Light Energy Input Research Articles

Catalytic Light-Driven Strategy for Transforming Oximes to Carbonyls.

Oxime and carbonyl functional groups serve as powerful chemical hubs for constructing complex synthetic targets and valuable molecular scaffolds. In furthering this value, we report a photopromoted catalytic deoximation protocol for converting oximes and their derivatives to carbonyl functional groups. This strategic approach benefits from the use of renewable light energy input and ambient air conditions, in addition to demonstrating good substrate scope, functional group tolerance, and product yields. In offering, insights into these reactivity mechanistic studies are communicated, and the value of this protocol is further shown through one-pot operations.

Nitrate removal by anammox bacteria utilizing photoexcited electrons via inward extracellular electron transfer channel

Dissimilatory nitrate reduction to ammonium (DNRA) has been found to occur in some anammox bacteria species, and the DNRA metabolites (nitrite and ammonium) can further be removed to nitrogen from water. However, the activation of DNRA pathway of anammox bacteria is usually limited by the access to electron donors. Herein, we constructed a photosensitized hybrid system combining anammox bacteria (Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia anammoxidans) with CdS nanoparticles semiconductor for energy-efficient NO3− removal. Such photosensitized anammox-CdS hybrid systems achieved NO3− removal with an average efficiency of 88% (the maximum of 91%) and a N2 selectivity of 72%, only with photoexcited electrons as donors. The DNRA-anammox metabolism of anammox bacteria was proved to responsible for NO3− removal via inward extracellular electron transfer channel. The greatly up-regulated genes encoding c-type cytochrome proteins (5 or 11 hemes) in the outer membrane, c-type cytochrome protein (4 hemes) and electron transport protein RnfA-E in the inner membrane, ferredoxin (2Fe-2S) in the cytoplasm and c-type cytochrome bc1 in anammoxosome membrane were supposed to play key roles in the inward extracellular electron transfer pathway. This work provides a novel insight into the design of the biotic-abiotic hybrid photosynthetic systems, and opens a new strategy for light-driven NO3− removal from the perspective of light energy input.

Self-Oscillating Liquid Crystal Elastomer Helical Spring Oscillator with Combined Tension and Torsion.

Self-oscillation is the autonomous maintenance of continuous periodic motion through energy absorption from non-periodic external stimuli, making it particularly attractive for fabricating soft robots, energy-absorbing devices, mass transport devices, and so on. Inspired by the self-oscillating system that presents high degrees of freedom and diverse complex oscillatory motions, we created a self-oscillating helical spring oscillator with combined tension and torsion under steady illumination, among which a mass block and a liquid crystal elastomer (LCE) helical spring made with LCE wire are included. Considering the well-established helical spring model and the dynamic LCE model, a nonlinear dynamic model of the LCE helical spring oscillator under steady illumination is proposed. From numerical calculation, the helical spring oscillator upon exposure to steady illumination possesses two motion regimes, which are the static regime and the self-tension-torsion regime. Contraction of the LCE wire under illumination is necessary to generate the self-tension-torsion of the helical spring oscillator, with its continuous periodic motion being maintained by the mutual balance between light energy input and damping dissipation. Additionally, the critical conditions for triggering the self-tension-torsion, as well as the vital system parameters affecting its frequencies and amplitudes of the translation and the rotation, were investigated in detail. This self-tension-torsion helical spring oscillator is unique in its customizable mechanical properties via its structural design, small material strain but large structural displacement, and ease of manufacture. We envision a future of novel designs for soft robotics, energy harvesters, active machinery, and so on.

Light-powered self-oscillation in liquid crystal elastomer auxetic metamaterials with large volume change

Self-oscillation can harvest energy directly from the environment to maintain its motion and is characterized by its autonomy, with various promising applications in the fields of actuators, soft robots and medical devices. Limited to conventional materials, challenges remain in designing novel self-oscillating systems. Auxetic metamaterials can exhibit exceptional properties of negative Poisson's ratio and volume expansion, and the integration of metamaterial structures into self-oscillation can provide additional functionality and improve existing properties and its application. This paper proposes a liquid crystal elastomer (LCE) auxetic metamaterial, and theoretically investigates the self-oscillation of the LCE auxetic metamaterial-mass system under steady illumination. The system can undergo a supercritical Hopf bifurcation between the static pattern and self-oscillation pattern, which arises from the light-driven contraction of LCE fibers and is maintained by light energy input from the environment to compensate for the damping dissipation. This paper also investigates the Hopf bifurcation conditions, as well as the vital systematic parameters affecting frequency and amplitude of the self-oscillation pattern in detail. Different from the existing self-oscillating systems, this LCE metamaterial structure can provide additional functionality and potentially improve existing properties such as large volume change. More generally, the idea of integrating LCE fibers into the re-entrant honeycomb lattices can be applied to other auxetic structures such as arrows and chirality, and it is expected to offer more diverse design ideas of metamaterial and motion control for artificial hearts, hydraulic pumps, sensors, and energy harvesters.

Enlightening dynamic functions in molecular systems by intrinsically chiral light-driven molecular motors.

Chirality is a fundamental property which plays a major role in chemistry, physics, biological systems and materials science. Chiroptical artificial molecular motors (AMMs) are a class of molecules which can convert light energy input into mechanical work, and they hold great potential in the transformation from simple molecules to dynamic systems and responsive materials. Taking distinct advantages of the intrinsic chirality in these structures and the unique opportunity to modulate the chirality on demand, chiral AMMs have been designed for the development of light-responsive dynamic processes including switchable asymmetric catalysis, chiral self-assembly, stereoselective recognition, transmission of chirality, control of spin selectivity and biosystems as well as integration of unidirectional motion with specific mechanical functions. This review focuses on the recently developed strategies for chirality-led applications by the class of intrinsically chiral AMMs. Finally, some limitations in current design and challenges associated with recent systems are discussed and perspectives towards promising candidates for responsive and smart molecular systems and future applications are presented.

Lemna as a Sustainable, Highly Nutritious Crop: Nutrient Production in Different Light Environments

Development of a nutritious, sustainable food source is essential to address worldwide deficiencies in human micronutrients. Aquatic floating plants (e.g., species in the family Lemnaceae, duckweeds) are uniquely suited for area-efficient productivity with exceptionally high rates of growth and nutritional quality. Here, we provide an overview of the role of dietary micronutrients (with a focus on carotenoids) in human health and the promise of Lemnaceae as sustainable crops. We examine the effect of growth light environment on plant biomass production and levels of the carotenoids zeaxanthin, lutein, and pro-vitamin A (β-carotene), as well as the antioxidant vitamin E (α-tocopherol), and protein. Data on each of these nutrients are reported on a plant dry biomass basis (as relevant for nutrition) as well as relative to the required input of light energy (as relevant to resource-use efficiency).

Performance and mechanisms for tetrabromobisphenol A efficient degradation in a novel homogeneous advanced treatment based on S2O42− activated by Fe3+

Tetrabromobisphenol A (TBBPA), a representative brominated flame retardant (BFR), generally could be debrominated and degraded effectively in photolysis systems with the high energy consumption. In this study, the novel sulfate radical (SO4•-) generation resource of dithionite (S2O42−), activated by the common transition metal of Fe3+, has been applied for establishing an innovative homogeneous advance treatment system for BFR treatment in water. When coupling Fe3+ with S2O42−, TBBPA degradation efficiency could be remarkably improved from 38.7% to 93.8% with the debromination and mineralization efficiency of 83.9% and 18.5% in 60 min, respectively. The primary reactive species also have been identified as SO3•-, SO4•- and •OH responsible for TBBPA treatment and the contributions of SO4•- and •OH have been calculated as 43.8% and 28.4% for TBBPA degradation, respectively. In Fe3+/S2O42− system, TBBPA was effectively degraded in a wide initial pH range (3.0–9.0), whose activation energy was calculated as 32.01 kJ mol−1. Due to the only operation of reagents dosing, the energy consumption and cost could be decreasing significantly without any light energy input and reaction conditions (e.g., pH and dissolved oxygen) adjustment compared with the general photolysis process. Moreover, some possible degradation approaches of TBBPA also have been proposed via GC–MS including debromination, hydroxylation, methylation, and mineralization in Fe3+/S2O42− system. And these probable degradation pathways also have been confirmed with the decreased Gibbs free energy (ΔG) based on density functional theory (DFT). This study has revealed that it was promising of Fe3+/S2O42− system for BFRs degradation and detoxification efficiently through the simple operation and mild condtions.

Energy- and atom-efficient chemical synthesis with endergonic photocatalysis.

Endergonic photocatalysis is the use of light to perform catalytic reactions that are thermodynamically unfavourable. While photocatalysis has become a powerful tool in facilitating chemical transformations, the light-energy efficiency of these processes has not gathered much attention. Exergonic photocatalysis does not take full advantage of the light energy input, producing low-energy products and heat, whereas endergonic photocatalysis incorporates a portion of the photon energy into the reaction, yielding products that are higher in free energy than the reactants. Such processes can enable catalytic, atom-economic syntheses of reactive compounds from bench-stable materials. With respect to environmental friendliness and carbon neutrality, endergonic photocatalysis is also of interest to large-scale industrial manufacturing, where better energy efficiency, less waste and value addition are highly sought. We therefore assess here the thermochemistry of several classes of reported photocatalytic transformations to showcase current advances in endergonic photocatalysis and point to their industrial potential.

Kinetic and energetic insights into the dissipative non-equilibrium operation of an autonomous light-powered supramolecular pump.

Natural and artificial autonomous molecular machines operate by constantly dissipating energy coming from an external source to maintain a non-equilibrium state. Quantitative thermodynamic characterization of these dissipative states is highly challenging as they exist only as long as energy is provided. Here we report on the detailed physicochemical characterization of the dissipative operation of a supramolecular pump. The pump transduces light energy into chemical energy by bringing self-assembly reactions to non-equilibrium steady states. The composition of the system under light irradiation was followed in real time by 1H NMR for four different irradiation intensities. The experimental composition and photon flow were then fed into a theoretical model describing the non-equilibrium dissipation and the energy storage at the steady state. We quantitatively probed the relationship between the light energy input and the deviation of the dissipative state from thermodynamic equilibrium in this artificial system. Our results provide a testing ground for newly developed theoretical models for photoactivated artificial molecular machines operating away from thermodynamic equilibrium.

Dissipative biocatalytic cascades and gated transient biocatalytic cascades driven by nucleic acid networks.

Living systems consist of complex transient cellular networks guiding structural, catalytic, and switchable functions driven by auxiliary triggers, such as chemical or light energy inputs. We introduce two different transient, dissipative, biocatalytic cascades, the coupled glucose oxidase (GOx)/horseradish peroxidase (HRP) glucose–driven oxidation of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS2−) to the radical anion (ABTS•−) and the lactate dehydrogenase (LDH)/nicotinamide adenine dinucleotide (NAD+) lactate–driven reduction of NAD+ to NADH. The transient biocatalytic systems are driven by nucleic acid reaction modules using a nucleic acid fuel strand L1′ and a nicking enzyme, Nt.BbvCI, as fuel-degrading catalyst, leading to the dynamic spatiotemporal transient formation of structurally proximate biocatalysts activating the biocatalytic cascades and transient coupled processes, including the generation of chemiluminescence and the synthesis of alanine. Subjecting the mixture of biocatalysts to selective inhibitors allows the gated transient operation of the biocatalysts. The kinetics of transient biocatalytic cascades are accompanied by kinetic models and computational simulations.

A kaleidoscope of photosynthetic antenna proteins and their emerging roles.

Photosynthetic light-harvesting antennae are pigment-binding proteins that perform one of the most fundamental tasks on Earth, capturing light and transferring energy that enables life in our biosphere. Adaptation to different light environments led to the evolution of an astonishing diversity of light-harvesting systems. At the same time, several strategies have been developed to optimize the light energy input into photosynthetic membranes in response to fluctuating conditions. The basic feature of these prompt responses is the dynamic nature of antenna complexes, whose function readily adapts to the light available. High-resolution microscopy and spectroscopic studies on membrane dynamics demonstrate the crosstalk between antennae and other thylakoid membrane components. With the increased understanding of light-harvesting mechanisms and their regulation, efforts are focusing on the development of sustainable processes for effective conversion of sunlight into functional bio-products. The major challenge in this approach lies in the application of fundamental discoveries in light-harvesting systems for the improvement of plant or algal photosynthesis. Here, we underline some of the latest fundamental discoveries on the molecular mechanisms and regulation of light harvesting that can potentially be exploited for the optimization of photosynthesis.

Light-driven oxidation of CH4 to C1 chemicals catalysed by an organometallic Ru complex with O2.

CH4 conversion is one of the most challenging chemical reactions due to its inertness in terms of physical and chemical properties. We have achieved photo-induced C–H bond breaking of CH4 and successive C–O bond formation to form CH3OH concomitant with HCHO by an organometallic Ru complex with O2.

Diversity and origin of carotenoid biosynthesis: its history of coevolution towards plant photosynthesis

The development of photosynthesis was a highlight in the progression of bacteria. In addition to the photosystems with their structural proteins, the photosynthesis apparatus consists of different cofactors including essential carotenoids. Thus, the evolution of the carotenoid pathways in relation to the functionality of the resulting structures in photosynthesis is the focus of this review. Analysis of carotenoid pathway genes indicates early evolutionary roots in prokaryotes. The pathway complexity leading to a multitude of structures is a result of gene acquisition, including their functional modifications, emergence of novel genes and gene exchange between species. Along with the progression of photosynthesis, carotenoid pathways coevolved with photosynthesis according to their advancing functionality. Cyanobacteria, with their oxygenic photosynthesis, became a landmark for evolutionary events including carotenogenesis. Concurrent with endosymbiosis, the cyanobacterial carotenoid pathways were inherited into algal plastids. In the lineage leading to Chlorophyta and plants, carotenoids evolved to their prominent role in protection and regulation of light energy input as constituents of a highly efficient light-harvesting complex.

Light-powered self-excited bouncing of a liquid crystal elastomer ball

Light-powered self-excited motions of liquid crystal elastomers (LCEs) have great application prospects in the fields of actuators, soft robots, medical devices and micro-nano devices, and are capable of collecting energy directly from the environment to maintain its own motion without complex controller and additional battery. In this paper, a new light-powered self-excited bouncing system made up of LCE is originally established, and the self-excited bouncing is studied theoretically based on the well-established dynamic LCE model and Hertz contact theory. Numerical calculation shows that the LCE ball can develop into two motion modes: static mode and bouncing mode. The feedback mechanism of the bouncing mode is elucidated to be expansion-in-contact mechanism, of which the coupling of expansion and contact process enables light energy input from the environment to compensate for damping dissipation of the system. The phase diagrams and triggering conditions for provoking self-excited bouncing are quantitatively described for different system parameters. The results show that self-excited bouncing can be regulated by the system parameters, such as light illumination zone, gravitational acceleration, light intensity, equivalent modulus, contraction coefficient and damping coefficient. In addition, the system parameters have important effects on the amplitude and frequency of the self-excited bouncing of the LCE ball. It is expected that the study may provide some instructive suggestions for the design and motion control of active jumping machines.

Synergistic dynamics of critical cofactors effectuates fuel relevant metabolic profile of Scenedesmus sp.: Targeting cleaner energy production

Microalgae based biofuel is dictated to a great extent by certain synergistic interactions between critical nutrients as well as the quality and quantity of light energy available. For latitude regions with high light irradiance for a greater part of year, it is important to optimize the proportions of critical nutrients for microalgae species to display a suitable metabolic profile and not loose advantage when total light energy input increases. In this study, the conjunct impact of light intensity using white LED, together with photoperiod and nutrients (nitrate, phosphate and glucose) depleted and replete conditions on energy storage metabolites and fuel characteristics of Scenedesmus sp. were investigated under a mixotrophic growth regime. Results show that Scenedesmus sp. could efficiently exploit even very intense light, for longer duration (216 μmolm−2s−1 at 16:8 light: dark photoperiod) in presence of 1.5 g/L of sodium nitrate, 0.04 g/L of di-sodium hydrogen phosphate and 5 g/L of glucose (G5N1.5P0.04) to produce a biomass of 1782.4 ± 56.8 μg/mL with a specific growth rate of 0.2 ± 0.007 day−1. High light intensity (216 μmolm−2s−1) and organic carbon at 16:8 light: dark photoperiod (L16:D8) led to increased synthesis of carbohydrate content in the absence of nitrate and phosphate (1924.8 ± 128.6 μg/mg at G5N0P0), increased TFA in the absence of nitrate (59.5 μg/mg at G5N0P0.04) and high lipid content (154.1 ± 7.7 μg/mg at G5N1.5P0.04) without obliterating growth. Certain vital properties that determine the biodiesel quality were computed and compared to the parallel parameters put forth by European and American biodiesel norms. These results stand to be a baseline for sustainable algal bio-refinery and create futuristic vistas for further evaluation of Scenedesmus sp. for bio-energy applications in countries like India having tropical climate with high solar incoming radiation for a greater part of the year.

Construction and control of gel active matter aiming at autonomous pulsation by sunlight

The modern world is built on motors, which are operated by electricity and fossil fuels. These have been extremely successful at creating cheap and efficient machines capable of fulfilling all kinds of functions. However, they are vulnerable in extreme situations. They need constant supplies of energy that also needs to be transported to their location. This can be extremely expensive, hazardous or even impossible in remote places and during natural disasters. At the same time, the motors themselves are made from multiple mechanical parts that may not endure well in these environments and under those circumstances. Therefore, there is a need for a novel device that can generate power to run useful basic functions such as pumping water. Such a device would need to have few, if any, mechanical parts and should be able to use the energy sources available in-situ. Associate Professor Takayuki Narita of the Department of Chemistry and Applied Chemistry at Saga University, Japan is working to develop such a device. His work is focussed on harnessing the unusual properties of gels that can respond to light energy inputs.

REDUCTION OF THE CONTROL VOLTAGE IN THE AMPLITUDE ELECTROOPTIC MODULATOR AT MULTIPLE-INTERFERENCE IN A RING RESONATOR

In this paper, it’s described a method that allows to implement highly efficient amplitude modulation of radiation at the output of a ring resonator by controlling its artificial light losses, which are derived from it using two Y-shaped couplers. At the same time, the necessary constant level of light energy is provided in the resonator, which, due to the absence of radiation losses when entering it into the ring resonator, allows one to achieve a significantly lower value of the required control electric voltage than existing electro-optical modulators, and, therefore, a smaller amount of consumed electric power and an increase in working frequency range of modulation of optical radiation. The possibility of implementing the method under consideration is ensured by the fact that the input of light energy into the ring resonator can be carried out without loss, in addition, single-mode waveguides are able to maintain the temporal coherence of transmitted radiation, which ensures the implementation of multipath interference. The stabilization of the optical characteristics of a ring resonator, which is very sensitive to changes in various external factors, for example, temperature, pressure, vibrations, can be achieved by electro-optical correction of the length of the optical path of the resonator by introducing a controlled phase element operating on the transverse electro-optical effect into the ring resonator and implementing corresponding optoelectronic feedback circuit.

Light-Activated Organic Molecular Motors and Their Applications.

Molecular motors are at the heart of cellular machinery, and they are involved in converting chemical and light energy inputs into efficient mechanical work. From a synthetic perspective, the most advanced molecular motors are rotators that are activated by light wherein a molecular subcomponent rotates unidirectionally around an axis. The mechanical work produced by arrays of molecular motors can be used to induce a macroscopic effect. Light activation offers advantages over biological chemically activated molecular motors because one can direct precise spatiotemporal inputs while conducting reactions in the gas phase, in solution and in vacuum, while generating no chemical byproducts or waste. In this review, we describe the origins of the first light-activated rotary motors and their modes of function, the structural modifications that led to newer motor designs with optimized rotary properties at variable activation wavelengths. Presented are molecular motor attachments to surfaces, their insertion into supramolecular structures and photomodulating materials, their use in catalysis, and their action in biological environments to produce exciting new prospects for biomedicine.

Performance Index and PSII Connectivity Under Drought and Contrasting Light Regimes in the CAM Orchid Phalaenopsis.

Crassulacean acid metabolism (CAM) is a specialized mode of photosynthesis characterized by improved water use efficiency mediated by major nocturnal CO2 fixation. Due to its inherent metabolic plasticity CAM represents a successful physiological strategy for plant adaptation to abiotic stress. The present study reports on the impact of drought stress and different light intensities (PPFD 50 and 200 μmol m–2 s–1) on the photosynthetic performance of the obligate CAM orchid Phalaenopsis “Edessa” by integrating diel gas exchange patterns with assessments of the light reactions by analyzing fast chlorophyll a fluorescence induction. Parameters such as PIabs (performance index), different energy fluxes per active reaction centre (RC) reflecting the electron flow from photosystem II to photosystem I and the energetic communication between PSII complexes defined as connectivity were considered for the first time in a CAM plant. A higher PS II connectivity for plants grown under low light (p ∼ 0.51) compared to plants grown under high light (p ∼ 0.31) brought about similar specific energy fluxes of light absorbance, dissipation and processing through the electron transport chain, irrespective of the light treatment. With a 25% higher maximum quantum yield and comparable biomass formation, low light grown plants indeed proved to process light energy more efficiently compared to high light grown plants. The performance index was identified as a very reliable and sensitive parameter to indicate the onset and progress of drought stress. Under restricted CO2 availability (due to closed stomata) leaves showed higher energy dissipation and partial inactivation of PSII reaction centres to reduce the energy input to the electron transport chain and as such aid in avoiding overexcitation and photodamage. Especially during CAM idling there is a discrepancy between continuous input of light energy but severely reduced availability of both water and CO2, which represents the ultimate electron acceptor. Taken together, our results show a unique flexibility of CAM plants to optimize the light reactions under different environmental conditions in a dual way by either attenuating or increasing energy flux.

Functional Role of Fibrillin5 in Acclimation to Photooxidative Stress.

The functional role of a lipid-associated soluble protein, fibrillin5 (FBN5), was determined with the Arabidopsis thaliana homozygous fbn5-knockout mutant line (SALK_064597) that carries a T-DNA insertion within the FBN5 gene. The fbn5 mutant remained alive, displaying a slow growth and a severe dwarf phenotype. The mutant grown even under growth light conditions at 80 µmol m-2 s-1 showed a drastic decrease in electron transfer activities around PSII, with little change in electron transfer activities around PSI, a phenomenon which was exaggerated under high light stress. The accumulation of plastoquinone-9 (PQ-9) was suppressed in the mutant, and >90% of the PQ-9 pool was reduced under growth light conditions. Non-photochemical quenching (NPQ) in the mutant functioned less efficiently, resulting from little contribution by energy-dependent quenching (qE). The ultrastructure of thylakoids in the mutant revealed that their grana were unstacked and transformed into loose and disordered structures. Light-harvesting complex (LHC)-containing large photosystem complexes and photosystem core complexes in the mutant were less abundant than those in wild-type plants. These results suggest that the lack of FBN5 causes a decrease in PQ-9 and imbalance of the redox state of PQ-9, resulting in misconducting both short-term and long-term control of the input of light energy to photosynthetic reaction centers. Furthermore, in the fbn5 mutant, the expression of genes involved in jasmonic acid biosynthesis was suppressed to ≤10% of that in the wild type under both growth-light and high-light conditions, suggesting that FBN5 functions as a transmitter of 1O2 in the stroma.