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Comparison of UV-LEDs and LPUV on inactivation and subsequent reactivation of waterborne fungal spores
摘要： Recently, the contamination of fungi in water supply systems has been an area of increasing concern, such as Aspergillus spp. and Penicillium spp. It can cause some waterborne issues such as odor, taste and formation of mycotoxins. Ultraviolet light emitting diodes (UV-LEDs) are considered as a potential alternative to conventional mercury lamps for water disinfection. This study has compared the performance of LPUV (low pressure ultraviolet) and UV-LEDs with emissions at 265, 280 nm and combination emissions at 265/280 nm to test inactivation efficiency, reactivation, viability and electrical energy consumption in the treatment of three water-borne fungal species (Aspergillus niger, Penicillium polonicum, Trichoderma harzianum) at a batch water disinfection system. The results showed that the performances of UV-LEDs were superior for the inactivation of fungal spores compared to the 254 nm (LP), while no statistically differences were observed among the UV-LEDs (p > 0.05). The average photoreactivation rate (k1) of fungal spores irradiated by UV-LEDs and 254 nm (LP) follows the order: T. harzianum > A. niger > P. polonicum. Compared with LPUV, UV-LEDs irradiation at 280 nm and 265/280 nm more efficiently inhibits photoreactivation, which was attributed to that irradiation of 280 nm and 265/280 nm would cause greater membrane damage and increase intracellular reactive oxygen species level of fungal spores according to the flow cytometric results. The electrical energy consumption of UV-LEDs was higher than that of LPUV, which was due to its lower wall plug efficiency. The results of this study can provide additional and beneficial information for the reasonable exploitation of UV-LEDs in water disinfection.
关键词： UV-LEDs disinfection,Membrane permeabilized spores,Reactivation,Intracellular reactive oxygen species,Fungal spores
更新于2025-09-19 17:13:59
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Cross-band infrared laser absorption of carbon monoxide for thermometry and species sensing in high-pressure rocket flows
摘要： A novel cross-band laser absorption spectroscopy technique has been developed for quantitative measurements of gas temperature and carbon monoxide (CO) in high-pressure, high-temperature rocket combustion flows. The strategy enables a broad range of sensor operability by simultaneously probing rovibrational transitions in both the fundamental and first overtone bands of CO near 4.98 μm and 2.32 μm, respectively, which sustain large differences in temperature dependence despite collisional broadening. Scanned-wavelength modulation spectroscopy methods are integrated for noise rejection in the harsh rocket operating environment. Initial experiments using the cross-band thermometry technique have been conducted on a single-element-injector rocket combustor with RP-2/GOx and CH4∕GOx propellant combinations at pressures up to 75 bar. Measurements of the first overtone bandhead (2.32 μm) maintained adequate signal-to-noise at even higher pressures (up to 105 bar), although deviating significantly from spectral simulations. To account for collisional effects at high gas densities, empirical models for line mixing, developed via shock tube studies, were employed to enable quantitative interpretation of measured signals for temperature and CO mole fraction in the rocket combustor.
关键词： thermometry,high-pressure rocket flows,species sensing,carbon monoxide,cross-band laser absorption spectroscopy
更新于2025-09-19 17:13:59
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A Multiparametric Evaluation of Quantum Dot Size and Surface-Grafted Peptide Density on Cellular Uptake and Cytotoxicity
摘要： Despite the progress in nanotechnology for biomedical applications, great efforts are still being employed in optimizing nanoparticle (NP) design parameters to improve functionality and minimize bionanotoxicity. In this study, we developed CdSe/CdS/ZnS core/shell/shell quantum dots (QDs) that are compact ligand-coated and surface-functionalized with an HIV-1-derived TAT cell-penetrating peptide (CPP) analog to improve both biocompatibility and cellular uptake. Multiparametric studies were performed in different mammalian and murine cell lines to compare the effects of varying QD size and number of surface CPPs on cellular uptake, viability, generation of reactive oxygen species, mitochondrial health, cell area, and autophagy. Our results showed that the number of cell-associated NPs and their respective toxicity are higher for the larger QDs. Meanwhile, increasing the number of surface CPPs also enhanced cellular uptake and induced cytotoxicity through the generation of mitoROS and autophagy. Thus, here we report the optimal size and surface CPP combinations for improved QD cellular uptake.
关键词： cellular uptake,mitochondrial health,cytotoxicity,biomedical applications,reactive oxygen species,nanotechnology,autophagy,quantum dots
更新于2025-09-19 17:13:59
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An <i>in situ</i> assembled WO <sub/>3</sub> a??TiO <sub/>2</sub> vertical heterojunction for enhanced Z-scheme photocatalytic activity
摘要： The face-to-face contact of a vertical heterojunction is beneficial to charge interaction in photocatalysis. However, constructing a vertical heterojunction with uncompromised redox ability still remains a challenge. Herein, we report the successful synthesis of a WO3–TiO2 vertical heterojunction via establishing an internal electric field across the interface. Experimental investigation and computational simulations reveal that strong electric coupling occurs at the WO3–TiO2 interface forming an internal electric field. The internal electric field induces a Z-scheme charge-carrier transfer through the heterojunction under light irradiation, which leads to effective charge separation and maintains high reaction potentials of charge-carriers. The improved photocatalytic activity of the WO3–TiO2 heterojunction is proved by enhanced generation of reactive oxygen species and accelerated Escherichia coli (E. coli) disinfection. This study provides new insights into understanding and designing Z-scheme heterogeneous photocatalysts.
关键词： vertical heterojunction,Z-scheme,E. coli disinfection,WO3–TiO2,reactive oxygen species,photocatalysis
更新于2025-09-19 17:13:59
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Sustained photodynamic effect of single chirality-enriched single-walled carbon nanotubes
摘要： Semiconducting single-walled carbon nanotubes (s-SWNTs) are capable of fluorescence emission as well as photothermal and photodynamic actions, resulting from their near-infrared (NIR) absorptions corresponding to their S11 and S22 transitions. Here, we show that one chiral s-SWNTs, (6,4)-SWNTs, photogenerates all three of the major reactive oxygen species, i.e., singlet oxygen (1O2), superoxide anion (O2?–), and hydroxyl radical (?OH), in a sustainable manner. Its efficiency for ?OH generation is dramatically higher than those of the other two chiral s-SWNTs tested, as well as a clinical NIR dye. This sustained and relatively high photodynamic effect in (6,4)-SWNTs is due to their extraordinary high photostability and relatively high generation efficiency of their triplet excited state. In the colloidal stabilization of (6,4)-SWNTs under physiological conditions, a serum protein consisting of a tandem repeat of amphiphilic a -helices is found to be useful for dispersion. The protein-coated (6,4)-SWNTs are capable of effectively ablating cancer cells and disintegrating amyloid beta peptide aggregates through sustained photodynamic action.
关键词： Single-walled carbon nanotubes,Photodynamic effect,Cancer therapy,Reactive oxygen species,Photostability,Amyloid beta peptide
更新于2025-09-19 17:13:59
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Interference-type plasmonic polarizers and generalized law of Malus
摘要： BACKGROUND: The wasp Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae), a Eucalyptus (Myrtaceae) pest native to Australia, has caused economic and ecologic losses in China. It is a serious pest in southern provinces. Because climate is a limiting factor in insect distribution, we used the model CLIMEX to predict the effect of climate change on potential current and future distributions of L. invasa in China. Data were collected on the current locations of this wasp, along with the damage incurred to Eucalyptus. These data were used to create a forecast model to predict potential current and future distribution maps of L. invasa in China. RESULTS: The verification results showed that 99.5% of the distribution samples formulated by the model are highly reliable and accurate. The result predicted that the potential current distribution of L. invasa will concentrate south of the Yellow River basin. The future distribution maps predicted a small-scale potential expansion north–northwest of Guangxi and more areas within China will provide increasingly suitable habitats for colonization by L. invasa. CONCLUSION: These distribution predications will be useful in determining where preventive and control measures should be implemented against this pest wasp in Eucalyptus throughout China.
关键词： Eucalyptus,climate change,CLIMEX,species distribution modeling
更新于2025-09-19 17:13:59
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<p>InP/ZnS Quantum Dots Cause Inflammatory Response in Macrophages Through Endoplasmic Reticulum Stress and Oxidative stress</p>
摘要： Quantum dots (QDs) are widely used semiconductor nanomaterials. Indium phosphide/zinc sulfide (InP/ZnS) QDs are becoming potential alternatives to toxic heavy metal-containing QDs. However, the potential toxicity and, in particular, the immunotoxicity of InP/ZnS QDs are unknown. This study aimed to investigate the impacts of InP/ZnS QDs on inflammatory responses both in vivo and in vitro. Methods: Mice and mouse bone marrow-derived macrophages (BMMs) were exposed to polyethylene glycol (PEG) coated InP/ZnS QDs. The infiltration of neutrophils and the release of interleukin-6 (IL-6) were measured using a hematology analyzer and an enzyme-linked immunosorbent assay (ELISA) for the in vivo test. Cytotoxicity, IL-6 secretion, oxidative stress and endoplasmic reticulum (ER) stress were studied in the BMMs, and then, inhibitors of oxidative stress and ER stress were used to explore the mechanism of the InP/ZnS QDs. Results: We found that 20 mg/kg PEG-InP/ZnS QDs increased the number of neutrophils and the levels of IL-6 in both peritoneal lavage fluids and blood, which indicated acute phase inflammation in the mice. PEG-InP/ZnS QDs also activated the BMMs and increased the production of IL-6. In addition, PEG-InP/ZnS QDs triggered oxidative stress and the ER stress-related PERK-ATF4 pathway in the BMMs. Moreover, the inflammatory response caused by the PEG-InP/ZnS QDs could be attenuated in the macrophages by blocking the oxidative stress or the ER stress with inhibitors. Conclusion: InP/ZnS QDs can activate macrophages and induce acute phase inflammation both in vivo and in vitro, which may be regulated by oxidative stress and ER stress. Our present work is expected to help clarify the biosafety of InP/ZnS QDs and promote their safe application in biomedical and engineering fields.
关键词： indium phosphide,inflammation,endoplasmic reticulum stress,quantum dots,reactive oxygen species
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Broadband Multi-Species Trace Gas Detection by Up-Converting Mid-Infrared Supercontinuum Light into the Near-Infrared
摘要： Recent advancement in compact, stable, and broadband mid-infrared supercontinuum (SC) sources has provided attractive scientific and industrial applications in metrology, sensing, and communications [1]. The wide spectral coverage in the so-called molecular fingerprint region is the main advantage of such SC sources, opening up new opportunities for efficient multi-species trace gas detection at short time scale. Presently, there is a lack of sensitive, low-cost, uncooled MIR photodetectors. The alternative approach involves up-converting mid-infrared light into the near-infrared region via non-linear conversion, leveraging the benefits of sensitive and cost-effective CCD detectors [2]. Here, we present the development of a multi-species trace gas sensor utilizing a mid-infrared SC source in combination with a multipass absorption cell and an up-conversion-based spectrometer. The customized SC source (NKT Photonics) has a total power of 450 mW covering the 1.5 – 4.5 μm spectral window. The astigmatic Herriott multipass cell (AMAC-76, Aerodyne Research) provides an effective optical pathlength of 76 meters improving the detection sensitivity. Details of the up-conversion-based spectrometer (NLIR) have been recently published. [3]. Note that in the present upconversion system the intracavity laser at 1064 nm is generated by pumping the Nd:YVO4 gain medium at 808 nm instead of 880 nm. In order to enhance the long term stability for single species detection, the amplitude drift of the SC source is minimized by counterbalancing the SC intensity with a non-absorbing reference. Multispecies broadband absorbance spectra have been obtained for, amongst others, mixtures of ethane and acetaldehyde at ppm levels in nitrogen as shown in Fig. 1 (a). A non-negative least squares global fitting method has been applied to extract the concentration of individual sub-component. To check system linearity by different gas concentrations, the absorbance with various mixing ratios were measured at a pressure of 900 mar for 60 s. A linear fit of these measurements that agreed with the calculated ones is depicted in Fig. 1 (b) for ethane. The sensor is capable of detecting sub-ppmv gas concentrations (e.g. ~300 ppbv ethane) in a wide range of spectrum (over 600 cm-1) with a ~5 cm-1 spectral resolution. Broadening the spectrum to a wider range by using chirped crystals in the up-converter system and further experiments are under progress. More details and the results for the on-going experiments will be presented at the conference.
关键词： multi-species,mid-infrared supercontinuum,up-conversion,broadband,trace gas detection
更新于2025-09-16 10:30:52
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Organic composition tailored perovskite solar cells and light-emitting diodes: Perspectives and advances
摘要： Recent years have witnessed a significant performance breakthrough in both metal halide perovskite (MHP) solar cells and light-emitting diodes, but their unsatisfactory operating stabilities are still the main challenges toward commercialization. We have summarized different kinds of organic species including organic cations in MHP crystal, functional molecules in MHP polycrystalline bulk films, ligands attached on MHP quantum dots, covered polymers in composite films and encapsulants coated on devices. They assume key roles in film formation, stabilizing black phase, passivating defects, extending photoluminescence lifetime, inhibiting charge-recombination and preventing degradation. This review further examines the relationship among crystal structure, optical and electrical properties, performance and stability, revealing several irreplaceable roles of organic species in determining the performance and stability of MHP devices. Finally, we call on establishing standard stability measurements and exploring efficient encapsulation methods to improve the stabilities of MHP solar cells and LEDs, which pushes them from a promise to a production and promotes a continuous progress in this field.
关键词： Performance,Perovskite light-emitting diodes,Perovskite solar cells,Organic species,Stability
更新于2025-09-16 10:30:52
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[IEEE 2018 IEEE 8th International Conference Nanomaterials: Application & Properties (NAP) - Zatoka, Ukraine (2018.9.9-2018.9.14)] 2018 IEEE 8th International Conference Nanomaterials: Application & Properties (NAP) - Efficient Two-Photon Luminescence for Bioimaging Using Polymer Conjugations of Graphene Quantum Dots Based Materials
摘要： In this study, examination results revealed that conjugated polymers containing nitrogen and sulfur atoms lead to a higher quantum confinement of emissive energy trapped on the surface of material (graphene quantum dot (GQD)-polymers), resulting in a high luminescence quantum yield and impressive two-photon properties. Additionally, the GQD-polymers generated nonreactive oxygen species-dependent oxidative stress on cells. Furthermore, we demonstrated the effective use of two-photon excitation-mediated high two-photon luminescence intensity in an acidic environment enabled GQD-polymers to act as a promising contrast probe. When cancer cells are labeled with specific antibody GQD-polymers conjugates, molecular-specific imaging can be performed deep into a tissue phantom with extremely high signal-to-noise ratios. In situations in which imaging depths are limited by the maximum available power that can be delivered to the three-dimensional (3D) bioimaging plane without causing damage to tissue, GQD-polymers might provide sufficient brightness to extend the maximum depth of imaging. Moreover, we demonstrated that the use of GQD-polymers can expand the capabilities of two-photon imaging to allow noninvasive 3D bioimaging of a variety of new molecular signatures.
关键词： photostability,reactive oxygen species,three-dimensional bioimaging,photodynamic therapy,two-photon excitation,contrast probe,graphene,quantum dot-polymer,two-photon luminescence,two-photon,contrast agent,nitrogen-doped graphene quantum dots
更新于2025-09-16 10:30:52