3D-printed engineered bacteria-laden gelatin/sodium alginate composite hydrogels for biological detection of ionizing radiation

Nuclear safety is a global growing concern,where ionizing radiation(IR)is a major injury factor resulting in serious damage to organisms.The detection of IR is usually conducted with physical dosimeters;however,biological IR detection methods are deficient.Here,a living composite hydrogel consisting of engineered bacteria and gelatin/sodium alginate was 3D-printed for the biological detection of IR.Three strains of PrecA::egfp gene circuit-containing engineered Escherichia coli were constructed with IR-dependent fluorescence,and the DH5αstrain was finally selected due to its highest radiation response and fluorescence.Engineered bacteria were loaded in a series of gelatin/sodium alginate matrix hydrogels with different rheology,3D printability and bacterial applicability.A high-gelatin-content hydrogel containing 10%gelatin/1.25%sodium alginatewas optimal.The optimal living composite hydrogelwas 3D-printedwith the special bioink,which reported significant green fluorescence underγ-ray radiation.The living composite hydrogel provides a biological strategy for the detection of environmental ionizing radiation.

Mindfulness Associates Life Satisfaction:The Mediating Role of Internal Control and the Presence of Meaning in Life

This study explored the internal mechanism of the effect of mindfulness on life satisfaction from the perspective of logotherapy theory and achievement attribution theory.We recruited 1021 college students using a combination of random sampling and cluster sampling.They completed the relevant questionnaire.The results showed that,from the perspective of logotherapy theory,wefind that the presence of meaning in life is an important intermediary between mindfulness and life satisfaction.From the perspective of achievement attribution theory,we found that internal control was an important intermediary between mindfulness and life satisfaction.In addition,we also found the chain mediating path that mindfulness positively predicted life satisfaction by influencing internal control and then influencing the presence of meaning in life.This study proves for thefirst time that the theory of logotherapy and achievement attribution explain the internal mechanism of the relation of mindfulness on life satisfaction.This study provides an important reference for how to effectively improve life satisfaction from the perspective of mindfulness.

Host-Guest Strategy Enabling Nonhalogenated Solvent Processing for High-Performance All-Polymer Hosted Solar Cells

The power conversion efficiencies(PCEs)of all-polymer solar cells(all-PSCs),usually processed from low-boiling-point and toxic sol-vents,have reached high values of 18%.However,poor miscibility and uncontrollable crystallinity in polymer blends lead to a nota-ble drop in the PCEs when using green solvents,limiting the practical development of all-PSCs.Herein,a third component(guest)BTO was employed to optimize the miscibility and enhance the crystallinity of PM6/PY2Se-F host film processed from green solvent toluene(TL),which can effectively suppress the excessive aggregation of PY2Se-F and facilitate a nano-scale interpenetrating net-work morphology for exciton dissociation and charge transport.As a result,TL-processed all-polymer hosted solar cells(all-PHSCs)exhibited an impressive PCE of 17.01%.Moreover,the strong molecular interaction between the host and guest molecules also en-hances the thermal stability of the devices.Our host-guest strategy provides a unique approach to developing high-efficiency and stable all-PHSCs processed from green solvents,paving the way for the industrial development of all-PHSCs.

Multi-Label Feature Selection Based on Improved Ant Colony Optimization Algorithm with Dynamic Redundancy and Label Dependence

The world produces vast quantities of high-dimensional multi-semantic data.However,extracting valuable information from such a large amount of high-dimensional and multi-label data is undoubtedly arduous and challenging.Feature selection aims to mitigate the adverse impacts of high dimensionality in multi-label data by eliminating redundant and irrelevant features.The ant colony optimization algorithm has demonstrated encouraging outcomes in multi-label feature selection,because of its simplicity,efficiency,and similarity to reinforcement learning.Nevertheless,existing methods do not consider crucial correlation information,such as dynamic redundancy and label correlation.To tackle these concerns,the paper proposes a multi-label feature selection technique based on ant colony optimization algorithm(MFACO),focusing on dynamic redundancy and label correlation.Initially,the dynamic redundancy is assessed between the selected feature subset and potential features.Meanwhile,the ant colony optimization algorithm extracts label correlation from the label set,which is then combined into the heuristic factor as label weights.Experimental results demonstrate that our proposed strategies can effectively enhance the optimal search ability of ant colony,outperforming the other algorithms involved in the paper.

Organic-semiconductor-assisted dielectric screening effect for stable and efficient perovskite solar cells

Perovskite solar cells(pero-SCs)performance is essentially limited by severe non-radiative losses and ion migration.Although numerous strategies have been proposed,challenges remain in the basic understanding of their origins.Here,we report a dielectric-screening-enhancement effect for perovskite defects by using organic semiconductors with finely tuned molecular structures from the atoms level.Our method produced various perovskite films with high dielectric constant values,reduced charge capture regions,suppressed ion migration,and it provides an efficient charge transport pathway for suppressing non-radiative recombination beyond the passivation effect.The resulting pero-SCs showed a promising power conversion efficiency(PCE)of 23.35%with a high open-circuit voltage(1.22 V);and the 1-cm^(2) pero-SCs maintained an excellent PCE(21.93%),showing feasibility for scalable fabrication.The robust operational and thermal stabilities revealed that this method paved a new way to understand the degradation mechanism of pero-SCs,promoting the efficiency,stability and scaled fabrication of the pero-SCs.

Host-Guest Active Layer Enabling Annealing-Free,Nonhalogenated Green Solvent Processing for High-Performance Organic Solar Cells

Recent advances in non-fullerene acceptors(NFAs)like Y6 have pushed the power conversion efficiencies(PCEs)of organic solar cells(OSCs)above 19%.However,the harsh fabrication conditions,such as the use of the highly volatile chloroform(CF)solvent and the thermal annealing process,are not suitable for large-area printing technologies and environmental standards.Here,a series of guest molecules,BT2O,BTO,and BT4O,are designed and synthesized with different numbers of oligo ethylene glycol(OEG)repeating units in side chains.All these guest molecules could tune the crystallization kinetics of the annealing-free host-guest active layers by inducing the self-assembly of Y6 in non-halogenated paraxylene(PX)solution.The increasing number of OEG repeating units in guest molecules could enhance the molecular assembly ability but molecular stacking steric hindrance simultaneously.Therefore,BTO with three OEG repeating units blended with PM6:PM7:Y6 delivers the highest PCE of 17.78%.Our results demonstrate controlling the crystallization kinetics via delicate side-chain engineering of guest molecules is an effective way to achieve efficient OSCs in non-halogenated solution.