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The use of photovoltaics (PVs) and/or photo-thermal (PTs) as primary solar-energy solutions is limited by the low solar conversion of PVs due to the spectral mismatch between the incident radiation and/or the PV material. The PTs are curtailed by the limited absorbance and the low thermal conductivity of the working fluid. A possible solution is the use of luminophores able to perform luminescent down-shifting (LDS) conversion and to incorporate them in liquid or solid layers, which act as spectral beam splitters (SBSs). Dispersed in solid polymer layers, luminophores lead to luminescent solar concentrators (LSC). When dispersed in liquid and placed in front of PVs, luminophores act as working fluids and as SBS, leading to hybrid photovoltaic–photo-thermal (PVT) systems. Here, the SBS filters for PV and PVT systems are reviewed. The contribution of luminophores to electrical and thermal energy production is discussed from theoretical, experimental, and economical perspectives. Recent SBS architectural concepts which combine different optical elements are also considered. These architectures can harness the advantageous properties of LSCs, spectral modulators, and hybridisation in a single structure. By combining these different light-management strategies inside of a single structure, an improvement in the electrical and/or thermal energy production can be achieved. [ABSTRACT FROM AUTHOR]

Combining photovoltaic (PV) and photo-thermal (PT) energy collection strategies in a single system can enhance solar energy conversion efficiencies, leading to increased economic returns and wider adoption of renewable energy sources. This study focuses on incorporating a commercial luminescent organic dye (BASF Lumogen F Red 305) into ethylene glycol to explore its potential for PVT applications. The optical and electrical characteristics of the working fluid were evaluated at different temperatures under direct solar irradiance. Pristine ethylene glycol reduced the maximum PV cell temperature by 10 °C. The inclusion of luminescent dye at various concentrations further reduced the maximum temperature, with the lowest concentration achieving a 7 °C decrease compared to pristine ethylene glycol. The highest dye concentration (0.50 wt%) resulted in a significant temperature reduction of 12 °C. While electrical conversion efficiencies decreased with increasing dye concentration, all concentrations exhibited higher fill factors compared to the bare PV cell during the 100-min illumination period. A ray-tracing model was employed to analyze the behavior of the luminescent dye and quantify transmitted energy for electricity and thermal energy production. Different concentrations showed varying energy outputs, with lower concentrations favoring electrical energy and higher concentrations favoring thermal energy. Economic assessment revealed the viability of certain concentrations for specific countries, highlighting the trade-off between thermal and electrical energy generation. These findings provide valuable insights for PVT system applications in different geographical and economic contexts. [ABSTRACT FROM AUTHOR]

F1Fo ATP synthase functions as a biological generator and makes a major contribution to cellular energy production. Proton flow generates rotation in the Fo motor that is transferred to the F1 motor to catalyze ATP production, with flexible F1/Fo coupling required for efficient catalysis. F1Fo ATP synthase can also operate in reverse, hydrolyzing ATP and pumping protons, and in bacteria this function can be regulated by an inhibitory ε subunit. Here we present cryo-EM data showing E. coli F1Fo ATP synthase in different rotational and inhibited sub-states, observed following incubation with 10 mM MgATP. Our structures demonstrate how structural transitions within the inhibitory ε subunit induce torsional movement in the central stalk, thereby enabling its rotation within the Fο motor. This highlights the importance of the central rotor for flexible coupling of the F1 and Fo motors and provides further insight into the regulatory mechanism mediated by subunit ε. Cryo-EM structures of E. coli F1Fo ATP synthase highlight the role of the inhibitory ε subunit in regulating the torsional movement of the central stalk within the Fo motor and central stalk flexibility in coupling the F1 and Fo motors. [ABSTRACT FROM AUTHOR]

Chemical modifications of histone tails influence genome accessibility and the transcriptional state of eukaryotic cells. Lysine acetylation is one of the most common modifications and acetyllysine‐binding bromodomains (BDs) provide a means for acetyllysine marks to be translated into meaningful cellular responses. Here, we have investigated the mechanism underlying the reported association between the Bromodomain and Extra Terminal (BET) family of BD proteins and the essential histone variant H2A.Z. We use NMR spectroscopy to demonstrate a physical interaction between the N‐terminal tail of H2A.Z and the BDs of BRD2, BRD3, and BRD4, and show that the interaction is dependent on lysine acetylation in H2A.Z. The BDs preferentially engage a diacetylated H2A.Z‐K4acK7ac motif that is reminiscent of sequences found in other biologically important BET BD target proteins, including histones and transcription factors. A H2A.Z‐K7acK11ac motif can also bind BET BDs—with a preference for the second BD of each protein. Chemical shift perturbation mapping of the interactions, together with an X‐ray crystal structure of BRD2‐BD1 bound to H2A.Z‐K4acK7ac, shows that H2A.Z binds the canonical AcK binding pocket of the BDs. This mechanism mirrors the conserved binding mode that is unique to the BET BDs, in which two acetylation marks are read simultaneously by a single BD. Our findings provide structural corroboration of biochemical and cell biological data that link H2A.Z and BET‐family proteins, suggesting that the function of H2A.Z is enacted through interactions with these chromatin readers. PDB Code(s): 7JX7; [ABSTRACT FROM AUTHOR]

Objective: Although there is a considerable body of literature probing the knowledge and awareness of doctors of guidelines on medical fitness to drive, little is known of knowledge and awareness of such guidelines among the general public. We investigated awareness, perceptions and attitudes among a range of adults toward risk and personal responsibility in the context of medical fitness to drive.Methods: This quasi-experimental between groups study assessed response differences between healthcare (33%) and non-healthcare professionals. Five hundred and fourteen adults (f = 342) completed a 15-item online survey, which assessed their license status, direct and secondhand experience with key medical conditions, perceptions of risk, driving intentions if advised to stop driving by a doctor and beliefs about responsibility for ensuring driver fitness.Results: Most of the participants had a driver license. Although the majority (87%) had no first-hand experience with key medical conditions contained in the Irish medical fitness to drive guidelines, two-thirds knew someone with at least one of these conditions. No participant admitted to an alcohol or drug misuse/dependence problem. Alcohol misuse/dependence and fatigue/chronic sleep loss were perceived as the greatest crash risk for drivers and for vulnerable road users. Risk perceptions in general public and the medical professionals were similar for most conditions but where they differed, the medical professionals perceived lower risk. Most respondents indicated that they would cease driving immediately if advised by their doctor for temporary and long-term conditions. No effects of age, gender, experience with medical conditions or professional status were noted on perceived intentions to cease driving. Perceptions about who is responsible for ensuring people are fit to drive fell into two categories. Drivers were perceived as chiefly responsible where alcohol, non-prescription drugs, fatigue and age were factors and doctors were identified as responsible in cases of diabetes, epilepsy, stroke, heart conditions and physical disabilities.Conclusions: These results suggest that more needs to be done to raise awareness of the risks posed by medical and other factors that reduce driver capability and also about drivers' responsibility to ensure that they are fit to drive and thus improve road safety. [ABSTRACT FROM AUTHOR]

Commensal bacteria serve as an important line of defense against colonisation by opportunisitic pathogens, but the underlying molecular mechanisms remain poorly explored. Here, we show that strains of a commensal bacterium, Haemophilus haemolyticus, make hemophilin, a heme‐binding protein that inhibits growth of the opportunistic pathogen, non‐typeable Haemophilus influenzae (NTHi) in culture. We purified the NTHi‐inhibitory protein from H. haemolyticus and identified the hemophilin gene using proteomics and a gene knockout. An x‐ray crystal structure of recombinant hemophilin shows that the protein does not belong to any of the known heme‐binding protein folds, suggesting that it evolved independently. Biochemical characterisation shows that heme can be captured in the ferrous or ferric state, and with a variety of small heme‐ligands bound, suggesting that hemophilin could function under a range of physiological conditions. Hemophilin knockout bacteria show a limited capacity to utilise free heme for growth. Our data suggest that hemophilin is a hemophore and that inhibition of NTHi occurs by heme starvation, raising the possibility that competition from hemophilin‐producing H. haemolyticus could antagonise NTHi colonisation in the respiratory tract. [ABSTRACT FROM AUTHOR]

Introduction: DOF proteins are a family of plant-specific transcription factors with a conserved zinc finger (ZF) DNA-binding domain. Although several studies have demonstrated their specific DNA binding, quantitative affinity data is not available for the binding of DOF domains to their binding sites. Methods: ZF domains of DOF2.1, DOF3.4, and DOF5.8 from Arabidopsis thaliana were expressed and purified. Their DNA binding affinities were assessed using gel retardation assays and microscale thermophoresis with two different oligonucleotide probes containing one and two copies of recognition sequence AAAG. Results: DOF zinc finger domains (DOF-ZFs) were shown to form independently folded structures. Assessments using microscale thermophoresis demonstrated that DOF-ZFs interact more tightly (~100 fold) with double-motif probe than the single-motif probe. The overall Kd values for the DOF3.4-ZF and DOF5.8-ZF to the double-motif probe were ~2.3±1 and 2.5±1 µM, respectively. Conclusion: Studied DOF-ZF domains formed stable complexes with the double-motif probe. Although DOF3.4-ZF and DOF5.8-ZF do not dimerize with an appreciable affinity in the absence of DNA (judging from size-exclusion and multiangle laser light scattering data), it is possible that these ZFs form protein-protein contacts when bound to this oligonucleotide, consistent with previous reports that DOF proteins can homo- and hetero-dimerize. [ABSTRACT FROM AUTHOR]

RNA biology has changed completely in the past decade with the discovery of non-coding RNAs. Unfortunately, obtaining mechanistic information about these RNAs alone or in cellular complexes with proteins has been a major problem. X-ray crystallography of RNA and RNA-protein complexes has suffered from the major problems encountered in preparing and purifying them in large quantity. Here, we review the available techniques and methods in vitro and in vivo used to prepare and purify RNA and RNA-protein complex for crystallographic studies. We also discuss the future directions necessary to explore the vast number of RNA species waiting for their atomic-resolution structure to be determined. [ABSTRACT FROM AUTHOR]

Exploiting solar energy using photo-thermal (PT) and/or hybridised photovoltaic/thermal (PVT) systems can represent a viable alternative to the growing demand for renewable energy. For large-scale implementation, such systems require thermal fluids able to enhance the combined conversion efficiency achievable by controlling the 'thermal' and 'electrical' components of the solar spectrum. Nanofluids are typically employed for these purposes and they should exhibit high heat-transfer capabilities and optical properties tuned towards the peak performance spectral window of the photovoltaic (PV) component. In this work, novel nanofluids, composed of highly luminescent organic molecules and Ag nanoparticles dispersed within a base fluid, were tested for PT and PVT applications. These nanofluids were designed to mimic the behaviour of luminescent down-shifting molecules while offering enhanced thermo-physical characteristics over the host base fluid. The nanofluids' conversion efficiency was evaluated under a standard AM1.5G weighted solar spectrum. The results revealed that the Ag nanoparticles' inclusion in the composite fluid has the potential to improve the total solar energy conversion. The nanoparticles' presence minimizes the losses in the electrical power component of the PVT systems as the thermal conversion increases. The enhanced performances recorded suggest that these nanofluids could represent suitable candidates for solar energy conversion applications. [ABSTRACT FROM AUTHOR]

Almost all eukaryotic proteins receive diverse post-translational modifications (PTMs) that modulate protein activity. Many histone PTMs are well characterized, heavily influence gene regulation, and are often predictors of distinct transcriptional programs. Although our understanding of the histone PTM network has matured, much is yet to be understood about the roles of transcription factor (TF) PTMs, which might well represent a similarly complex and dynamic network of functional regulation. Members of the bromodomain and extra-terminal domain (BET) family of proteins recognize acetyllysine residues and relay the signals encoded by these modifications. Here, we have investigated the acetylation dependence of several functionally relevant BET-TF interactions in vitro using surface plasmon resonance, nuclear magnetic resonance, and X-ray crystallography. We show that motifs known to be acetylated in TFs E2F1 and MyoD1 can interact with all bromodomains of BRD2, BRD3, and BRD4. The interactions are dependent on diacetylation of the motifs and show a preference for the first BET bromodomain. Structural mapping of the interactions confirms a conserved mode of binding for the two TFs to the acetyllysine binding pocket of the BET bromodomains, mimicking that of other already established functionally important histone- and TF-BET interactions. We also examined a motif from the TF RelA that is known to be acetylated but were unable to observe any interaction, regardless of the acetylation state of the sequence. Our findings overall advance our understanding of BET-TF interactions and suggest a physical link between the important diacetylated motifs found in E2F1 and MyoD1 and the BET-family proteins.

Chemical modifications of histone tails influence genome accessibility and the transcriptional state of eukaryotic cells. Lysine acetylation is one of the most common modifications and acetyllysine-binding bromodomains (BDs) provide a means for acetyllysine marks to be translated into meaningful cellular responses. Here, we have investigated the mechanism underlying the reported association between the Bromodomain and Extra Terminal (BET) family of BD proteins and the essential histone variant H2A.Z. We use NMR spectroscopy to demonstrate a physical interaction between the N-terminal tail of H2A.Z and the BDs of BRD2, BRD3, and BRD4, and show that the interaction is dependent on lysine acetylation in H2A.Z. The BDs preferentially engage a diacetylated H2A.Z-K4acK7ac motif that is reminiscent of sequences found in other biologically important BET BD target proteins, including histones and transcription factors. A H2A.Z-K7acK11ac motif can also bind BET BDs-with a preference for the second BD of each protein. Chemical shift perturbation mapping of the interactions, together with an X-ray crystal structure of BRD2-BD1 bound to H2A.Z-K4acK7ac, shows that H2A.Z binds the canonical AcK binding pocket of the BDs. This mechanism mirrors the conserved binding mode that is unique to the BET BDs, in which two acetylation marks are read simultaneously by a single BD. Our findings provide structural corroboration of biochemical and cell biological data that link H2A.Z and BET-family proteins, suggesting that the function of H2A.Z is enacted through interactions with these chromatin readers., (© 2020 The Protein Society.)