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Photodynamic therapy (PDT) is recognized as a powerful method to inactivate cells. However, the photosensitizer (PS), a key component of PDT, has suffered from undesired photobleaching. Photobleaching reduces reactive oxygen species (ROS) yields, leading to the compromise of and even the loss of the photodynamic effect of the PS. Therefore, much effort has been devoted to minimizing photobleaching in order to ensure that there is no loss of photodynamic efficacy. Here, we report that a type of PS aggregate showed neither photobleaching nor photodynamic action. Upon direct contact with bacteria, the PS aggregate was found to fall apart into PS monomers and thus possessed photodynamic inactivation against bacteria. Interestingly, the disassembly of the bound PS aggregate in the presence of bacteria was intensified by illumination, generating more PS monomers and leading to an enhanced antibacterial photodynamic effect. This demonstrated that on a bacterial surface, the PS aggregate photo-inactivated bacteria via PS monomer during irradiation, where the photodynamic efficiency was retained without photobleaching. Further mechanistic studies showed that PS monomers disrupted bacterial membranes and affected the expression of genes related to cell wall synthesis, bacterial membrane integrity, and oxidative stress. The results obtained here are applicable to other types of PSs in PDT.

Natural products and metals play a crucial role in cancer research and the development of anti-tumor drugs. We designed and synthesized three new carboline-based cyclometalated iridium complexes [Ir(C-N)2(PPβC)](PF6), where PPβC = N-(1,10-phenanthrolin-5-yl)-1-phenyl-9H-pyrido[3,4-b]indole-3-carboxamide, C-N = 2-phenylpyridine (ppy, Ir1), 2-(2,4-difluorophenyl) pyridine (dfppy, Ir2), 7,8-benzoquinoline (bzq, Ir3), by combining iridium with β-carboline derivative. These iridium complexes exhibited high potential antitumor effects after being promptly taken up by A549 cells. Accumulating in mitochondria rapidly and preferentially, Ir1-3 caused a series of changes in mitochondrial events, including the loss of mitochondrial membrane potential, the depletion of cellular ATP, and the elevation of reactive oxygen species, leading to significant death of A549 cells. Moreover, the activation of intracellular caspase pathway and apoptosis was further validated to contribute to iridium complexes-induced cytotoxicity. These novel iridium complexes exerted a prominent inhibitory effect on tumor growth in a 3D multicellular tumor spheroid model.

A novel cycle model of the capacitive salinity/heat engine mainly consisting of nano-porous super-capacitors is established for harvesting mixed free energy caused by salinity difference between the river water and the seawater, and the thermal energy due to the temperature difference. The heat engine is charged and discharged in the cycle of a low temperature brine and a high temperature fresh water, respectively. The analytical expressions of the cyclic work output and efficiency are given. General performance characteristics of the capacitive salinity/heat engine are analyzed. The temperature of the heat reservoir and salt concentration of seawater are optimized to improve the efficiency of the capacitive salinity/heat engine. The optimal selection ranges of several main parameters are provided. When the Stern distance is equal to 1 nm and the charging voltage is equal to 3.5V, the energy conversion efficiency of the capacitive salinity/heat engine is about 40%, while the pure thermal efficiency in the cycle is about 16.9%. The energy conversion efficiency of the capacitive salinity/heat engine is significantly larger than that of the capacitive heat engine. The results obtained can facilitate the application of this technology to real life, which can reduce the consumption of fossil fuels.

It is pointed out that the equivalence of the Nernst theorem and the heat capacity statement of the third law of thermodynamics can be mathematically proved through a simple method.

Although evidence suggests the ubiquity of meso- and microplastics (MMPs) in mangrove forests, our knowledge of their bioavailability and risk on mangrove leaves is scarce. Here, we investigated MMP contamination concerning submerged mangrove leaves and herbivorous snails that mainly feed on them from the four mangrove forests located in Beibu Gulf, Guangxi Province, China. Results showed that the MMP abundance on the mangrove leaves ranged from 0.01 ± 0.00 to 0.42 ± 0.15 items cm

One general consequence of the Nernst theorem is derived, i.e., the various heat capacities of a thermodynamic system under different constraints approach zero as the temperature approaches absolute zero. The temperature dependence of the heat capacity of any thermodynamic system at ultra-low temperatures is revealed through this consequence. Moreover, the general form and the simplest expression of the heat capacities of thermodynamic systems at ultra-low temperatures are deduced. Some significant discussion and results are given. One new research method is provided by using this consequence. Finally, the equivalence between the Nernst theorem and its consequence is rigorously proved, so that this consequence may be referred to another description of the third law of thermodynamics.

Energy harvesting from sun and outer space using thermoradiative devices (TRDs), despite being promising renewable energy sources, is limited only to daytime and nighttime period, respectively. Such a system with 24-hour continuous electric power generation remains an open question thus far. Here, a TRD-based power generator that harvests solar energy via concentrated solar irradiation during daytime and via thermal infrared emission towards the outer space at nighttime is proposed, thus achieving the much sought-after 24-hour electrical power generation. Correspondingly, a rigorous thermodynamical model is developed to investigate the all-day performance characteristics, parametric optimum design, and the role of various energy loss mechanisms. The calculated results predict that the daytime TRD-based system yields a peak efficiency of 12.6% under 10 suns, thus significantly outperforming the state-of-art record-setting solar thermoelectric generator. This work reveals the potential of TRD towards 24-hour electricity generation and future renewable energy technology.

The production of redundant waste heat limits the performance of photovoltaic cells, so removing waste heat and converting it back into electricity is a promising way to improve the utilization of solar energy. A new concentrated solar spectrum photovoltaic-thermophotovoltaic hybrid system mainly is proposed. Full-spectrum solar energy is split into different parts according to specific requirements. Expressions for the efficiency and power output of the system are derived. The effects of the voltage output and area ratio of the two subsystems, the bandgap energy of semiconductor in the photovoltaic cell, and the solar concentration factor on the system performance are analyzed comprehensively. By optimizing several key parameters, the problem of the optimal matching between two subsystems is solved. The performance characteristics of the system are revealed, and the maximum efficiency and corresponding power output density of the hybrid system are calculated numerically, reaching 47.74% and 31.13W cm−2, respectively, which are 9.190% and 19.25% higher than those of a single photovoltaic cell. The optimal selection criteria of several key parameters are provided. By comparison with other PV-based systems, the proposed system not only maintains a high energy conversion efficiency but also produces a relatively larger power output density.

A model of the thermophotovoltaic device combining a near-field thermal emitter and a hot-carrier solar cell is established. The fluctuating electromagnetic near-field theory for the radiative thermal transport and Landauer's formula for the carrier extraction are introduced. Expressions for the efficiency and the power output of the device are derived. How the voltage and the extraction energy of the energy selective contacts affect the performance of the device is revealed. The results show that the efficiency of the proposed device can be greatly enhanced by exploiting the radiation between the emitter and the cell and extracting carriers through electron tunneling effects.

A neoteric model of the solar-driven integrated device mainly composed of a thermionic generator (TIG) with a graphene-based anode and a thermophotovoltaic cell is presented, where the major irreversible losses inside and outside the system are considered. The analytical expressions for the power output and efficiency of two subsystems and the integrated device are derived. The temperatures of the emitter and collector are determined through heat balance equations. The effects of the voltage outputs of the generator and cell, area ratio of the absorber to the emitter, bandgap energy of the cell, and solar concentration factor on the systemic performance are evaluated. Several main parameters are optimized and parametric selection criteria are provided. The maximum efficiencies of the integrated device operated at different conditions are calculated. For example, under 1000 solar concentration, the efficiency of the integrated device attains 45.23%, which is obviously higher than that of a single solar-driven TIG (STIG) or other existing hybrid systems with a traditional TIG. It is found that replacing metallic anode by graphene anode and integrating a photovoltaic cell into the STIG largely enhance the conversion efficiency of solar energy.

From the experimental data of the isofield heat capacity of the MnFe-based magnetocaloric materials, magnetic entropy change versus temperature characteristic curves are obtained by using numerical value calculation procedure. Three kinds of MnFe-based magnetocaloric materials, in which there are all a large magnetocaloric effect, are selected as the constituent materials to establish a novel composite magnetocaloric material, for which keeping large magnetic entropy change over a wide temperature range is desired. By means of thermodynamic analysis and optimal control theory, the molar mass ratios of each constituent material to the composite material are optimally determined for differently applied magnetic fields. The optimum results show that when the applied magnetic field μ0H″=2 T, the optimum molar mass ratios x1opt, x2opt, and x3opt of Mn1.24Fe0.76P0.75Ge0.25, Mn1.2Fe0.8P0.75Ge0.25, and Mn1.1Fe0.9P0.78Ge0.22 to the composite are equal to 0.44, 0.11, and 0.45, respectively. Furthermore, the regenerative Ericsson refrigeration cycle employing the composite or constituent materials as the working substance is set up. The effects of the non-perfect regeneration on the net cooling quantity, COP, etc. of the refrigeration cycle are analyzed and evaluated. The cycle performances of the composite material are compared with those of the constituent materials. It shows that the net cooling quantity and COP of the composite are much larger than those of any constituent material. The numerical calculation results obtained can provide some reference for the selection of working substances and the optimal parameter design of room temperature magnetic refrigerators.

Cancer therapeutics are varied and target diverse processes in cancer progression. Photodynamic therapy (PDT), photothermal therapy (PTT), and the inhibition of pro-cancer proteases are non-invasive anticancer therapeutics that attract increasing attentions for their enhanced specificities and milder systemic toxicities compared to traditional therapeutics. These modalities offer advantages to compensate for the shortcomings of their counterparts. For instance, PDT or PTT efficiently eliminates locally confined tumor cells while exhibiting no effect on metastatic tumor cells. In contrast, the inhibition of pro-cancer proteases systemically suppresses the proliferation and metastasis of cancer cells but does not eradicate existing cancer cells. To synergize these therapeutics, we hereby report a versatile nanoparticle that integrates the effects of PDT, PTT, and enzyme-inhibition. This nanoparticle (CIKP-NP) was synthesized by covalently or non-covalently modifying a photothermal nanoparticle with a photosensitizer, a pro-cancer protease inhibitor, and an albumin-binding molecule. After confirming the PDT, PTT, albumin-binding, and enzyme-inhibition properties at the molecular level, we demonstrated that CIKP-NP killed tumor cells through PDT or PTT and suppressed tumor cell invasion through enzyme-inhibition. In addition, through a breast cancer xenograft mouse model, we demonstrated that CIKP-NP suppressed tumor growth by PDT or PTT effect. Notably, the synergism of PDT and PTT significantly enhanced its anticancer efficiency. Furthermore, CIKP-NP significantly suppressed cancer metastasis in a lung metastatic mouse model. Last, biodistribution and the in vivo retention of CIKP-NP confirmed the tumor-targeting property. Beyond demonstrating the anti-tumor and anti-metastatic efficacy of CIKP-NP, our study also suggests a new strategy to synergize multiple anticancer therapeutics.

Escherichia coli ( E. coli ) DH5α has been recognized as a non-pathogenic bacterial strain with tumor colonization ability. However, whether such a bacteria-driven drug-delivery system can improve the targeting of tumor therapy or not remains essentially untouched. Herein, a series of zinc phthalocyanine (ZnPc) photosensitizers with different numbers of charges were prepared and their electrostatic adhesion properties on E. coli were investigated via measuring their fluorescence intensities by flow cytometer. Among these ZnPc photosensitizers investigated, the ZnPc conjugate with four positive charges (named ZnPc-IR710) exhibited the highest loading capacity and the best fluorescence imaging performance of E. coli . With the help of E. coli , E. coli @ZnPc-IR710 presented a significantly enhanced cytotoxicity on human breast cancer MCF-7 cells compared with ZnPc-IR710 (survival rate of tumor cells was 39% vs . 57% at a concentration of 50 nmol L−1). Moreover, in vivo study showed that E. coli @ZnPc-IR710 remarkably inhibited the tumor growth and resulted in a complete tumor growth suppress in subcutaneous mouse 4T1 breast tumor model. These results demonstrated the great promise of bacterial-guided photodynamic therapy (PDT) in the treatment of solid tumors, and provide a unique strategy to enhance the antitumor efficacy of PDT by utilizing bacterial vectors in tumors.

An irreversible model of the thermophotonic cell (TPC) with a heated forward-based light-emitting diode (LED) as an emitter and a photovoltaic cell (PVC) is established. The performances of the TPC are optimized and compared with those of the thermophotovoltaic cell (TPVC) based on finite-time thermodynamics. The results obtained show that there exist the optimally operating ranges of the voltages and band-gap energies of the LED and PVC. The thermal flow emitted from the heated LED dramatically exceeds that from the pure thermal emitter. The maximum efficiency of the TPC is less than that of the TPVC, whereas the maximum power density of the TPC surpasses that of the TPVC under an arbitrary emitter temperature. The TPC has the advantages of the relatively high optimal band-gap energies and relatively low-operating temperatures so that it is easier to be made than the TPVC.

Combined cooling, heating, and power (CCHP) is an economic and eco-friendly technology to mitigate energy issues with remarkable energy efficiency improvement. This study formulates a mixed integer nonlinear programming (MINLP) model for a combined CCHP system coupled with renewable energy, i.e. RCCHP system, which is applied in five different buildings to evaluate the economic and environmental performance under two optimization modes. Net present value (NPV), internal rate of return (IRR) and dynamic payback period (DPP) are introduced as economic indexes, while CO2 emission reduction rate (CER) is considered as the environmental indicator to determine the optimal combination, capacity, and operation strategies for energy technologies. Results indicate that a combination of electricity purchased at valley period during night with power generated by the combined heating and power (CHP) unit coupled with wind turbine in peak period during daytime is cost-optimal which also enables higher energy efficiency. Meanwhile, the feed-in tariff as well as the uncoordinated electrical and thermal loads both show a significant impact on real-time operation strategies. Compared with the reference separate production (SP) system, the combined system shows better performance when applied to shopping mall under both optimization modes, e.g., with NPV up to 67.65 and 46.61 million RMB, IRR up to 20.70% and 25.10%, and the minimum DPP is 5.49 and 4.82 years under NPV and IRR maximization, respectively.

Targeted therapy showed broad application prospects in the treatment of various types of cancer. Through carriers such as aptamers, antibodies, proteins and peptides, targeted therapy can selectively deliver drugs into tumor cells. Compared with traditional treatment methods such as chemo- and radiotherapy, targeted drug delivery systems can reduce the toxic effects of drugs on normal cells and avoid adverse reactions. Herein, an aptamer-cyclometalated iridium(III) complex conjugate (ApIrC) has been designed and developed as a targeted anticancer agent. Owing to the targeting ability of aptamers, ApIrC specifically bound to nucleolin over-expressed on the surface of cancer cells and showed strong fluorescence signal for tumor imaging and diagnosis. ApIrC had more substantial cellular uptake in cancer cells than the iridium complex alone and exhibited favorable low toxicity to normal cells. After uptake by cells through endocytosis, ApIrC can selectively accumulated in mitochondria and induced caspase-3/7-dependent cell death. Remarkably, ApIrC can also specifically target 3D multicellular spheroids (MCSs) and show excellent tumor permeability. So, it can effectively reach the interior of MCSs and cause cell damage. To our knowledge, this is the first report of the aptamer-cyclometalated iridium(III) complex conjugate which studied for cancer targeted therapy. The developed conjugate has great potential to be developed as novel therapeutics for effective and low-toxic cancer treatment.

Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain the optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1 cm−2, the integrated system operates in an optimum state and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.

A nanostructured thermoelectric device is designed by connecting a double-barrier resonant tunneling heterostructure to two electron reservoirs. Based on Landauers equation and Fermi-Dirac statistics, the exact solution of the heat flow is calculated. The maximum power output and efficiency are calculated through the optimizations of several key parameters. The optimum characteristic curve of the performance is obtained. The reasonably working region of the device is determined, the selection criteria of main parameters are provided, and the optimum configuration of the device is drawn. Results show that the heterojunction becomes a perfect energy filter by appropriately regulating the chemical potentials of electron reservoirs and optimally choosing the widths of barrier and quantum well and the nanostructured thermoelectric device with resonance tunneling may obtain simultaneously a large power output and a high efficiency., thermoelectric, nanostructured,heterostructure

By considering the actual equivalent circuit model of three quantum dots with Coulomb coupling, a thermodynamic pump driven by Maxwell’s demon is proposed. The pump may be a quantum chemical pump operated between two material reservoirs or a quantum heat pump operated between two heat reservoirs, and the demon may be a subsystem operated between two heat reservoirs or between two material reservoirs. The Markov stochastic thermodynamics is used to analyze how information is generated in the demon, which drives the mass or heat transfer in the pump. Nonequilibrium free energy theorems demonstrate that the information provided by Maxwell’s demon makes the quantum pump work normally without energy input. It is proved that the proposed system does not violate the second law of thermodynamics. Moreover, the modified entropy-production rate containing information flow and the local rates of nonequilibrium free energy of quantum pumps are calculated. The results obtained may be helpful to the deep understanding of the inter-conversion of both information and work.

A quantum engine fueled by quantum measurement is proposed. Under the finite-time unitary transformation, the conversion of heat to work is realized without the compression and expansion of the resonance frequency. The work output, quantum heat, and efficiency are derived, highlighting the important role of the thermal divergence recently reappearing in open quantum systems. The key problem of how the measurement basis can be optimized to enhance the performance is solved by connecting the thermal divergence to the nonequilibrium free energy and entropy. The spin-engine architecture offers a comprehensive platform for future investigations of extracting work from quantum measurement.

The novel cycle model of a three-quantum-dot cooler, which possesses three Fermi reservoirs connected by three quantum dots to form a ring, is proposed. The roles of the properties of thermal reservoirs and the energy levels of quantum dots in determining the thermodynamic characteristics of the cooler are revealed. Quantitative analyses of the necessary conditions of cooling in the cases of particle flows moving clockwise or counterclockwise in the ring are obtained. The energy levels of quantum dots and the chemical potentials of heat reservoirs are selected optimally so that the cooler attains its maximum cooling rate. The effects of the chemical potentials of heat reservoirs on the systemic performance are analyzed. The optimal values of other parameters at the maximum cooling rate are calculated numerically, and the optimal selection criteria of main parameters are provided. All these results obtained here reveal a useful approach toward high-performance quantum refrigerators in multi-terminal nanoscale systems. This work establishes a quantum cooler considering three Fermi reservoirs connected by three quantum dots to form a ring. The necessary conditions of cooling in the cases of electron flows moving clockwise or counterclockwise in the ring are obtained, and the effects of characteristic parameters at the maximum cooling rate are discussed. The proposed model can open a new avenue for building practical coolers where thermal manipulation at micro-level is required.

Numerous nanoscale studies that are related to harnessing photon energy focus on quantum effects. Thermodynamics analyses indicate the occurrence of a paradox for the standard model of the photocell with the power generated by a decay process. In order to measure the power accurately, a light-harvesting system connecting to Fermi contacts is proposed. Results show that the interference effect between different transition channels plays a decisive role in enhancing the power output of a photocell. The proposed model may provide a foundation for the future development of photoelectric converters.

Both ruthenium (Ru) and isoquinoline (IQ) compounds are regarded as potential anticancer drug candidates. Here, we report the synthesis and characterization of three novel cyclometalated Ru(II)-isoquinoline complexes: RuIQ-3, RuIQ-4, and RuIQ-5, and evaluation of their in vitro cytotoxicities against a panel of cell lines including A549/DDP, a cisplatin-resistant human lung cancer cell line. A549/DDP 3D multicellular tumor spheroids (MCTSs) were also used to detect the drug resistance reversal effect of Ru(II)-IQ complexes. Our results indicated that the cytotoxic activities against cancer cells of Ru(II)-IQ complexes, especially RuIQ-5, were superior compared with cisplatin. In addition, RuIQ-5 exhibited low toxicity towards both normal HBE cells in vitro and zebrafish embryos in vivo. Further investigation on cellular mechanism of action indicated that after absorption by A549/DDP cells, RuIQ-5 was mainly distributed in the nucleus, which is different from cisplatin. Besides, RuIQ-5 could induce apoptosis through mitochondrial dysfunction, reactive oxygen species (ROS) accumulation, ROS-mediated DNA damage, and cycle arrest at both S and G2/M phases. Moreover, RuIQ-5 could inhibit the overexpression of Nrf2 through regulation of Akt/GSK-3β/Fyn signaling pathway and hindering the nuclear translocation of Nrf2. Based on these findings, we firmly believe that the studied Ru(II)-IQ complexes hold great promise as anticancer therapeutics with high effectiveness and low toxicity.

A novel model of the coupling system consisting of a solar collector and an alkali metal thermal electric converter (AMTEC) is proposed, in which various irreversible losses are considered. Analytical expressions for the efficiencies of the solar collector, AMTEC, and coupling system are derived. The operative temperatures of the solar collector and AMETC are determined by energy balance equations rather than some specified parameters. The influences of the thickness of the electrolyte membrane, current density, and area ratio of the absorber to the AMTEC on the performance of the system are discussed. The maximum efficiency and power output density for a given value of the solar concentration ratio are calculated and revealed to be two different operation states of the coupling system. The effects of the solar concentration ratio on the optimal regions of some key parameters are discussed in detail. The optimum selection criteria of these parameters are provided.

Antimicrobial photodynamic therapy (aPDT) is a new therapeutical modality highly advocated recently to meet the challenge of drug resistant bacteria. In this study, we developed a composite material to combine silver nanoparticle, a commonly used disinfectant, with a potent photosensitizer for aPDT. Interestingly, we found the photosensitizer activated the silver nanoparticles into silver ions under light illumination. At the same time, silver nanoparticles enhanced the generation of ROS by the photosensitizer. Together, the two components activates each other, leading to remarkable antimicrobial efficacy against not only gram-positive and -negative bacteria, but also drug resistant bacteria (Methicillin Resistant S. aureus, MRSA). Such antimicrobial effect was further demonstrated on a bacterial infection model on mice. We showed that the chemical treatment, the high temperature or the pressure during the preparation did not affect the cellulosic structures of the fabric based on the characterization of optical, mechanical and thermal properties of the composite material. aPDT is typically a localized therapy, depending on the contact of bacteria to the photosensitizers, while the silver nanoparticles released the silver ions into the solution and can kill the bacteria thereof. Thus, our current study demonstrates the complementarity of aPDT and silver nanoparticles and mutual promotion of antibacterial effects to even drug-resistant bacteria.