X-ray Photoelectron Spectroscopy Research Articles

Peptide-Functionalized Gold Nanoparticles as Organocatalysts for Asymmetric Aldol Reactions

The use of high catalyst loading is required for most of the organocatalyzed asymmetric aldol reactions in organic synthesis, and this often presents challenges during purification and difficulties in catalyst recovery from the reaction mixture. The immobilization of the catalyst onto gold nanoparticles (AuNPs) can change the structural conformations of the catalyst, thereby improving its catalytic activity and reusability. Herein we report on the synthesis of aldolase mimetic peptide coupled to gold nanoparticles (AuNPs) as efficient organocatalysts for asymmetric aldol reaction. AuNPs were synthesized using the Turkevich method. The conjugation of the peptide to AuNPs was characterized using surface plasmon resonance (SPR), Raman and X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM) was used for particle size determination. The produced nanoparticles, whose sizes depended on the reduction method, were quasi-spherical with a relatively narrow size distribution. The peptide–AuNP conjugates were evaluated for aldol reaction catalytic activity between carbonyls p-nitrobenzaldehyde and cyclohexanone. The products were obtained with good yields (up to 85%) and enantioselectivity (up to 94%). The influence of organic solvents, pH and buffer solutions was also investigated. The results showed that the buffer solutions regulated the colloidal stability of AuNPs, resulting in a significant enhancement in the catalytic rate of the peptide–AuNP conjugate.

Two in One Gram Negative Antibacterial Agent and Organic Dye Photocatalyst from Green Synthesized Ocimum Sanctum-Based N and O Co-Doped Carbon Dot Silver Nanocomposite.

This study reports, successful synthesis of Oxygen(O) and Nitrogen(N) co-doped Ocimum Sanctum plant-based or tulsi carbon dots-silver nanoparticle nanocomposites (TCD-AgNP) for the development of an efficient, highly active, low-cost fingerprint antibacterial agent against gram-negative organisms and a highly efficient photocatalyst for the degradation of methylene blue (MB). Green synthesized, high quantum yield (47 %), intensely blue fluorescent, highly stable N and O co-doped TCDs from carbonization technique of tulsi leaves is achieved without any chemical treatment or surface fascination which could act as an efficient green reducing agent for the development green TCD-AgNP nanocomposites. The novelty and advantage of this study is the development of highly stable, blue fluorescent, high quantum yield (40 %) environmental -friendly TCD-AgNP nanocomposite through reduction method by using green TCDs. TCD-AgNP nanocomposites were synthesized by varying the concentrations of AgNO3 into a fixed amount of green TCDs. Spectrochemical characteristics of synthesized TCDs and TCD-AgNP nanocomposites were investigated through UV-Vis absorbance, Photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential measurements confirming excellent fluorescence, unique stability and effective O and N doping. High-resolution transmission electron microscopy (HR-TEM) images confirms that the synthesized TCDs and TCD-AgNP nanocomposites were spherical in shape with an average size of 6.3 nm and 11.5 nm respectively. The antibacterial studies proved that TCD-AgNP nanocomposites ware highly effective against Gram-negative (Serratia marcescens, E. coli, and Pseudomonas aeruginosa) microbial organisms and showed zones of inhibition 12, 9 and 18 mm as compared to streptomycin sulphate. Besides, TCD-AgNP nanocomposite was used as a photocatalyst for the degradation of MB (10 ppm) under sunlight irradiation for regular intervals of time at room temperature with a photodegradation efficiency of 95.63 % and a photocatalytic rate constant of 0.0195 min-1.

Easy-to-Engineer Flexible Nanoelectrode Sensor from an Inexpensive Overhead Projector Sheet for Sweat Neuropeptide-Y Detection.

In this paper, we report an inexpensive and easy-to-engineer flexible nanobiosensor electrode platform by exploring a nonconductive overhead projector (OHP) sheet for sweat Neuropeptide-Y (NPY) detection, a potential biomarker for stress, cardiovascular regulation, appetite, etc. We converted a nonconductive OHP sheet into a conductive nanobiosensor electrode platform with a hybrid polymerization method, which consists of interfacial polymerization of pyrrole and a template-free electropolymerization technique to decorate the electrode platform with poly(EDOT-COOH-co-EDOT-EG3) nanotubes. The selection of poly(EDOT-COOH) features an easy conjugation of NPY antibody (NPY-Ab) through EDC/Sulfo-NHS coupling chemistry, while poly(EDOT-EG3) is best known to reduce nonspecific binding of biomolecules. The antibody conjugation on the polymer surface was characterized by a quartz crystal microbalance, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and chronoamperometry techniques. The OHP nanosensor platform exhibited the successful detection of NPY analyte through a chronoamperometry method in phosphate-buffered saline with a wide range of concentrations from 1 pg/mL to 1 μg/mL with a limit of detection of 0.68 pg/mL having good linearity (R2 = 0.9841). The sensor platform exhibited excellent stability, reproducibility, repeatability, and a shelf-life of 13 days. Furthermore, the sensor showed superior selectivity to a 100 pg/mL NPY analyte among other interfering compounds such as tumor necrosis factor α, cortisol, and Interleukin-6. The clinical practicality of the sensor was confirmed through the detection of 100 pg/mL NPY spiked artificial perspiration, highlighting the possibility of integrating the sensor platform to wearable healthcare applications.

A Facile Method to Incorporate Di-Dopant Elements (F and Sb) into Crystalline Mesoporous Tin Dioxide Nano Powder at Ambient Temperature and Pressure.

A simple two step synthetic method for di-doped crystalline mesoporous tin dioxide powder containing antimony and fluoride at ambient pressure and temperature has been developed. This approach produced materials with high surface areas and improved electrical and optoelectrical conductance. The two dopant elements; antimony and fluoride were introduced to tin dioxide by two approaches. Both approaches produced mesoporous tin dioxide with antimony and fluoride that are integrated in the framework. The structures of these materials are analyzed by powder X-ray diffraction, N2 sorption analysis, transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The conductance of the materials improved by factor of 13-34 compared to undoped mesoporous tin dioxide. The effect of the di-doped elements on structure, conductance and optoelectronic properties of these materials are discussed in this paper.

Mechanistic Insights into the Reaction of Wulfenite with Aqueous Sodium Sulfide Solution and Its Industrial Implications.

The purpose of this study was to investigate the reaction mechanism of wulfenite with an aqueous sodium sulfide solution and thereby provide guidance for the sulfidization flotation and sodium sulfide leaching of wulfenite. For this purpose, dissolution/leaching behavior analysis, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM) were performed. The dissolution/leaching analysis indicated that sodium sulfide can induce the dissolution of PbMoO4. The XRD and Raman spectra results demonstrated that PbMoO4 was replaced by PbS at the wulfenite-sodium sulfide solution interface, and the sulfidized wulfenite particles had a PbMoO4/PbS core-shell structure. The XPS results also indicated the transformation of PbMoO4 to PbS. The FESEM images showed the growth of PbS nanoparticles on the surface of wulfenite and the dissolution pits after treatment with sodium sulfide solution. These findings showed that wulfenite sulfidization proceeds through an interface-coupled dissolution-precipitation mechanism. In the presence of sodium sulfide solution, the less stable PbMoO4 dissolves, and the more stable PbS phase precipitates, both of which are coupled at the wulfenite-sodium sulfide aqueous solution interface.

Surface Activation and Characterization of Basalt Fiber by Plasma Treatment and Its Interfacial Adhesion with Epoxy.

The weakness of the fiber-matrix interface restricts the practical application of basalt fiber (BF) as a reinforcing material. In order to improve the interfacial adhesion between the BF and epoxy matrix, surface activation of the BF was carried out using low-pressure O2 and H2-Ar plasma under various conditions. The interfacial shear strength (IFSS), evaluated by a micro-droplet de-bonding test, was adopted to demonstrate the bonding effects at the BF/epoxy interphase. Compared to bare BF, the IFSS between the modified fibers and epoxy matrix was efficiently improved with an increment of 38.4% and 14.4% for O2 plasma and H2-Ar plasma treatment, respectively. Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM) analysis indicated that H2-Ar plasma-treated BF had a much rougher and more rugged surface than O2 plasma-treated samples. X-ray Photoelectron Spectroscopy (XPS) and surface energy results revealed that O2 plasma activation could effectively increase the content of oxygenous groups on the BF surface, thus resulting in a higher total surface energy value. Based on the results, O2 plasma modification at a power of 200 W and pressure of 80 Pa for 0.5 min was considered to be the most favorable condition for the surface activation of BF.

Probing coherence properties of shallow implanted NV snsembles under different oxygen terminations

Abstract Nitrogen vacancy (NV) color centers in diamond have shown great potential for various applications in quantum technology due to their long coherence times, high sensitivity to magnetic fields and atomic scale resolution. However, one major challenge in utilizing near surface NV centers is the decoherence caused by spins and charges fluctuating on the surface, which affects the spin properties of the sensors. To reduce the induced noise, various oxygen surface treatments such as low power oxygen plasma treatment and annealing under oxygen atmosphere have been explored to terminate the diamond surface and reduce its impact on NV coherence. We showed that the NV center's coherence time can be enhanced up to a factor of 3 over a large spectral range of noise. Double electron electron resonance (DEER) measurements revealed an extra source of decoherence, scaling similarly as the P1 spin bath. The improvement in coherence times is accompanied with an increase in measured ketone/ether content and reduction of sp2 signal in X-ray photoelectron spectroscopy (XPS) measurements. Finally we compared the performance of different NV ensembles and surface treatments for sensing external proton spins. The oxygen annealing is an effective procedure of enhancing the spin coherence times and reducing broad band spin noise experienced by shallow implanted ensemble NV centers in diamond.

Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [IrIII(ppy)2(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)2(FcCOCHCORc)

The series of iridium(III) complexes, [Ir(ppy)2(RCOCHCOR')], with R = CH3 and R' = CH3 (1), Rc (2), and Fc (3), as well as R = Rc and R' = Rc (4) or Fc (5), and R = R' = Fc (6), ppy = 2-phenylpyridinyl, Fc = FeII(η5-C5H4)(η5-C5H5), and Rc = RuII(η5-C5H4)(η5-C5H5), has been investigated by single-crystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS) supplemented by DFT calculations. Here, in the range of 3.74 ≤ ΣχR ≤ 4.68, for Ir 4f, Ru 3d and 3p and N 1s orbitals, binding energies unexpectedly decreased with increasing ΣχR (ΣχR = the sum of Gordy group electronegativities of the R groups on β-diketonato ligands = a measure of electron density on atoms), while in Fe 2p orbitals, XPS binding energy, as expected, increased with increasing ΣχR. Which trend direction prevails is a function of main quantum level, n = 1, 2, 3…, sub-quantum level (s, p, d, and f), initial state energies, and final state relaxation energies, and it may differ from compound series to compound series. Relations between DFT-calculated orbital energies and ΣχR followed opposite trend directions than binding energy/ΣχR trends. X-ray-induced decomposition of compounds was observed. The results confirmed good communication between molecular fragments. Lower binding energies of both the Ir 4f7/2 and N 1s photoelectron lines are associated with shorter Ir-N bond lengths. Cytotoxic tests showed that 1 (IC50 = 25.1 μM) and 3 (IC50 = 37.8 μM) are less cytotoxic against HeLa cells than cisplatin (IC50 = 1.1 μM), but more cytotoxic than the free β-diketone FcCOCH2COCH3 (IC50 = 66.6 μM).

Optimizing Cu 3d Bands with Nanotubular SnO2 to Boost Their Catalytic Transfer Hydrogenation Activity.

Catalytic transfer hydrogenation (CTH) using Cu nanocatalysts offers significant advantages over direct high-pressure hydrogenation. However, the active hydrogen (H*) in this process exhibits poor adsorption and tends to release H2 readily due to the fully occupied 3d states of Cu. To address this issue, a tubular SnO2 support with electron-accepting ability was selected to host Cu nanoparticles, aiming to optimize the Cu 3d bands. The Cu/SnO2 nanohybrids were prepared through an electrospinning technique, followed by hydrothermal synthesis. As evidenced by X-ray photoelectron spectroscopy (XPS) binding energy shifts and density functional theory (DFT) simulations, some electrons from Cu transferred to SnO2 in the Cu/SnO2 nanohybrids due to their different work functions. Such electron transfer enables the Cu 3d orbitals to lose electrons and alters its valence configuration from 3d10 to 3d10-x, which enhances the adsorption of active H* atoms and thereby inhibits undesirable H2 release. The 15 wt % Cu/SnO2 exhibits improved catalytic hydrogenation of 4-nitrophenol with NaBH4, with an optimal normalized rate constant of 56.98 mg-1 min-1 and a turnover frequency of 4.82 min-1, surpassing most reported catalysts. The enhanced activity is attributed to the optimized electronic states, improved hydrogen adsorption, and the tubular structure of the support. This work might shed light on developing more non-noble metal nanocatalysts for CTH by tuning their d bands with appropriate oxide supports.

On the Non-Catalytic Role of Lytic Polysaccharide Monooxygenases in Boosting the Action of PETases on PET Polymers.

Synthetic polymers are resistant to biological attack, resulting in their long-term accumulation in landfills and in natural aquatic and terrestrial habitats. Lytic polysaccharide monooxygenases (LPMOs) are enzymes which oxidatively cleave the polysaccharide chains in recalcitrant polysaccharides such as cellulose. It has been widely hypothesised that LPMOs could be used to aid in the enzymatic breakdown of synthetic polymers. Herein, through the use of biochemical assays, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) we show that LPMOs can bind to polyethylene terephthalate (PET), and - in doing so - the hydrophobic surface of PET becomes more hydrophilic such that product release is boosted by subsequent treatment with classical PETases. The boosting effect is however, only observed in reactions when the LPMO and the PETase are added sequentially rather than simultaneously to the PET. Moreover, the same boosting effect is also seen when a catalytically-inactive mutant of LPMO is used, showing that the principal means by which AA9 LPMOs boost the degradation of synthetic polymers is through their role as a "hydrophobin" rather than as an oxygenase. Indeed, in accord with this role of LPMOs, we further show that this effect can be extended to other ostensibly 'non-catalytic' proteins beyond LPMOs, such as bovine serum albumin and lactate dehydrogenase.

Tailoring Superatomic Stability with Transition Metals in Silicon Cages: Shrinking to M@Si15 (M = Re, Os, Ir).

The design of materials with intriguing electronic properties is crucial for advancing nanoscale technologies, where precise control over atomic structure and electronic behavior is essential. Metal-encapsulating silicon cage superatoms (SAs) provide a new paradigm for molecular-scale material design, allowing fine-tuning of both structure and electronic characteristics. The formation of superatoms mimicking halogens, noble gases, and alkali metals has been well-studied, particularly with M@Si16, where early transition metals from groups 3 to 5 stabilize within a Si16 cage, achieving a 68-electron configuration. For late transition metals with excess electrons, a Si15 cage offers enhanced stability by fulfilling the 68-electron rule with one fewer Si atom. This research synthesizes Si15 cage-SAs with rhenium (Re) from group 7 and iridium (Ir) from group 9 on p-type and n-type organic substrates. The stability of Re@Si15 and Ir@Si15 is evaluated via oxidative reactivity with X-ray photoelectron spectroscopy and theoretical calculations, including osmium (Os) from group 8. Re@Si15-, Os@Si150, and Ir@Si15+ exhibit superatomic behaviors similar to halogens, noble gases, and alkali metals due to the 68-electron shell closure. Among them, Re@Si15- on p-type organic substrates shows superior electronic and geometric properties. These findings advance our understanding of M@Sin systems for transition metals, addressing longstanding questions about their properties at n = 15 and 16.

Coverage- and temperature-induced self-metalation of tetraphenyltransdibenzoporphyrin on Cu(111).

We have investigated the adsorption and self-metalation of free-base tetraphenyltransdibenzoporphyrin (2H-TPtdBP) on Cu(111) as a function of coverage and temperature using scanning tunneling microscopy, X-ray photoelectron spectroscopy, temperature programmed desorption, and density-functional theory calculations. At low coverages (<0.16 molecules/nm2), we observe isolated individual molecules with an inverted conformation and no self-metalation up to 363 K. At higher coverages, both the formation of ordered islands and self-metalation are observed over time already at room temperature, and accelerate upon heating to 363 K. At 423 K, complete self-metalation occurs for all coverages up to the completed first layer. By comparing our results for 2H-TPtdBP to the existing literature on other tetraphenyl-based porphyrins, we demonstrate how adsorption and self-metalation can be tailored by the choice of substituents.&#xD.

Oleylamine-grafted carbon nanoparticles as the friction-reducing and anti-wear additives of aviation lubricating oils

Purpose This paper aims to try to develop new, environmentally friendly and efficient lubricating additives; study the compatibility of carbon-based additives with different base oils [Polyalphaolefin (PAO)-3, PAO-20 and NPE-2]; and explore the lubrication mechanism. Design/methodology/approach Oleylamine modified carbon nanoparticles (CNPs-OA) were prepared and the dispersion stability of CNPs-OA in PAO-3, PAO-20 and NPE-2 base oils was investigated by transmission electron microscopy, Fourier transform infrared, thermogravimetric analysis, energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Universal Mechanical Tester (UMT) platform was used to carry out experiments on the effects of different additive concentrations on the lubricating properties of base oil. Findings The mean friction coefficient of PAO-3, PAO-20 and NPE-2 reduced by 32.8%, 10.1% and 11.4% when the adding concentration of CNPs-OA was 1.5, 2.0 and 0.5 Wt.%, respectively. Generally, The CNPs-OA exhibited the best friction-reducing and anti-wear performance in PAO-3. Originality/value The agglomeration phenomenon of carbon nanoparticles as lubricating additive was improved by surface modification, and the lubricating effect of carbon nanoparticles in three synthetic aviation lubricating base oils was compared.

Oxygen 1s X-ray Photoelectron Spectra of Iridium Oxides as a Descriptor of the Amorphous-Rutile Character of the Surface.

Characterization of the surface of iridium oxide (IrOx) materials is of crucial importance to understand catalysts for the oxygen evolution reaction (OER) in low-temperature water electrolysis. While much of our current knowledge is based on well-defined single-crystal surfaces, surface-sensitive techniques like X-ray photoelectronic spectroscopy (XPS) are relevant to characterize the nanostructures considered. In this work, we describe a simple approach to use oxygen 1s spectra as an identifier of the amorphous/crystalline characteristics of iridium oxide structures from purely amorphous to purely crystalline. This conceptual approach was validated on seven commercially available materials. The presence of oxygen-associated defects in the surface moieties/species is shown even for purely crystalline materials with defect concentration increasing with greater amorphous character. This methodology provides us with an accessible ex situ descriptor of the catalyst surface as a baseline for further studies of the impact on catalytic properties.

Wear energy approach for evaluation of tribological properties of Cr2O3-TiO2 coating

Abstract In the present work, Cr2O3-TiO2 ceramic coating was deposited by atmospheric plasma spray (APS) method. Tribological response of coating was thoroughly examined using two different sizes of SiC abrasives under four distinct loads. Coatings were characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction, Raman spectroscopy and X-Ray Photoelectron Spectroscopy. The coating experienced 31–40% lower friction coefficient at coarser particle size whereas 1.4–1.6 times lower wear rates were obtained at finer particle size. Results were explained on the basis of adhesion-abrasion components of friction. Consequences of formation of a tribo-oxide film and its implications on specific energy for material removal along with wear mechanisms are also discussed. A modified wear energy parameter (WEP) is used and showed good correlation with experimentally measured wear rates and friction coefficient of the coating.

Effect of ultraviolet treatment on soft tissue healing and bacterial attachment to titania-coated zirconia

Zirconia is the most promising implant abutment material due to its excellent aesthetic effect, good biocompatibility and corrosion resistance. To obtain ideal soft tissue sealing, the implant abutment surface should facilitate cell adhesion and inhibit bacterial colonization. In this study, pre-sintered zirconia was placed in a suspension of titania (TiO2) and zirconium oxychloride (ZrOCl2) and heated in a water bath for dense sintering. A titania coating was prepared on the zirconia surface and subjected to UV irradiation. The surface morphology, elemental composition and chemical state of each group of samples were analyzed by scanning electron microscope, x-ray energy spectrometer, x-ray photoelectron spectroscopy and x-ray diffraction. The responses of human gingival fibroblasts (HGFs) and common oral pathogensStreptococcus mutans(S. mutans) andPorphyromonas gingivalis(P. gingivalis) to modified zirconia were systematically assessed. Our findings demonstrated that the surface of titania-coated zirconia after UV irradiation produced a large number of hydroxyl groups, and its hydrophilicity was significantly improved. Meanwhile, the UV irradiation also greatly removed the hydrocarbon contaminants on the surface of the titania-coated zirconia. The UV-treated titania coating significantly promoted the proliferation, spreading, and up-regulation of adhesion-related genes and proteins of HGFs. Furthermore, the titania coating irradiated with UV could reduce the adhesion, colonization and metabolic activity ofS. mutansandP. gingivalis. Therefore, UV irradiation of titania-coated zirconia can promote the biological behavior of HGFs and exert a significant antibacterial effect, which has broad clinical application prospects for improving soft tissue integration around zirconia abutments.

Destructive Effects of Slag from Municipal Waste Incineration Plants on Cement Composites.

The increasing production of solid waste and the scarcity of natural aggregates as a matter of fact have made waste recycling a necessity. One such waste, which is generated in large quantities, is slag. However, slag from incineration plants may contain harmful elements that adversely affect the physical, chemical and mechanical properties of cement composites. This study presents laboratory research results on the effect of slag from the Poznan Municipal Waste Thermal Conversion Plant (Poland) on the physicochemical properties of cement composites. The samples were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was shown that the slag analyzed contained significant amounts of aluminum, which had a direct effect on the structure of the concrete. An example of this influence is the release of hydrogen during reactions, which causes swelling and cracking of the concrete and reduces its mechanical strength. The authors emphasize that waste aggregate (slag) can be effectively used in the production of concrete after appropriate processing that reduces the risk of adverse effects.

Programmed Charge Transfer in Conjugated Polymers with Pendant Benzothiadiazole Acceptor for Simultaneous Photocatalytic H2O2 Production and Organic Synthesis.

While being important candidate for heterogeneous photocatalyst, conjugated polymer typically exhibits random charge transfers between the alternating donor and acceptor units, which severely limits its catalytic efficiency. Herein, inspired by natural photosystem, the concept of guiding the charge migration to specific reaction sites is employed to significantly boost photocatalytic performance of linear conjugated polymers (LCPs) with pendant functional groups via creating programmed charge-transfer channels from the backbone to its pendant moiety. The pendant benzothiadiazole, as revealed in both in situ X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations, can act as electron "reservoir" that aggregates electrons at the active sites. Moreover, the presence of charge-transfer channels, evidenced by transient absorption spectroscopy (TAS), accelerates the electron transfer, preventing the recombination of electrons and holes. As a result, in this elaborately-designed architecture, the photogenerated electron can move smoothly towards the reduction sites, facilitating the reduction of O2 into H2O2, while remaining holes are directed to oxidation centers, simultaneously oxidizing furfuryl alcohol to furoic acid. The optimized photocatalyst LCP-BT demonstrates a competitive catalytic performance with H2O2 productivity of 868.3 μmol L-1 h-1 (9.8 times higher than conventional random charge-transfer polymer LCP-1) and furfuryl alcohol conversion over 95% after 6 h.

Berberine-loaded iron oxide nanoparticles alleviate cuprizone-induced astrocytic reactivity in a rat model of multiple sclerosis.

Berberine (BBN) is a naturally occurring alkaloid as a secondary metabolite in many plants and exhibits several benefits including neuroprotective activities. However, data on the neuromodulating potential of nanoformulated BBN are still lacking. In the present study, BBN loaded within iron oxide nanoparticles (BBN-IONP) were prepared and characterized by transmission electron microscopy FTIR, X-ray photoelectron spectroscopy particle-size distribution, zeta potential, and HPLC. The remyelinating neuroprotective potential of BBN-IONP relative to free BBN was evaluated against cuprizone (CPZ)-induced neurotoxicity (rats administered 0.2% CPZ powder (w/w) for five weeks). CPZ rats were treated with either free BBN or IONP-BBN (50 mg/kg/day, orally) for 14 days. Cognitive function was estimated using Y-maze. Biochemically, total antioxidant capacity lipid peroxides and reduced glutathione in the brain tissue, as well as, serum interferon-gamma levels were estimated. Moreover, the genetic expression contents of myelin basic protein Matrix metallopeptidase-9 Tumor necrosis factor-α (TNF-α), and S100β were measured. The histopathological patterns and immunohistochemical assessment of Glial Fibrillary Acidic Protein in both cerebral cortex and hippocampus CA1 regions were investigated. CPZ-rats treated with either free BBN or IONP-BBN demonstrated memory restoring, anti-oxidative, anti-inflammatory, anti-astrocytic, and remyelinating activities. Comparing free BBN with IONP-BBN revealed that the latter altered the neuromodulating activities of BBN, showing superior neuroprotective activities of IONP-BBN relative to BBN. In conclusion, both forms of BBN possess neuroprotective potential. However, the use of IONPs for brain delivery and the safety of these nano-based forms need further investigation.

Atomic Layer Deposition of ZnO on CsPbBr3 Perovskite Nanocrystals: Surface-Dependent Mechanistic Insights.

In this study, we investigate the atomic layer deposition (ALD) process on all-inorganic CsPbBr3 perovskite nanocrystals (PNCs) to introduce an inorganic electron transport layer (ETL) in light-emitting diode (LED) devices. Two types of CsPbBr3 PNCs were synthesized with oleate (OA) and oleylammonium (OLA) ligands on the surface. We found that CsPbBr3 PNCs with Cs oleate surfaces experienced severe photoluminescence (PL) quenching after the ALD process, while those with oleylammonium bromide surfaces did not show any significant PL drop. Transmission electron microscopy and X-ray photoelectron spectroscopy revealed that significant Pb metal formation and Ruddlesden-Popper planar faults, linked to uncoordinated Pb2+ ion defects, were generated in CsPbBr3 PNCs terminated with Cs oleate after ALD ZnO. Finally, we fabricated LEDs using PNCs with an ALD ZnO process to introduce inorganic ZnMgO nanoparticles as the ETL. The devices processed with ALD exhibited superior luminance and external quantum efficiency compared to those without the ALD process. This research provides crucial insights into the surface-dependent chemistry of PNCs and the surface-dependent performance of perovskite-based optoelectronic devices.