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Coherence turned on by incoherent light
摘要： One of the most pertinent problems in the debate on non-trivial quantum effects in biology concerns natural photosynthesis. Since sunlight is composed of thermal photons, it was argued to be unable to induce quantum coherence in matter, and that quantum mechanics is therefore irrelevant for the dynamical processes following photoabsorption. Our present analysis of a toy 'molecular aggregate'—composed of two dipole–dipole interacting two-level atoms treated as an open quantum system—however shows that incoherent excitations indeed can trigger persistent, coherent dynamics in both the site and the exciton bases: we demonstrate that collective decay processes induced by the dipole–dipole interactions create coherent intermolecular transport—regardless of the coherence properties of the incoming radiation. Our analysis shows that the steady state coherence is mediated by the population imbalance between the molecules and, therefore, increases with the energy difference between the two-level atoms. Our results establish the importance of collective decay processes in the study of ultrafast photophysics, and especially their potential role to generate stationary coherence in incoherently driven quantum transport.
关键词： molecular aggregate,energy transfer,coherence,dipole–dipole interaction,thermal photons
更新于2025-09-19 17:15:36
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Study on Irradiation Effect of Mid-Infrared Free Electron Laser on Hen Egg-White Lysozyme by Using Terahertz-Time Domain Spectroscopy and Synchrotron-Radiation Vacuum-Ultraviolet Circular-Dichroism Spectroscopy
摘要： Mid-infrared free-electron laser (MIR-FEL) is potentially applicable for tissue ablation and dissociation of pathological peptide aggregates in medicine. However, it is still poorly understood how the MIR-FEL irradiation influences on functional proteins such as enzymes. In the current study, the effect of MIR-FEL on both aggregate and non-aggregate (= native) states of hen egg-white lysozyme (HEWL) as a representative enzyme has been investigated. Absorption intensity at terahertz region (0.3–1.2 THz, 10–40 cm?1) of the aggregate of HEWL was lower than that of the native HEWL, but the former was increased nearly to the same level with the latter after the MIR-FEL irradiation tuned to 6 μm that corresponds to carbonyl stretching vibrational mode of amide bonds (amide I). This indicates that the aggregate of HEWL was converted to the native state by the irradiation. On the other hand, synchrotron-radiation vacuum-ultraviolet circular-dichroism spectroscopy showed that protein conformation of the native HEWL, which was rich in α-helix, was little changed after the MIR-FEL irradiation under the same condition with the case of the aggregate of HEWL. Furthermore, the enzymatic hydrolysis activity of the native HEWL against bacterial glycan was not remarkably decreased by the irradiation. Therefore, it can be estimated that the native structure of HEWL is little damaged although the aggregate state can be easily dissociated by the resonant excitation at amide bonds.
关键词： Vacuum-ultraviolet circular-dichroism spectroscopy,Mid-infrared free-electron laser,Protein aggregate,Terahertz-time domain spectroscopy
更新于2025-09-19 17:13:59
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Resonant waveguide grating based assays for colloidal aggregate detection and promiscuity characterization in natural products
摘要： Small molecules, including natural compounds, in aqueous buffer that self-associate into colloidal aggregates is the main cause of false results in the early stage of drug discovery. Here we reported resonant waveguide grating (RWG) based assays to identify natural compound aggregation and characterize its influence on membrane receptors in living cells. We first applied a cell-free aggregation assay to determine compound critical aggregation concentration (CAC) values. Then we characterized the aggregators' influence on membrane receptors using three types of dynamic mass redistribution (DMR) assays. Results showed that colloidal aggregates may cause false activity in DMR desensitization assays; some of the false activities can be implied by the large response in DMR agonism assays and can further be identified by DMR antagonism assays. Furthermore, the aggregation mechanism was confirmed by addition of 0.025% tween-80, with cell signals attenuated and potency decreased. Finally, these observations were used for aggregate examination and promiscuity investigation of a traditional herbal medicine, Rhodiola rosea, which ultimately led to the revealing of the true target and reduced the risk of a bioactivity tracking process at the very first stage. This study highlights that the RWG based assays can be used as practical tools to distinguish between real and false hits to provide reliable results in the early stage of drug discovery.
关键词： natural products,drug discovery,colloidal aggregate detection,resonant waveguide grating,false results
更新于2025-09-16 10:30:52
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Aggregate Formation of BODIPY-Tethered Oligonucleotides That Led to Efficient Intracellular Penetration and Gene Regulation
摘要： Exogenous nucleic acids showed low e?ciency regarding cellular uptake and low stability in biological conditions; therefore, a number of techniques have been developed to improve their basic properties. One of the best solutions is the application of nanosized particles consisting of oligonucleotides that penetrate the cell membrane without any additives and exhibit high stability in cells. In this report, we employed a simple approach to address the basic properties of nanoparticles of oligonucleotides in biological systems. We prepared BODIPY-labeled oligonucleotides that carried an exclusive modi?cation at the strand end. BODIPY shows high hydrophobicity and ?uorescent emission; therefore, the oligonucleotides formed nanosized aggregates in aqueous solution and their behaviors in cells or tissues were easily revealed that aggregate formation was tracked. Detailed experiments indispensable for the oligonucleotides via scavenger-receptor-mediated endocytosis. In addition, the aggregates provided an e?cient gene regulation in living cells and tumor tissues transplanted into mice.
关键词： gene regulation,aggregate formation,BODIPY,cellular uptake,amphiphilic oligonucleotides
更新于2025-09-16 10:30:52
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pH-Controlled Intracellular in Situ Reversible Assembly of Photothermal Agent for Smart Chemo-Photothermal Synergetic Therapy and ATP Imaging
摘要： To advance anti-tumor efficiency and lessen adverse effect caused by nanodrug residues in body, a smart nanoagent system is developed and successfully used in intracellular ATP-imaging and in vivo chemo-photothermal synergetic therapy. The nanoagent system is facilely prepared using DNA complex to modify gold nanoparticles (AuNPs). The DNA complex is formed by three oligonucleotides (ATP aptamer, rC-DNA and rG-DNA). CG-rich structure in ternary DNA complex could be exploited for payload of chemotherapeutic medicine doxorubicin (DOX), thus making efficient DOX transport into tumor site possible. In tumor cells, especially in acidic organelles (e.g. endosome and lysosome), DOX could be rapidly released via the dual stimuli of over-expressed ATP and pH. What’s more, the specific recognition of fluorescent-labelled aptamer strand to ATP can achieve the intracellular ATP imaging. pH-controlled reversible folding and unfolding of intermolecular i-motif formed by C-rich strands can lead to intracellular in situ assembly of AuNP aggregates with high photothermal conversion efficiency, and promote relatively facile renal clearance of AuNPs through the disassociation of the aggregates in extracellular environments. Experiments in vivo and vitro present feasibility for synergetic chemo-photothermal therapy. Such an in situ reversible assembly strategy of chemo-photothermal agent also presents a new paradigm for smart and highly efficient disease treatment with reduced side effects.
关键词： chemo-photothermal therapy,doxorubicin,ATP-imaging,AuNP aggregate,intracellular in situ reversible assembly
更新于2025-09-16 10:30:52
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Studying the mix design and investigating the photocatalytic performance of pervious concrete containing TiO2-Soaked recycled aggregates
摘要： Demolished concrete, as one main form of construction and demolition wastes, has been widely studied of being utilized as recycled aggregates (RAs) in new concrete production. However, existing studies of applying RAs have been limited to the mechanical and durability issues of cementitious composites containing RAs. There has not been sufficient research of adopting RAs in cementitious products to also address the environmental sustainability. On the other hand, existing research utilizing cementitious products (e.g., concrete pavement) for air purification purpose have not adequately considered RA usage. Aiming to address the two sustainable objectives (i.e., waste diversion and air purification) simultaneously in concrete mix, this research adopted a two-step approach. Firstly, we studied and identified the optimal mix design of pervious concrete containing TiO2-soaked recycled coarse aggregates (RCAs) in order to achieve the higher compressive strength; secondly, we investigated the photocatalytic performance of pervious concrete containing RCAs coated with TiO2 photocatalysts. The photocatalytic performance of pervious concrete was also tested by applying a 10-min heavy rainwater wash. Experimental test results revealed that the internal voids of adhered mortar enabled RCAs to absorb more TiO2 particles. The NO degradation rate of TiO2-soaked RCAs increased from 71.4% to 80.6% when RCAs’ size decreased from 15-20 mm to 5e10 mm. The orthogonal experimental investigation indicated that water-to-binder ratio had the most significant effect on concrete compressive strength, followed by ratio of RCAs to binder, and replacement ratio of RCAs to natural aggregates. The optimized mix design for pervious concrete containing RCAs was identified to achieve highest strength (i.e., water-to-binder ratio at 0.35, coarse aggregate-to-binder ratio of 3 by mass, fly ash replacement rate to Portland cement at 5%, and 50% replacement ratio of RCAs to NCAs). The concentration of TiO2 solution at 0.3% was identified as the optimal ratio to achieve the highest NO degradation rate at 70% before rainwater wash. The NO degradation rates of pervious concrete still reached nearly 50% after 10-min heavy rainwater wash, indicating that pervious concrete using RCAs coated with TiO2 could largely maintain its photocatalytic capacity. This study addresses two main social and environmental issues in developing countries (e.g., China), namely overwhelming amount of construction & demolition wastes being generated, and air pollution. It leads to the cleaner production in concrete pavement construction by achieving the optimization between waste reuse, air purification, and engineering properties of porous concrete.
关键词： Pervious concrete,Photocatalytic effects,Mechanical properties,Recycled aggregate concrete,Titanium dioxide,Recycled aggregate
更新于2025-09-11 14:15:04
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Sulfur Dioxide Degradation by Composite Photocatalysts Prepared by Recycled Fine Aggregates and Nanoscale Titanium Dioxide
摘要： To alleviate the heavy burden on landfilling, construction and demolition wastes (C&DWs) are recycled and reused as aggregates in cementitious materials. However, the inherent characteristics of recycled fine aggregates (RFA), such as the high crushing index and high-water absorption, magnify the reusing difficulty. Nevertheless, attributing to the high porosity and high level of calcium hydroxides existing in the old mortar, RFA is featured with a high specific surface area and a high alkalinity. These features are useful to augment the total photo-degradation of SO2 by nano-TiO2 (NT) intermixed mortar, leading RFA to be an excellent potential carrier to load nano-TiO2 and prepare the composite photocatalyst. Hence, this study proposed to load NT onto the surface of RFAs and river sands (RSs) (the control) by the soaking method, preparing composite photocatalysts denoted as NT@RFA and NT@RS, respectively. The prepared composite photocatalysts were then utilized as sands in photocatalytic mortar to evaluate for SO2 degradation. Experiments identified a 50% higher amount of NT was loaded onto the surface of FRA relative to the control. This higher loading amount plus higher alkalinity ultimately translated into a higher photocatalytic activity. In addition, the mortar containing NT@RFA exhibited 46.3% higher physiochemical absorption and 23.9% higher photocatalytic activity than that containing NT@RS. In addition, the durability, embodied by the reuse and anti-abrasive properties, of NT@RFA exceeded that of NT@RS. The overall findings reveal that the NT@RFA not only garners beneficial effect from the high porosity but also generates positive effect from the high alkalinity. Though a number of studies deal with building materials with NT, this study is the first to load NT onto RFA and prepare composite photocatalysts which were then used as fine aggregates in building materials. Consequently, this study proves the potential high-added-value reusability of RFA in green construction materials and provides a low-cost, high-efficiency approach to degrade atmospheric SO2.
关键词： construction waste,composite photocatalyst,nano-TiO2,SO2 degradation,recycled fine aggregate,photocatalytic mortar
更新于2025-09-11 14:15:04
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Estimation of aggregate gradation from partial gradation information obtained by multiple imaging equipment
摘要： The aggregate gradation is an important consideration in bound or unbound mixes, as it influences the engineering properties of the mixes (both during and after construction). In recent times, effort is being made to employ imaging methods to predict the gradation of aggregates in the mix. This approach involves acquisition of two- (or three-) dimensional image of the aggregates distributed within the mix and subsequent image analysis. The size of the aggregates for a given mix typically varies by several orders of magnitude, and thus, it may not be possible to capture the entire size-range of the aggregates using a single imaging equipment. Different imaging equipment may be effective for different size ranges, and hence would individually provide partial information on the size distribution. In the present study, a simple formulation is developed (for two-dimensional images) that can be utilised to collate the partial information (obtained by various imaging equipment) to generate the overall aggregate size distribution of a given mix. To illustrate the formulation developed, two-dimensional images of asphalt mix acquired by scanner, camera and scanning electron microscope are utilised so as to predict the overall aggregate gradation originally used in the asphalt mix.
关键词： imaging equipment,image analysis,aggregate gradation,Asphalt mix
更新于2025-09-10 09:29:36
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[IEEE 2018 Global Internet of Things Summit (GIoTS) - Bilbao, Spain (2018.6.4-2018.6.7)] 2018 Global Internet of Things Summit (GIoTS) - Aggregate-Signcryption for Securing Smart Camera IoT Applications
摘要： Smart cameras are considered as key sensors in Internet of Things (IoT) applications ranging from home to city scales. Since these cameras often capture highly sensitive information, security is a major concern. An elliptic curve (EC) based signcryption achieves resource-ef?ciency by performing data encryption and signing in a single step. In this work, we present aggregate-signcryption which extends the EC-based signcryption approach to a cluster-based multi-camera setup. The signcrypted data from the smart cameras within a cluster is aggregated on a speci?c node called cluster head. Aggregate-signcryption reduces the communication overhead and requires fewer steps for the unsigncryption as compared to individual signcryption.
关键词： Data Security,Internet of Things,Aggregate-signcryption,Smart cameras
更新于2025-09-10 09:29:36
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Ultrapure Films of Polythiophene Derivatives are Born on a Substrate by Liquid Flow
摘要： Almost all ?lms of conjugated polymers are composed of mixtures of two di?erent structures called H- or J-aggregates, which are side-by-side and head-to-tail structures, respectively, between polymer chains. The mixture of H- and J-aggregates is responsible for the mixed optical and/or electrical properties of a conjugated polymer ?lm. If a highly puri?ed conjugated polymer ?lm composed of only a single species of aggregate was obtained, its properties would enable the realization of new soft electronics, such as ?exible solar cells, wearable sensors, and arti?cial skin. However, there have been no reports on a method to prepare such a highly puri?ed polymer ?lm so far. Here, we show a facile method to obtain an ultrapure 99.8% H-aggregate polymer ?lm by dropping a solution of poly(3-hexylthiophene) (P3HT) on a substrate at room temperature, inspired by the co?ee-ring e?ect.According to contact angle measurements, photoluminescence and Raman spectroscopy, and X-ray di?raction, a critical step for achieving the ultrapure H-aggregate ?lm was a two-step drying process of the polymer solution droplet on a speci?c substrate. The pinning of the droplet caused this drying process and yielded a ?ow-induced extension of the P3HT chains on the substrate, followed by the formation of ultrapure H-aggregates. We also found a 6-fold enhancement in carrier density using the ultrapure (99.8%) H-aggregate P3HT ?lm. Furthermore, ?ve conjugated polymers of polythiophene derivatives, used as state-of-the-art polymer solar cells, revealed the same trends to ultrapure H-aggregates, whose structure enhances performance of solar cell. The proposed method could provide a new approach to make solution-processable ?lms for next-generation soft and ?exible electronics.
关键词： π-conjugated polymer,contact angle,aggregate,soft electronics,co?ee ring
更新于2025-09-10 09:29:36