Resonance Plasma Research Articles

Research status and prospect of nano silver (Ag)-modified photocatalytic materials for degradation of organic pollutants.

Nano silver (Ag) was metallic Ag monomers with particle size to the nanoscale. Photocatalyst was a kind of semiconductor material with photocatalytic function. Loading precious metal Ag onto semiconductor surfaces by microwave, laser-induced, solvent-thermal and hydrothermal methods could capture photogenerated electrons, reduced the compounding rate of holes and photogenerated electrons during the photocatalytic process, thereby improving the electron transfer efficiency of photocatalysis and enhancing the absorption of visible light by silver nanoparticles through the plasma resonance effect. The highly reactive free radicals produced by photocatalysts were used in the organic degradation process to degrade organic matter into inorganic matter and was a faster, more efficient and less polluting method of pollutant degradation, which has attracted a lot of attention from researchers. This review discussed the modification of various types of photocatalysts by nano Ag through different methods. The photocatalytic degradation of dyes, antibiotics and persistent organic pollutants by different modified composites was also analyzed. This review covered the several ways and means in which nano Ag has modified diverse photocatalytic materials as well as the photocatalytic degradation of dyes, antibiotics and persistent organic pollutants. This review identified the drawbacks of the existing nano Ag-modified photocatalytic materials, including their low yield and lack of recyclability, and it also offered suggestions for potential future directions for their improvement. The purpose of this review was to further research on the technology of nano Ag-modified photocatalytic materials and to encourage the creation of new modified photocatalytic nanomaterials for the treatment of organic pollutant degradation.

Enhanced Catalytic Performance of Ag NP/0.95AgNbO3-0.05LiTaO3 Heterojunction from the Combination of Surface Plasma Resonance Effect and Piezoelectric Effect Using Facile Mechanical Milling.

An internal built electric field can suppress the recombination of electron-hole pairs and distinctly enhance the catalytic activity of a photocatalyst. Novel t-Ag/0.95AgNbO3-0.05LiTaO3 heterojunction was prepared by reducing silver nanoparticles (Ag NPs) on the surface of the piezoelectric powder 0.95AgNbO3-0.05LiTaO3 (0.05-ANLT) using a simple mechanical milling method. The effects of milling time and excitation source used for the degradation of organic dye by heterojunction catalysts were investigated. The results demonstrate that the optimized 1.5-Ag/0.05-ANLT heterojunction removes 97% RhB within 40 min, which is 7.8 times higher than that of single piezoelectric catalysis and 25.4 times higher than that of single photocatalysis. The significant enhancement of photocatalytic activity can be attributed to the synergistic coupling of the surface plasmon resonance (SPR) effect and the piezoelectric effect.

Tuneable Anisotropic Plasmonics with Shape-Symmetric Conducting Polymer Nanoantennas.

A wide range of nanophotonic applications rely on polarization-dependent plasmonic resonances, which usually requires metallic nanostructures that have anisotropic shape. This work demonstrates polarization-dependent plasmonic resonances instead by breaking symmetry via material permittivity. The study shows that molecular alignment of a conducting polymer can lead to a material with polarization-dependent plasma frequency and corresponding in-plane hyperbolic permittivity region. This result is not expected based only on anisotropic charge mobility but implies that also the effective mass of the charge carriers becomes anisotropic upon polymer alignment. This unique feature is used to demonstrate circularly symmetric nanoantennas that provide different plasmonic resonances parallel and perpendicular to the alignment direction. The nanoantennas are further tuneable via the redox state of the polymer. Importantly, polymer alignment could blueshift the plasma wavelength and resonances by several hundreds of nanometers, forming a novel approach toward reaching the ultimate goal of redox-tunable conducting polymer nanoantennas for visible light.

Construction of g- C3N4/Au/MgAl2O4 photocatalysts with different coupling methods to improve the photodegradation behavior and performance prediction

A novel g-C3N4/Au/MgAl2O4 (CN-Au-MAO) system have been developed to improve the photocatalytic activity of CN and MAO for the simulated sunlight -driven chlortetracycline hydrochloride (CTC-HCl) removal. The Au particles act as a surface plasmon resonance center to separate and accumulate electrons from the conduction band of CN and MAO, promoting the transfer of photo-generated carriers, thereby maintaining high oxidative capacities of MAO. The prepared photocatalysts revealed that the plasma resonance wavelength and photocatalytic efficiency of CN -Au -MAO photocatalysts strongly depend on the coupling order of CN, Au, and MAO. The effects of mass percentages of Au, CN and Au-CN, catalyst content, drug concentration and pH value on the degradation of CTC-HCl were explored in depth. The CN-Au-MAO photocatalysts exhibited a high photocatalytic efficiency of 92.56% toward the photodegradation of CTC-HCl with the optimum catalyst content of 1 g/L, drug concentration of 200 mg/L and pH= 11. The genetic algorithm was used to predict the photocatalytic activity of CN-Au-MAO photocatalyst, and the minimum data set that can effectively predict its photocatalytic activity was explored. The active species detection experiments, degradation pathways, and toxicity estimates were also performed. A reasonable mechanism of the CN-Au-MAO system was proposed. This work effectively solves the problem of coupling MAO with the noble metal particles, which makes MAO easy to hydrolyze, and the problem of predicting the effective minimum data set required for the photocatalytic activity through neural network algorithms.

Novel CD123xCD3 Bispecific Igm Antibody, Igm-2537, Potently Induces T-Cell Mediated Cytotoxicity of Acute Myeloid Leukemia Cells In Vivo and in Vitro with Minimal Cytokine Release

Introduction: New therapeutics are needed for the effective treatment of acute myeloid leukemia (AML), as standard chemotherapeutics are poorly tolerated and ~50% of patients relapse primarily due to the incomplete elimination of leukemia stem cells (LSCs). CD123, the IL-3Rα chain, is highly expressed on leukemic blasts and LSCs, and is further increased in patients with poor prognostic factors. Bispecific T-cell engager (TCE) antibodies and CAR-T cells targeting CD123 have shown promising clinical efficacy in AML patients, but cytokine release syndrome limits their therapeutic window and remains a major safety concern. IGM-2537 is a novel pentameric IgM bispecific TCE antibody engineered with ten anti-CD123 binding sites, and an anti-CD3ε single chain Fv domain fused to the joining chain to engage T-cells. Here, we report that IGM-2537 not only potently induces T-cell mediated cytolytic killing of AML cells in vitro and in vivo but also demonstrates minimal cytokine release, and little to no effect on normal hematopoietic progenitor cells and human vascular endothelial cells (HUVECs) with in vitro and ex vivo studies. Additionally, an improved tolerability, excellent pharmacodynamic (PD) response and lower cytokine release was observed with a cynomolgus cross-reactive IgM TCE in monkeys. Materials and Methods:Surface plasma resonance (SPR), cell membrane protein array, and alanine scanning were utilized to characterize human CD123 binding affinity, specificity and epitope mapping, respectively. T-cell dependent cellular cytotoxicity (TDCC) assays were employed to evaluate the potency of IGM-2537 target cytotoxicity, T cell activation and cytokine release. Ex vivo AML colony formation assays were used to assess the activity on AML blasts. Human MV-4-11 and MOLM-13 xenograft tumor models in humanized NSG dKO mice were utilized to determine in vivo anti-tumor activity of IGM-2537. Healthy human PBMCs and bone marrow (BM) samples as well as HUVECs were used in ex vivo assays to address potential safety concerns of IGM-2537 mediated effects on hematopoietic progenitor cells and HUVECs, respectively. Lastly, to confirm that a CD123 directed IgM-based TCE molecule can potentially provide better safety profile in vivo, a cynomolgus-cross reactive IgM TCE comparator was assessed in monkeys for tolerability and PK/PD responses. Results and Conclusions: IGM-2537 bound with high affinity and avidity to CD123. In vitro, IGM-2537 engaged both CD123 and CD3 to induce potent T-cell activation and T-cell mediated cytotoxicity of CD123 + AML cells, and autologous CD123 + basophils and plasmacytoid dendritic cells (pDCs). Though IGM-2537 demonstrated comparable maximal killing activity to a comparator IgG TCE, IGM-2537 demonstrated minimal cytokine release. In ex vivo patient-derived AML or normal BM colony formation assays, IGM-2537 eliminated AML colony forming cells at physiologically relevant effector/target (E/T) ratios but had little or no effect on normal hematopoietic progenitors. In addition, IGM-2537 demonstrated no cytotoxicity against HUVECs regardless of their CD123 expression at basal levels or at maximal levels upregulated by TNF-a and IFN-g, in contrast to a comparator IgG TCE. In vivo, IGM-2537 completely inhibited tumor growth in two AML xenograft tumor models, a subcutaneous MV-4-11 model, and a systemic MOLM-13 model in humanized NSG dKO mice. To further evaluate the potency and safety of the CD123xCD3 IgM bispecific TCE format in vivo, a cynomolgus cross-reactive CD123xCD3 IgM bispecific TCE was evaluated for tolerability and PD responses in cynomolgus monkeys using single doses. All animals tolerated the cross-reactive bispecific IgM TCE well at doses up to 10 mg/kg (the maximal dose level evaluated), a dose 100-fold greater than published doses of a comparator IgG TCE. Complete depletion of CD123 + basophils and substantial reductions of pDCs were seen in blood and BM with minimal to no cytokine induction. In summary, IGM-2537 demonstrated potent in vitro and in vivo T-cell mediated cytotoxicity of AML cell lines with minimal cytokine induction. The encouraging preclinical safety profiles were further supported by little/no effect on normal hematopoietic progenitor cells and HUVECs. These preclinical data support the clinical development of IGM-2537 for the treatment of AML and other hematological malignancies.

Highly efficient visible-light photocatalyst Ag/Ag3PO4/Bi2O2CO3 enabled by the synergistic effect of heterojunction and surface plasma resonance

Highly efficient visible-light photocatalyst Ag/Ag3PO4/Bi2O2CO3 enabled by the synergistic effect of heterojunction and surface plasma resonance

Revolutionary solar evaporation system: Harnessing the power of bacterial cellulose/Ag NPs/polypyrrole with its promoted antibacterial applications

Extensive research is being conducted on a promising technology that utilizes solar energy and photothermal materials to address the global challenges of freshwater scarcity and energy shortage. Real-world applications of this technology require materials with specific properties such as mechanical flexibility and antimicrobial characteristics. Herein, a self-supporting membrane for interfacial photothermal water evaporation is developed, incorporating bacterial cellulose (BC) as a resilient and hydrophilic backbone material, along with Polypyrrole（PPy）loading and silver nanoparticles (Ag NPs) doping. The addition of Ag NPs not only enhances the antibacterial properties of the material, but also improves light absorption through plasma resonance, resulting in enhanced photothermal conversion efficiency. Experimental results demonstrate that the BC/Ag/PPy hybridized membrane exhibits an outstanding photothermal evaporation efficiency of 91%. Additionally, the membrane maintains a stable evaporation rate and favorable mechanical properties. With its exceptional performance, this BC/Ag/PPy membrane offers a practical solution for long-term seawater desalination applications.

Exploring the optoelectronic and thermoelectric nature in Cd-based direct band gap materials: For optoelectronic devices

The direct band gap semiconductors are exceptional for their use as solar cells and in most optoelectronic devices. Using the full-potential linearized augmented plane wave (FP-LAPW) technique, the structural, electronic, optical, and thermoelectric characteristics of novel La2CdX4 (X = S, Se, Te) semiconductors are studied. The electronic band profiles support the density of state calculations and demonstrate a direct band gap nature. These materials appear thermodynamically stable based on the calculated phonon dispersion plots and from their predicted negative formation energy values. Furthermore, the significant optical properties were computed and described extensively. The predicted energy loss function with a few prominent peaks corresponds well with the plasma resonance that occurs at plasma frequency. Based on the reflectivity spectrum, the materials under consideration could be used as UV shielding or anti-reflective coating materials. From the investigation of the calculated significant thermoelectric characteristics, the materials were proven to be appropriate for thermoelectric devices. The current research will support advancement of numerous promising semiconducting technologies and their applications in general.

Advances in the Fabrication of Nanoporous Anodic Aluminum Oxide and Its Applications to Sensors: A Review.

Nanoporous anodic aluminum oxide (AAO) is an important template for 1D nanomaterial synthesis. It is used as an etching template for nanopattern transfer in a variety of contexts, including nanostructured material synthesis, electrical sensors, optical sensors, photonic and electronic devices, photocatalysis, and hardness and anticorrosion improvement. In this review, we focus on various fabrication methods, pore geometry modification, and recent advances of AAO, as well as sensor applications linked to our environment, daily life, and safety. Pore geometry is concerned with the material composition, applied voltage mold, electrolyte type, temperature, and anodizing time during the fabrication of AAOs and for adjusting their pore size and profile. The applied voltage can be divided into four types: direct current anodization (DCA), reverse pulse anodization, pulse anodization (PA), and hybrid pulse anodization (HPA). Conventional AAOs are fabricated using DCA and mild anodization (MA) at a relatively low temperature (-5~15 °C) to reduce the Joule heating effect. Moreover, the issues of costly high-purity aluminum and a long processing time can be improved using HPA to diminish the Joule heating effect at relatively high temperatures of 20-30 °C with cheap low-purity (≤99%) aluminum. The AAO-based sensors discussed here are primarily divided into electrical sensors and optical sensors; the performance of both sensors is affected by the sensing material and pore geometry. The electrical sensor is usually used for humidity or gas measurement applications and has a thin metal film on the surface as an electrode. On the contrary, the AAO optical sensor is a well-known sensor for detecting various substances with four kinds of mechanisms: interference, photoluminescence, surface plasma resonance, and surface-enhanced Raman scattering (SERS). Especially for SERS mechanisms, AAO can be used either as a solid support for coating metal nanoparticles or a template for depositing the metal content through the nanopores to form the nanodots or nanowires for detecting substances. High-performance sensors will play a crucial role in our living environments and promote our quality of life in the future.

SnO2 tetragonal nanonails with enhanced optical and photoelectric performances via localized surface plasmon resonance effect of Au nanoparticles

Enhanced optical and photoelectric characteristics of semiconductors via Localized Surface Plasma Resonance (LSPR) effect strategy has drawn extensive attentions and researches in the fields of semiconductor industry. Specially, Au/SnO2 tetragonal nanonails (TNs) Schottky heterojunctions have been innovatively synthesized by modified CVD and hydrothermal methods. Au/SnO2 TNs Schottky heterojunction fabricated at the volume ratio of 0.5/45 HAuCl4/Water (0.5 Au/SO) exhibits the remarkable photocurrent density about of 52.8 μA cm−2 at 0.5 V vs. Ag/AgCl, which is about of 1.5 and 1.2 times than that of SO-550 (36.4 μA cm−2) and 0.7 Au/SO (44.8 μA cm−2) photoelectrodes, respectively. Optical absorption properties of all Au/SnO2 TNs Schottky heterojunctions have obviously improved in ultraviolet–visible regions due to the strong LSPR effect of Au nanoparticles (NPs). Au NPs also act as photosensitizers, which can generate more high-energy active electrons by LSPR excitation and then inject into CB of SnO2 TNs photoelectrode. This process can effectively enhance separation and transportation efficiencies of photogenerated charge carriers, further improving photoelectric performances of Au/SnO2 TNs Schottky heterojunctions. This work can provide novel strategies to synthesize one-dimensional metallic oxide photoelectrodes and Schottky heterojunctions, and further laying the foundation for exploring the interface/surface novel effects of heterojunctions at the applications of catalysis, sensors or detection fields.

Reflection of the Electromagnetic Wave from the Region of Electron Cyclotron Absorption in Thermonuclear Plasma

A new approach to the problem of the passage of the extraordinary wave through the region of the electron–cyclotron resonance in inhomogeneous plasma was considered in the framework of the full set of Maxwell’s equations, taking into account the effects of spatial dispersion and resonance dissipation. For the model one-dimensional geometry, field distributions were calculated in the vicinity of the cyclotron resonance at the second harmonic for the normal incidence of the extraordinary wave and the reflection, transmission, and absorption coefficients were found depending on the parameters of the resonance region. As a result, the fine effect of the reflection of electromagnetic radiation from the cyclotron resonance region in transparent plasma was described and the results were compared with the observations of this effect in the experiments on the microwave heating of the plasma at the L-2M stellarator.

Reflection of the Electromagnetic Wave from the Region of Electron Cyclotron Absorption in Thermonuclear Plasma

A new approach to the problem of the passage of the extraordinary wave through the region of the electron–cyclotron resonance in inhomogeneous plasma was considered in the framework of the full set of Maxwell’s equations, taking into account the effects of spatial dispersion and resonance dissipation. For the model one-dimensional geometry, field distributions were calculated in the vicinity of the cyclotron resonance at the second harmonic for the normal incidence of the extraordinary wave and the reflection, transmission, and absorption coefficients were found depending on the parameters of the resonance region. As a result, the fine effect of the reflection of electromagnetic radiation from the cyclotron resonance region in transparent plasma was described and the results were compared with the observations of this effect in the experiments on the microwave heating of the plasma at the L-2M stellarator.

Structural, electronic, and optical properties of cubic perovskites BiMO3 (M = Al, Ga & In) – A computational study

The Density Functional Theory (DFT) incorporating Full Potential Linearized Augmented Plane Wave (FP-LAPW) was used for the study of BiMO3 (M = Al, Ga, and In). The energy band structure, the density of states (DOS), and charge density calculation were used for their structural, electronic, and optical properties identification. With the optimized energy, the band gap was found to be 0.315 eV of the indirect type. The Bi-O has ionic bonding, and M (Al, Ga, and In) -O has a mixture of ionic and strong covalent bonds. The energy range of 0–30 eV was used to study the optical properties. The zero frequency reflectivity is 56.96 %, with its maximum (29.34 %) at 14.02 eV, maximum energy loss indicating plasma resonance is at 28.19 eV, and optical conductivity at 7767.27 Ω−1 cm−1) at 13.41 eV where the maxima of absorption coefficient lie. An indirect band gap of 0.315 eV between the M - Γ symmetry point was found. Thus the observations showed their efficiency as memories, capacitors, actuators, sensors, piezoelectric devices, solar cells, and other devices.

High-order Harmonics of a Kink Wave and a Narrow Quasiperiodic Fast-propagating Wave Train Excited Simultaneously in a Plasma Resonator

We present the observations of multimode kink waves and a narrow quasiperiodic fast-propagating (QFP) wave train in association with a jet on 2011 December 11. The jet impinged on a loop, which excited a propagating kink mode transitioning into a standing kink mode and also excited a QFP wave train away from the jet. Motion magnification is used to fit the higher harmonic standing wave oscillation profile with three periods at three different spatial locations. The periods have the ratio 6:3:2. The ratio of the fundamental mode to the second harmonic of the standing wave is about 1.95, suggesting that the magnetic field strength variation effect is strong enough to cancel out the density stratification. The differential emission measure is used to estimate the loop’s plasma property at these three points, and it found the density and the temperature are roughly constant. The magnetic field strength, B = 51 ± 16 G, is derived by the coronal seismology using the fundamental kink mode. It is striking to find that the the ratio of the second harmonic to the third harmonic of the kink wave coincides with that of the periods of the QFP wave train, and the ratio of periods is about 1.5 in both cases. We propose that the excitation of the high-order harmonics and the QFP wave train could be the nonlinear response of the steep density-gradient plasma interacting with electromagnetic field in the southwest foot region. This region, like a resonator, might play an important role in energy reservoir capture and act as a frequency filter to generate propagating waves of particular frequencies.

Valorization of Momordica charantia seeds into phytogenically synthesized silver nanoparticles for the protection of oyster mushrooms against Trichoderma pleuroticola

Green mold caused by Trichoderma pleuroticola is the most invasive disease of oyster mushrooms, causing massive losses worldwide. Herein, we valorized food waste, the Momordica seed extract (MSE), into silver nanoparticles (AgNPs-MSE). The synthesis parameters were optimized, and the biogenic AgNPs showed a remarkable antifungal activity against T. pleuroticola. Quantitative and qualitative analyses showed that the MSE was rich in bioactive compounds. The highly stable AgNPs-MSE was synthesized under the following conditions: MSE–AgNO3 ratio, 5:95; synthesis time, 9 min; temperature, 60 °C; and pH, 8.0. The UV absorption spectra showed surface plasma resonance peak at 428 nm, confirming the presence of spherical nanoparticles. FTIR spectra ascertained the involvement of phytoconstituents in the MSE during synthesis, and X-ray diffraction analysis revealed a face-centered cubic (fcc) crystalline structure with an average particle size of 11.34 nm. HR-TEM analysis corroborated the spherical shape, with a nanoparticle size of 8.0 nm. EDX analysis revealed the presence of silver, carbon, oxygen, nitrogen, sulfur, and chlorine in the AgNPs-MSE, which was further substantiated by XPS analysis. A zeta potential of − 29.7 mV and PDI of 0.144 revealed the good stability and uniformity of the synthesized AgNPs-MSE. The optimized AgNPs-MSE exhibited a potent antifungal activity against T. pleuroticola at 300 ppm in vitro. SEM and TEM analyses of AgNPs-MSE-treated T. pleuroticola showed hyphal system breakage and leakage of cytoplasmic contents that leads to cell death. Therefore, the use of the AgNPs-MSE as a nanoparticle-based fungicide has the potential to effectively control T. pleuroticola for oyster mushroom protection.

Recent Advances and Perspective in Electrically Regulated Surface‐Enhanced Raman Spectroscopy

Surface‐enhanced Raman spectroscopy (SERS) has emerged as a distinctive fingerprinting technique, offering a broad spectrum of applications encompassing environmental monitoring, chemical detection, and biomolecular analysis. Electrically modulated SERS (E‐SERS) stands as a technique which leverages an electric field to finely control the Raman signal based on the foundational principles of SERS. Through the manipulation of the physicochemical attributes of a metal or 2D material substrate, E‐SERS brings about an enhancement of the SERS signal. This enhancement occurs through a charge transfer process and modulation of the plasma resonance. This article showcases recent strides in the domain of E‐SERS, encompassing advancements such as the integration of paired integrated electrodes, piezoelectric materials, and pyroelectric materials in the construction of substrates. An exhaustive analysis of the mechanism underpinning the enhancement of the Raman signal is undertaken, alongside an exploration of the prominent attributes characterizing diverse methods for conditioning Raman signals. Elucidations are provided on the significance of employed electric fields in the augmentation of SERS and their manifold applications in drug identification, chemical detection, and catalysis. In summation, a delineation of challenges and perspectives inherent to E‐SERS substrates is presented, delineating a path for prospective comprehensive exploration within this auspicious realm of research.

Nano-composite rGO-Ag-Cu-Ni mediated photocatalytic degradation of anthracene and benzene

Polycyclic aromatic hydrocarbons (PAHs) are omnipresent, persistent, and carcinogenic pollutants continuously released in the atmosphere due to the rapid increase in population and industrialization worldwide. Hence, there is an ultimate rise in concern about eliminating the toxic PAHs and their related aromatic hydrocarbons from the air, water, and soil environment by employing efficient removal technologies using nanoparticles as a catalyst. Here, the degradation of selective PAHs viz., anthracene and benzene using laboratory synthesized rGO-Ag-Cu-Ni nanocomposite (catalyst) was studied. Characterization studies revealed the nanocomposites exhibited surface plasma resonance at 350 - 450 nm, confirming the presence of Ag, Cu, and Ni metal ions embedded on the reduced graphene substrate. It was found that the nanocomposites synthesized were spherical, amorphous in nature, and aggregated together with measurements ranging from 423 to 477 nm. An SEM-EDX analysis of the nanocomposite demonstrated that it contained 25.13% O, 14.24% Ni, 27.79% Cu, and 32.84% Ag, which confirms the synthesis of the nanocomposite. Crystalline, sharp nanocomposites of average size 17–41 nm with an average diameter of 118.5 nm (X-ray diffraction and DLS) were observed. FTIR spectra showed that the nanocomposites had the functional groups alkanes, alkenes, alkynes, carboxylic acids, and halogen derivatives. Batch adsorption studies revealed that the maximum degradation achieved at optimum nano-composite concentration of 10 μg/mL, pH value of 5, PAHs concentration of 2 μg/mL and effective irradiation source being UV radiations in the case of both benzene and anthracene pollutants. The degradation of benzene and anthracene followed Freundlich & Langmuir isotherm with the highest R2 value of 0.9894 & 0.9885, respectively. Adsorption kinetic studies under optimum conditions revealed that the adsorption of both benzene and anthracene followed Pseudo-second order kinetics. Antimicrobial studies revealed that the synthesized nano-composite exhibited potential antimicrobial activity against Gram positive bacterium (Bacillus subtilis, Staphylococcus aureus), Gram negative bacterium (Klebsiella pneumonia, Escherichia coli) and fungal strain (Aspergillus niger) respectively. Thus, the synthesized rGO-Ag-Cu-Ni nano-composite acts as an effective antimicrobial agent as well as a PAHs degrading agent, helping to overcome antibiotics resistance and to mitigate the overgrowing PAHs pollution in the environment.

The Synthesis of BODIPY-TKI Conjugates and Investigation of Their Ability to Target the Epidermal Growth Factor Receptor

A near-IR BODIPY was covalently conjugated via its isothiocyanate groups to one or two Erlotinib molecules, a known tyrosine kinase inhibitor (TKI), via triethylene glycol spacers, to produce two novel BODIPY-monoTKI and BODIPY-diTKI conjugates. The ability of these conjugates to target the intracellular domain of the epidermal growth factor receptor (EGFR) was investigated using molecular modeling, surface plasma resonance (SPR), EGFR kinase binding assay, time-dependent cellular uptake, and fluorescence microscopy. While both the BODIPY-monoTKI and the BODIPY-diTKI conjugates were shown to bind to the EGFR kinase by SPR and accumulated more efficiently within human HEp2 cells that over-express EGFR than BODIPY alone, only the BODIPY-monoTKI exhibited kinase inhibition activity. This is due to the high hydrophobic character and aggregation behavior of the BODIPY-diTKI in aqueous solutions, as shown by fluorescence quenching. Furthermore, the competition of the two Erlotinibs in the diTKI conjugate for the active site of the kinase, as suggested by computational modeling, might lead to a decrease in binding relative to the monoTKI conjugate. Nevertheless, the efficient cellular uptake and intracellular localization of both conjugates with no observed cytotoxicity suggest that both could be used as near-IR fluorescent markers for cells that over-express EGFR.

Review of the Status and Prospects of Fiber Optic Hydrogen Sensing Technology

With the unprecedented development of green and renewable energy sources, the proportion of clean hydrogen (H2) applications grows rapidly. Since H2 has physicochemical properties of being highly permeable and combustible, high-performance H2 sensors to detect and monitor hydrogen concentration are essential. This review discusses a variety of fiber-optic-based H2 sensor technologies since the year 1984, including: interferometer technology, fiber grating technology, surface plasma resonance (SPR) technology, micro lens technology, evanescent field technology, integrated optical waveguide technology, direct transmission/reflection detection technology, etc. These technologies have been evolving from simply pursuing high sensitivity and low detection limits (LDL) to focusing on multiple performance parameters to match various application demands, such as: high temperature resistance, fast response speed, fast recovery speed, large concentration range, low cross sensitivity, excellent long-term stability, etc. On the basis of palladium (Pd)-sensitive material, alloy metals, catalysts, or nanoparticles are proposed to improve the performance of fiber-optic-based H2 sensors, including gold (Au), silver (Ag), platinum (Pt), zinc oxide (ZnO), titanium oxide (TiO2), tungsten oxide (WO3), Mg70Ti30, polydimethylsiloxane (PDMS), graphene oxide (GO), etc. Various microstructure processes of the side and end of optical fiber H2 sensors are also discussed in this review.

WAKE EXCITATION OF PLASMA AND ELECTROMAGNETIC OSCILLATIONS BY A RELATIVISTIC ELECTRON BUNCH IN A PLASMA RESONATOR

The process of the excitation of plasma and electromagnetic oscillations by a relativistic electron bunch in a plasma resonator is considered. It is shown that the potential electric field of plasma oscillations contains the field of a bulk wake plasma wave and the fields of two surface plasma oscillations. Surface plasma oscillations are localized in the vicinity of the input and output ends of the plasma resonator. In a plasma resonator, as a result of the effect of transition radiation at the ends of the resonator, the electron bunch will also excite eigen electromagnetic oscillations of the resonator. The spatio-temporal structure of the electromagnetic field of these oscillations has been studied.