- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
The effect of iodide and temperature on enhancing antibacterial properties of nanoparticles with an encapsulated photosensitizer
摘要： Aqueous dispersions of sulfonated polystyrene nanoparticles (average diameter: 30 ± 14 nm) with encapsulated 5,10,15,20-tetraphenylporphyrin (TPP) are promising candidates for antibacterial treatments due to the photogeneration of cytotoxic singlet oxygen species O2(1Δg) under physiological conditions using visible light. The antibacterial effect on gram-negative Escherichia coli was significantly enhanced after the addition of nontoxic potassium iodide (0.001–0.01 M) because photogenerated O2(1Δg) oxidized iodide to I2/I3-, which is another antibacterial species. The improved antibacterial properties were predicted using luminescence measurements of O2(1Δg), transient absorption of TPP triplets and singlet oxygen-sensitized delayed fluorescence (SODF). In contrast to a solution of free photosensitizers, the aqueous dispersion of photoactive nanoparticles did not exhibit any quenching of the excited states after the addition of iodide or any tendency toward aggregation and/or photo-aggregation. We also observed a decrease in the lifetime of O2(1Δg) and a significant increase in SODF intensity at higher temperatures, due to the increased oxygen diffusion coefficient in nanoparticles and aqueous surroundings. This effect corresponds with the significantly stronger antibacterial effect of nanoparticles at physiological temperature (37 °C) in comparison with that at room temperature (25 °C).
关键词： Nanoparticles,Antibacterial,Potassium iodide,Singlet oxygen-sensitized delayed fluorescence,Singlet oxygen
更新于2025-09-23 15:22:29
-
Facile Preparation of Micrometer KClO4/Zr Energetic Composite Particles with Enhanced Light Radiation
摘要： Developing energetic composite materials consisting of fuel and oxidizer is an effective strategy to enhance the energy release property. However, this strategy has rarely been applied in Potassium Perchlorate (KClO4)-containing energetic materials, even though KClO4 is a much stronger oxidizer than most previously reported metal-oxide oxidizer. One of the main obstacles is the lack of simple and in situ ways to introduce KClO4 into the composite. In present work, micrometer KClO4/Zirconium (KClO4/Zr) composite particles were successfully prepared using a facile chemical solution-deposition method. The structure and particle morphologies of as-obtained KClO4/Zr composite were characterized by X-ray diffraction (XRD) and scanning electronic microscope (SEM)-EDS (Energy Dispersive Spectrometer). The evolutionary combustion behavior was evaluated using flame-based light-radiation spectra and successive photography technique. Results showed that the morphology, light-radiation properties and flame-evolution characteristics of KClO4/Zr composite varied with the content of KClO4 and the particle size of Zr. Compared with the mechanical mixture of KClO4/Zr, the KClO4/Zr composite showed much higher light-radiation intensity and longer light-emission duration time after reasonably controlling the preparation parameters. Flame photographs revealed that the enhanced light radiation of KClO4/Zr composite should be ascribed to higher use efficiency of “oxygen” in the oxidizer, which promoted both the solid–solid and solid–gas reaction pathways between KClO4 and Zr.
关键词： Potassium Perchlorate/Zirconium (KClO4/Zr) composite,frame photographs,reaction pathways,light radiation
更新于2025-09-23 15:22:29
-
Potassium channel-based optogenetic silencing
摘要： Optogenetics enables manipulation of biological processes with light at high spatio-temporal resolution to control the behavior of cells, networks, or even whole animals. In contrast to the performance of excitatory rhodopsins, the effectiveness of inhibitory optogenetic tools is still insufficient. Here we report a two-component optical silencer system comprising photo-activated adenylyl cyclases (PACs) and the small cyclic nucleotide-gated potassium channel SthK. Activation of this ‘PAC-K’ silencer by brief pulses of low-intensity blue light causes robust and reversible silencing of cardiomyocyte excitation and neuronal firing. In vivo expression of PAC-K in mouse and zebrafish neurons is well tolerated, where blue light inhibits neuronal activity and blocks motor responses. In combination with red-light absorbing channelrhodopsins, the distinct action spectra of PACs allow independent bimodal control of neuronal activity. PAC-K represents a reliable optogenetic silencer with intrinsic amplification for sustained potassium-mediated hyperpolarization, conferring high operational light sensitivity to the cells of interest.
关键词： Potassium channel,Neuronal silencing,Photo-activated adenylyl cyclases,Optogenetics,Cardiomyocyte excitation
更新于2025-09-23 15:21:21
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Control of Vacancy Defects in Reactively Sputtered (Ag,Cu)(In,Ga)Se <sub/>2</sub> Solar Cells
摘要： We report positron annihilation spectroscopy measurements revealing the prevalence of VSe-VCu divacancy defects in reactively sputtered ACIGS solar cells. Together with compositional and structural analysis as well as capacitance-voltage measurements, an intricate interplay is observed between divacancies, (Cu+Ag)/III ratio, grain size, and carrier concentration. These properties can be tuned during absorber growth by varying growth temperature and alkali content. Exploiting this interplay may be the key to achieving high efficiency in ACIGS solar cells.
关键词： ACIGS,positron annihilation,defects,potassium,vacancies,reactive sputtering,photovoltaic cells
更新于2025-09-23 15:21:01
-
Potassium Treatments for Solution-Processed Cu(In,Ga)(S,Se) <sub/>2</sub> Solar Cells
摘要： Cu(In,Ga)(S,Se)2 (CIGSe, CIGSSe) has emerged as an attractive thin-film solar cell absorber material owing to its high light absorption coefficient and tunable bandgap. In CIGSSe processing and fabrication, the use of alkali treatments has been implemented as sodium doping is considered a requirement for high efficiency CIGSSe solar cell devices and has been used extensively. One of the more significant developments in recent years has been the discovery of the beneficial effects that potassium post-deposition treatments have on vacuum-processed CIGSSe solar cells as they are responsible for a major increase in CIGSSe solar cell performance. Here, we conduct a study of the effect of potassium treatments to solution-processed CIGSSe films grown from colloidal sulfide-based nanoparticle inks. By adding potassium through e-beam evaporation of KF prior to selenization and grain growth, we find that the grain growth of CIGSSe is enhanced with potassium addition and that a larger-grained film results compared to untreated selenized CIGSSe film, similar to what is observed in sodium-treated films. We also observe through XPS that films treated with K show the presence of the high-bandgap K-In-Se surface phase. Fabricating devices, we find that films that have been subjected simultaneously to both sodium and potassium treatments have enhanced optoelectronic performance mainly manifested in higher open-circuit voltage and higher short-circuit current.
关键词： CIGS,alkali treatment,Cu(In,Ga)(S,Se)2,solution-processed solar cells,potassium fluoride,chalcopyrite solar cell,sodium fluoride
更新于2025-09-23 15:21:01
-
Potassium Induced Phase Stability Enables Stable and Efficient Widea??Bandgap Perovskite Solar Cells
摘要： The incorporation of potassium can remarkably stabilize wide-bandgap perovskites with a high Br content by the synergistic effect of the formation of 2D K2PbI4 at the grain boundaries and the interstitial occupancy in the perovskite lattices, which can effectively reduce the trap density and inhibit ion migration, thus suppressing the nonradiative recombination and photoinduced phase segregation.
关键词： phase segregation,wide-bandgap perovskite solar cells,potassium incorporation,defect passivation
更新于2025-09-23 15:21:01
-
Resolving fine spectral features in lattice vibrational modes using femtosecond coherent spectroscopy
摘要： We show resolution of fine spectral features within several Raman active vibrational modes in potassium titanyl phosphate (KTP) crystal. Measurements are performed using a femtosecond time-domain coherent anti-Stokes Raman scattering spectroscopy technique that is capable of delivering equivalent spectral resolution of 0.1 cm?1. The Raman spectra retrieved from our measurements show several spectral components corresponding to vibrations of different symmetry with distinctly different damping rates. In particular, linewidths for unassigned optical phonon mode triplet centered at around 820 cm?1 are found to be 7.5±0.2 cm?1, 9.1±0.3 cm?1, and 11.2±0.3 cm?1. Results of our experiments will ultimately help to design an all-solid-state source for sub-optical-wavelength waveform generation that is based on stimulated Raman scattering.
关键词： damping rates,potassium titanyl phosphate,Raman active vibrational modes,femtosecond coherent spectroscopy,spectral resolution
更新于2025-09-23 15:21:01
-
Light addressable ion sensing for real-time monitoring of extracellular potassium
摘要： Visualization of ion distribution has broad applications. We report here on a light addressable potassium (K+) sensor where light illumination of a semiconducting silicon electrode substrate results in a localized activation of the faradaic electrochemistry at the illuminated spot. This allows one, by electrochemical control, to oxidize surface bound ferrocene moieties that in turn trigger K+ transfer from the overlaid K+-selective film to the solution phase. The resulting voltammetric response is shown to be K+-selective, where peak position is a direct function of K+ activity at the surface of electrode. This concept was used to measure extracellular K+ concentration changes by stimulating living breast cancer cells. The associated decrease of intracellular K+ level was confirmed with a fluorescent K+ indicator. In contrast to light addressable potentiometry, the approach introduced here relies on dynamic electrochemistry and may be performed in tandem with other electrochemical analysis when studying biological events on the electrode.
关键词： physiological condition,potassium,light activated electrochemistry,ion-selective electrode,potentiometry
更新于2025-09-23 15:21:01
-
Light addressable ion sensing for real-time monitoring of extracellular potassium
摘要： Visualization of ion distribution has broad applications. We report here on a light addressable potassium (K+) sensor where light illumination of a semiconducting silicon electrode substrate results in a localized activation of the faradaic electrochemistry at the illuminated spot. This allows one, by electrochemical control, to oxidize surface bound ferrocene moieties that in turn trigger K+ transfer from the overlaid K+-selective film to the solution phase. The resulting voltammetric response is shown to be K+-selective, where peak position is a direct function of K+ activity at the surface of electrode. This concept was used to measure extracellular K+ concentration changes by stimulating living breast cancer cells. The associated decrease of intracellular K+ level was confirmed with a fluorescent K+ indicator. In contrast to light addressable potentiometry, the approach introduced here relies on dynamic electrochemistry and may be performed in tandem with other electrochemical analysis when studying biological events on the electrode.
关键词： physiological condition,potassium,light activated electrochemistry,ion-selective electrode,potentiometry
更新于2025-09-23 15:21:01
-
Low-power laser and potassium oxalate gel in the treatment of cervical dentin hypersensitivitya??a randomized clinical trial
摘要： Objective To evaluate the effectiveness of different protocols for the treatment of cervical dentin hypersensitivity (CDH) in non-carious cervical lesions (NCCLs). Materials and methods The CONSORT checklist was used to design this study. The sample with n = 74 participants (389 NCCLs) was randomly allocated into three groups: G1, potassium oxalate (Oxa-Gel BF); G2, GaAlAs (gallium-aluminum-arsenate) low-power laser (100 mW, 808nn, 60 J/cm2); and G3, potassium oxalate (Oxa-Gel BF) associated with the GaAlAs low-power laser. The CDH was triggered by the evaporative stimulus test (EST) and by the tactile stimulus test (TST). The visual analog scale (VAS) was used to quantify the degree of CDH. Changes in sensitivity were assessed from baseline over 3 weeks. Data were analyzed for NCCLs using mixed-effects models with unstructured direct product covariance structure (α = 0.05). Results After the first application, participants from G1 and G3 had a reduction in CDH (p < 0.05) compared with group G2 for TST. After the second application, G3 participants had a reduction in CDH (p < 0.05) in relation to G2 for both stimuli. Reduction in CDH (p < 0.05) occurred over 3 weeks for EST and TST for all groups; however, there was no difference between groups at the end of the therapies. Conclusion Potassium oxalate was more effective in reducing immediate CDH. After four applications, all groups showed similar results for the reduction of CDH. Clinical relevance GaAlAS laser irradiation and oxalate potassium gel could reduce the symptoms of CDH; thus, they are viable alternatives for the treatment of this condition. Chemical occlusion of dental tubules showed effective results after a shorter time interval. Trial registration Brazilian Clinical Trials Registration Platform under protocol number RBR-4ybjmt. http://www.braziliantrials.com/?keywords=RBR-4ybjmt&order=%7Eensaios.patrocinador_primario
关键词： Clinical study,Non-carious cervical lesion,Cervical dentin hypersensitivity,Potassium oxalate,Low-power laser
更新于2025-09-23 15:21:01