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"Energy charge"
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Energy landscapes and dynamics of ion translocation through membrane transporters: a meeting ground for physics, chemistry, and biology
2021
The dynamics of ion translocation through membrane transporters is visualized from a comprehensive point of view by a Gibbs energy landscape approach. The ΔG calculations have been performed with the Kirkwood–Tanford–Warshel (KTW) electrostatic theory that properly takes into account the self-energies of the ions. The Gibbs energy landscapes for translocation of a single charge and an ion pair are calculated, compared, and contrasted as a function of the order parameter, and the characteristics of the frustrated system with bistability for the ion pair are described and quantified in considerable detail. These calculations have been compared with experimental data on the ΔG of ion pairs in proteins. It is shown that, under suitable conditions, the adverse Gibbs energy barrier can be almost completely compensated by the sum of the electrostatic energy of the charge–charge interactions and the solvation energy of the ion pair. The maxima in ΔGKTW with interionic distance in the bound H+ – A− charge pair on the enzyme is interpreted in thermodynamic and molecular mechanistic terms, and biological implications for molecular mechanisms of ATP synthesis are discussed. The timescale at which the order parameter moves between two stable states has been estimated by solving the dynamical equations of motion, and a wealth of novel insights into energy transduction during ATP synthesis by the membrane-bound FOF1-ATP synthase transporter is offered. In summary, a unifying analytical framework that integrates physics, chemistry, and biology has been developed for ion translocation by membrane transporters for the first time by means of a Gibbs energy landscape approach.
Journal Article
Optimizing energy efficiency in induction skull melting process: investigating the crucial impact of melting system structure
2024
Induction skull melting (ISM) technology could melt metals with avoiding contamination from crucible. A long-standing problem of ISM is that the low charge energy utilization and inhomogeneous fields have obstructed its application in many critical metal materials and manufacturing processes. The present work investigated the problem through the structure optimization strategy and established a numerical electromagnetic-field model to evaluate components’ eddy current loss. Based on the model, the effect of crucible and inductor structure on charge energy utilization, etc. was studied. Furtherly, the charge energy utilization was increased from 27.1 to 45.89% by adjusting the system structure. Moreover, structure modifications are proposed for enhancing electromagnetic intensity and uniformity, charge soft contact and uniform heating. The work constructed a basis for framing new solutions to the problem through ISM device structure optimization.
Journal Article
Experimental and numerical study on dynamic crack propagation of shaped charge at different angles
2025
To study the crack propagation characteristics of the V-shaped energy- accumulating charge at different angles, a new numerical laser caustics test system was used to observe the fracture process of the V-shaped energy-concentrating charge; the mechanical distribution mechanism around the blast hole of the energy-accumulating charge was analyzed, and fractal theory was used to evaluate the damage degree of the energy-accumulating charge. A series of caustics test results show that the main crack has a longer expansion length in the energy-concentrating direction, and the crack expansion length is shorter in the nonenergy-concentrating direction. The fractal damage results of the energy gathering perforating charge indicate that as the angle of the charge increases, the damage caused by energy gathering blasting gradually increases, the complexity of crack propagation increases, and the main crack follows the direction of energy accumulation. The directivity becomes increasingly less obvious. When the energy gathering angle is 120°, the main crack propagation process is similar to that of the circular charge (control group). The shaped charge can be used for directional fracture control blasting, which helps to control the direction and number of cracks and improve the blasting effect.
Journal Article
Metabolic and immune status of Pacific white shrimp Penaeus vannamei concerning farming conditions
by
Matsumoto, Takeo
,
Apún-Molina, Juan Pablo
,
Robles-Romo, Arlett
in
Agricultural industry
,
Agriculture
,
Bioenergetics
2024
Biomarkers for monitoring shrimp health have been proposed but scarcely evaluated at the farm level. We analyzed several indicators of energy status in shrimp under farming conditions concerning stocking densities (100 m-2 with biofloc, 15 and 7 m-2). The influence of the year's season (temperature) was also analyzed, and, finally, an unfortunate event of White spot syndrome virus (WSSV) infection occurred on the 7 m-2 farms, adding another condition. At shrimp sampling from ponds, the effect of acute handling stress was also analyzed for indicators typically affected by such procedure with a 3- and 10-fold increase in glucose and lactate levels in hemolymph, respectively, regardless of density. This response was partially blunted at lower temperatures and WSSV incidence. Increased levels of protein in the hepatopancreas, adenylic energy charge (AEC) in both hepatopancreas and muscle and phosphagens in muscle were observed in shrimp from the 100 m-2 farms, suggesting a better nutritional and energetic status in shrimp cultured at high density with biofloc technology. Shrimp with WSSV presented lower hemocyanin levels in hemolymph, most likely associated with its role in the immune response. In WSSV-infected shrimp, the stress response regarding glucose increase was blunted, whereas a stress-induced increase in triglycerides (TG) levels in hemolymph was observed only with WSSV. Increased TG levels in those shrimp hepatopancreas could indicate a switch from carbohydrate to lipid-based metabolism associated with the preferential use of carbohydrates (Warburg effect) for virus replication in the early infection state.
Journal Article
High-energy guanine nucleotides as a signal capable of linking growth to cellular energy status via the control of gene transcription
by
Hesketh, Andy
,
Oliver, Stephen G.
in
Adenosine triphosphate
,
Biochemistry
,
Biomedical and Life Sciences
2019
This mini-review considers the idea that guanylate nucleotide energy charge acts as an integrative signal for the regulation of gene expression in eukaryotic cells and discusses possible routes for that signal’s transduction. Gene expression is intimately linked with cell nutrition and diverse signaling systems serve to coordinate the synthesis of proteins required for growth and proliferation with the prevailing cellular nutritional status. Using short pathways for the inducible and futile consumption of ATP or GTP in engineered cells of
Saccharomyces cerevisiae,
we have recently shown that GTP levels can also play a role in determining how genes act to respond to changes in cellular energy supply. This review aims to interpret the importance of GTP as an integrative signal in the context of an increasing body of evidence indicating the spatio-temporal complexity of cellular de novo purine nucleotide biosynthesis.
Journal Article
Mechanically strong MXene/Kevlar nanofiber composite membranes as high-performance nanofluidic osmotic power generators
by
Yang, Sheng
,
Zhang, Panpan
,
Chen, Guangbo
in
639/4077/4072/4062
,
639/638/455/303
,
Aramid fiber reinforced plastics
2019
Two-dimensional nanofluidic channels are emerging candidates for capturing osmotic energy from salinity gradients. However, present two-dimensional nanofluidic architectures are generally constructed by simple stacking of pristine nanosheets with insufficient charge densities, and exhibit low-efficiency transport dynamics, consequently resulting in undesirable power densities (<1 W m
−2
). Here we demonstrate MXene/Kevlar nanofiber composite membranes as high-performance nanofluidic osmotic power generators. By mixing river water and sea water, the power density can achieve a value of approximately 4.1 W m
−2
, outperforming the state-of-art membranes to the best of our knowledge. Experiments and theoretical calculations reveal that the correlation between surface charge of MXene and space charge brought by nanofibers plays a key role in modulating ion diffusion and can synergistically contribute to such a considerable energy conversion performance. This work highlights the promise in the coupling of surface charge and space charge in nanoconfinement for energy conversion driven by chemical potential gradients.
Nanofluidic channels can capture osmotic energy from salinity gradients, but output power densities should be improved for practical applications. Here the authors report high-strength nanosheet/nanofiber composite membranes for harvesting osmotic energy from natural water with high output power.
Journal Article
Adenosine Triphosphate and Adenylate Energy Charge in Ready-to-Eat Food
by
Kuznetsov, Artur I.
,
Lyalin, Daniil
,
Raudsepp, Piret
in
Adenosine
,
Adenosine triphosphate
,
adenylate energy charge
2024
It is commonly accepted that dietary nucleotides should be considered as essential nutrients originating mainly but not exclusively from meat and fish dishes. Most research in food science related to nutrition nucleotides is focused on raw products, while the effects of thermal processing of ready-to-eat food on nucleotide content are largely overlooked by the scientific community. The aim of this study is to investigate the impact of thermal processing and cold storage on the content of dietary nucleotides in freshly prepared and canned ready-to-eat meat and fish food. The concentrations of ATP, ADP, AMP, IMP, Ino, and Hx were determined using NMR, HPLC, FPMLC, and ATP bioluminescence analytical techniques; freshness indices K and K1 and adenylate energy charge (AEC) values were estimated to assess the freshness status and confirm a newly unveiled phenomenon of the reappearance of adenylate nucleotides. It was found that in freshly prepared at 65 °C ≤ T ≤ +100 °C and canned food, the concentration of free nucleotides was in the range of 0.001–0.01 µmol/mL and remained unchanged for a long time during cold storage; the correct distribution of mole fractions of adenylates corresponding to 0 < AEC < 0.5 was observed compared to 0.2 < AEC < 1.0 in the original raw samples, with either a high or low content of residual adenylates. It could be assumed that heating at nonenzymatic temperatures T > 65 °C can rupture cell membranes and release residual intracell nucleotides in quite a meaningful concentration. These findings may lead to a conceptual change in the views on food preparation processes, taking into account the phenomenon of the free adenylates renaissance and AEC bioenergetics.
Journal Article
Electric energies of a charged sphere surrounded by electrolyte
2021
By using the recently generalized version of Newton's Shell Theorem[6]analytical equations are derived to calculate the electric potential energy needed to build up a charged sphere, and the field and polarization energy of the electrolyte inside and around the sphere. These electric energies are calculated as a function of the electrolyte's ion concentration and the radius of the charged sphere. The work needed to build up the charged sphere, ECC (i.e. the total charge-charge interaction energy) decreases with increasing ion concentration of the electrolyte because of the electrolyte ions' increasing screening effect on the charge-charge interaction. The work needed to build up the charged sphere appears as a sum of the field and polarization energy of the electrolyte. At zero ion concentration the electrolyte's field energy is equal with ECC while the polarization energy is zero. At high electrolyte ion concentrations (C > 10mol/m3) 50% of ECC appears as the polarization energy of the electrolyte, 25% as the electrolyte's field energy inside the sphere and 25% as the electrolyte's field energy around the sphere.
Journal Article
Non-fullerene acceptor with asymmetric structure and phenyl-substituted alkyl side chain for 20.2% efficiency organic solar cells
by
Zhu, Xiaozhang
,
Sun, Shaoming
,
Ran, Guangliu
in
639/301/1005/1007
,
639/4077/909/4101/4096/946
,
Asymmetric structures
2024
For organic solar cells (OSCs), bridging the gap with Shockley–Queisser limit necessitates simultaneously reducing the energy loss for a high open-circuit voltage, improving light utilization for enhanced short-circuit current density and maintaining ideal nanomorphology with a high fill factor through molecular design and device engineering. Here we design and synthesize an asymmetric non-fullerene acceptor (Z8) featuring tethered phenyl groups to establish an alloy acceptor in ternary OSCs. The asymmetric structure minimizes non-radiative energy loss and charge recombination owing to delocalized excitons. The phenyl-substituted alkyl side chain impacts on the intermolecular interactions, improving the film nanomorphology with efficient exciton dissociation and reduced charge recombination. We demonstrate OSCs with an efficiency of 20.2% (certified 19.8%) based on the D18:Z8:L8-BO ternary blend. Through theoretical calculations, we examine the overall distribution of photon and carrier losses and analyse the potential for improvement on open-circuit voltage, short-circuit current density and fill factor, providing rational guidance for further development of the OSC performance.
Molecular design is key to the power conversion efficiency in organic photovoltaics. Jiang, Sun, Xu et al. develop a non-fullerene acceptor with asymmetric structure and phenyl-substituted side chains that minimizes photon and carrier losses, enabling 20.2% efficiency.
Journal Article
Efficient energy conversion mechanism and energy storage strategy for triboelectric nanogenerators
2024
Energy management strategy is the essential approach for achieving high energy utilization efficiency of triboelectric nanogenerators (TENGs) due to their ultra-high intrinsic impedance. However, the proven management efficiency in practical applications remains low, and the output regulation functionality is still lacking. Herein, we propose a detailed energy transfer and extraction mechanism addressing voltage and charge losses caused by the crucial switches in energy management circuits. The energy conversion efficiency is increased by 8.5 times through synergistical optimization of TENG and switch configurations. Furthermore, a TENG-based power supply with energy storage and regularization functions is realized through system circuit design, demonstrating the stable powering electronic devices under irregular mechanical stimuli. A rotating TENG that only works for 21 s can make a hygrothermograph work stably for 417 s. Even under hand driving, various types of TENGs can consistently provide stable power to electronic devices such as calculators and mini-game consoles. This work provides an in-depth energy transfer and conversion mechanism between TENGs and energy management circuits, and also addresses the technical challenge in converting unstable mechanical energy into stable and usable electricity in the TENG field.
Effective energy management is essential to enable triboelectric nanogenerators for realistic applications. Here, the authors optimize TENG and switch configurations to improve energy conversion efficiency and design a TENG-based power supply with energy storage and output regulation functionalities.
Journal Article