Search Results (40)

The performance of synchrotron beamlines critically depends on the optimal coupling between the undulator and the monochromator. This work presents the implementation and quantitative characterization of a synchronized scanning system for the elliptically polarizing undulator (EPU) and the variable-line-spacing plane-grating monochromator at the BL07U beamline of the Shanghai Synchrotron Radiation Facility (SSRF). The system ensures that the monochromator’s narrow bandwidth dynamically tracks the brilliant central cone of the undulator radiation. A linear correlation between the monochromator energy and the undulator gap, justified theoretically for small scan ranges and reinforced by a robust real-time calibration procedure, forms the control basis. The automation is built upon a standard software stack comprising EPICS for device control, the Bluesky Suite for experimental orchestration, and Phoebus for the human–machine interface. Through comparative X-ray absorption spectroscopy (XAS) measurements at the Fe L_2,3-edges, the synchronized mode is shown to enhance beam brilliance by 37% and stabilize the incident flux, reducing its variation from 4.2% to 1.8%. This directly results in absorption spectra with superior lineshape fidelity, a 40% reduction in noise, and the elimination of pre- and post-edge artifacts, unequivocally isolating the synchronization effect. This advancement provides a stable, high-brilliance photon source essential for high-quality XAS and X-ray magnetic circular/linear dichroism (XMCD/XMLD) studies. Full article

Gold nanoparticles (AuNPs) are of significant interest due to their unique properties and applications in biomedicine. While hyaluronic acid (HA) has been used to modify pre-formed AuNPs, its thiolated derivative (HA−SH) has been less explored for the direct synthesis and stabilization of AuNPs. This study investigates the use of thiolated hyaluronic acid as a key component in the synthesis of AuNPs. A series of HA-AuNPs (HA-AuNP1-4) were synthesized by reacting HA-SH with HAuCl₄ at different mass ratios. The resulting nanoparticles were characterized using UV-Vis spectroscopy, scanning/transmission electron microscopy (SEM/STEM), X-ray photoelectron spectroscopy (XPS), photon cross-correlation spectroscopy (PCCS), and zeta potential measurements. The chemical transformations of the thiol ligand were studied using NMR spectroscopy. The morphologies and sizes of AuNPs depended on the HA-SH-to-HAuCl₄ ratio, ranging from icosahedral and triangular particles (≥146 nm) to quasi-spherical particles with a bimodal distribution (6–7 nm and 45–60 nm). XPS confirmed the presence of metallic gold (Au⁰) and a Au−S bond, while NMR and XPS revealed the partial oxidation of thiol groups to sulfonic acid. Zeta potential measurements showed that lower HAuCl₄ concentrations resulted in higher negative charge (up to −41.5 mV), enhancing colloidal stability. This work demonstrates a versatile approach to the synthesis of hyaluronic acid-based gold nanomaterials with tunable properties for potential biomedical applications. Full article

The topical administration of drugs on the skin by nanovesicular systems can represent a tool to treat skin pathologies. The study of nanovesicle biodistribution after skin administration is crucial to understanding their transdermal potential. A formative study enabled us to investigate the influence of some methods in the production of nanovesicles based on phosphatidylcholine, differing in their ethanol amount. Particularly, both liposomes and ethosomes produced by different methods, i.e., microfluidics and solvent injection, were considered. The evaluation of size distribution, shape and internal morphology was performed using photon correlation spectroscopy, cryogenic electron microscopy, hyperspectral dark-field microscopy and small-angle X-ray scattering. Transmission electron microscopy was then used to observe and compare the transdermal passage of selected liposomes and ethosomes applied to human skin explants in a bioreactor. The mean diameters of nanovesicles prepared by the ethanol injection method were smaller with respect to those obtained by microfluidics, measuring roughly 140 and 230 nm, respectively. The uni- or multilamellar ultrastructure of the vesicles was influenced by the solvent injection procedure. Ultrastructural analysis of skin penetration revealed (i) the ability of intact vesicles to cross the different skin layers, with ethosomes produced by the water injection method showing greater transdermal potential and (ii) the role of ethanol as a penetration enhancer. Full article

A preformulative study was conducted to produce and characterize ethosomes for the transdermal delivery of gossypin. This plant-derived compound possesses many pharmacological properties, including antitumoral potential. Ethosome dispersions were designed as transdermal delivery systems for gossypin, employing two different production procedures. The evaluation of vesicle size distribution by photon correlation spectroscopy, morphology by cryogenic transmission electron microscopy, and gossypin entrapment capacity, as well as in vitro release and permeation by vertical diffusion cells, enabled us to select a production strategy based on the injection of a phosphatidylcholine ethanolic solution in water. Indeed, vesicles prepared by this method were almost unilamellar and measured roughly 150 nm mean diameter while displaying an entrapment capacity higher than 94%. Moreover, vesicles prepared by the ethanol injection method enabled us to control gossypin release and to improve its permeation with respect to the solution of the drug. To obtain semi-solid forms suitable for cutaneous gossypin administration, ethosome dispersions were thickened with 0.5% w/w xanthan gum, selected by a spreadability test. These ethosome gels were then further characterized by small- and wide-angle X-ray scattering, while their antioxidant activity was demonstrated in vitro by a radical scavenging assay. Finally, in vitro biological studies were conducted on A375 melanoma cell lines. Namely, wound healing and cell migration assays confirmed the potential antitumoral effect of gossypin, especially when loaded in the selected ethosomal gel. The promising results suggest further investigation of the potential of gossypin-loaded ethosomal gel in the treatment of melanoma. Full article

Here, we report a two-dimensional (2D) amorphous photonic structure (APS) discovered in the central layer of the periostracum of the mussel Perna canaliculus, based on field emission scanning electron microscopy, X-ray diffractometer, attenuated total reflection Fourier transform infrared spectroscopy, and fiber optic spectrometry combined with the image processing technology and pair correlation function analysis. This APS contains ~29% in volume of protein fibers embedded in a protein matrix. These fibers, with diameters of 103 ± 17 nm, are densely arranged and unevenly crimped. In addition, they are locally parallel with each other and exhibit short-range order with a nearest-neighbor distance of 189 nm. Interestingly, the APS is humidity-responsive with a vivid green structural color (~530 nm) in the wet state, which disappears in the dry state. Moreover, the APS is sandwiched by two dense layers in the periostracum, which is flexible in wet and can spontaneously or artificially deform into various shapes. We hope this APS may provide new inspirations for the design and synthesis of 2D amorphous photonic materials. Full article

In this study, the interplay among the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) as a model membrane, the nonsteroidal anti-inflammatory drug naproxen, and the saponin $\beta$-aescin are investigated. The naproxen amount was fixed to 10 mol%, and the saponin amount varies from 0.0 to 1.0 mol%. Both substances are common ingredients in pharmaceutics; therefore, it is important to obtain deeper knowledge of their impact on lipid membranes. The size and properties of the DMPC model membrane upon naproxen and aescin addition were characterized with differential scanning calorimetry (DSC), small- and wide-angle X-ray scattering (SAXS, WAXS), and photon correlation spectroscopy (PCS) in a temperature-dependent study. The interaction of all substances was dependent on the lipid phase state, which itself depends on the lipid’s main phase transition temperature $T_{\mathrm{m}}$. The incorporation of naproxen and aescin distorted the lipid membrane structure and lowers $T_{\mathrm{m}}$. Below $T_{\mathrm{m}}$, the DMPC–naproxen–aescin mixtures showed a vesicle structure, and the insertion of naproxen and aescin influenced neither the lipid chain–chain correlation distance nor the membrane thickness. Above $T_{\mathrm{m}}$, the insertion of both molecules instead induced the formation of correlated bilayers and a decrease in the chain–chain correlation distance. The presented data clearly confirm the interaction of naproxen and aescin with DMPC model membranes. Moreover, the incorporation of both additives into the model membranes is evidenced. Full article

Linking the physics of the relaxation behavior of viscoelastic fluids as they form arrested gel states to the underlying chemical changes is essential for developing predictive controls on the properties of the suspensions. In this study, 3 wt.% laponite suspensions are studied as model systems to probe the influence of salt-induced relaxation behavior arising from the assembly of laponite nanodisks. X-ray Photon Correlation Spectroscopy (XPCS) measurements show that laponite suspensions prepared in the presence of 5 mM concentrations of CaCl₂, MgCl₂ and CsCl salts accelerate the formation of arrested gel states, with CaCl₂ having a significant impact followed by CsCl and MgCl₂ salts. The competing effects of ion size and charge on relaxation behavior are noted. For example, the relaxation times of laponite suspensions in the presence of Mg²⁺ ions are slower compared to Cs+ ions despite the higher charge, suggesting that cation size dominates in this scenario. The faster relaxation behavior of laponite suspensions in the presence of Ca²⁺ ions compared to Cs⁺ ions shows that a higher charge dominates the size of the ion. The trends in relaxation behavior are consistent with the cluster formation behavior of laponite suspensions and the electrostatic interactions predicted from MD simulations. Charge balance is achieved by the intercalation of the cations at the negatively charged surfaces of laponite suspensions. These studies show that the arrested gel state of laponite suspensions is accelerated in the presence of salts, with ion sizes and charges having a competing effect on relaxation behavior. Full article

In the present work, an experimental study is performed to study the radiation shielding characteristics of SrTiO₃ (STO) perovskite ceramic added with different amounts (x = 0, 2, 5, and 10%) of tungsten trioxide nanoparticles (WO₃ NPs). The four ceramic samples were prepared using the solid-state reaction method. The structural properties were examined using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. The analysis showed the successful formation of WO₃- doped STO samples. The crystallite size, estimated using the Scherrer equation, was found in the range of 50.86–41.17 nm. The effect of WO₃ NPs on the radiation shielding performance of these ceramics was studied. Different parameters, such as linear attenuation coefficient (LAC) and other related factors, were experimentally determined. The linear attenuation coefficient results demonstrated that the additional amount of WO₃ in the ceramics correlates with an improvement in their shielding abilities. The half-value layer (HVL) values for the ceramics with 2% WO₃ nanoparticles are equal to 0.071, 1.760, 2.407, and 2.564 cm at 0.060, 0.662, 1.173, and 1.333 MeV, respectively. As the energy increases, more radiation can pass through the material; therefore, a larger thickness is required to absorb half of the total photons, leading to a greater HVL. The tenth value results reaffirmed that increasing the WO₃ content in the STO ceramics improves their shielding efficiency. The radiation protection efficiency (RPE) of the four prepared STO ceramics was reported. From the RPE, we found that more photons can be attenuated at lower energies. Full article

In this study, using the Box–Behnken model, we optimized the ethanolic extraction of phytochemicals from Enantia chloranta bark for the first time, assessed the composition with HPLC-MS/MS, performed the green synthesis of silver nanoparticles (AgNPs) and characterized them with UV-Vis spectrophotometry, photon cross-correlation spectroscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. The antibacterial and antibiotic-resistance reversal properties of optimized extract (O-ECB) and AgNPs were assessed on various microorganisms (15 Gram−, 7 Gram+, and 2 fungi) using the well diffusion method and microbroth dilution assay. The mechanism of action was investigated on growth kinetic and proton pumps of Escherichia coli. The in vivo antimicrobial activity and toxicity were assessed on Galleria mellonella larvae. The optimal mass yield (14.3%) related to the highest antibacterial activity (31 mm vs. S. aureus ATCC 6538) was obtained with the following operating conditions: % EtOH—100%; ratio m/v—20 g/mL; and extraction time—6 h. All the compounds identified in O-ECB were alkaloids and the major constituents were palmatine (51.63%), columbamine +7,8-dihydro-8-hydroxypalmatine (19.21%), jatrorrhizine (11.02%), and pseudocolumbamine (6.33%). Among the minerals found in O-ECB (S, Si, Cl, K, Ca, Mn, Fe, Zn, and Br), Br, Fe, and Cl were the most abundant with mean fluorescence intensities of 4.6529, 3.485,4, and 2.5942 cps/uA, respectively. The synthesized AgNPs revealed a strong absorption plasmon band between 430 and 450 nm and an average hydrodynamic diameter ×50 of 59.74 nm, and the presence of Ag was confirmed by a characteristic peak in the spectrum at the silver Kα line of 22.105 keV. Both O-ECB and AgNPs displayed noteworthy and broad-spectrum antimicrobial activities against 20/24 and 24/24 studied microorganisms, respectively, with recorded minimal inhibitory concentrations (MICs) ranging from 8 to ≥1024 µg/mL and 2 to 64 µg/mL. O-ECB and AgNPs showed antibiofilm properties and significantly enhanced the efficacy of conventional antibiotics against selected multidrug-resistant bacteria, and the mechanistic investigations revealed their interference with bacterial growth kinetic and the inhibition of H+-ATPase proton pumps. LD50s were 40 mg/mL and 0.6 mg/mL for O-ECB and AgNPs, respectively. In conclusion, the current study provides a strong experimental baseline to consider Enantia chlorantha bark and their green synthetized AgNPs as potent antimicrobial compounds in this era of antimicrobial resistance. Full article

Red fluorescent proteins with a large Stokes’ shift (LSSRFPs) are genetically encoded and efficiently excited by 488 nm light, allowing simultaneous dual-color one- and two-photon fluorescence imaging and fluorescence correlation spectroscopy in combination with green fluorescent proteins FPs. Recently, based on the conventional bright mScarlet RFP, we developed the LSSRFP LSSmScarlet. LSSmScarlet is characterized by two pKa values at pH values of 1.9 and 5.8. In this study, we developed improved versions of LSSmScarlet, named LSSmScarlet2 and LSSmScarlet3, which are characterized by a Stokes’ shift of 128 nm and extreme pH stability with a single pKa value of 2.2. LSSmScarlet2 and LSSmScarlet3 had 1.8-fold faster and 3-fold slower maturation than LSSmScarlet, respectively. In addition, both LSSRFPs were 1.5- to 1.6-fold more photostable and more chemically resistant to denaturation by guanidinium chloride and guanidinium thiocyanate. We also compared the susceptibility of the LSSmScarlet2, LSSmScarlet3, and other LSSRFPs to the reagents used for whole-mount imaging, expansion microscopy, and immunostaining techniques. Due to higher pH stability and faster maturation, the LSSmScarlet3-LAMP3 fusion was 2.2-fold brighter than LSSmScarlet-LAMP3 in lysosomes of mammalian cells. The LSSmScarlet3-hLAMP2A fusion was similar in brightness to LSSmScarlet-hLAMP2A in lysosomes. We successfully applied the monomeric LSSmScarlet2 and LSSmScarlet3 proteins for confocal imaging of structural proteins in live mammalian cells. We also solved the X-ray structure of the LSSmScarlet2 protein at a resolution of 1.41 Å. Site-directed mutagenesis of the LSSmScarlet2 protein demonstrated the key role of the T74 residue in improving the pH and chemical stability of the LSSmScarlet2 protein. Full article

Three dimensional (3D) perovskite solar cells (PSCs) are a promising candidate for third-generation photovoltaics (PV) technology, which aims to produce efficient photon conversion devices to electricity using low-cost fabrication processes. Hybrid organic-inorganic perovskites for-lmed using low-cost solution processing are explored here, which have experienced a stupendous rise in power conversion efficiency (PCE) over the past decade and serve as a prime candidate for third-generation PV systems. While significant progress has been made, the inherent hygroscopic nature and stability issue of the 3D perovskites (3DPs) are an impediment to its commercialization. In this work, we have studied two-dimensional (2D) organometallic halide (CH₃(CH₂)₃NH₃)₂(CH₃NH₃)_n−1Pb_nI_3n+1) layered perovskites in the Ruddlesden Popper structure, represented as BA₂MA₃Pb₄I₁₃ for the n = 4 formulation, for both photoabsorbers in a two-terminal architecture and solar cells, given that these material are considered to be inherently more stable. In the two-terminal photo absorber devices, the photocurrent and responsivity were measured as a function of incoming laser wavelength, where the location of the peak current was correlated to the emission spectrum arising from the 2DP film using photoluminescence (PL) spectroscopy. The 2D (BA)2(MA)3Pb4I13 films were then integrated into an n-i-p solar cell architecture, and PV device figures of merit tabulated, while our 3D MAPbI₃ served as the reference absorber material. A comparative study of the 3DP and 2DP film stability was also conducted, where freshly synthesized films were inspected on FTO substrates and compared to those exposed to elevated humidity levels, and material stability was gauged using various material characterization probes, such as PL and UV-Vis optical absorption spectroscopy, scanning electron microscopy and X-ray diffraction. While the PCE of the 3D-PSCs was higher than the 2D-PSCs, our results confirm the enhanced environmental stability of the 2DP absorber films compared to the 3DP absorbers, suggesting their promise to address the stability issue broadly encountered in 3D PSCs toward third-generation PV technology. Full article

We present the technical realization of a high-speed hard X-ray single-photon counting-detection scheme based on a commercial avalanche silicon photodiode and high-speed oscilloscope. The development is motivated by the need to perform pulse-resolved photon-correlation and pump-probe studies at synchrotron sources with densely packed pulse patterns that result in high repetition rate pulses on the order of hundreds of MHz. Commissioning experiments are performed at the 1C PAL-KRISS beamline at PLS-II of South Korea operating at a burst mode maximum repetition rate of 500 MHz. In such a high count-rate measurement, detector dead-time can lead to a distortion of counting statistics. We are able to model the counting behavior of our detector under these conditions with a detector dead-time comparable to time between X-ray pulses, implying that nanosecond X-ray photon correlation spectroscopy should be possible at diffraction-limited light sources. Full article

The present paper is focused on the analysis of Ni²⁺, Co²⁺, Fe³⁺, and Ho³⁺ ion co-reduction in the background equimolar NaCl-KCl melt at 973 K using the method of cyclic voltammetry. It was found that the co-reduction potentials of Ho³⁺ and iron triad ions differ greatly. The depolarization of metallic holmium electrodeposition on one of the iron triad metals preliminary deposited on the tungsten electrode was determined. This process resulted in the formation of the Ho_xNi_y, Ho_xCo_y, and Ho_xFe_y intermetallic compounds. It was observed that the Ho_xNi_y, Ho_xCo_y, and Ho_xFe_y intermetallic compounds may be synthesized in a kinetic regime. The influence of the current density, electrolytic bath composition, and electrolysis time on the composition of the obtained intermetallic compounds was studied. The possibility of synthesizing cathode deposits composed solely of intermetallic compounds is verified. It is demonstrated that the intermetallic compounds may be formed by the addition of the iron triad metals (in particular, metallic iron) via anode dissolution. Synthesized Ho_xNi_y, Ho_xCo_y, and Ho_xFe_y samples were characterized by X-ray diffraction analysis, scanning electron microscopy, and photon correlation spectroscopy. Full article

As a typical representative of natural structural colors, the wings of butterflies living in different zones present colors due to different chromogenic mechanisms. In this work, Papilio maackii, a common species of butterfly living in China, was studied in order to clarify the photophysics of its wing scales. A FESEM was applied to observe the microstructure of the scales, and we found that they have a periodic photonic crystal structure. X-ray photoelectron spectroscopy was applied to clarify the wings’ chemical composition. Additionally, the optical properties of the scales were investigated using a UV-vis-NIR microspectrophotometer. Then, a simplified three-dimensional photonic crystal model was built according to the microstructure of the wing scales, and the plane-wave expansion method was used to calculate the band gap. The correlation between the calculated band gap and the practical reflective spectrum was also established for the wing scales of Papilio maackii. Full article