Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
J. Silva
Sustainability · 2023
Wastewater treatment involves the extraction of pollutants, removal of coarse particles, and elimination of toxicants. Moreover, wastewater treatment kills pathogens and produces bio-methane and fresh manure for agricultural production. The connection between waste management and sustainability created the basis for this research. Wastewater treatment is part of the efforts to minimize water waste, minimize pressure on natural sources of water, and create a pathway for clean energy. A systematic literature review was selected for this study to evaluate and synthesize the available evidence in support of wastewater treatment for both economic and environmental sustainability. The articles were evaluated using the PRISMA framework to identify the most appropriate articles for inclusion. A total of 46 articles were selected based on their content validity, relevance to the research question, strength of evidence, year of publication (2000–2023), and relevance to sustainable resource management. The findings indicate that wastewater treatment enables sustainable resource management by improving the supply of clean water, and minimizing pressure on natural resources, energy recovery, and agricultural support. Wastewater treatment provides one of the most sustainable approaches to water conservation, energy production, and agricultural productivity.
Herbert T. Buxton, D. Kolpin
Water Encyclopedia · 2002
To provide the first nationwide reconnaissance of the occurrence of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in water resources, the U.S. Geological Survey used five newly developed analytical methods to measure concentrations of 95 OWCs in water samples from a network of 139 streams across 30 states during 1999 and 2000. The selection of sampling sites was biased toward streams susceptible to contamination (i.e. downstream of intense urbanization and livestock production). OWCs were prevalent during this study, being found in 80% of the streams sampled. The compounds detected represent a wide range of residential, industrial, and agricultural origins and uses with 82 of the 95 OWCs being found during this study. The most frequently detected compounds were coprostanol (fecal steroid), cholesterol (plant and animal steroid), N,N-diethyltoluamide (insect repellant), caffeine (stimulant), triclosan (antimicrobial disinfectant), tri(2-chloroethyl)phosphate (fire retardant), and 4-nonylphenol (nonionic detergent metabolite). Measured concentrations for this study were generally low and rarely exceeded drinking-water guidelines, drinking-water health advisories, or aquatic-life criteria. Many compounds, however, do not have such guidelines established. The detection of multiple OWCs was common for this study, with a median of seven and as many as 38 OWCs being found in a given water sample. Little is known about the potential interactive effects (such as synergistic or antagonistic toxicity) that may occur from complex mixtures of OWCs in the environment. In addition, results of this study demonstrate the importance of obtaining data on metabolites to fully understand not only the fate and transport of OWCs in the hydrologic system but also their ultimate overall effect on human health and the environment.
Michael D. Kirchhoff, Thomas Parr, E. Palacios et al.
Journal of The Royal Society Interface · 2018
This work addresses the autonomous organization of biological systems. It does so by considering the boundaries of biological systems, from individual cells to Home sapiens, in terms of the presence of Markov blankets under the active inference scheme—a corollary of the free energy principle. A Markov blanket defines the boundaries of a system in a statistical sense. Here we consider how a collective of Markov blankets can self-assemble into a global system that itself has a Markov blanket; thereby providing an illustration of how autonomous systems can be understood as having layers of nested and self-sustaining boundaries. This allows us to show that: (i) any living system is a Markov blanketed system and (ii) the boundaries of such systems need not be co-extensive with the biophysical boundaries of a living organism. In other words, autonomous systems are hierarchically composed of Markov blankets of Markov blankets—all the way down to individual cells, all the way up to you and me, and all the way out to include elements of the local environment.
M. Berezin, S. Achilefu
Chemical Reviews · 2010
When a molecule absorbs a photon of appropriate energy, a chain of photophysical events ensues, such as internal conversion or vibrational relaxation (loss of energy in the absence of light emission), fluorescence, intersystem crossing (from singlet state to a triplet state) and phosphorescence, as shown in the Jablonski diagram for organic molecules (Fig. 1). Each of the processes occurs with a certain probability, characterized by decay rate constants (k). It can be shown that the average length of time τ for the set of molecules to decay from one state to another is reciprocally proportional to the rate of decay: τ = 1/k. This average length of time is called the mean lifetime, or simply lifetime. It can also be shown that the lifetime of a photophysical process is the time required by a population of N electronically excited molecules to be reduced by a factor of e. Correspondingly, the fluorescence lifetime is the time required by a population of excited fluorophores to decrease exponentially to N/e via the loss of energy through fluorescence and other non-radiative processes. The lifetime of photophycal processes vary significantly from tens of femotoseconds for internal conversion1,2 to nanoseconds for fluorescence and microseconds or seconds for phosphorescence.1
Linhong Xiao, Xin Chen, Xinyue Yang et al.
ACS Applied Polymer Materials · 2020
The photothermal effect, which is a phenomenon of converting light energy into thermal energy using photothermal conversion materials, has recently attracted significant attention in biological app...
B. Denisow, M. Denisow-Pietrzyk
Journal of the Science of Food and Agriculture · 2016
Natural products, including bee products, are particularly appreciated by consumers and are used for therapeutic purposes as alternative drugs. However, it is not known whether treatments with bee products are safe and how to minimise the health risks of such products. Among others, bee pollen is a natural honeybee product promoted as a valuable source of nourishing substances and energy. The health-enhancing value of bee pollen is expected due to the wide range of secondary plant metabolites (tocopherol, niacin, thiamine, biotin and folic acid, polyphenols, carotenoid pigments, phytosterols), besides enzymes and co-enzymes, contained in bee pollen. The promising reports on the antioxidant, anti-inflammatory, anticariogenic antibacterial, antifungicidal, hepatoprotective, anti-atherosclerotic, immune enhancing potential require long-term and large cohort clinical studies. The main difficulty in the application of bee pollen in modern phytomedicine is related to the wide species-specific variation in its composition. Therefore, the variations may differently contribute to bee-pollen properties and biological activity and thus in therapeutic effects. In principle, we can unequivocally recommend bee pollen as a valuable dietary supplement. Although the bee-pollen components have potential bioactive and therapeutic properties, extensive research is required before bee pollen can be used in therapy. © 2016 Society of Chemical Industry.
R. Muñoz, Leslie Meier, I. Díaz et al.
Reviews in Environmental Science and Bio/Technology · 2015
The lack of tax incentives for biomethane use requires the optimization of both biogas production and upgrading in order to allow the full exploitation of this renewable energy source. The large number of biomethane contaminants present in biogas (CO2, H2S, H2O, N2, O2, methyl siloxanes, halocarbons) has resulted in complex sequences of upgrading processes based on conventional physical/chemical technologies capable of providing CH4 purities of 88–98 % and H2S, halocarbons and methyl siloxane removals >99 %. Unfortunately, the high consumption of energy and chemicals limits nowadays the environmental and economic sustainability of conventional biogas upgrading technologies. In this context, biotechnologies can offer a low cost and environmentally friendly alternative to physical/chemical biogas upgrading. Thus, biotechnologies such as H2-based chemoautrophic CO2 bioconversion to CH4, microalgae-based CO2 fixation, enzymatic CO2 dissolution, fermentative CO2 reduction and digestion with in situ CO2 desorption have consistently shown CO2 removals of 80–100 % and CH4 purities of 88–100 %, while allowing the conversion of CO2 into valuable bio-products and even a simultaneous H2S removal. Likewise, H2S removals >99 % are typically reported in aerobic and anoxic biotrickling filters, algal-bacterial photobioreactors and digesters under microaerophilic conditions. Even, methyl siloxanes and halocarbons are potentially subject to aerobic and anaerobic biodegradation. However, despite these promising results, most biotechnologies still require further optimization and scale-up in order to compete with their physical/chemical counterparts. This review critically presents and discusses the state of the art of biogas upgrading technologies with special emphasis on biotechnologies for CO2, H2S, siloxane and halocarbon removal.
S. Naleway, M. Porter, J. McKittrick et al.
Advanced Materials · 2015
Eight structural elements in biological materials are identified as the most common amongst a variety of animal taxa. These are proposed as a new paradigm in the field of biological materials science as they can serve as a toolbox for rationalizing the complex mechanical behavior of structural biological materials and for systematizing the development of bioinspired designs for structural applications. They are employed to improve the mechanical properties, namely strength, wear resistance, stiffness, flexibility, fracture toughness, and energy absorption of different biological materials for a variety of functions (e.g., body support, joint movement, impact protection, weight reduction). The structural elements identified are: fibrous, helical, gradient, layered, tubular, cellular, suture, and overlapping. For each of the structural design elements, critical design parameters are presented along with constitutive equations with a focus on mechanical properties. Additionally, example organisms from varying biological classes are presented for each case to display the wide variety of environments where each of these elements is present. Examples of current bioinspired materials are also introduced for each element.
J. Brodbelt, L. Morrison, Inês C. Santos
Chemical Reviews · 2019
The development of new ion-activation/dissociation methods continues to be one of the most active areas of mass spectrometry owing to the broad applications of tandem mass spectrometry in the identification and structural characterization of molecules. This Review will showcase the impact of ultraviolet photodissociation (UVPD) as a frontier strategy for generating informative fragmentation patterns of ions, especially for biological molecules whose complicated structures, subtle modifications, and large sizes often impede molecular characterization. UVPD energizes ions via absorption of high-energy photons, which allows access to new dissociation pathways relative to more conventional ion-activation methods. Applications of UVPD for the analysis of peptides, proteins, lipids, and other classes of biologically relevant molecules are emphasized in this Review.
Mingjie Li, Lu Zong, Weiqing Yang et al.
Advanced Functional Materials · 2019
Electricity harvest from ubiquitous water has been endeavored, using nanogenerators based on carbon nanomaterials, to acquire renewable and clean energy and cope with fossil depletion and pollution as well. Meanwhile, though many biological organisms can harness water for bioelectricity, it is still challenging to produce biological nanogenerators based on biological nanomaterials with billions of tons of annual production in nature. Herein biological nanofibrils, including cellulose, chitin, silk fibroin, and amyloid, are produced either by liquid‐exfoliation of biomasses or by supramolecular assembly of bio‐macromolecules. With the intrinsic hydrophilicity and charged states, they can capture moisture from air and form hydrated nanochannels, in analogue to ionic channels of cytomembranes. When exposing their aerogels to moist air flow, there is a balance of water absorption and evaporation, thus producing a streaming potential and an open‐circuit voltage across the aerogel. With flexibility, sustainability, biocompatibility, and biodegradability, these biological nanogenerators can harvest electricity from moist air flow in nature (e.g., wind, respiration and perspiration) and in industry, and serve for environmentally‐friendly, low‐cost, high‐efficiency, wearable, and miniaturized power devices.
Wei Li, Shuangshuang Wu, Haoran Zhang et al.
Advanced Functional Materials · 2018
Enhancing solar energy conversion is imperative and maximizing solar energy capture remains significant. Here, nanotechnology toward engineering hybrid photosystem involving biological photosynthetic chloroplasts and dual‐emissive carbon dots (CDs) is employed for improved photosynthesis by harnessing more effective light. Specifically, the as‐prepared CDs show strong absorption in ultraviolet (UV) light region and exhibit intense blue and red light in water, which exactly match the absorption spectrum of chloroplasts. After coating the CDs on the surface of extracted chloroplasts, the hybrid photosystem produces 2.8 times more adenosine triphosphate (ATP) than chloroplasts themselves in vitro. Moreover, CD‐induced enhancement of photosynthesis in living plant is proved as well, showing a maximum increase of 25% in electron transport rates over the leaves without CDs, demonstrating the effective nanobionics engineering of plant performance in vivo. This is the first report on employing the unique dual‐emission trait of nanoparticles, especially the red emission, to augment photoabsorption of both extracted chloroplasts and intact leaves for enhanced photosynthetic properties. This work provides a promising strategy for engineering biological photosynthetic system with dual‐emissive CDs to enhance solar energy conversion both in vivo and in vitro, and promotes the development in the field of nanobionic.
S. Archibald, C. Lehmann, C. Belcher et al.
Environmental Research Letters · 2018
Roughly 3% of the Earth’s land surface burns annually, representing a critical exchange of energy and matter between the land and atmosphere via combustion. Fires range from slow smouldering peat fires, to low-intensity surface fires, to intense crown fires, depending on vegetation structure, fuel moisture, prevailing climate, and weather conditions. While the links between biogeochemistry, climate and fire are widely studied within Earth system science, these relationships are also mediated by fuels—namely plants and their litter—that are the product of evolutionary and ecological processes. Fire is a powerful selective force and, over their evolutionary history, plants have evolved traits that both tolerate and promote fire numerous times and across diverse clades. Here we outline a conceptual framework of how plant traits determine the flammability of ecosystems and interact with climate and weather to influence fire regimes. We explore how these evolutionary and ecological processes scale to impact biogeochemical and Earth system processes. Finally, we outline several research challenges that, when resolved, will improve our understanding of the role of plant evolution in mediating the fire feedbacks driving Earth system processes. Understanding current patterns of fire and vegetation, as well as patterns of fire over geological time, requires research that incorporates evolutionary biology, ecology, biogeography, and the biogeosciences.
N. Hildebrandt, C. Spillmann, W. R. Algar et al.
Chemical Reviews · 2017
Luminescent semiconductor quantum dots (QDs) are one of the more popular nanomaterials currently utilized within biological applications. However, what is not widely appreciated is their growing role as versatile energy transfer (ET) donors and acceptors within a similar biological context. The progress made on integrating QDs and ET in biological configurations and applications is reviewed in detail here. The goal is to provide the reader with (1) an appreciation for what QDs are capable of in this context, (2) how this field has grown over a relatively short time span, and, in particular, (3) how QDs are steadily revolutionizing the development of new biosensors along with a myriad of other photonically active nanomaterial-based bioconjugates. An initial discussion of QD materials along with key concepts surrounding their preparation and bioconjugation is provided given the defining role these aspects play in the QDs ability to succeed in subsequent ET applications. The discussion is then divided around the specific roles that QDs provide as either Förster resonance energy transfer (FRET) or charge/electron transfer donor and/or acceptor. For each QD-ET mechanism, a working explanation of the appropriate background theory and formalism is articulated before examining their biosensing and related ET utility. Other configurations such as incorporation of QDs into multistep ET processes or use of initial chemical and bioluminescent excitation are treated similarly. ET processes that are still not fully understood such as QD interactions with gold and other metal nanoparticles along with carbon allotropes are also covered. Given their maturity, some specific applications ranging from in vitro sensing assays to cellular imaging are separated and discussed in more detail. Finally a perspective on how this field will continue to evolve is provided.
Jinran Yu, Guoyun Gao, Jinrong Huang et al.
Nature Communications · 2021
Low power electronics endowed with artificial intelligence and biological afferent characters are beneficial to neuromorphic sensory network. Highly distributed synaptic sensory neurons are more readily driven by portable, distributed, and ubiquitous power sources. Here, we report a contact-electrification-activated artificial afferent at femtojoule energy. Upon the contact-electrification effect, the induced triboelectric signals activate the ion-gel-gated MoS2 postsynaptic transistor, endowing the artificial afferent with the adaptive capacity to carry out spatiotemporal recognition/sensation on external stimuli (e.g., displacements, pressures and touch patterns). The decay time of the synaptic device is in the range of sensory memory stage. The energy dissipation of the artificial afferents is significantly reduced to 11.9 fJ per spike. Furthermore, the artificial afferents are demonstrated to be capable of recognizing the spatiotemporal information of touch patterns. This work is of great significance for the construction of next-generation neuromorphic sensory network, self-powered biomimetic electronics and intelligent interactive equipment. Low power electronics endowed with artificial intelligence and biological afferent characters are beneficial to neuromorphic sensory network. Here, the authors report contact-electrification-activated artificial afferent at femtojoule energy, which is able to carry out spatiotemporal recognition on external stimuli.
Benjamin S. Lazarus, Audrey Velasco-Hogan, T. Gómez-del Río et al.
· 2020
Abstract Biological systems must have the capability to withstand impacts generated during collisions due to combat and defense. Thus, evolution has created complex materials’ architectures at various length scales that are capable of withstanding repeated, low-to-medium-velocity impacts (up to 50 m/s). In this paper, we review impact resistant biological systems with a focus on their recurrent structural design elements, material properties, and energy absorbing mechanisms. We classify these impact resistant structures at the micro- and meso-scales into layered, gradient, tubular, sandwich, and sutured and show how they construct global hierarchical, composite, porous, and interfacial architectures. Additionally, we review how these individual structures and their design parameters can provide a tailored response. We conclude with a future outlook and discussion of their potential for impact resistant bioinspired designs.
F. Wollmann, Stefan Dietze, J. Ackermann et al.
Engineering in Life Sciences · 2019
Current global environmental issues raise unavoidable challenges for our use of natural resources. Supplying the human population with clean water is becoming a global problem. Numerous organic and inorganic impurities in municipal, industrial, and agricultural waters, ranging from microplastics to high nutrient loads and heavy metals, endanger our nutrition and health. The development of efficient wastewater treatment technologies and circular economic approaches is thus becoming increasingly important. The biomass production of microalgae using industrial wastewater offers the possibility of recycling industrial residues to create new sources of raw materials for energy and material use. This review discusses algae‐based wastewater treatment technologies with a special focus on industrial wastewater sources, the potential of non‐conventional extremophilic (thermophilic, acidophilic, and psychrophilic) microalgae, and industrial algae‐wastewater treatment concepts that have already been put into practice.
Wusheng Xiao, Ruisheng Wang, D. Handy et al.
Antioxidants & Redox Signaling · 2018
SIGNIFICANCE The nicotinamide adenine dinucleotide (NAD+)/reduced NAD+ (NADH) and NADP+/reduced NADP+ (NADPH) redox couples are essential for maintaining cellular redox homeostasis and for modulating numerous biological events, including cellular metabolism. Deficiency or imbalance of these two redox couples has been associated with many pathological disorders. Recent Advances: Newly identified biosynthetic enzymes and newly developed genetically encoded biosensors enable us to understand better how cells maintain compartmentalized NAD(H) and NADP(H) pools. The concept of redox stress (oxidative and reductive stress) reflected by changes in NAD(H)/NADP(H) has increasingly gained attention. The emerging roles of NAD+-consuming proteins in regulating cellular redox and metabolic homeostasis are active research topics. CRITICAL ISSUES The biosynthesis and distribution of cellular NAD(H) and NADP(H) are highly compartmentalized. It is critical to understand how cells maintain the steady levels of these redox couple pools to ensure their normal functions and simultaneously avoid inducing redox stress. In addition, it is essential to understand how NAD(H)- and NADP(H)-utilizing enzymes interact with other signaling pathways, such as those regulated by hypoxia-inducible factor, to maintain cellular redox homeostasis and energy metabolism. FUTURE DIRECTIONS Additional studies are needed to investigate the inter-relationships among compartmentalized NAD(H)/NADP(H) pools and how these two dinucleotide redox couples collaboratively regulate cellular redox states and cellular metabolism under normal and pathological conditions. Furthermore, recent studies suggest the utility of using pharmacological interventions or nutrient-based bioactive NAD+ precursors as therapeutic interventions for metabolic diseases. Thus, a better understanding of the cellular functions of NAD(H) and NADP(H) may facilitate efforts to address a host of pathological disorders effectively. Antioxid. Redox Signal. 28, 251-272.
Jialin Shi, Jiansheng Jie, Wei Deng et al.
Advanced Materials · 2022
Photosynaptic organic field‐effect transistors (OFETs) represent a viable pathway to develop bionic optoelectronics. However, the high operating voltage and current of traditional photosynaptic OFETs lead to huge energy consumption greater than that of the real biological synapses, hindering their further development in new‐generation visual prosthetics and artificial perception systems. Here, a fully solution‐printed photosynaptic OFET (FSP‐OFET) with substantial energy consumption reduction is reported, where a source Schottky barrier is introduced to regulate charge‐carrier injection, and which operates with a fundamentally different mechanism from traditional devices. The FSP‐OFET not only significantly lowers the working voltage and current but also provides extraordinary neuromorphic light‐perception capabilities. Consequently, the FSP‐OFET successfully emulates visual nervous responses to external light stimuli with ultralow energy consumption of 0.07–34 fJ per spike in short‐term plasticity and 0.41–19.87 fJ per spike in long‐term plasticity, both approaching the energy efficiency of biological synapses (1–100 fJ). Moreover, an artificial optic‐neural network made from an 8 × 8 FSP‐OFET array on a flexible substrate shows excellent image recognition and reinforcement abilities at a low energy cost. The designed FSP‐OFET offers an opportunity to realize photonic neuromorphic functionality with extremely low energy consumption dissipation.
Qianli Zou, Manzar Abbas, Luyang Zhao et al.
Journal of the American Chemical Society · 2017
Photothermal agents can harvest light energy and convert it into heat, offering a targeted and remote-controlled way to destroy carcinomatous cells and tissues. Inspired by the biological organization of polypeptides and porphyrins in living systems, here we have developed a supramolecular strategy to fabricate photothermal nanodots through peptide-modulated self-assembly of photoactive porphyrins. The self-assembling nature of porphyrins induces the formation of J-aggregates as substructures of the nanodots, and thus enables the fabrication of nanodots with totally inhibited fluorescence emission and singlet oxygen production, leading to a high light-to-heat conversion efficiency of the nanodots. The peptide moieties not only provide aqueous stability for the nanodots through hydrophilic interactions, but also provide a spatial barrier between porphyrin groups to inhibit the further growth of nanodots through the strong π-stacking interactions. Thermographic imaging reveals that the conversion of light to heat based on the nanodots is efficient in vitro and in vivo, enabling the nanodots to be applied for photothermal acoustic imaging and antitumor therapy. Antitumor therapy results show that these nanodots are highly biocompatible photothermal agents for tumor ablation, demonstrating the feasibility of using bioinspired nanostructures of self-assembling biomaterials for biomedical photoactive applications.
A. Winfree
The Mathematical Gazette · 1991
1980 Preface * 1999 Preface * 1999 Acknowledgements * Introduction * 1 Circular Logic * 2 Phase Singularities (Screwy Results of Circular Logic) * 3 The Rules of the Ring * 4 Ring Populations * 5 Getting Off the Ring * 6 Attracting Cycles and Isochrons * 7 Measuring the Trajectories of a Circadian Clock * 8 Populations of Attractor Cycle Oscillators * 9 Excitable Kinetics and Excitable Media * 10 The Varieties of Phaseless Experience: In Which the Geometrical Orderliness of Rhythmic Organization Breaks Down in Diverse Ways * 11 The Firefly Machine 12 Energy Metabolism in Cells * 13 The Malonic Acid Reagent ('Sodium Geometrate') * 14 Electrical Rhythmicity and Excitability in Cell Membranes * 15 The Aggregation of Slime Mold Amoebae * 16 Numerical Organizing Centers * 17 Electrical Singular Filaments in the Heart Wall * 18 Pattern Formation in the Fungi * 19 Circadian Rhythms in General * 20 The Circadian Clocks of Insect Eclosion * 21 The Flower of Kalanchoe * 22 The Cell Mitotic Cycle * 23 The Female Cycle * References * Index of Names * Index of Subjects
Youhong Guo, Jiwoong Bae, Z. Fang et al.
Chemical Reviews · 2020
Energy and water are of fundamental importance for our modern society, and advanced technologies on sustainable energy storage and conversion as well as water resource management are in the focus of intensive research worldwide. Beyond their traditional biological applications, hydrogels are emerging as an appealing materials platform for energy- and water-related applications owing to their attractive and tailorable physiochemical properties. In this review, we highlight the highly tunable synthesis of various hydrogels, involving key synthetic elements such as monomer/polymer building blocks, cross-linkers, and functional additives, and discuss how hydrogels can be employed as precursors and templates for architecting three-dimensional frameworks of electrochemically active materials. We then present an in-depth discussion of the structure-property relationships of hydrogel materials based on fundamental gelation chemistry, ultimately targeting properties such as enhanced ionic/electronic conductivities, mechanical strength, flexibility, stimuli-responsiveness, and desirable swelling behavior. The unique interconnected porous structures of hydrogels enable fast charge/mass transport while offering large surface areas, and the polymer-water interactions can be regulated to achieve desirable water retention, absorption, and evaporation within hydrogels. Such structure-derived properties are also intimately coordinated to realize multifunctionality and stability for different target devices. The plethora of stimulating examples is expounded with a focus on batteries, supercapacitors, electrocatalysts, solar water purification, and atmospheric water harvesting, which showcase the unprecedented technological potential enabled by hydrogels and hydrogel-derived materials. Finally, we study the challenges and potential ways of tackling them to reveal the underlying mechanisms and transform the current development of hydrogel materials into sustainable energy and water technologies.
D. Matyushov
The IUPAC Compendium of Chemical Terminology · 2023
The theory of electron transfer reactions establishes the conceptual foundation for redox solution chemistry, electrochemistry, and bioenergetics. Electron and proton transfer across the cellular membrane provide all energy of life gained through natural photosynthesis and mitochondrial respiration. Rates of biological charge transfer set kinetic bottlenecks for biological energy storage. The main system-specific parameter determining the activation barrier for a single electron-transfer hop is the reorganization energy of the medium. Both harvesting of light energy in natural and artificial photosynthesis and efficient electron transport in biological energy chains require reduction of the reorganization energy to allow fast transitions. This review article discusses mechanisms by which small values of the reorganization energy are achieved in protein electron transfer and how similar mechanisms can operate in other media, such as nonpolar and ionic liquids. One of the major mechanisms of reorganization energy reduction is through non-Gibbsian (nonergodic) sampling of the medium configurations on the reaction time. A number of alternative mechanisms, such as electrowetting of active sites of proteins, give rise to non-parabolic free energy surfaces of electron transfer. These mechanisms, and nonequilibrium population of donor-acceptor vibrations, lead to a universal phenomenology of separation between the Stokes shift and variance reorganization energies of electron transfer.
W. Yi, Kenneth K. Tsang, Stephen K. Lam et al.
Nature Communications · 2018
Neuromorphic networks of artificial neurons and synapses can solve computationally hard problems with energy efficiencies unattainable for von Neumann architectures. For image processing, silicon neuromorphic processors outperform graphic processing units in energy efficiency by a large margin, but deliver much lower chip-scale throughput. The performance-efficiency dilemma for silicon processors may not be overcome by Moore’s law scaling of silicon transistors. Scalable and biomimetic active memristor neurons and passive memristor synapses form a self-sufficient basis for a transistorless neural network. However, previous demonstrations of memristor neurons only showed simple integrate-and-fire behaviors and did not reveal the rich dynamics and computational complexity of biological neurons. Here we report that neurons built with nanoscale vanadium dioxide active memristors possess all three classes of excitability and most of the known biological neuronal dynamics, and are intrinsically stochastic. With the favorable size and power scaling, there is a path toward an all-memristor neuromorphic cortical computer.The neuromorphic computing based on complementary metal-oxide-semiconductor transistors holds promise for artificial intelligence, but it suffers from the trade-off between scalability and biological fidelity. Yi et al. emulate 23 types of biological neuronal behaviors using scalable VO2 active memristors.
Wei Huang, David Restrepo, Jae-Young Jung et al.
Advanced Materials · 2019
Biological materials found in Nature such as nacre and bone are well recognized as light‐weight, strong, and tough structural materials. The remarkable toughness and damage tolerance of such biological materials are conferred through hierarchical assembly of their multiscale (i.e., atomic‐ to macroscale) architectures and components. Herein, the toughening mechanisms of different organisms at multilength scales are identified and summarized: macromolecular deformation, chemical bond breakage, and biomineral crystal imperfections at the atomic scale; biopolymer fibril reconfiguration/deformation and biomineral nanoparticle/nanoplatelet/nanorod translation, and crack reorientation at the nanoscale; crack deflection and twisting by characteristic features such as tubules and lamellae at the microscale; and structure and morphology optimization at the macroscale. In addition, the actual loading conditions of the natural organisms are different, leading to energy dissipation occurring at different time scales. These toughening mechanisms are further illustrated by comparing the experimental results with computational modeling. Modeling methods at different length and time scales are reviewed. Examples of biomimetic designs that realize the multiscale toughening mechanisms in engineering materials are introduced. Indeed, there is still plenty of room mimicking the strong and tough biological designs at the multilength and time scale in Nature.
Giorgio Baiocco, S. Barbieri, Gabriele Babini et al.
Scientific Reports · 2016
The understanding of the impact of radiation quality in early and late responses of biological targets to ionizing radiation exposure necessarily grounds on the results of mechanistic studies starting from physical interactions. This is particularly true when, already at the physical stage, the radiation field is mixed, as it is the case for neutron exposure. Neutron Relative Biological Effectiveness (RBE) is energy dependent, maximal for energies ~1 MeV, varying significantly among different experiments. The aim of this work is to shed light on neutron biological effectiveness as a function of field characteristics, with a comprehensive modeling approach: this brings together transport calculations of neutrons through matter (with the code PHITS) and the predictive power of the biophysical track structure code PARTRAC in terms of DNA damage evaluation. Two different energy dependent neutron RBE models are proposed: the first is phenomenological and based only on the characterization of linear energy transfer on a microscopic scale; the second is purely ab-initio and based on the induction of complex DNA damage. Results for the two models are compared and found in good qualitative agreement with current standards for radiation protection factors, which are agreed upon on the basis of RBE data.
Qingquan Liu, L. Luo, Luqing Zheng
International Journal of Molecular Sciences · 2018
Lignin is one of the main components of plant cell wall and it is a natural phenolic polymer with high molecular weight, complex composition and structure. Lignin biosynthesis extensively contributes to plant growth, tissue/organ development, lodging resistance and the responses to a variety of biotic and abiotic stresses. In the present review, we systematically introduce the biosynthesis of lignin and its regulation by genetic modification and summarize the main biological functions of lignin in plants and their applications. We hope this review will give an in-depth understanding of the important roles of lignin biosynthesis in various plants’ biological processes and provide a theoretical basis for the genetic improvement of lignin content and composition in energy plants and crops.
Renwu Zhou, Rusen Zhou, Peiyu Wang et al.
Journal of Physics D: Applied Physics · 2020
Novel plasma-based technologies that offer maximum efficiency at minimal environmental costs are expected to further promote the sustainable societal and economic development. Unique transfer of chemical reactivity and energy from gaseous plasmas to water takes place in the absence of any other chemicals, but results in a product with a notable transient broad-spectrum biological activity, referred to as plasma-activated water (PAW). These features make PAW a green prospective solution for a wide range of biotechnology applications, from water purification to biomedicine. Here, we present a succinct review of how novel, efficient methods based on non-equilibrium reactive plasma chemistries can be applied to low-cost natural water sources to produce a prospective product with a wide range of applications while at the same time minimising the process steps and dramatically reducing the use of expensive and/or hazardous reagents. Despite the recent exciting developments in this field, there presently is no topical review which specifically focuses on the underlying physics and chemistry related to plasma-activated water. We focus specifically on the PAW generation, origin of reactive species present in PAW, its related analytical chemistry and potentially different mechanisms that regulate the bio-activities of PAW in different biotech-applications and their roles in determining PAW efficacy and selectivity. We then review recent advances in our understanding of plasma-water interactions, briefly outlining current and proposed applications of PAW in agriculture, food and biomedicine. Finally, we outline future research directions and challenges that may hinder translation of these technologies into real-life applications. Overall, this review will provide much needed insights into the fundamental aspects of PAW chemistry required for optimization of the biochemical activity of PAW and translation of this environment- and human-health-friendly, and energy-efficient strategy into real life applications.
Farshid Salimijazi, E. Parra, B. Barstow
Journal of Biological Engineering · 2019
The availability of renewable energy technologies is increasing dramatically across the globe thanks to their growing maturity. However, large scale electrical energy storage and retrieval will almost certainly be a required in order to raise the penetration of renewable sources into the grid. No present energy storage technology has the perfect combination of high power and energy density, low financial and environmental cost, lack of site restrictions, long cycle and calendar lifespan, easy materials availability, and fast response time. Engineered electroactive microbes could address many of the limitations of current energy storage technologies by enabling rewired carbon fixation, a process that spatially separates reactions that are normally carried out together in a photosynthetic cell and replaces the least efficient with non-biological equivalents. If successful, this could allow storage of renewable electricity through electrochemical or enzymatic fixation of carbon dioxide and subsequent storage as carbon-based energy storage molecules including hydrocarbons and non-volatile polymers at high efficiency. In this article we compile performance data on biological and non-biological component choices for rewired carbon fixation systems and identify pressing research and engineering challenges.
Jihyeon Kim, Sunghyun Ko, Chanwoo Noh et al.
Angewandte Chemie International Edition · 2019
Exploiting organic materials participating in the biological energy transduction processes can inspire the discovery of new electrode chemistry for rechargeable batteries, considering the analogy in their electrochemical reactions involving the redox activity. Nicotinamide adenine dinucleotide (NAD+) is one of the most well-known redox cofactors carrying electrons. Herein, we firstly report that intrinsically charged NAD+ motif can serve as an active electrode in electrochemical lithium cells. Through anchoring NAD+ motif by the anion-incorporation, redox activity of the NAD+ is successfully implemented in conventional batteries, exhibiting the average voltage of 2.3 V. We also show that the operating voltage and capacity are tunable by altering the anchoring anion species without modifying the redox center itself. This work not only demonstrates the redox capability of NAD+, but also suggests that anchoring the charged molecules with anion-incorporation is a viable new approach to exploit various charged biological cofactors in rechargeable battery systems.
O. Kühn, V. Rupasov, S. Mukamel
The Journal of Chemical Physics · 1996
The role of medium‐induced relaxation of intermediate (bridge) sites in energy and charge transfer processes in molecular aggregates of arbitrary size and geometry is explored by means of Green’s function techniques. The coupling of electronic and (solvent and intramolecular) nuclear degrees of freedom is incorporated using the Brownian oscillator model, which allows an exact calculation of the necessary two‐point and four‐point correlation functions of exciton operators. The signatures of energy transfer and spectral diffusion in time‐ and frequency‐resolved fluorescence spectroscopy are studied. A unified expression for the frequency‐dependent transfer rate is derived, which interpolates between the sequential and superexchange limits. Numerical results and a Liouville space pathway analysis for a donor–acceptor system coupled through a single bridge molecule are presented.
T. Tsong
Annual Review of Biophysics and Biophysical Chemistry · 1990
PERSPECTIVE AND OVERVIEW 83 PULSED ELECTRIC FIELD METHOD.. .. ... ........ 85 ELECTROPORATION AND ELECTROFUSION OF CELL MEMBRANES .... 87 ELECTROCONFORMATIONAL CHANGES ..... ........ ...... ....... ....... .. 89 ELECTRIC-FIELD-INDUCED Na+, K+, AND Rb+ PUMPING BY Na,K-ATPase 91 ATP SYNTHESIS INDUCED B Y ELECTRIC FIELDS 93 ENERGETICS OF ELECTRIC FIELD INTERACTION WITH A CHEMICAL EQUILIBRIUM.. ... ........ ... 95 ENFORCED CONFORMATIONAL OSCILLATION FOR ENERGY TRANSDUCTION 97 MODULATION OF A STATIONARY TRANSMEMBRANE ELECTRIC FIELD 98 MICHAELIS-MENTEN ENZYME, ENERGY, AND SIGNAl. TRANSDUCTIONS.. 101 ELECTRIC SIGNALS AND ELECTRIC NOISES.... ... ... 102
H. Baltscheffsky
Journal of Theoretical Biology · 1997
The metabolism of living organisms has long been usefully divided into anabolism and catabolism. Anabolism is constructive, being concerned with the assembly of complex molecules, whereas catabolism is destructive in the sense that it involves the degradation of molecules. In addition to the well-known word catastrophe for sudden, drastic destruction and its consequences, it has been found practical to introduce in the evolutionary context the word "anastrophe" (an old greek word for turning back, in the opposite direction-from anastrephein, where ana = back and strephein = to turn) to cover sudden, drastic constructive events and their consequences. Mutations in genes and genomes giving selective advantage to an organism are typical anastrophic events. A single site mutation in a gene coding for a protein may be good, neutral or bad, or anastrophic, neutral or catastrophic, respectively, for the organism. The consequence of an anastrophic mutation may be a decisive first step on the long way to a new species, whereas a catastrophic mutation may lead to major cell damage or death. This example of the use of the anastrophe concept in biological evolution leads to the question about its applicability to other parts and paths of the cosmic evolutionary process, such as physical, chemical, social and cultural evolution. Here it will be mainly considered in connection with the energy conversion aspects of the chemical evolution leading to the origin of life and of the subsequent early biological evolution. More specifically, it will be attempted to describe possible major anastrophes in energy conversion both before and after the first occurrence of life on earth.
A. Stuchebrukhov
Journal of Theoretical and Computational Chemistry · 2003
Cytochrome oxidase (COX) is the terminal component of electron transport chain of the respiratory system in mitochondria, and one of the key enzymes responsible for energy generation in cells. COX functions as a proton pump that utilizes free energy of oxygen reduction for translocation of protons across the mitochondrion membrane. The proton gradient created in the process is later utilized to drive synthesis of ATP. Although the structure of COX has been recently resolved, the molecular mechanism of proton pumping remains unknown. In this paper, general principles and possible molecular mechanisms of energy transformations in this enzyme will be discussed. The main question is how exactly chemical energy of oxygen reduction and water formation is transformed into a proton gradient; or, how exactly electron transfer reactions are utilized to translocate protons across the mitochondrion membrane against the electrochemical gradient. A key to the solution of this problem is in understanding correlated transport of electrons and protons. Here, theoretical models are discussed for coupled electron and proton transfer reactions in which an electron is tunneling over long distance between two redox cofactors, and a coupled proton is moving along a proton conducting channel in a classical, diffusion-like random walk fashion. Such reactions are typical for COX and other enzymes involved in biological energy transformations.
J. Brocklehurst
Physics Bulletin · 1980
The universal currency of biological energy conversion is the molecule adenosine triphosphate (ATP). Primary energy sources (light, food, etc) are used to synthesise ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi) – this is the process of phosphorylation.
R. J. Williams
Annual Review of Biophysics and Biophysical Chemistry · 1988
SOURCES AND SINKS OF PROTON GRADIENTS .••••• •..•.••......••••........•.••••........• 74 Organelle (Bacterial) ATPase 74 Structures of Energy-Transducing Systems 75 Proton EIE2 A TPase of the Outer Membrane .... .. . ........ . . .. . . ........ . . .. 79 Proton Gradient Production Systems: Summary of General Characteristics 8 1 Proton/ X Exchangers ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 82 DISTRIBUTIONS OF PROTON SOURCES AND SINKS AWNG MEMBRANES 83 Circuits Along Membranes and Within the Cytoplasm ........ . . . . . . .. . . . . . . . . . .. . . . .. . . . . . . . . . . . . . . 85 Proton Gradients and Intracellular Metabolism 87 Structures Interacting With Proton Flow..... . . . . . . . ...... . . . . . . ........ . . . . . 88 The Grey Volume Between Source and Sink 88 Studies of Bilayer Films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ ...... . . . . . . . . . . . . . . . 89 PROTON FLOW ...... ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . 90 Selectivity and Proton Channels . . . . . . . . . . . . . . . . . . ........ . . . . . . . . . . . .... . . . . . . ......... . . . . . .... 90 Basic Ideas on Proton Conduction 90 Protein Proton Conductors ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 92 pKa Values ...... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 93 Swinging-Arm (Piggyback) Conduction ......... . . . . . . . ....... . . . ........ ... ..... . . . . . . ....... . . . . . . . ..... 94 Biological Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . 94
H. Westerhoff, K. Hellingwerf, J. Arents et al.
Proceedings of the National Academy of Sciences · 1981
A procedure, called "mosaic nonequilibrium thermodynamics," for describing ion movement and energy transduction in biological membranes is tested in a model system: bacteriorhodopsin liposomes. The important steps in the theoretical derivations are summarized; one of the experimental tests of the postulated fundamental flow-force relationships is shown. Furthermore, how the quantitative method, even if used only qualitatively, facilitates analysis and understanding of experimental results (in this case, the effect of medium composition on the development of pH gradient and membrane potential in the bacteriorhodopsin liposomes) is shown. The main advantage of this method lies in its quantitative description of the effect of variation of system parameters on the performance of, in this case, the reconstituted proton pump bacteriorhodopsin. As an example, the method is shown to explain quantitatively the dependence of the steady-state pH gradient on the light intensity. Even in more refined analyses of experiments, the quantitative theoretical description is in full accordance with the experimental results; this is illustrated by considering the effect of valinomycin on the dependence of the initial rate of proton uptake into bacteriorhodopsin liposomes on light intensity. It is concluded that mosaic nonequilibrium thermodynamics describes ion movement and energy transduction in the model system of bacteriorhodopsin liposomes and, therefore, may be applied to any other biological system performing such processes.
Jian Cao, W. Yuan, Z. Pei et al.
Journal of Manufacturing Science and Engineering · 2009
A grand vision of an algal biofuel energy manufacturing system is presented here. The proposed system, from manufacturing engineering and system points of view, aims to provide technical solutions to two major challenges that the algal biofuel industry faces, i.e., low productivity and energy intensive harvesting and drying, which result in prohibitively high costs. The proposed idea is to have an integrated "conveyor belt" system floating on the water surface powered by windmills or a hybrid energy source. The conveyor belt is made of corrosion-resistant steel sheets that have microdimple surface features to significantly enhance the attachment of algae cells to the "belt" compared with a surface without microdimple features. The grown algae on the belt will then be mechanically scraped off, collected, dried, and squeezed for oil extraction. This paper addresses one of many fundamental problems in this vision, i.e., whether algae can grow effectively on textured stainless steel surfaces. Through both static and dynamic tests, it was found that the growth of algae on textured surfaces was several times more active than that on a flat sample.
Urry, Peng, Hayes et al.
Biotechnology and Bioengineering · 1998
Metabolism is the conversion of available energy sources to those energy forms required for sustaining and propagating living organisms; this is simply biological energy conversion. Proteins are the machines of metabolism; they are the engines of motility and the other machines that interconvert energy forms not involving motion. Accordingly, metabolic engineering becomes the use of natural protein-based machines for the good of society. In addition, metabolic engineering can utilize the principles, whereby proteins function, to design new protein-based machines to fulfill roles for society that proteins have never been called upon throughout evolution to fulfill. This article presents arguments for a universal mechanism whereby proteins perform their diverse energy conversions; it begins with background information, and then asserts a set of five axioms for protein folding, assembly, and function and for protein engineering. The key process is the hydrophobic folding and assembly transition exhibited by properly balanced amphiphilic protein sequences. The fundamental molecular process is the competition for hydration between hydrophobic and polar, e.g., charged, residues. This competition determines Tt, the onset temperature for the hydrophobic folding and assembly transition, Nhh, the numbers of waters of hydrophobic hydration, and the pKa of ionizable functions. Reported acid-base titrations and pH dependence of microwave dielectric relaxation data simultaneously demonstrate the interdependence of Tt, Nhh and the pKa using a series of microbially prepared protein-based poly(30mers) with one glutamic acid residue per 30mer and with an increasing number of more hydrophobic phenylalanine residues replacing valine residues. Also, reduction of nicotinamides and flavins is shown to lower Tt, i.e., to increase hydrophobicity. Furthermore, the argument is presented, and related to an extended Henderson-Hasselbalch equation, wherein reduction of nicotinamides represents an increase in hydrophobicity and resulting hydrophobic-induced pKa shifts become the basis for understanding a primary energy conversion (proton transport) process of mitochondria. Copyright 1998 John Wiley & Sons, Inc.
B. Cartling
The Journal of Chemical Physics · 1985
The principles of biological energy transduction are discussed by means of a mathematical model of a donor–acceptor system of electron transfer enzymes in which electronic and conformational states are coupled. The internal nuclear motion of the enzymes is considered to be composed of transitions between local potential energy wells, which define conformational states, and vibrations within these. The conformational transitions are treated as a stochastic process of the diffusion type on a conformational potential energy surface. Dissipative processes are avoided by restricting electron transfer with respect to conformational states and molecular mechanisms of such electron gating are discussed. Different types of transient kinetics, determined by the relative rates of electronic and conformational transitions, are demonstrated in terms of probability density functions, which describe the probability for the system to be in different electronic and conformational states as a function of time. The experime...
Hongli Zhu, W. Luo, Peter N. Ciesielski et al.
Chemical Reviews · 2016
With the arising of global climate change and resource shortage, in recent years, increased attention has been paid to environmentally friendly materials. Trees are sustainable and renewable materials, which give us shelter and oxygen and remove carbon dioxide from the atmosphere. Trees are a primary resource that human society depends upon every day, for example, homes, heating, furniture, and aircraft. Wood from trees gives us paper, cardboard, and medical supplies, thus impacting our homes, school, work, and play. All of the above-mentioned applications have been well developed over the past thousands of years. However, trees and wood have much more to offer us as advanced materials, impacting emerging high-tech fields, such as bioengineering, flexible electronics, and clean energy. Wood naturally has a hierarchical structure, composed of well-oriented microfibers and tracheids for water, ion, and oxygen transportation during metabolism. At higher magnification, the walls of fiber cells have an interesting morphology-a distinctly mesoporous structure. Moreover, the walls of fiber cells are composed of thousands of fibers (or macrofibrils) oriented in a similar angle. Nanofibrils and nanocrystals can be further liberated from macrofibrils by mechanical, chemical, and enzymatic methods. The obtained nanocellulose has unique optical, mechanical, and barrier properties and is an excellent candidate for chemical modification and reconfiguration. Wood is naturally a composite material, comprised of cellulose, hemicellulose, and lignin. Wood is sustainable, earth abundant, strong, biodegradable, biocompatible, and chemically accessible for modification; more importantly, multiscale natural fibers from wood have unique optical properties applicable to different kinds of optoelectronics and photonic devices. Today, the materials derived from wood are ready to be explored for applications in new technology areas, such as electronics, biomedical devices, and energy. The goal of this study is to review the fundamental structures and chemistries of wood and wood-derived materials, which are essential for a wide range of existing and new enabling technologies. The scope of the review covers multiscale materials and assemblies of cellulose, hemicellulose, and lignin as well as other biomaterials derived from wood, in regard to their major emerging applications. Structure-properties-application relationships will be investigated in detail. Understanding the fundamental properties of these structures is crucial for designing and manufacturing products for emerging applications. Today, a more holistic understanding of the interplay between the structure, chemistry, and performance of wood and wood-derived materials is advancing historical applications of these materials. This new level of understanding also enables a myriad of new and exciting applications, which motivate this review. There are excellent reviews already on the classical topic of woody materials, and some recent reviews also cover new understanding of these materials as well as potential applications. This review will focus on the uniqueness of woody materials for three critical applications: green electronics, biological devices, and energy storage and bioenergy.