Irradiation Conditions Research Articles

Reductive Dissolution Mechanisms of Manganese Oxide Mediated by Algal Extracellular Organic Matter and the Effects on 17α-Ethinylestradiol Removal.

Reductive dissolution of manganese oxide (MnOx) is a major process that improves the availability of manganese in natural aquatic environments. The extracellular organic matter (EOM) secreted by algae omnipresent in eutrophic waters may affect MnOx dissolution thus the fate of organic micropollutants. This study investigates the mechanisms of MnOx reductive dissolution mediated by EOM and examines the effects of this process on 17α-ethinylestradiol degradation. The influences of EOM concentration (1.0-20.0 mgC/L) and pH (6.0-9.0) in both dark and irradiated conditions were assessed. In the dark, EOM was found to facilitate MnOx reductive dissolution via the ligand-to-metal charge transfer (LMCT). The dissolution was further enhanced under irradiation, with the participation of superoxide ions (O2•-). Higher EOM concentrations increased the contents of available reducing substances and O2•-, accelerating the reductive dissolution. Higher pH slowed the photoreductive dissolution rates, while O2•--mediated reduction became more important. Polyphenols and highly unsaturated carbon and phenolic formulas in EOM were found to drive the reductive dissolution. Soluble reactive Mn(III) formed through reductive dissolution of MnOx effectively removed 17α-ethinylestradiol in solution. Overall, the findings regarding the mechanisms behind reductive dissolution of MnOx have broad implications for Mn geochemical cycles and organic micropollutant fate.

Construction of a 0D-2D-2D Sandwich-like Ag/g-C3N4/MoS2 Photocatalyst with Bidirectional Electron Transfer Channels for Photocatalytic Hydrogen Evolution.

Hydrogen (H2) production technology has sparked a boom in research aimed at alleviating environmental pollution and the pressure of nonrenewable energy sources. A key factor in this technology is the use of efficient photocatalysts. In this work, we successfully synthesized a 0D-2D-2D sandwich-like Ag/g-C3N4/MoS2 catalyst with bidirectional electron transfer channels via a calcination-hydrothermal method. The H2 evolution reaction of the Ag/g-C3N4/MoS2 catalyst under simulated solar light irradiation conditions revealed that it achieved a maximum H2 evolution rate of 1061.13 μmol·g-1·h-1, representing a 43.12-fold improvement over pristine g-C3N4. Based on systematic characterization with a combination of theoretical simulations, time-resolved photoluminescence, and electron spin resonance spectra, we demonstrate that the remarkable improvement in photocatalytic performance was ascribed to the bidirectional electron transport channels and 0D-2D-2D structure of the ternary catalyst. This unique structure, which was characterized by a large specific surface area, provided numerous active sites for photocatalytic reactions. Bidirectional electron transfer channels expedited the migration of photogenerated electrons reaching cocatalysts MoS2 and Ag from the conduction band of g-C3N4, consequently enhancing the photocatalytic activity. This study highlights the effectiveness of the bidirectional electron transfer channels in promoting charge carrier migration and suppressing charge carrier recombination for boosting photocatalytic hydrogen evolution and provides an efficient strategy for the actual application of g-C3N4-based photocatalysts.

Impact of Microwave Pre-Curing on Pore Structure and Environmental Performance of Metakaolin- and Fly Ash-Based Geopolymers

Microwave technology in geopolymer synthesis offers a transformative, sustainable alternative to traditional methods, enhancing material properties and production efficiency. However, the effects of microwave-induced changes on pore structure and their relationship with mechanical strength and environmental performance, such as heavy metal leachability, are not fully understood. This study investigates the impact of microwave pre-curing on geopolymers, focusing on how microwave power and duration influence their pore structure and environmental performance. A total of 48 mixtures were prepared using sodium silicate and sodium hydroxide as alkali activators, with metakaolin and fly ash as raw materials. The modulus was adjusted to 1.5, and the liquid-to-solid ratio was set at 1.6 for metakaolin and 0.7 for fly ash. Microwave irradiation power settings of 100 W, 300 W, 440 W, 600 W, and 800 W were tested. The heating times ranged from 30 s to 90 s at intervals of 15 s. Our findings reveal that optimal microwave settings (100 watts for 45 s) can significantly enhance mechanical properties, with compressive strengths reaching 15.9 MPa for fly ash-based and 9.094 MPa for metakaolin-based geopolymers. However, excessive microwave energy leads to increased porosity, with adverse effects on structural integrity. Moreover, microwave pre-curing effectively reduces heavy metal leachability. Chromium (III) was used in leaching tests and it was demonstrated that ion concentrations as low as 0.097 mg/L enhance environmental safety. Advanced techniques like Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray CT were applied for the analysis of the atomic bonding, phases and pore structure of the studied geopolymers along with their ability to withstand compression (MPa). Chromium (III) was encapsulated and its leached concentration was measured by ICP-MS to evaluate the performance of the synthesized geopolymers. These results underscore the need for precise control over microwave irradiation parameters to maximize the benefits while mitigating negative impacts. This study provides valuable insights into the controlled use of microwave technology for geopolymer synthesis, recommending optimal irradiation conditions for improved performance and sustainability and advancing sustainable construction materials. The developed geopolymers show promise for applications in construction, waste stabilization, and heavy metal immobilization, contributing to more sustainable and environmentally friendly materials in these industries.

A preliminary assessment of a solid-state lithium-ion battery in radiation environment by Geant4 simulations

This study investigates the impact of irradiation on solid-state lithium batteries, which is critical for their deployment in challenging environments such as space missions and nuclear facilities. By utilizing Geant4 simulations, we examine the effects of neutrons and gamma irradiation on battery materials, with a particular emphasis on the generation of hydrogen and helium isotopes, non-ionizing energy loss (NIEL), and potential radiation-induced leakage current. Our simulations indicate that the induced radioactivity is negligible at the ex-core site of the pressurized water reactor. Notably, neutron irradiation results in higher NIEL values than gamma rays, suggesting more significant displacement damage in battery materials. In particular, we observe a directional leakage current induced by gamma-ray irradiation, with the solid-state electrolyte LLZTO demonstrating the most pronounced response. This phenomenon could potentially lead to alterations at the electrode/electrolyte interface. These findings provide valuable insights into the design and optimization of solid-state lithium batteries in irradiated conditions.

Multiscale modeling of short pulse laser induced amorphization of silicon

Silicon surface amorphization by short pulse laser irradiation is a phenomenon of high importance for device manufacturing and surface functionalization. To provide insights into the processes responsible for laser-induced amorphization, a multiscale computational study combining atomistic molecular dynamics simulations of nonequilibrium phase transformations with continuum-level modeling of laser-induced melting and resolidification is performed. Atomistic modeling provides the temperature dependence of the melting/solidification front velocity, predicts the conditions for the transformation of the undercooled liquid to the amorphous state, and enables the parametrization of the continuum model. Continuum modeling, performed for laser pulse durations from 30 ps to 1.5 ns, beam diameters from 5 to 70 μm, and wavelengths of 532, 355, and 1064 nm, reveals the existence of two threshold fluences for the generation and disappearance of an amorphous surface region, with the kinetically stable amorphous phase generated at fluences between the lower and upper thresholds. The existence of the two threshold fluences defines the spatial distribution of the amorphous phase within the laser spot irradiated by a pulse with a Gaussian spatial profile. Depending on the irradiation conditions, the formation of a central amorphous spot, an amorphous ring pattern, and the complete recovery of the crystalline structure are predicted in the simulations. The decrease in the pulse duration or spot diameter leads to an accelerated cooling at the crystal–liquid interface and contributes to the broadening of the range of fluences that produce the amorphous region at the center of the laser spot. The dependence of the amorphization conditions on laser fluence, pulse duration, wavelength, and spot diameter, revealed in the simulations, provides guidance for the development of new applications based on controlled, spatially resolved amorphization of the silicon surface.

Dithiolanes and Oxathiolanes Obtained from Cymantrene Derivatives: Synthesis and Properties

AbstractNovel cymantrene derivatives containing dithiolane and oxathiolane five‐membered cycles were prepared. Their spectral, optical, and redox properties were investigated by NMR, IR, UV–vis spectroscopy, and CV. Under the conditions of irradiation and subsequent dark reaction, the effect of ligand exchange on physicochemical properties was studied. Photolysis of tricarbonyl complexes leads to the formation of rare, stable four‐membered chelate complexes with Mn─S bond, one of which has been successfully isolated and characterized by X‐ray. However, in the presence of a competitive external ligand (L), the Mn─S bond dissociated, followed by the formation of new dicarbonyl complexes with the Mn─L bond, that shows the hemilabile nature of the Mn─S bond in chelate complexes.

ASYMMETRIC LEAVES2 repression confers lobed leaves by regulating lignin biosynthesis of leaf veins in Betula pendula

Lobed leaves are a desirable phenotypic trait in conditions of high irradiance and environmental stresses. Betula pendula 'Dalecarlica', an intraspecific variation of B. pendula, shows a unique leaf shape with deeply lobed leaves in contrast to the serrated ovate leaves of B.pendula. The leaf vein pattern is critically important for the formation of leaf lobes. However, the underlying regulatory mechanisms remain elusive. In this study, we investigated a gene regulatory network using RNA-seq data from different development stages of midveins in B.pendula 'Dalecarlica'. We identified BpAS2 as a key negative regulator in vein development of lobed leaves. RNA-seq analysis revealed that genes related to lignin biosynthesis were significantly upregulated in bpas2 mutant plants created using the CRISPR/Cas9 genome editing system. Loss-of-function of BpAS2 gene results in overdeveloped veins in lobed leaves. Furthermore, ChIP assay confirms that BpAS2 physically binds the promoter of BpKNAT1, and represses its gene expression of BpKNAT1 which is a molecular regulator of leaf dissection and lignin biosynthesis. Our results indicate that BpAS2 represses BpKNAT1 to downregulate lignin biosynthesis, thereby, inhibiting the development of leaf vein patterns and the formation of lobed leaves.

Effects of 660 nm red light and 850 nm near infrared light on human blood lymphocytes

Abstract The applications of light emitting diodes (LED) as a red light therapy (RLT) source for the management of various conditions such as wound treatment, control of inflammation and pain have been growing continually. Despite its extensive medical application, the effects of RLT on living cells are still highly contested. This study is conducted to test the effects of RLT using combined LED source with 660 nm (red) and 850 nm (near infrared) light on cultured human lymphocytes in vitro. To analyze the effect of RLT on human peripheral blood lymphocyte’s proliferation, the mitotic index (cytostatic effect) is monitored under different irradiation exposure time parameters and conditions. This value indicates how a particular treatment affected cell division, either proliferatively, inhibitory, or had no effect at all. The interpretation of the results of the mitotic index is done in relation to the mitotic index of the untreated (unirradiated) control cells. Our data shows higher lymphocyte proliferation for all of the irradiated samples, and is particularly enhanced by multiple exposures to red light. The effectiveness of RLT on cell activity is of importance in determination of suitable treatment for diseases related to the immune system. To better understand the molecular and metabolic mechanisms involved in red LED-induced photobiomodulation, the study will be extended to investigate the RLT effect on cell protein synthesis.

Thermodynamic instability of polycrystalline tungsten exposed to low-energy hydrogen irradiation

The stability of polycrystalline tungsten (W) exposed to low-energy (120 eV) and large-flux (1.5×1022 ions/m2⋅s) hydrogen (H) irradiation at low-pressure has been evaluated by using scanning electron microscopy-electron backscatter diffraction, energy dispersive spectroscopy, and conductive atomic force microscopy. Both surface degeneration and formation of ultra-fine W crystal grains have been observed during the annealing in the range of 200-900 °C. The thermodynamic stability of irradiated W is significantly affected by the annealing temperature. Our finding suggests that the serious erosion of polycrystalline W by H irradiation results from the thermodynamic instability of irradiated W while the instability is attributed to the strong diffusion of interstitial W atoms under fusion-relevant irradiation conditions. Our calculation confirms the instability of W atoms close to the H clusters, leading to the formation of self-interstitial W atoms in W crystal.

Autonomous Street Lighting System based on Solar Energy and LEDs

This paper introduces a solar-powered autonomous street lighting system designed primarily for areas without access to the grid, such as rural roads and intersections. It utilizes solar panels as the primary energy source, with batteries serving as backup, and employs light-emitting diodes (LEDs) for illumination. The proposed system is optimized for efficiency by employing direct current (DC) power at all stages. To replace a 70W high-pressure sodium (HPS) lamp, an LED fixture design is discussed, considering human scotopic vision. Experimental outcomes for the LED driver and battery charger are provided, demonstrating features such as maximum power point tracking (MPPT), constant current, and constant voltage modes. The system ensures MPPT under varying solar irradiance and temperature conditions by analyzing the battery charger input impedance.

Response of CaSO4:Dy Teflon embedded thermoluminescent dosimeter badge on different ISO phantoms for photons and beta sources using FLUKA and GEANT4

In this study, Monte Carlo codes FLUKA and GEANT4 were used to assess the angular variation in the response of CaSO4:Dy Teflon disc based TLD badge. These badges were positioned on various ISO phantoms to simulate the angular exposures ranging from 0° to 60° for photons within the energy range of 12.3 keV to 1.25 MeV, as well as for 90Sr/90Y and 106Rh/106Ru beta sources. Plots showing the TL response of the discs in terms of Hp(10), Hp(3), and Hp(0.07) as a function of photon energy were obtained for ISO slab, cylindrical, and pillar phantoms, respectively. Additionally, the study estimated the angular variation in the response of disc ratios (R12 and R32) with respect to both photon and beta energies. The simulation results revealed that the response of the open disc (D3) was higher for lower X-ray energies, attributed to an increase in the photoelectric effect. Conversely, the response of the disc under the metal filter (D1) was observed to increase with the angle, indicating the Compton scattering from the cassette body and phantom, especially at lower X-ray energies. Beta response of both disc D2 (under PMMA filter) and D3 found to be decreasing with the angle of incidence while R32 ratio found to be increasing with the angle of incidence for both 90Sr/90Y and 106Rh/106Ru beta sources. Notably, the simulated results demonstrated good agreement with experimental observations, reinforcing the reliability of the Monte Carlo simulations for complex interactions and responses of TLD badges under different irradiation conditions.

Reduced graphene oxide – CeO2 nanocomposites for photocatalytic dye degradation

Over the past few decades, the widespread use of dyes has led to considerable environmental pollution, posing serious threats to human health and ecosystems. In this context, here focus on a tailored nanocomposite comprising reduced graphene oxide (rGO) and cerium oxide (CeO2) to eradicate methylene blue (MB) dye. The fabrication process involves a facile synthesis wherein CeO2 nanoparticles are anchored onto rGO sheets through co-precipitation treatment by mixing a precursor salt of cerium with graphene oxide (GO) in presence of reducing agent. The resulting nanocomposites were characterized using X-ray diffraction (XRD) analysis which confirms the crystallite size of CeO2 and rGO-CeO2 determined to be 21.61 nm and 10.74 nm respectively. Further FE-SEM analysis vividly illustrates the relatively spherical form of CeO2, which is dispersed on the rGO surface and energy dispersive X-ray spectroscopy (EDX) results provide clear evidence of the presence of carbon, cerium and oxygen in the composite. Additionally, Fourier-transform infrared spectroscopy (FTIR) confirms the composition of the rGO-CeO2 nanocomposites demonstrating the existence of various oxygen-containing groups, including O–H, C=O and Ce–O bonds. Thermogravimetric analysis (TGA) highlights that the rGO-CeO2 nanocomposites exhibits higher thermal stability with only 21.88 % weight loss up to 400 °C. Moreover, the photocatalytic activity of rGO-CeO2 nanocomposite exhibits a remarkable 94.92 % degradation of MB dye within 80 min under optimal conditions of UV light irradiation (λ = 254 nm), with a catalyst dosage of 7 mg in a 20 ppm of MB dye solution at pH 9. In contrast, pristine rGO and CeO2 achieved only 32.27 % and 38.48 % in 100 and 90 min respectively. The kinetics of photocatalysis process were meticulously studied and revealed that they followed pseudo-second order kinetic model suggesting chemisorption of MB dye onto nanocomposites prior to degradation. The stability of the nanocomposite was assessed under optimal conditions, demonstrating robust MB degradation (78 %) even up to the 4th cycle. Overall, the successful outcomes of this study show significant potential for degrading MB dye in wastewater by using the rGO-CeO2 nanocomposite.

Exploring the regenerative capacity of the spleen following irradiation

IntroductionHaematopoietic stem cell transplantation (HSCT) is commonly used to treat patients with haematological disorders. Myeloablative conditioning is an important preparation for patients receiving haematopoietic stem cells (HSC) or haematopoietic stem and progenitor cells (HSPC). While widely successful, HSCT is still associated with high rates of mortality. The recovery time between complete myeloablation and haematopoietic recovery is a large factor in the recovery rate. Successful engraftment of HSC is also directly correlated with the number of HSC niches available. This highlights the importance of the haematopoietic niche and its recovery from myeloablation as an important therapeutic target.MethodsThis murine model study specifically considers changes in spleen tissue architecture and cellular composition involving stromal and vascular cells that occur following lethal irradiation.ResultsSpleen recovered fully between 4- and 8-weeks after irradiation due to reconstitution by HSPC from bone marrow. Specific temporal changes in spleen architecture were identified, and these were linked to the cell types that constitute the white pulp, red pulp and marginal zones. Mesenchymal stromal cells returned before endothelial cells, and reticular cell types recovered more quickly in spleen following irradiation. Losses in gp38+ fibroblastic reticular cells and MAdCAM-1+ marginal reticular cells were associated with loss of the white pulp in the first 4 weeks following irradiation. White pulp was restored following recovery of supporting reticular cells.DiscussionThis study tests how spleen regeneration following a lethal dose of irradiation can be influenced by co-infusion of bone marrow HSPC together with either neonatal spleen stromal cells, or cells of the stromal STX3 line. Both the infusion of neonatal spleen stromal cells and STX3 stromal cells hastened recovery of both mesenchymal and vascular compartments. Following neonatal spleen stromal cell infusion, endothelial cells increased early, but a delay in structural reformation of distinct red and white pulp areas was found. Results from this study show that spleen regeneration can be influenced and even hastened through cellular therapy. Neonatal spleen stromal cells, co-infused together with HSPC following irradiation conditioning, represent a potential therapeutic opportunity for hastening spleen regeneration.

Study on the performance and mechanism of photocatalytic hydrogen production by NiO/ZnO-graphene composite materials under low irradiation conditions

Using different mass ratios of NiO, ZnO, and corn stover-based graphene (GR), NiO/ZnO-graphene (NZGR) composite photocatalytic materials, which demonstrated photocatalytic water splitting for hydrogen production under low irradiation, were prepared by an in-situ deposition method. The microstructure and optoelectronic properties of the NZGR materials were characterized. The heterostructure formed by NiO and ZnO in the photocatalytic NZGR material was coupled with the graphene-like structure of GR, resulting in the rapid transfer of electrons to the graphene surface, causing electron accumulation and ensuring the ability of the material to produce hydrogen by the photocatalytic decomposition of water under low irradiation. Under the optimal mixing ratio of the components of the NZGR photocatalyst with a graphene mass fraction of 30 %, hydrogen production exhibited the highest rate and was 350 times faster than the photocatalytic hydrogen production of NiO/ZnO under the same conditions. This study provides a new approach to producing hydrogen by the photocatalytic decomposition of water under low irradiation conditions.

Degradation of Tetracycline (TC) by ZrO2-3DG/PMS System: Revealing the Role of Defects in the Conditions of Light Irradiation and Sulfate Accumulation

The application of advance oxidation processes (AOPs) based on the activation of peroxymonosulfate (PMS) is a great concern for wastewater treatment. Herein, ZrO2-3DG was constructed using a hydrothermal method for the degradation of tetracycline (TC) with PMS. The defective ZrO2-3DG materials were also prepared with plasma treatment. SEM and XPS results show that the ZrO2-3DG composite and the corresponding defective materials were successfully fabricated. The ZrO2 particles are distributed uniformly on the substrate material. Plasma can induce defects on the composite materials and create highly active sites. TC degradation results show that the ZrO2-3DG/PMS system can achieve a degradation efficiency of 92.9% for TC. The influences of defects on materials, light irradiation and sulfate accumulation were investigated. It has been found that defects can induce an inhibiting effect on the degradation process, which can be tuned by plasma time. The defective ZrO2-3DG/PMS system exhibits excellent resistance to the accumulation of sulfate, even showing enhanced degradation performances in specific conditions. The light irradiation has led to a higher degradation efficiency with the accumulation of sulfate compared with a dark environment. These findings give great guidance to the application of the ZrO2-3DG/PMS system for environmental protection.

In situ synthesis of Fe3O4/ carboxylated multi-walled carbon nanotubes nanostructures on nylon fabric with efficient flame retardant and antibacterial properties

Knitted fabrics are ideal for flexible, conductive, and magnetic smart textiles but have low adhesion for materials, especially inorganic ones. In this study, carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and magnetite (Fe3O4) magnetic nanoparticles were synthesized in situ and then coated onto nylon knitted fabric. Using nylon and in situ coating of these nanostructures enhances nanotube absorption via hydrogen bonding and provides magnetite growth sites on both the coated nanotubes and the fabric surface, due to the direct attraction of positively charged iron salts to the polar bonds of nylon. The effect of the weight ratio on the characteristics was evaluated through the coatings with Fe3O4 to MWCNT-COOH at different ratios. Surface structure, chemical analysis, microstructure, electrical conductivity, magnetic properties, antibacterial properties, zeta potential, and thermal properties were studied. FESEM results and surface structure evaluation indicated that increasing the quantity of iron salts influenced the morphology: a single layer was observed at a 2:1 ratio and the combination of layers and particles at 4:1 and 6:1 ratios. At 8:1, there was a recurrence of a layered structure. Magnetite nanoparticles led to the fusion of carbon nanotubes and this was evident from the magnetic characteristic of the fabric. Magnetic properties showed an increasing trend up to the 6:1 ratio (from 0.06 emu/g to 1.00 emu/g) and then decreased at the 8:1 ratio (0.71 emu/g) due to an increase in the number of agglomerations in the solution. These observations were further supported by crystallography analysis of the synthesized magnetite nanoparticles which showed variations in the crystal size. The fabric had better adhesion of carbon nanotubes with increased iron salt content which helped in coating and conductivity. The introduction of these nanostructures also greatly enhanced the heat-resistant properties of the fabrics with the burning length reduced by about 70 % while the photothermal properties of the fabrics reached 81°C. In addition, a significant antibacterial effect was observed in the present study with a minimum of 64 % efficiency under non-irradiated conditions and up to 99 % bacterial killing under irradiated conditions.

GAFchromic EBT film lateral resolution and contrast reproduction in the UV-blue range

The sensitivity of radiochromic films to UV-blue light is increasingly considered for light dosimetry purposes, owing to their bidimensional detection capabilities and ease of use. While film response to radiation intensity has been widely investigated by commercial scanners, spatial resolution studies remain scarce, especially for small field-of-view applications. These are of growing interest due to the antimicrobial or photo-bio-stimulating effects of UV-blue light sources in in vitro, ex vivo and in vivo models, where precise knowledge of irradiation conditions with adequate spatial resolution is crucial. In this study, we report the spatial lateral resolution and contrast reproduction of GAFchromic EBT2 and EBT3 models. Upon film irradiation by a 405 nm laser source or 365 nm LED, a confocal microscope setup was employed to read the film response at 405, 470, 488, 532 and 570 nm wavelengths, with radiant exposure of 10–70 J/cm2. The measured lateral resolution ranged from 8 to 33 μm. The film capability to reproduce contrast across various spatial frequencies (4–14 lines/mm) was evaluated using modulation transfer function analysis with irradiation performed at 365 nm and 405 nm, revealing a pronounced dependency on both radiant exposure and reading wavelength. These results confirm the film capacity to detect and resolve light intensity variability with a ~ 10 μm resolution, with notable applications in micro-beam profiling and light dosimetry.

Continuous Monitoring of Therapeutic Monoclonal Antibody Using Regenerable Aptamer Based Electrochemical Sensor

Therapeutic humanized monoclonal antibodies (mAbs) are focused on as effective medicine owing to their high specificity and efficacy compared with conventional small-molecule pharmaceuticals. To avoid side effects and improve the treatment efficacy, controlling the dose of therapeutic mAbs for the patient is the most crucial. However, the monitoring of their concentrations demands highly specific discrimination from human immunoglobulin G (IgG), since most therapeutic mAbs are designed based on IgG, which is naturally present in large quantities in human blood and differs only in residues at the complementarity determining region (CDR).Previously, we developed the therapeutic mAbs aptamer sensor utilizing an anti-idiotype aptamer, that recognizes the complementarity determining region, CDR, of a target therapeutic antibody, Bevacizumab [1,2]. This sensor can distinguish the target antibody and other human natural antibodies and succeed in detecting the bevacizumab from artificial serum that contains a high concentration of human natural IgG. Since this sensor does not require a chemical reaction nor a free redox probe in the solution, they are very suitable for in vivo continuous monitoring. However, due to the high binding constant (~nM-pM) of aptamer, binding site regeneration is only possible by denaturing both the target protein and aptamer structures with guanidine hydrochloride. Currently, the most challenging task for future therapeutic mAb sensors employing aptamers with a high binding constant to realize in vivo continuous monitoring is the development of versatile methods and technologies suitable for the in situ regeneration of aptamer binding sites.To tackle this challenging task, we have been engaged in the designing of engineered aptamers which can be modulated in their binding constant by external signals. Azobenzene is an ideal photoresponsive molecule, which reversibly changes its cis/trans forms, by UV or visible light irradiation and this structure change drives aptamer structure change and releases the target [3,4]. In this study, we designed an azobenzene-inserted anti-idiotype bevacizumab aptamer and developed an electrochemical sensor that can regenerate its binding site by light irradiation.To design the photo-regenerated anti-idiotype bevacizumab aptamer, we investigated the appropriate position to insert azobenzene without affecting the binding ability. After the confirmation of binding ability, we applied these aptamers to electrochemical measurement. Azobenzene-inserted anti-bevacizumab idiotype aptamers were immobilized on the planar electrode. Electrochemical measurements were carried out using a constructed aptamer electrode as a working electrode. After the confirmation of target binding on the electrode, we tried to regenerate the aptamer-immobilized electrode by UV light irradiation. The release of the target antibody was confirmed electrochemically.We will present the characterization of the photo-regenerated anti-idiotype aptamer, focusing on the change in binding toward the target therapeutic mAb, bevacizumab in UV and visible light irradiated conditions. Finally, we will show repeated detection of bevacizumab using this novel-engineered aptamer combined with electrochemical detection such as an extended gate FET-based sensor toward the continuous monitoring of a therapeutic mAb, bevacizumab.[1] Saito et al., Biosensors and Bioelectronics, 2022,203,114027[2] Nagata et al., Int. J. Mol. Sci., 2023, 24(6) 5277[3] Liang et al., JACS, 2003, 125, 16408[4] Liang et al., Small, 2009, 5(5) 1761]

Behavior of Fe-based alloys in a liquid lead-bismuth environment under simultaneous proton irradiation and corrosion

The performance and longevity of nuclear reactors are significantly influenced by the behavior of their structural materials, particularly under conditions of corrosion and irradiation. This study investigates the combined effects of corrosion and irradiation on three alloys: Fe-Ni-Cr-Al-Nb, Fe-Cr-Al-Y, and Fe-12Cr-2Si, exposed to a liquid Pb-4wt% Bi mixture at 675 °C for 4 h. 3 MeV proton irradiation was employed to understand the simultaneous effects of irradiation on the corrosion behavior of these alloys. When exposed to liquid lead-bismuth at 675 °C for 4 h, the Fe-Cr-Al-Y and Fe-12Cr-2Si alloys exhibited superior corrosion resistance compared to the Fe-Ni-Cr-Al-Nb alloy. Conversely, the Fe-Ni-Cr-Al-Nb alloy demonstrated significant Pb-Bi penetration, which was further accelerated by proton irradiation, resulting in increased penetration depth. This revealed that irradiation-induced damage can accelerate the corrosion rate of Fe-Ni-Cr-Al-Nb steel in lead-bismuth environments. Microstructural analysis using SEM/EDX, STEM, and diffraction patterns uncovered complex alloy interactions and potential chemical transformations in the irradiated Fe-Ni-Cr-Al-Nb alloy. This included the presence of lamellar or rod-like structures near Pb-Bi penetration sites and the selective retention of nickel by aluminum. In contrast, the Fe-12Cr-2Si alloy exhibited effective corrosion resistance attributed to a uniform distribution of elements and the formation of a protective Si-rich oxide layer. The Fe-Cr-Al-Y alloy developed distinct oxide layers, with chromium oxide predominating and a slight aluminum oxide layer, indicating the critical role of chromium oxide as a protective barrier.

Enhancing Internal Electric Field of Metal-Free Donor-Acceptor Conjugated Photocatalysts for Efficient Photocatalytic Degradation of Tetracycline and CO2 Reduction.

Constructing alternating donor-acceptor (D-A) units within g-C3N4 represents an effective strategy for enhancing photocatalytic performance through improved charge carrier separation while concurrently addressing energy shortages and facilitating wastewater remediation. Here, a series of D-A-type conjugated photocatalysts (CNBTC-X) are prepared using g-C3N4 as an acceptor unit and different masses of 5-bromo-2-thiophenecarboxaldehyde (BTC) as a donor unit by a one-step thermal polymerization. CNBTC-50 presents higher photocatalytic properties for CO2 reduction coupled with tetracycline (TC) removal than those of g-C3N4, CNBTC-10, CNBTC-30, and CNBTC-70. The introduction of the unique electron-donor-acceptor structure effectively drives the separation and transfer of photoinduced carriers while reducing the internal carrier transfer hindrance. Photocatalytic experiments reveal that the CNBTC-50 photocatalyst achieves up to 94.6% TC removal under visible light irradiation conditions. Compared with that of the pristine g-C3N4, the photocatalytic degradation reaction rate constant of CNBTC-50 is significantly increased by about 3.87 times. The study examines the influence of various reaction parameters on degradation activity, including catalyst concentration, pH, and TC concentration. Additionally, LC-MS is utilized to perform a comprehensive analysis of the intermediates and pathways involved in TC degradation. Furthermore, CNBTC-50 demonstrates remarkable photocatalytic CO2 reduction activity, achieving rates of 20.83 μmol g-1 h-1 (CO) and 9.36 μmol g-1 h-1 (CH4), which are 10.68 and 5.98 times more efficient than those of g-C3N4, respectively. This work aims to offer valuable guidance for the rational design of nonmetal D-A-structured catalysts and effectively integrates reaction systems to couple CO2 reduction with antibiotic removal.