 at pH 9 and 80°C and that fall into ten reaction types: six pterin dependent alkyl or acyl transfers, ten S-adenosylmethionine dependent alkyl transfers, four acyl phosphate hydrolyses, 14 thioester hydrolyses, 30 decarboxylations, 35 ring closure reactions, 31 aromatic ring formations, and 44 carbon reductions by reduced nicotinamide, flavins, ferredoxin, or formate. The 402 reactions of the biosynthetic core trace to the last universal common ancestor (LUCA), and reveal that synthesis of LUCA’s chemical constituents required no external energy inputs such as electric discharge, UV-light or phosphide minerals. The biosynthetic reactions of LUCA uncover a natural thermodynamic tendency of metabolism to unfold from energy released by reactions of H2, CO2, NH3, H2S, and phosphate.

The Spatiotemporal Evolution of Temperature During Transient Heating of Nanoparticle Arrays

Nanoparticle (NP) are promising agents to absorb external energy excitation and generate heat. Cluster of NPs or NP array heating have found essential roles for biomedical applications, diagnostic techniques and chemical catalysis. Various studies have shed light on the heat transfer of nanostructures and greatly advanced our understanding of NP array heating. However, there is a lack of analytical tools and dimensionless parameters to describe the transient heating of NP arrays. Here we demonstrate a comprehensive analysis of the transient NP array heating. Firstly, we developed analytical solution for the NP array heating and provide a useful mathematical description of the spatial-temporal evolution of temperature for 2D, 3D and spherical NP array heating. Based on this, we proposed the idea of thermal resolution that quantifies the relationship between minimal heating time, NP array size, energy intensity and target temperature. Lastly, we define a dimensionless parameter that characterize the transition from confined heating to delocalized heating. This study advances the understanding of nanomaterials heating and provides guidance for rationally designing innovative approaches for NP array heating.

The Efficiency of Vapor Compression Transformation of Energy Flows for Heat Supply Based on the Sea Water

The results of the analytical study substantiated the operating conditions for the highly efficient use of the temperature potential of seawater in heat pump heating systems (HPHS) for buildings a building with correspondingly improved environmental indicators. Based on the analysis of the regional conditions of the Odessa water area of the Black Sea, the initial parameters have been substantiated and rational modes of operation of an improved HPHS with central, decentralized or local heating of the subscriber energy carrier have been determined. As indicators for evaluating the efficiency of the HPHS operation, the conversion factor of energy flows and the specific consumption of external energy for the drive of the compressor and the circulating pump of cooled water in the operation of heat pump units were considered. For seawater in the Odessa water area of the Black Sea during the entire heating period, the following temperatures were considered as initial data for analysis: water at the inlet to the evaporator (5–10) ° C, at the outlet (1 °C); calculated temperature difference of the coolant in the heating system (50–40) °C, indoor air (20 °C); estimated outdoor temperature (–18 °C). The characteristic correspondence between the flow rates of the cooled sea water and the heated energy carrier of the heat supply system was taken into account. The prerequisites of high efficiency of the heat pump heat supply system in which the actual conversion coefficient exceeds the seasonal normalized calculated and minimum value at an outdoor temperature of (–10) °C under the limiting conditions of the monoenergy regime for both new and reconstructed buildings were substantiated. In the course of the study, it has been determined that the total specific consumption of external energy for the compressor drive and the circulation of cooled water in the operation of a heat pump unit with a characteristic ratio of water equivalents, even under the limiting conditions of the monoenergetic mode of operation of the heat supply system at an outdoor temperature of (–10) °C, are within the range of generally accepted values (w = 0.28–0.34).

Binding Energy of Cubic Carbon Atoms

Energy spectrum of gas particles in plasma is broad, ranging from fractions to 10s of electron volts. Proportion of particles with required energetic parameters, participating in cubic carbon c-C synthesis, is small. External energy deposition can transfer an inert carbon atom to active state and change its electronic configuration. Binding energy of c-C atom depends on energy sources interaction. In this work, the calculations found the binding energy value that was compared with value of energy of the bond between the carbon atoms in ethane. The advisability of external source, activated carbon atoms generator, is marked. It has been established that by adding accelerated carbon atoms with energy of 9,687 eV into reactor it is possible to increase productivity of films, coatings and bulk crystals growth.