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Cyanobacteria must prevent imbalances between absorbed light energy (source) and the metabolic capacity (sink) to utilize it to protect their photosynthetic apparatus against damage. A number of photoprotective mechanisms assist in dissipating excess absorbed energy, including respiratory terminal oxidases and flavodiiron proteins, but inherently reduce photosynthetic efficiency. Recently, it has been hypothesized that some engineered metabolic pathways may improve photosynthetic performance by correcting source/sink imbalances. In the context of this subject, we explored the interconnectivity between endogenous electron valves, and the activation of one or more heterologous metabolic sinks. We coexpressed two heterologous metabolic pathways that have been previously shown to positively impact photosynthetic activity in cyanobacteria, a sucrose production pathway (consuming ATP and reductant) and a reductant-only consuming cytochrome P450. Sucrose export was associated with improved quantum yield of phtotosystem II (PSII) and enhanced electron transport chain flux, especially at lower illumination levels, while cytochrome P450 activity led to photosynthetic enhancements primarily observed under high light. Moreover, coexpression of these two heterologous sinks showed additive impacts on photosynthesis, indicating that neither sink alone was capable of utilizing the full "overcapacity" of the electron transport chain. We find that heterologous sinks may partially compensate for the loss of photosystem I (PSI) oxidizing mechanisms even under rapid illumination changes, although this compensation is incomplete. Our results provide support for the theory that heterologous metabolism can act as a photosynthetic sink and exhibit some overlapping functionality with photoprotective mechanisms, while potentially conserving energy within useful metabolic products that might otherwise be "lost." [ABSTRACT FROM AUTHOR]

LHC provides a chance to study the physical processes of γγ collision and γ p collision mode by adding a forward detector. In this paper, we investigate J/ψ-pair photoproduction in NRQCD framework at the LHC with γγ collision mode. We calculate the contributions from 3 S 1 1 , 3 S 1 (8) , 1 S 0 (8) , 3 P J (8) Fock states, and find that contribution from the colour octet 1 S 0 8 3 P J (8) and 3 P J (8) 3 P J (8) channels dominates this process with forward detector acceptance 0.0015 < ξ < 0.5. We present the differential cross section distributions of transverse momentum p t J / ψ and rapidity yJ/ψ with forward detector acceptances 0.0015 < ξ < 0.5, analyse the signal for J/ψ decaying to a opposite-sign (OS) muon pair. The results show that this process has the potential to be detected at the 13 TeV LHC with forward detector acceptance 0.0015 < ξ < 0.5. [ABSTRACT FROM AUTHOR]

We study the inclusive J/ψ production at large transverse momenta at lepton-hadron colliders in the limit when the exchange photon is quasi real, also referred to as photoproduction. Our computation includes the leading-PT leading-v next-to-leading αs corrections. In particular, we consider the contribution from J/ψ plus another charm quark, by employing for the first time in quarkonium photoproduction the variable-flavour-number scheme. We also include a QED-induced contribution via an off-shell photon which remained ignored in the literature and which we show to be the leading contribution at high PT within the reach of the EIC. In turn, we use our computation of J/ψ+charm to demonstrate its observability at the future EIC and the EIC sensitivity to probe the non-perturbative charm content of the proton at high x.