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The solution and crystal structures of a bacterial phytochrome photosensory core in both its resting and activated states are determined; switching between closed (resting) and open (activated) forms is found to be mediated by a conserved ‘tongue’, and the structures indicate that smaller changes in the vicinity of the chromophore are amplified in scale as they are transmitted through the tongue and beyond. Signal amplification by light-receptor proteins The crystal structure of the photosensory core of a bacterial phytochrome in both the resting and the active (illuminated) state has now been solved. Working with the phytochrome from the extremophile Deinococcus radiodurans , Sebastian Westenhoff and colleagues demonstrate that toggling between resting and active forms is mediated by a conserved 'tongue' that contacts the chromophore. Atomic-scale structural changes in the vicinity of the chromophore are amplified as they are transmitted through the tongue and beyond, culminating in a nanometre-scale conformational signal that feeds into the rest of the cellular signalling network. Sensory proteins must relay structural signals from the sensory site over large distances to regulatory output domains. Phytochromes are a major family of red-light-sensing kinases that control diverse cellular functions in plants, bacteria and fungi 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . Bacterial phytochromes consist of a photosensory core and a carboxy-terminal regulatory domain 10 , 11 . Structures of photosensory cores are reported in the resting state 12 , 13 , 14 , 15 , 16 , 17 , 18 and conformational responses to light activation have been proposed in the vicinity of the chromophore 19 , 20 , 21 , 22 , 23 . However, the structure of the signalling state and the mechanism of downstream signal relay through the photosensory core remain elusive. Here we report crystal and solution structures of the resting and activated states of the photosensory core of the bacteriophytochrome from Deinococcus radiodurans . The structures show an open and closed form of the dimeric protein for the activated and resting states, respectively. This nanometre-scale rearrangement is controlled by refolding of an evolutionarily conserved ‘tongue’, which is in contact with the chromophore. The findings reveal an unusual mechanism in which atomic-scale conformational changes around the chromophore are first amplified into an ångstrom-scale distance change in the tongue, and further grow into a nanometre-scale conformational signal. The structural mechanism is a blueprint for understanding how phytochromes connect to the cellular signalling network.

Materials exhibiting thermally activated delayed fluorescence (TADF) based on transition metal complexes are currently gathering significant attention due to their technological potential. Their application extends beyond optoelectronics, in particular organic light‐emitting diodes (OLEDs) and light‐emitting electrochemical cells (LECs), and include also photocatalysis, sensing, and X‐ray scintillators. From the perspective of sustainability, earth‐abundant metal centers are preferred to rarer second‐ and third‐transition series elements, thus determining a reduction in costs and toxicity but without compromising the overall performances. This review offers an overview of earth‐abundant transition metal complexes exhibiting TADF and their application as photoconversion materials. Particular attention is devoted to the types of ligands employed, helping in the design of novel systems with enhanced TADF properties. Thermally activated delayed fluorescence (TADF) is gaining particular attention for its promising technological application. This review focuses on earth‐abundant transition metal complexes exhibiting TADF and their employment as photoconversion materials, in organic light‐emitting diodes (OLEDs), light‐emitting electrochemical cells (LECs), photocatalysis, sensing, and X‐ray scintillators.

Near‐infrared (NIR) light is well‐suited for the optical imaging and wireless phototherapy of malignant diseases because of its deep tissue penetration, low autofluorescence, weak tissue scattering, and non‐invasiveness. Rare earth nanoparticles (RENPs) are promising NIR‐responsive materials, owing to their excellent physical and chemical properties. The 4f electron subshell of lanthanides, the main group of rare earth elements, has rich energy‐level structures. This facilitates broad‐spectrum light‐to‐light conversion and the conversion of light to other forms of energy, such as thermal and chemical energies. In addition, the abundant loadable and modifiable sites on the surface offer favorable conditions for the functional expansion of RENPs. In this review, the authors systematically discuss the main processes and mechanisms underlying the response of RENPs to NIR light and summarize recent advances in their applications in optical imaging, photothermal therapy, photodynamic therapy, photoimmunotherapy, optogenetics, and light‐responsive drug release. Finally, the challenges and opportunities for the application of RENPs in optical imaging and wireless phototherapy under NIR activation are considered. In this review, the authors focus on rare earth nanoparticles (RENPs) as media for light conversion and discuss the photoconversion process under near‐infrared (NIR) excitation, as well as recent achievements in optical imaging, photothermal therapy, photodynamic therapy, photoimmunotherapy, optogenetics, and light‐responsive drug release. Finally, the opportunities and challenges of NIR‐responsive RENPs for optical imaging and wireless phototherapy are discussed.

Pigments homologous to the green fluorescent protein (GFP) have been proposed to fine-tune the internal light microclimate of corals, facilitating photoacclimation of photosynthetic coral symbionts (Symbiodiniaceae) to life in different reef habitats and environmental conditions. However, direct measurements of the in vivo light conditions inside the coral tissue supporting this conclusion are lacking. Here, we quantified the intra-tissue spectral light environment of corals expressing GFP-like proteins from widely different light regimes. We focus on: (1) photoconvertible red fluorescent proteins (pcRFPs), thought to enhance photosynthesis in mesophotic habitats via wavelength conversion, and (2) chromoproteins (CPs), which provide photoprotection to the symbionts in shallow water via light absorption. Optical microsensor measurements indicated that both pigment groups strongly alter the coral intra-tissue light environment. Estimates derived from light spectra measured in pcRFP-containing corals showed that fluorescence emission can contribute to >50% of orange-red light available to the photosynthetic symbionts at mesophotic depths. We further show that upregulation of pink CPs in shallow-water corals during bleaching leads to a reduction of orange light by 10–20% compared to low-CP tissue. Thus, screening by CPs has an important role in mitigating the light-enhancing effect of coral tissue scattering and skeletal reflection during bleaching. Our results provide the first experimental quantification of the importance of GFP-like proteins in fine-tuning the light microclimate of corals during photoacclimation.

This work concerns the experimental verification of changes in the energy efficiency of photovoltaic installations through the use of bifacial modules. For this purpose, an experimental stand was designed and built for the comparative analysis of the efficiency of two types of photovoltaic panels: bifacial (bPV) and monofacial (mPV). The tests consisted of placing the panels at different heights above the ground surface and at different angles. During the tests, three substrates with different albedo were taken into account: green grass, gray concrete (fabric), and white snow (polystyrene). The tests for both types of panels were carried out simultaneously (in parallel), which guaranteed the same environmental conditions (temperature and solar radiation intensity). Based on the results of the voltage and current measurements for different angles of PV module inclination and, for bPV panels, different heights above the ground surface and different types of substrate, a series of current–voltage characteristics and power characteristics were plotted. The “additional” energy efficiency of bifacial panels compared to monofacial panels was also determined. It was shown that under favorable conditions, using bifacial panels instead of monofacial panels can increase the production of electricity by more than 56% from structures of the same dimensions. The research results can be of great value when designing photovoltaic installations.

Dendritic cells (DCs) are antigen-presenting cells specialized for activating T cells to elicit effector T-cell functions. Cross-presenting DCs are a DC subset capable of presenting antigens to CD8⁺ T cells and play critical roles in cytotoxic T-cell–mediated immune responses to microorganisms and cancer. Although their importance is known, the spatiotemporal dynamics of cross-presenting DCs in vivo are incompletely understood. Here, we study the T-cell zone in skin-draining lymph nodes (SDLNs) and find it is compartmentalized into regions for CD8⁺ T-cell activation by cross-presenting DCs that express the chemokine (C motif) receptor 1 gene, Xcr1 and for CD4⁺ T-cell activation by CD11b⁺ DCs. Xcr1-expressing DCs in the SDLNs are composed of two different populations: migratory (CD103hi) DCs, which immigrate from the skin, and resident (CD8αhi) DCs, which develop in the nodes. To characterize the dynamic interactions of these distinct DC populations with CD8⁺ T cells during their activation in vivo, we developed a photoconvertible reporter mouse strain, which permits us to distinctively visualize the migratory and resident subsets of Xcr1-expressing DCs. After leaving the skin, migratory DCs infiltrated to the deep T-cell zone of the SDLNs over 3 d, which corresponded to their half-life in the SDLNs. Intravital two-photon imaging showed that after soluble antigen immunization, the newly arriving migratory DCs more efficiently form sustained conjugates with antigen-specific CD8⁺ T cells than other Xcr1-expressing DCs in the SDLNs. These results offer in vivo evidence for differential contributions of migratory and resident cross-presenting DCs to CD8⁺ T-cell activation.

Binary oxide ceramics have emerged as key materials in solar energy research due to their versatility, chemical stability, and tunable electronic properties. This study presents a comparative analysis of seven prominent oxides (TiO2, ZnO, Al2O3, SiO2, CeO2, Fe2O3, and WO3), focusing on their functional roles in silicon, perovskite, dye-sensitized, and thin-film solar cells. A bibliometric analysis covering over 50,000 publications highlights TiO2 and ZnO as the most widely studied materials, serving as electron transport layers, antireflective coatings, and buffer layers. Al2O3 and SiO2 demonstrate highly specialized applications in surface passivation and interface engineering, while CeO2 offers UV-blocking capability and Fe2O3 shows potential as an absorber material in photoelectrochemical systems. WO3 is noted for its multifunctionality and suitability for scalable, high-rate processing. Together, these findings suggest that binary oxide ceramics are poised to transition from supporting roles to essential components of stable, efficient, and environmentally safer next-generation solar cells.

The majority of reaction conditions employed in SF 6 conversion research are characterized by elevated temperatures and pressures, resulting in a considerable expenditure of energy. The transformation of SF 6 under mild conditions represents a viable methodology at this time. It has been demonstrated that the conditions required for the photoconversion of SF 6 are relatively mild. Furthermore, the defect engineering of catalysts has been shown to be an effective strategy for enhancing the photocatalytic performance of photocatalysis. Thus, we utilized two-dimensional materials as a model for our research. These materials have active sites that are highly dense and uniform, allowing us to thoroughly examine how defects affect the SF 6 photoconversion process. By synthesizing ZnO atomic layers with oxygen vacancies and confirming their presence using various techniques, we found that these vacancies enhanced light absorption and promoted the separation of charge carriers. These results suggest that the oxygen-deficient ZnO atomic layers have superior SF 6 photoconversion performance compared to the pristine ZnO atomic layers. Overall, the findings of this study indicate that the incorporation of defects in photocatalysts is a crucial strategy for optimizing pivotal photocatalytic processes and enhancing the efficacy of SF 6 photoconversion. Graphical Abstract We initially built clear models of two-dimensional atomic layers with defect concentrations, and hence directly disclose the defect type and distribution at atomic level. As a prototype, defective ZnO nanosheets with atomic thickness are successfully synthesized. Also, we use defective ZnO atomic layers to achieve light conversion of SF 6 under mild conditions, which provides a new path to solve the environmental pollution of perfluorinated compounds.

The behavior and migration of human mesenchymal stromal cells (hMSCs) are focal points of research in the biomedical field. One of the major aspects is potential therapy using hMCS, but at present, the safety of their use is still controversial owing to limited data on changes that occur with hMSCs in the long term. Fluorescent photoconvertible proteins are intensively used today as “gold standard” to mark the individual cells and study single-cell interactions, migration processes, and the formation of pure lines. A crucial disadvantage of this method is the need for genetic modification of the primary culture, which casts doubt on the possibility of exploring the resulting clones in personalized medicine. Here we present a new approach for labeling and tracking hMSCs without genetic modification based on the application of cell-internalizable photoconvertible polyelectrolyte microcapsules (size: 2.6 ± 0.5 μm). These capsules were loaded with rhodamine B, and after thermal treatment, exhibited fluorescent photoconversion properties. Photoconvertible capsules demonstrated low cytotoxicity, did not affect the immunophenotype of the hMSCs, and maintained a high level of fluorescent signal for at least seven days. The developed approach was tested for cell tracking for four days and made it possible to trace the destiny of daughter cells without the need for additional labeling.

As compared to other deposition techniques such as atomic layer deposition, chemical vapour deposition and sputtering, aerosol deposition (AD) is a simple and cost-effective technique to produce ZnO thin films. In this work, the effect of deposition cycles on the structural, optical, and photo-conversion efficiency (PCE) of dye sensitized solar cells of ZnO thin films deposited by AD (AZ) was systematically studied. The structural, optical, and PCE% of two-cycle deposited ZnO thin film (AZ-II) exhibited the highest performance. Further increment in deposition cycle caused deterioration in the structural, optical, and PCE performance. The thickness of ZnO thin films decreased due to abrasion of the deposited film by the subsequent stream of highly energetic ZnO particles. Loosely bound particles could be found on the surface of ZnO thin film after three deposition cycles (AZ-III). The AZ-III films exhibited poor crystal quality, with many crystal defects such as interstitial oxygen as suggested in room temperature photoluminescence analysis.