The application of Neurospora sp., a fungus that commonly thrives on complex agricultural and plant wastes, has proven successful in utilizing citrus peel waste as a source of naringin. A UV-Vis spectrophotometric method proved the biotransformation of naringin, with an absorption maximum (λmax) observed at 310 nm for the biotransformed product, naringenin (NAR). Further verification of the conversion of naringin was provided through thin layer chromatography (TLC). The Neurospora crassa mediated biotransformation of naringin to NAR was utilized for the rapid (within 5 min) synthesis of silver (Ag) and gold (Au) nanoconjugates using sunlight to accelerate the reaction. The synthesized NAR-nano Ag and NAR-nano Au conjugates exhibited monodispersed spherical and spherical as well as polygonal shaped particles, respectively. Both of the nanoconjugates showed average particle sizes of less than 90 nm from TEM analysis. The NAR-Ag and NAR-Au nanoconjugates displayed potential enhancement of the antimicrobial activities, including antibacterial and nematicidal properties over either standalone NAR or Ag or Au NPs. This study reveals the potential of naringinase-producing Neurospora sp. for transforming naringin into NAR. Additionally, the resulting NAR-Ag and NAR-Au nanoconjugates showed promise as sustainable antibiotics and biochemical nematicides.

MnPt\'s exceptional stability and extremely high Néel temperature have generated a lot of interest in data storage applications. Previously, it was reported experimentally that the MnPt alloy shows ferromagnetic (FM) behavior at room temperature. In this study, the effects of partial substitution of Pt with Pd, Au, and Ag on magnetic properties is investigated using density functional theory. The stability of Mn50Pt50-xMx (M = Pd, Au, Ag, x = 6.25, 12.5, 18.75) alloys was assessed by determining their thermodynamic, magnetic, and mechanical properties. The calculated lattice constants of Mn50Pt50 agree well with available theoretical results. The Mn50Pt50-xMx alloys\' formability was assessed by measuring the thermodynamic stability using the heat of formation. It was found that B2 Mn50Pt50-xPdx alloys (0 ≤ x ≤ 18.75) are thermodynamically stable due to the negative heat of formation close to that of a pristine MnPt alloy. Based on the elasticity results, the B2 Mn50Pt50-xPdx is most likely to undergo martensitic transformation for the entire considered composition range. From the calculated values of the Poisson\'s ratio, it is shown that an increase in Pd, Ag, and Au effectively improves the ductility of the B2 Mn50Pt50-xMx compounds. It was revealed that ferromagnetism is maintained with Pd addition but significantly reduced in the case of Au and Ag. Thus, this work showed that density functional theory can be exploited to propose new possible compositions for future magnets in spintronic applications.

The current binary understanding of membership in international organizations (IOs), especially regional organizations (ROs), creates blind spots and biases in our understanding of who matters in IOs, as well as why and how they matter. Existing scholarship primarily looks at full member-states or non-state actors to capture who influences such organizations. Associated states are often portrayed as passive receivers of IO rules instead of active contributors. We address this blind spot and resulting analytical bias by exploring what types of association relationships exist and how they impact IOs. We propose a novel conceptualization of membership that we call memberness. On the level of IOs, memberness is based on the relative openness of organizational boundaries and stratified access via material and ideational contributions. On the level of states, memberness captures associated states\' individual choices to contribute materially and/or ideationally to an IO. Memberness moves away from a purely rights-based understanding of membership (or who you are in an IO) to include a capacity-based understanding (or what you do in an IO). This shift in focus uncovers new channels of influence on IOs. Associated states\' material and ideational contributions to IOs constitute three memberness types: payroller, sponsor, and advisor. We argue that these memberness types impact IOs\' vitality, design, and performance in previously unrecognized ways. We illustrate these types with empirical examples from ROs across the globe and discuss the implications of memberness for IO research programs.

Full and partial restorations in dentistry must replicate the characteristics of the patient\'s natural teeth. Materials must have good mechanical properties and be non-toxic and biocompatible. Microbes, which can form biofilms, are constantly in contact with restorations. In this study, we investigate how well Candida albicans adheres to a polymethyl methacrylate (PMMA) resin base with gold (Au) nanoparticles. We synthesized Au nanoparticles and characterized them. The average size of Au nanoparticles embedded in PMMA was 11 nm. The color difference ΔE between PMMA and PMMA/Au composites was 2.7 and was still esthetically acceptable to patients. PMMA/Au surfaces are smoother and more hydrophilic than pure PMMA surfaces, and the isoelectric point of both types of surfaces was 4.3. Above the isoelectric point, PMMA/Au surfaces are more negatively charged than PMMA surfaces. The added Au nanoparticles decreased the tensile strength, while the hardness did not change significantly. Adhesion measurements showed that PMMA surfaces modified with Au nanoparticles reduced the extent of microbial adhesion of Candida albicans.

Au decorated with type I collagen (Col) was used as a core material to cross-link with stromal cell-derived factor 1α (SDF1α) in order to investigate biological performance. The Au-based nanoparticles were subjected to physicochemical determination using scanning electron microscopy (SEM), dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) and Fourier-transform infrared spectroscopy (FTIR). Mesenchymal stem cells (MSCs) were used to evaluate the biocompatibility of this nanoparticle using the MTT assay and measuring reactive oxygen species (ROS) production. Also, the biological effects of the SDF-1α-conjugated nanoparticles (Au-Col-SDF1α) were assessed and the mechanisms were explored. Furthermore, we investigated the cell differentiation-inducing potential of these conjugated nanoparticles on MSCs toward endothelial cells, neurons, osteoblasts and adipocytes. We then ultimately explored the process of cell entry and transportation of the nanoparticles. Using a mouse animal model and retro-orbital sinus injection, we traced in vivo biodistribution to determine the biosafety of the Au-Col-SDF1α nanoparticles. In summary, our results indicate that Au-Col is a promising drug delivery system; it can be used to carry SDF1α to improve MSC therapeutic efficiency.

Titanium dioxide (TiO2) nanorods (NRs) are well-known semiconducting and catalytic material that has been widely applied, but their toxicities have also attracted recent interest. In this study, we investigated and compared the toxic effects of TiO2 NRs and TiO2 NRs loaded with Ag or Au NPs on boar spermatozoa. As a result, sperm incubated with Ag-TiO2 NRs showed lower motility than sperm incubated with controls (with or without TiO2 NRs) or Au-TiO2 NRs. In addition, sperm viability and acrosomal integrity were defective in the presence of Ag-TiO2 NRs, and the generation of intracellular reactive oxygen species (ROS) increased significantly when spermatozoa were incubated with 20 μg/ml Ag-TiO2 NRs. We discussed in depth the charge transfer mechanism between enzymatic NADPH and Ag-TiO2 NRs in the context of ROS generation in spermatozoa. The effects we observed reflected the fertilization competence of sperm incubated with Ag-TiO2 NRs; specifically sperm penetration and embryonic development rates by in vitro fertilization were reduced by Ag-TiO2 NRs. To summarize, our findings indicate that exposure to Ag-TiO2 NRs could affect male fertilization fecundity and caution that care be exercised when using these NRs.

Ag and Au nanostructures became increasingly interesting due to their localized surface plasmon resonance properties. These properties can be successfully exploited in order to enhance the light trapping in solar cell devices by appropriate light scattering phenomena. In solar cell applications, the Ag or Au nanoparticles are, usually, supported on or embedded in a thin transparent conductive oxide layer, mainly AZO and ITO for inorganic solar cells and PEDOT:PSS for organic solar cells. However, the light scattering properties strongly depend on the shape and size of the metal nanostructures and on the optical properties of the surrounding environment. Therefore, the systems need to be well designed to maximize scattering and minimize the light absorption within the metal nanoparticles. In this regard, this work reports, in particular, results concerning calculations, by using the Mie theory, of the angle-dependent light scattering intensity (I(θ)) for spherical Ag and Au nanoparticles coated by a shell of AZO or ITO or PEDOT:PSS. I(θ) and scattering efficiency Qscatt for the spherical core-shell nanoparticles are calculated by changing the radius R of the spherical core (Ag or Au) and the thickness d of the shell (AZO, ITO, or PEDOT:PSS). For each combination of core-shell system, the evolution of I(θ) and Qscatt with the core and shell sizes is drawn and comparisons between the various types of systems is drawn at parity of core and shell sizes. For simplicity, the analysis is limited to spherical core-shell nanoparticles so as to use the Mie theory and to perform analytically exact calculations. However, the results of the present work, even if simplified, can help in establishing the general effect of the core and shell sizes on the light scattering properties of the core-shell nanoparticles, essential to prepare the nanoparticles with desired structure appropriate to the application.

Due to excellent electric conductivity and chemical inertness, Au can be used in new microdevices for energy applications, microelectronics, and biomedical solutions. However, the chemical analysis of Au-containing systems using time-of-flight secondary ion mass spectrometry (TOF-SIMS) can be difficult because of the negative ionization of Au, as most metals form positive ions, and therefore cannot be detected from the same analytical volume. In this work, we present the potential of fluorine gas coinjection for altering the polarity, from the negative to positive, of Au secondary ions generated under Ga+ beam bombardment. The importance of detecting Au+ ions and representing their spatial distribution in nanoscale was demonstrated using a novel solid electrolyte for Li-ion solid-state batteries, amorphous Li7La3Zr2O12 (aLLZO). This allowed for assessing the migration of mobile Li+ ions outside the aLLZO layer and alloying the Au layer with Li, which explained the presence of an internal electric field observed during the polarization measurements. Remarkably, during fluorine gas-assisted TOF-SIMS measurements, the trace amount of Au content (5 ppm) was detected in a Pt layer (unattainable under standard vacuum conditions). In conclusion, fluorine gas-assisted TOF-SIMS can help understanding operation mechanisms and potential degradation processes of microdevices and therefore help optimizing their functionality.

Novel approaches are required to overcome the challenges associated with conventional microRNA (miRNA) detection methods and realize the early diagnosis of diseases. This work describes a novel label-free surface-enhanced Raman spectroscopy (SERS) method for the detection of the miRNA biomarkers for pneumoconiosis on a three-dimensional Au-coated ZnO nanorod array (Au-ZnO NRA). The Au-ZnO NRA substrate, which was fabricated via a modified seeding method combined with ion sputtering, provided a high enhancement factor and good spatial uniformity of the signal. With the Au-ZnO NRA, the SERS spectra of miRNAs were obtained in 30 s without labeling at room temperature. Density functional theory calculations were performed to understand the structural fingerprints of the miRNAs. Principal component analysis was carried out to identify the pneumoconiosis biomarkers based on their fingerprint SERS signals. Dual-logarithm linear relationships between the SERS intensity and the miRNA concentration were proposed for quantitative analysis. The label-free SERS method has limits of detection on the femtomolar level, which is much lower than the concentrations of the miRNA biomarkers for pneumoconiosis in lung fibroblasts.

Despite the reversible condensation properties of DNA, DNA metallization during controlled conformational transitions has been rarely investigated. We perform dynamic metallization of spherically condensed DNA nanoparticles (DNA NPs) via a globule-to-coil transition. A positively charged new Au3+ reagent is prepared via ligand-exchange of conventional complex Au3+ ions, which was used to synthesize spherically condensed DNA NPs simply based on the fundamental electrostatic and coordinative interactions between DNA and Au3+ions. Interestingly, the size of the Au3+-condensed DNA NPs (Au3+-DNA NPs) and the type of reducing agents lead to the formation of different Au nanostructures with unprecedented morphologies (cracked NPs, bowl-shaped NPs, and small NPs), owing to the controlled conformational changes in the Au3+-DNA NPs during metallization. The condensed DNA NPs play significant roles for Au nanostructures as (1) the dynamic template for the synthesis, (2) the reservoir and supply of Au3+ for the growth, and (3) the surface stabilizer. The synthesized Au nanostructures are remarkably stable against high ionic strength and exhibit catalytic activities and excellent SERS properties. This is the first study on the morphological control and concomitant dynamic metallization of spherically condensed DNA, proposing new synthetic routes for bioinorganic nanomaterials.