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Bimetallic silver/gold nanosystems are expected to significantly improve therapeutic efficacy compared to their monometallic counterparts by maintaining the general biocompatibility of gold nanoparticles (AuNPs) while, at the same time, decreasing the relatively high toxicity of silver nanoparticles (AgNPs) toward healthy human cells. Thus, the aim of this research was to establish a highly reproducible one-pot green synthesis of colloidal AuNPs and bimetallic Ag/Au alloy nanoparticles (NPs; Ag/AuNPs) using starch as reducing and capping agent. The optical properties, high reproducibility, stability and particle size distribution of the colloidal NPs were analyzed by ultraviolet (UV)-visible spectroscopy, dynamic light scattering (DLS) and -potential. The presence of starch as capping agent was determined by Fourier transform infrared (FT-IR) spectroscopy. The structural properties were studied by X-ray diffraction (XRD). Transmission electron microscopy (TEM) imaging was done to determine the morphology and size of the nanostructures. The chemical composition of the nanomaterials was determined by energy-dispersive X-ray spectroscopy (EDS) and inductively coupled plasma mass spectrometry (ICP-MS) analysis. To further study the biomedical applications of the synthesized nanostructures, antibacterial studies against multidrug-resistant (MDR) and methicillin-resistant (MRSA) were conducted. In addition, the NPs were added to the growth media of human dermal fibroblast (HDF) and human melanoma cells to show their cytocompatibility and cytotoxicity, respectively, over a 3-day experiment. UV-visible spectroscopy confirmed the highly reproducible green synthesis of colloidal AuNPs and Ag/AuNPs. The NPs showed a face-centered cubic crystal structure and an icosahedral shape with mean particle sizes of 28.5 and 9.7 nm for AuNPs and Ag/AuNPs, respectively. The antibacterial studies of the NPs against antibiotic-resistant bacterial strains presented a dose-dependent antimicrobial behavior. Furthermore, the NPs showed cytocompat-ibility towards HDF, but a dose-dependent anticancer effect was found when human melanoma cells were grown in presence of different NP concentrations for 72 hours. In this study, mono- and bimetallic NPs were synthesized for the first time using a highly reproducible, environmentally friendly, cost-effective and quick method and were successfully characterized and tested for several anti-infection and anticancer biomedical applications.

Background The aim of the study is to characterize a biomedical magnesium alloy and highlighting the loss of mechanical integrity due to the sterilization method. Ideally, when using these alloys is to delay the onset of degradation so that the implant can support body loads and avoid toxicological effects due to the release of metal ions into the body. Methods Standardized procedures according to ASTM F-1264 and ISO-10993-5 were used, respecting detailed methodological controls to ensure accuracy and reproducibility of the results, this testing methodology is carried out in accordance with the monographs of the Pharmacopoeia for the approval of medical devices and obtaining a health registration. An intramedullary implant (IIM) manufactured in magnesium (Mg) WE43 can support loads of the body in the initial period of bone consolidation without compromising the integrity of the fractured area. A system with these characteristics would improve morbidity and health costs by avoiding secondary surgical interventions. Results As a property, the fatigue resistance of Mg in aggressive environments such as the body environment undergoes progressive degradation, however, the autoclave sterilization method drastically affects fatigue resistance, as demonstrated in tests carried out under in vitro conditions. Coupled with this phenomenon, the relatively poor biocompatibility of Mg WE43 alloys has limited applications where they can be used due to low acceptance rates from agencies such as the FDA. However, Mg alloy with elements such as yttrium and rare earth elements (REEs) have been shown to delay biodegradation depending on the method of sterilization and the physiological solution used. With different sterilization techniques, it may be possible to keep toxicological effects to a minimum while still ensuring a balance between the integrity of fractured bone and implant degradation time. Therefore, the evaluation of fatigue resistance of WE43 specimens sterilized and tested in immersion conditions (enriched Hank’s solution) and according to ASTM F-1264, along with the morphological, crystallinity, and biocompatibility characterization of the WE43 alloy allows for a comprehensive evaluation of the mechanical and biological properties of WE43. Conclusions These results will support decision-making to generate a change in the current perspective of biomaterials utilized in medical devices (MDs), to be considered by manufacturers and health regulatory agencies. An implant manufactured in WE43 alloy can be used as an intramedullary implant, considering keeping elements such as yttrium-REEs below as specified in its designation and with the help of a coating that allows increasing the life of the implant in vivo.

This paper proposes the bio-fabrication of a porous scaffold from a selection procedure of elements taking into account biological behavior, using magnesium (Mg) alloyed with calcium (Ca) and zinc (Zn). The proposed scaffold could work as a treatment for specific pathologies in trauma and oncology, on the one hand, in addition to possible applications in osteosynthesis, through contrib-uting to osseointegration and infection control through the release of drugs. Finally, another pos-sible attribute of this alloy could be its use as a complementary treatment for osteosarcoma; this is due to the basification produced by oxidative degradation (attack on cancer cells). The evaluation of cell viability of an alloy of Mg - 25 wt% Ca - 5 wt% Zn will strengthen current perspectives on the use of Mg in the clinical evaluation of various treatments in trauma and oncology. Considera-tions on the preparation of an alloy of Mg - 25 wt% Ca - 5 wt% Zn and its morphological charac-terization will help researchers understand its applicability for the development of new surgical techniques and lead to a deeper investigation of alternative treatments. However, it is very im-portant to bear in mind the mechanical effect of elements such as Ca and Zn on the degradation of the alloy matrix; the best alternative to predict the biological-mechanical potential starts with the selection of the essential-nutritional elements and their mechanical evaluation by mi-cro-indentation due to the fragility of the matrix. Therefore, the morphological evaluation of the specimens of Mg - 25 wt% Ca - 5 wt% Zn will show the crystallinity of the alloy; these results to-gether contribute to the design of biomedical alloys for use in treatments for various medical spe-cialties. The results indicated that cell viability is not affected, and there are no morphological changes in the cells.

El objetivo de este trabajo es construir un estado del arte acerca de las investigaciones que se han realizado sobre el Mercado Integrado Latinoamericano (MILA), entendiéndose este como un acuerdo en el que participan las bolsas de valores y los depósitos de valores de Colombia, Chile, Perú y, recientemente, México. Por tal motivo, se tienen en cuenta artículos de revista con fecha de publicación posterior al año 2010, que están almacenados en bases de datos especializadas y se desarrolla la investigación en las etapas de contextualización, clasificación, categorización y análisis. Se aclara que la fecha de publicación de los artículos fue elegida porque el MILA empezó a operar oficialmente en 2011. Se construyó el estado del arte con un total de nueve artículos. Igualmente, se encontraron investigaciones que construyen modelos matemáticos, comparaciones de beneficios y dificultades, análisis de correlación, utilización de razones de Sharpe y test de Johansen, así como la aplicación del modelo CAPM. Se espera que futuras investigaciones incluyan a México, puesto que todas las que se han hecho hasta el momento lo excluyen, y, adicionalmente, consideren los impactos del MILA con otros mercados de valores integrados.

Glass matrices of Li 2 B 4 O 7 doped with Dy 3+ , Yb 3+ and Cu were synthesized using copper concentration as the control parameter by melt quenching technique. The amorphous phase of lithium borate was corroborated by X-Ray diffraction (XRD) while size distribution of Nanoparticles was obtained by transmittance electron microscopy (TEM) and crystal phase of Cu nanoparticles was obtained by high resolution transmittance electron microscopy (HRTEM). For photoluminescence, characterizations used were absorbance, photoluminescence emission (PL) and experimental decay times (τ exp ); from the data obtained we performed Judd–Ofelt analysis where we calculated Judd–Ofelt parameters ( Ω i ), transition probabilities (A), branching ratios ( β ) and decay times (τ calc ). With absorbance and PL characterizations in conjunction with CIE 1931, efficiency and shift to white light emission were evaluated. The insights gained from this study have significant implications for future research focused on enhancing the photoluminescence properties of rare earth-doped systems. A comprehensive understanding of the underlying mechanisms behind these phenomena enables us to leverage plasmon effects in similar systems, leading to diverse applications such as color tuning emission.

Carbon nanotubes (CNTs) and carbon microfibers (CMFs) have received significant attention due to their exceptional mechanical and electrical properties, which make them promising materials for various applications. This study introduces a novel approach to integrate CNTs and CMFs into a unified architecture by simultaneously conducting pyrolysis and chemical vapor deposition (CVD). The localized CVD of CNTs on suspended CMFs was achieved by utilizing Fe–Co nanoparticles (NPs) embedded in polyacrylonitrile (PAN) fibers as catalysts. Scanning electron microscopy and elemental analysis confirmed the formation of needle-like carbon structures on the pyrolyzed fiber surface, where carbon gases released from the pyrolyzing PAN fiber acted as the carbon source for the localized CVD. The incorporation of an additional carbon source, such as camphor vapor, significantly enhanced the growth and density of CNTs on the CMF. Various characterization techniques, including transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and Atomic Force Microscopy, were employed to analyse the properties of the synthesized materials. The substantial increase in electrical conductivity upon incorporating CNTs highlights their positive influence on electrical properties and defect reduction. These characterization results highlight the potential applications of the fabricated structures in various fields, including sensors, lithium-ion electrodes, and microfabrication. In addition, the economic advantages of optimizing the process by integrating CVD with pyrolysis were assessed, revealing decreased operation time, lower energy consumption, and reduced chemical costs in comparison to conventional methods involving multiple intermediate processing steps. Graphical Abstract

In the present work, the Ruddlesden-Popper (RP) phases La 2 NiO 4+δ (La2) and La 4 Ni 3 O 10±δ (La4) were employed as cathode materials with Gd 0.1 Ce 0.9 O 2-δ (GDC) electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Cathode inks were deposited on the GDC substrate by the dip-coating technique. The electrochemical properties of the cathode in symmetric cells with GDC were investigated. The area-specific resistance (ASR) of the La 4 Ni 3 O 10±δ cathode is lower than that of the La 2 NiO 4+δ cathode at 600, 700, and 800 ºC, with values of 6.91, 1.22, and 0.23 Ω cm 2 , respectively. These values are better than other RP families previously reported. This work combines cathode layers to form multilayers as a La2La4La2 symmetric cell, enhancing the oxygen reduction reaction (ORR) properties, which exhibit an ASR value of 0.12 Ω cm 2 at 800 °C. We report a performance in a symmetric cell using a configuration with La2 and La4 cathodes that could be a promising alternative for IT-SOFCs. Graphical abstract

This study deals with the fabrication and characterization of a magnetic hybrid film, IONP/EC, comprised of iron oxide nanoparticles and ethyl cellulose. Its manufacture followed two steps: the fabrication of a precursor hybrid film, and its alkaline treatment. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), and thermogravimetric analysis (TGA) demonstrated a successful in-situ synthesis of IONPs in the EC matrix. Furthermore, through vibrating sample magnetometer (VSM) and dynamic mechanical analysis (DMA), the magnetic and viscoelastic properties of the film were characterized, respectively. Using XRD analysis, the crystalline structure of IONPs showed to be an iron oxide hydroxide phase. Although it cannot be dismissed other phases, such as maghemite and magnetite. FTIR results revealed that the EC matrix preserved its chemical structure. Images obtained by HRTEM evidenced quasi-spherical IONPs embedded into the EC matrix with an average particle size of 2.4 nm. The IONP/EC film exhibited a superparamagnetic-like behavior, showing a blocking temperature at 20 K. After TGA analysis, IONPs slightly impacted the thermal stability of the EC matrix. Finally, DMA results revealed a modification on the structural relaxation phenomena of EC, which arose from the presence of IONPs in the matrix.

In the present work, the Ruddlesden-Popper (RP) phases La.sub.2NiO.sub.4+[delta] (La2) and La.sub.4Ni.sub.3O.sub.10±[delta] (La4) were employed as cathode materials with Gd.sub.0.1Ce.sub.0.9O.sub.2-[delta] (GDC) electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Cathode inks were deposited on the GDC substrate by the dip-coating technique. The electrochemical properties of the cathode in symmetric cells with GDC were investigated. The area-specific resistance (ASR) of the La.sub.4Ni.sub.3O.sub.10±[delta] cathode is lower than that of the La.sub.2NiO.sub.4+[delta] cathode at 600, 700, and 800 ºC, with values of 6.91, 1.22, and 0.23 [Omega] cm.sup.2, respectively. These values are better than other RP families previously reported. This work combines cathode layers to form multilayers as a La2La4La2 symmetric cell, enhancing the oxygen reduction reaction (ORR) properties, which exhibit an ASR value of 0.12 [Omega] cm.sup.2 at 800 °C. We report a performance in a symmetric cell using a configuration with La2 and La4 cathodes that could be a promising alternative for IT-SOFCs.

We report on the development of hybrid nanostructured materials (HNM) based on spinel-metal-oxide nanoparticles (SMON) stabilized in carboxymethyl-cellulose (CMC)/cetyltrimethyl-ammonium-bromide (CTAB) templates, with tunable magnetic characteristics. These HNM were synthesized using a one-pot chemical approach to obtain CMC/CTAB templates with controllable size and morphology, where the SMON could be densely arranged. The synthesized HNM were characterized by transmission electron microscopy and its related techniques, such as bright field (BF) and Z-contrast (HAADF-STEM) imaging, and selected area electron diffraction, as well as static magnetic measuring. Experimental evidence suggests that the morphology and size of the CMC/CTAB templates are highly dependent on the weight ratio of CTAB:SMON, as well as the hydration days of the CMC that is used for the synthesis of the HNM. Controlling these parameters allows modifying the density of the SMON arrangement in the CMC/CTAB templates. Moreover, magnetic features such as remanence, coercivity, and blocking/de-blocking processes of the particles’ magnetic moments are highly dependent on the interactions among the SMON assembled in the templates. Hence, the magnetic characteristics of HNM can be modulated or tuned by controlling the manner the SMON are arranged within the CMC/CTAB templates.