Chemical Energy Generation Research Articles

Exploring the photocatalytic activity of doped novel SrMoO4 nanoparticles in dye degradation: catalyzing change

To avert future energy crises, it is crucial to pursue sustainable energy sources nonstop. Due to its purity, sustainability, and dependability, solar energy stands out among the variety of evolving options. The utilization of solar energy for the generation of chemical energy has captured considerable attention, presenting the prospect of providing dependable and adaptable energy solutions. In this work, Sol-Gel method is used to synthesize extremely effective novel photocatalysts in the form of Strontium Molbydate (SM), 2.5 % Cerium doped Strontium Molbydate (SM2.5), and 5 % Cerium doped Strontium Molbydate (SM5) nanoparticles. The investigation includes a thorough examination of the photocatalytic study, structural analysis, and morphology of pure and doped samples. X-ray Diffraction (XRD) analysis of all the samples exhibit tetragonal structures, before and after degradation of dye. Scanning electron microscopy (SEM) was used to examine the morphology of each sample. To find out the functional groups present in the samples, Fourier Transform Infrared Spectroscopy (FT-IR) is employed. Liquid Chromatography Mass Spectrometry (LCMS) of the samples have also been done to find out the degradation product. The Mott-Schottky curves for SM, SM2.5, and SM5 exhibited positive slopes, indicating n-type semiconductor behavior. To determine the ecotoxicity of by-products of the CR ECOSAR program was operated. Ultraviolet visible spectroscopy (UV–Vis) results indicated the band gap for SM, SM2.5, and SM5 is 4.12 eV, 3.92 eV, and 3.74 eV, respectively. We employed the degradation of methylene blue (MB) in the presence of UV light irradiation to evaluate the photocatalytic activity. SM5 nanoparticles had the highest photocatalytic activity, reaching 95.5 % in 150 min. Pseudo second order kinetid model is best fitted, and the rate of reaction is 0.0021 (g mg⁻1 min⁻1), 0.0038 (g mg⁻1 min⁻1), 0.00413 (g mg⁻1 min⁻1) for SM, SM2.5, and SM5 respectively.

Modelling energy-harvesting processes in primitive cells: Proton transport across bilayers driven by the oxidation of sulfite

A frequently debated topic related to the origin of life centers around the question of how complex forms of life on today's Earth may have evolved over time from simpler predecessors. For example, the question of how proton concentration gradients across cellular membranes developed in ancestral protocells remains unanswered. This process, which is indispensable for the generation of chemical energy in modern organisms, is driven by energy derived from redox processes in the respiratory chain. Since it is highly unlikely that the complex machinery of the respiratory chain was available on early Earth, we provide an example of how proton gradients can be established in less complex systems. Utilizing liposomes as models of primitive cells, we were able to generate proton gradients of about two pH units across the liposome bilayers using redox reactions as the driving force. Electrons were transferred from sodium sulfite present on the outside of the liposomes to ferricyanide, which was trapped on the inside. A lipid-soluble phenazine derivative served as a shuttle that transferred both electrons and protons across the lipid bilayer. Because sulfite would have been an abundant reduced solute available to the earliest cells, we propose that it may have been a primary source of redox energy for primitive chemiosmotic energy transduction.

Mechanisms and regulation of protein synthesis in mitochondria.

Mitochondria are cellular organelles responsible for generation of chemical energy in the process called oxidative phosphorylation. They originate from a bacterial ancestor and maintain their own genome, which is expressed by designated, mitochondrial transcription and translation machineries that differ from those operating for nuclear gene expression. In particular, the mitochondrial protein synthesis machinery is structurally and functionally very different from that governing eukaryotic, cytosolic translation. Despite harbouring their own genetic information, mitochondria are far from being independent of the rest of the cell and, conversely, cellular fitness is closely linked to mitochondrial function. Mitochondria depend heavily on the import of nuclear-encoded proteins for gene expression and function, and hence engage in extensive inter-compartmental crosstalk to regulate their proteome. This connectivity allows mitochondria to adapt to changes in cellular conditions and also mediates responses to stress and mitochondrial dysfunction. With a focus on mammals and yeast, we review fundamental insights that have been made into the biogenesis, architecture and mechanisms of the mitochondrial translation apparatus in the past years owing to the emergence of numerous near-atomic structures and a considerable amount of biochemical work. Moreover, we discuss how cellular mitochondrial protein expression is regulated, including aspects of mRNA and tRNA maturation and stability, roles of auxiliary factors, such as translation regulators, that adapt mitochondrial translation rates, and the importance of inter-compartmental crosstalk with nuclear gene expression and cytosolic translation and how it enables integration of mitochondrial translation into the cellular context.

Toxicity Going Nano: Ionic Versus Engineered Cu Nanoparticles Impacts on the Physiological Fitness of the Model Diatom Phaeodactylum tricornutum

Increasing input of Metal Engineered Nano Particles (MeENPs) in marine ecosystems has raised concerns about their potential toxicity on phytoplankton. Given the lack of knowledge on MeENPs impact on these important primary producers, the effects of Copper Oxide (CuO) ENPs on growth, physiology, pigment profiles, fatty acid (FA) metabolism, and oxidative stress were investigated in the model diatom Pheodactylum tricornutum, to provide suitable biomarkers of CuO ENP exposure versus its ionic counterpart. Diatom growth was inhibited by CuO ENPs but not Ionic Cu, suggesting CuO ENP cytotoxicity. Pulse Modulated Amplitude (PAM) phenotyping evidenced a decrease in the electron transport energy flux, pointing to a reduction in chemical energy generation following CuO ENPs exposure, as well as an increase in the content of the non-functional Cu-substituted chlorophyll a (CuChl a). A significant decrease in eicosapentaenoic acid (C20:5) associated with a significant rise in thylakoid membranes FAs reflected the activation of counteractive measures to photosynthetic impairment. Significant increase in the omega 6/omega 3 ratio, underline expectable negative repercussions to marine food webs. Increased thiobarbituric acid reactive substances reflected heightened oxidative stress by CuO ENP. Enhanced Glutathione Reductase and Ascorbate Peroxidase activity were also more evident for CuO ENPs than ionic Cu. Overall, observed molecular changes highlighted a battery of possible suitable biomarkers to efficiently determine the harmful effects of CuO ENPs. The results suggest that the occurrence and contamination of these new forms of metal contaminants can impose added stress to the marine diatom community, which could have significant impacts on marine ecosystems, namely through a reduction of the primary productivity, oxygen production and omega 6 production, all essential to sustain heterotrophic marine life.

Isolation of Physiologically Active and Intact Mitochondria from Chickpea.

Chickpea is an important leguminous crop that belongs to Fabaceae family, highly valued for its nutritious seeds. Seeds contain reserve food for the developing embryos. Mitochondria are crucial organelle for generation of chemical energy in the form of ATP which is required for achieving metabolically active state; therefore, investigating mitochondrial function and respiration rate is crucial for exploring various metabolic and physio-biochemical changes that occur during seed germination. Here we describe a method for isolation of mitochondria from germinating seeds of two chickpea varieties, i.e., Desi and Kabuli. Structure of Mitotracker-stained isolated mitochondria was observed by confocal microscopy and respiration rate was measured using an oxygen microsensor.

ATP hydrolysis assists phosphate release and promotes reaction ordering in F1-ATPase.

F1-ATPase (F1) is a rotary motor protein that can efficiently convert chemical energy to mechanical work of rotation via fine coordination of its conformational motions and reaction sequences. Compared with reactant binding and product release, the ATP hydrolysis has relatively little contributions to the torque and chemical energy generation. To scrutinize possible roles of ATP hydrolysis, we investigate the detailed statistics of the catalytic dwells from high-speed single wild-type F1 observations. Here we report a small rotation during the catalytic dwell triggered by the ATP hydrolysis that is indiscernible in previous studies. Moreover, we find in freely rotating F1 that ATP hydrolysis is followed by the release of inorganic phosphate with low synthesis rates. Finally, we propose functional roles of the ATP hydrolysis as a key to kinetically unlock the subsequent phosphate release and promote the correct reaction ordering.

Examining Drp1 Conformational Changes and Domain Interactions in the Mitochondrial Fission Complex using Cryo-Em

Mitochondria are essential organelles involved in the generation of chemical energy, maintenance of calcium levels and induction of apoptosis. Mitochondria are also highly dynamic, undergoing continuous cycles of fission and fusion. This dynamic cycle is integral to mitochondrial proliferation, distribution, organelle morphology, bioenergetics and cell death. Excessive fusion leads to interconnected, collapsed and dysfunctional mitochondria. Conversely, excessive fission promotes mitochondrial fragmentation and the release of apoptotic proteins that promote cell death.

Combination of a photosystem 1-based photocathode and a photosystem 2-based photoanode to a Z-scheme mimic for biophotovoltaic applications.

Combination of a photosystem 1-based photocathode and a photosystem 2-based photoanode to a Z-scheme mimic for biophotovoltaic applications.

Covalent and Noncovalent Phthalocyanine−Carbon Nanostructure Systems: Synthesis, Photoinduced Electron Transfer, and Application to Molecular Photovoltaics

Photosynthesis is used by nature to convert light energy into chemical energy in some living systems. In such a process, a cascade of very efficient, short-range energy and electron transfer events between well-arranged, light-harvesting organic donor and acceptor pigments takes place within the photosynthetic reaction center, leading to the overall generation of chemical energy from sunlight with near quantum efficiency.1-8 During the past decade, a significant effort has been made by the scientific community toward the preparation of synthetic model compounds of natural photosynthetic systems able to convert light into other energy sources,9 probably fostered by the increasing concerns related to the utilization of fossils fuels for the production of electricity in terms of both availability and environmental issues. However, considering the structural complexity presented by the natural photosynthetic systems, much of the scientific effort has been devoted toward the preparation and study of structurally simpler systems, with the aim of reproducing some of the fundamental steps occurring in natural photosynthesis, one of the most important being the photoinduced charge separation (CS).10-12 Among the chromophores that have been used as molecular components in artificial photosynthetic systems, porphyrinoids, the ubiquitous molecular building blocks employed by nature in natural photosynthesis, have been the preferred and obvious choice, due to their intense optical absorption and rich redox chemistry.13-20 Within the large family of porphyrinoid systems, phthalocyanines (Pcs) enjoy a privileged position (Figure 1a). These chromophores, which have a two-dimensional 18-πelectron aromatic system isoelectronic with that of porphyrins (Pors), possess in fact unique physicochemical properties which render these macrocycles valuable building blocks in materials science.21-32 Pcs are thermally and chemically stable compounds which present an intense absorption in the red/near-infrared (IR) region of the solar spectrum with extinction coefficients (as high as 200 000 M-1 cm-1) and fluorescence quantum yields * To whom correspondence should be addressed. E-mail: tomas.torres@uam.es (T.T.); dirk.guldi@chemie.uni-erlangen.de (D.M.G.). † Universidad Autonoma de Madrid. ‡ Friedrich-Alexander-Universitat Erlangen-Nurnberg. § IMDEA-Nanociencia. Chem. Rev. 2010, 110, 6768–6816 6768

Diversity of bacteriorhodopsins in different hypersaline waters from a single Spanish saltern.

Haloarchaeal rhodopsins are a diverse group of transmembrane proteins that use light energy to drive several different cellular processes. Two rhodopsins, bacteriorhodopsin and halorhodopsins, are H+ and Cl- ion pumps, respectively, and two rhodopsins, sensory rhodopsin I and II, regulate phototaxis. Bacteriorhodopsin is of special interest as it is a non-chlorophyll-based type of phototrophy (i.e. generation of chemical energy from light energy). However, very little is known about the diversity and distribution of rhodopsin genes in hypersaline environments. Here, we have used environmental PCR and cloning techniques to directly retrieve rhodopsin genes from three different salinity ponds located in a sea salt manufacturing facility near Alicante, Spain. Our survey resulted in the discovery of previously concealed variation including what is hypothesized to be bacteriorhodopsin genes from the uncultivated square morphotype that dominates these environments. In some instances, identical genes were discovered in seemingly different habitats suggesting that some haloarchaea are present over widely varying concentrations of salt.

A bond graph model of chemo-mechanical transduction in the mammalian left ventricle

We present a new lumped model of the pump behaviour of the mammalian left ventricle based on simple but physiologically plausible sub-models of chemo-mechanical energy transduction in muscle, mechano-hydraulic energy transduction in the ventricular wall and hemodynamical coupling of the ventricle and its arterial load. The model builds upon the foundation of classical analog ventricular models (dynamic compliance and visco-elastic models). However, we show that these classical models are not coherent from an energy viewpoint. To insure this coherency, we introduce explicit cross-bridge mechanisms linked to the mechano-hydraulical part of the model by a two-port capacitive (2PC) transducer representing chemo-mechanical coupling. We show that this 2PC is thermodynamically plausible and, when coupled to dissipative models of chemical energy generation and transfer, provides a novel and consistent characterisation of cardiac energetics at the global pump level. Finally, we briefly discuss some generalisations using nonlinear elements described by functional equations to represent muscle memory and sur-activation. It is a well-known fact that languages shape perception. Of all the lumped modelling languages, the bond graph (BG) method is the only one to use the notion of a 2PC as a primitive modelling concept. Our hypothesis (mental model) is thus directly inspired by the fact that we use the BG language. Our claim is thus that our work demonstrates very clearly the heuristic and descriptive power of BGs in shaping new ideas about multi-energy and nonlinear physiological applications.