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In this paper a comparative study of the effect of preparation methods, sol-gel auto-combustion, co-precipitation and hydrothermal method in structural and magnetic properties of nanoparticles of cobalt ferrite CoFe2O4 has been carried out. The samples were characterized using: X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. Magnetization measurements as a function of the applied field verified the marked influence of the synthesis method on the magnetic properties of the nanoparticles, reaching a maximum magnetization of 92.64 emu/g for the ferrite prepared using the sol-gel auto-combustion method. [ABSTRACT FROM AUTHOR]

This study pursues to determine the effect of price policies applied to cereals during the last five decades in Chile, analyzing the characteristics of the policies for wheat, corn and rice. The reaction level of cereal growers facing price changes was established and the effect of price policies on the sown land in the Country was determined for three crops: wheat, corn and rice. It was estimated that in the case of wheat the hectare price elasticity was 1.4, demonstrating the sensibility of this crop to changes in prices. The results show that a wheat grower facing good prices increases his intention of farming a larger surface for this crop. In the case of corn, the price elasticity does not vary significantly, compared to the figures found in the literature. Rice has a particular behavior, given by the cultivation conditions in the Country, and the hectare price elasticity of supply, estimated at 0.05. [ABSTRACT FROM AUTHOR]

Samarium-doped nanohydroxyapatite is a biomaterial with nerve regeneration activity and bioimaging. In this work, Sm/HAp; (Ca 10- x Sm x (PO 4 ) 6 (OH) 2 ) (0 ≤ x ≤ 1) was synthesized using the hydrothermal method and thermally treated from 200 to 800 °C. The samples were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, and luminescence spectroscopy. The results confirmed the successful integration of Sm 3+ ions into the hydroxyapatite. Our findings revealed the influence of the Sm 3+ content and thermal treatment on the emission properties, obtaining a maximum emission at Sm = 0.05 thermally treated at 800 °C. The SH-SY5Y neuroblastoma cell viability study revealed a Sm 3+ concentration-and particle size-dependent response. This research emphasizes the optical and cell viability of Sm/HAp in SH-SY5Y neuroblastoma cells, making them suitable for further research as agents that activate regenerative processes in cells and neurons., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In this work, the photochemical reduction method was used at 440 or 540 nm excitation wavelengths to optimize the deposition of silver nanoparticles on the diatom surface as a potential DNA biosensor. The as-synthesized nanocomposites were characterized by ultraviolet-visible spectroscopy (UV-Vis), Fourier transforms infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), fluorescence microscopy, and Raman spectroscopy. Our results revealed a 5.5-fold enhancement in the fluorescence response of the nanocomposite irradiated at 440 nm with DNA. The enhanced sensitivity comes from the optical coupling of the guided-mode resonance of the diatoms and the localized surface plasmon of the silver nanoparticles interacting with the DNA. The advantage of this work involves the use of a low-cost green method to optimize the deposition of plasmonic nanoparticles on diatoms as an alternative fabrication method for fluorescent biosensors.

Optimizing the antibacterial properties of nanocomposites is a fundamental challenge for many biomedical applications. Here, we study how we may optimize the antibacterial activity of narrow-sized anisotropically flat silver nanoprisms (S-NPs) on graphene oxide (GO) against Escherichia coli . To do so, we transformed silver nanoparticles (AgNPs) into S-NPs and anchored them to GO via a facile and low-cost photochemical reduction method by varying the irradiation wavelength during the synthesis process in the visible range (440 to 650 nm and white light). We performed a physicochemical characterization of the resulting S-NP/GO nanocomposite using a combination of UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Our results reveal a synergistic effect between the silver nanoprism and the oxygen functional groups of the GO surface. The antibacterial activity of the S-NPs/GO nanocomposite shows a significantly higher 53% inhibition efficiency after being irradiated with a 540 nm wavelength light source, compared to AgNPs with a 1% inhibition efficiency, respectively. In so doing, we have demonstrated the utility of a low-cost photoreduction method to control the structural properties of silver nanoprism on GO and, in this way, enhance the antibacterial properties of the nanocomposite. These results should be of great interest in a wide range of biomedical applications and medical devices., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Glyphosate is one of the most widely used herbicides globally, and there are several concerns about its environmental impact. In this work, we revealed the molecular interaction between chitosan, graphene, and CoFe 2 O 4 nanoparticles with commercial glyphosate. The binding interaction was studied by Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The structural and magnetic properties were characterized using scanning electron microscopy (SEM) and vibrating-sample magnetometry (VSM). To quantify the removal of glyphosate from water, UV-vis spectroscopy was used. Our results demonstrate the strong interaction between glyphosate with the components of the nanocomposite by the coordination through the phosphate and carboxylic groups and a complex formation with the nanoparticles. The advantage of this work is the use of a low-cost nanocomposite as bioadsorbent and the understanding of the binding interactions for glyphosate removal., (Copyright © 2022. Published by Elsevier Inc.)

The use of natural diatoms is currently a topic of interest for therapeutic applications due to its facilities, low cost, and biocompatibility. Here, we report the chemical modification of diatoms Aulacoseria genus microalgae-derived biosilica from Guayllabamba - Ecuador decorated with gold nanoparticles by In-situ and Ex-situ methods to study the in vitro gentamicin loading and release properties in simulated body fluid (SBF). Successful decoration of the diatoms and loaded with gentamicin was confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy and Fluorescence Microscopy. We follow the In-vitro drug release by using Ultraviolet-Visible Spectroscopy (UV-vis). Our results revealed that diatoms decorated with gold nanoparticles using the Ex-situ method (Au/CTAB-Diatom) showed a faster release reaching a maximum of 93% in 10 days and a lower loading rate, while the samples decorated by the In-situ method presented longer and slower release behavior. Fluorescence properties were enhanced after the gentamicin loaded. The advantage of this work is the control of the structural and optical properties of diatoms decorated with gold nanoparticles for the gentamicin drug delivery., (Copyright © 2021. Published by Elsevier B.V.)

Blends of chitosan (CS) and polyvinylpyrrolidone (PVP) with cobalt ferrite nanoparticles (CoFe 2 O 4 ) have the potential for use in several biomedical applications as drug delivery systems and for hyperthermia applications. Herein, we present a detailed study of the effect of chitosan and PVP on the structural, magnetic and specific absorption rate (SAR) properties of Co x Fe 3-x O 4 (x = 0.25, 0.50, 0.75 and 1.00) as an effective heat nanomediator for hyperthermia. Structural characterization was carried out using X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Magnetic properties as a function of the Co 2+ content were studied using a vibrating sample magnetometer (VSM) at room temperature. Hyperthermia investigations were performed at 454 ± 20 kHz with a magnetic field amplitude of 5.5 mT. CS-PVP coated nanoparticles at x = 1.00 show a maximum SAR of 386 W/g, while bare nanoparticles show a SAR of 270 W/g. The advantage of the designed nanoparticles coated system lies in the fact that the versatile blending of chitosan and PVP enhance the SAR properties for hyperthermia of cobalt ferrite nanoparticles and provide biocompatibility and stability to the samples., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Ecuador is one of the most affected countries, with the coronavirus disease 2019 (COVID-19) infection, in Latin America derived from an ongoing economic crisis. One of the most important methods for COVID-19 detection is the use of techniques such as real time RT-PCR based on a previous extraction/purification of RNA procedure from nasopharyngeal cells using functionalized magnetic nanoparticles (MNP). This technique allows the processing of ~ 10,000 tests per day in private companies and around hundreds per day at local Universities guaranteeing to reach a wide range of the population. However, the main drawback of this method is the need for specialized MNP with a strong negative charge for the viral RNA extraction to detect the existence of the SARS-CoV-2 virus. Here we present a simplified low cost method to produce 10 g of nanoparticles in 100 mL of solution that was scaled to one litter by parallelizing the process 10 times in just two days and allowing for the possibility of making ~ 50,000 COVID-19 tests. This communication helps in reducing the cost of acquiring MNP for diverse biomolecular applications supporting developing country budgets constraints and chemical availability specially during the COVID-19 International Health Emergency.

Ecuadorian pottery is renowned for its beauty and the particularly rich colour of its pigments. However, a major challenge for art historians is the proper assessment of the provenance of individual pieces due to their lack of archaeological context. Of particular interest is the Jama-Coaque culture, which produced fascinating anthropomorphic and zoomorphic pottery from ca. 240 B.C. until the Spanish Conquest of 1532 A.D. in the coastal region of Ecuador. Using a combination of microscopic and spectroscopic techniques, i.e., transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), energy-dispersive x-ray spectroscopy (EDX), and scanning electron microscopy (SEM); we are able to characterize these pieces. We have found several kinds of iron-oxide based nanostructures in all the colour pigments we investigated for the Jama-Coaque culture, suggesting the same unique volcanic source material was used for their clay. Such nanostructures were absent from the pigment samples studied from other contemporary coastal-Ecuadorian cultures, i.e., the Tumaco-La Tolita and Bahía cultures. In the yellow pigments of goethite we find carbon nanofibres, indicating these pigments were subjected to a thermal treatment. Finally, in the blue, green, and black pigments we detect modern pigments (phthalocyanine blue, lithopone, and titanium white), suggesting modern restoration. Our results demonstrate the power of TEM, Raman, FTIR, EDX, and SEM archaeometric techniques for characterizing pieces without a clear archaeological context. Furthermore, the characterization of nanostructures present in such pieces could be used as a possible fingerprint for a provenance study.

Cobalt ferrite hollow spheres with chitosan (CoFe 2 O 4 /CS) were synthesized by two different approaches using the solvothermal method. The first approach involves in-situ incorporation of FeCl 3 :6H 2 O and CoNO 3 :6H 2 O in the solvothermal reaction (M1) and in second approach already prepared CoFe 2 O 4 nanoparticles (NPs) using the thermal decomposition method was placed in the solvothermal reaction to form the hollow spheres (M2). Structural identification of the samples were characterized by Fourier transform infrared spectra (FTIR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analyses (DSC-TGA) and energy dispersive X-ray spectroscopy (EDX). The magnetic properties were evaluated using a vibrating sample magnetometer (VSM). The presence of chitosan on the hollow sphere was confirmed by FTIR. The XRD analyses proved that the synthesized samples were cobalt ferrite with spinel structure. The structure of the surface and the average particle size of the spheres were observed by SEM and TEM showing the nano scale of the CoFe 2 O 4 component. Structural characterization demonstrating that chitosan does not affect the crystallinity, chemical composition, and magnetic properties of the CoFe 2 O 4 /CS. This work demonstrates that the CoFe 2 O 4 /CS prepared using the as synthesized CoFe 2 O 4 NPs have better structural and magnetic properties., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objective: The aim of this article is to highlight our experience with autologous pericranium graft in wide exposures (≥3 mm). The pericranium graft was taken from the parietal region of the scalp in six consecutive clinical cases of orbital implant exposure in anophthalmic sockets., Material and Methods: This is a prospective, descriptive case series study of patients who had orbital implant exposures and were treated with autologous pericranium graft., Results: The average postoperative follow-up period was 10 months, and the mean time for conjunctivalization of the graft was 3 months. In all cases, complete conjunctivalization was achieved, and no re-exposure of the implant was observed., Conclusions: The pericranium graft from the parietal region is an effective technique to treat both small and large orbital implant exposures with no comorbidity. Time to complete conjunctivalization is similar to that of other autologous grafts. It is a simple and convenient method for the oculoplastic surgeon that constitutes a good alternative for covering anophthalmic cavities. Further studies with more cases and longer follow-up are required to confirm the effectiveness of this technique., (Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

A single in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gestation day 15 decreased epididymal sperm count in adult rats and thus was used to establish a tolerable daily intake for TCDD. However, several laboratories have been unable to replicate these findings. Moreover, conflicting reports of TCDD effects on daily sperm production suggest that spermatogenesis may not be as sensitive to the adverse effects of TCDD as previously thought. We performed a PubMed search using relevant search terms linking dioxin exposure with adverse effects on reproduction and spermatogenesis. Developmental exposure to TCDD is consistently linked with decreased cauda epididymal sperm counts in animal studies, although at higher dose levels than those used in some earlier studies. However, the evidence linking in utero TCDD exposure and spermatogenesis is not convincing. Animal studies provide clear evidence of an adverse effect of in utero TCDD exposure on epididymal sperm count but do not support the conclusion that spermatogenesis is adversely affected. The mechanisms underlying decreased epididymal sperm count are unknown; however, we contest [corrected] that epididymal function is the key target for the adverse effects of TCDD.

Background: A single in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gestation day 15 decreased epididymal sperm count in adult rats and thus was used to establish a tolerable daily intake for TCDD. However, several laboratories have been unable to replicate these findings. Moreover, conflicting reports of TCDD effects on daily sperm production suggest that spermatogenesis may not be as sensitive to the adverse effects of TCDD as previously thought., Data Sources: We performed a PubMed search using relevant search terms linking dioxin exposure with adverse effects on reproduction and spermatogenesis., Data Synthesis: Developmental exposure to TCDD is consistently linked with decreased cauda epididymal sperm counts in animal studies, although at higher dose levels than those used in some earlier studies. However, the evidence linking in utero TCDD exposure and spermatogenesis is not convincing., Conclusions: Animal studies provide clear evidence of an adverse effect of in utero TCDD exposure on epididymal sperm count but do not support the conclusion that spermatogenesis is adversely affected. The mechanisms underlying decreased epididymal sperm count are unknown; however, we postulate that epididymal function is the key target for the adverse effects of TCDD.

The objective of the present study was to determine the frequency of lupus anticoagulant (LA), in patients with terminal chronic renal failure (TCRF), and its association with thrombotic events. Sixty three patients were separated into two groups: Group A, consisted of 32 patients under treatment with hemodialysis, and Group B was formed of 31 patients who were treated in a conservative manner. Presence of LA was found in 4 patients from Group A and none from Group B. Seven thrombotic events were registered, all in patients from Group A, and three of the episodes happened in 2 patients with LA, showing a statistically significant difference with LA negative patients from the same Group A (p < 0.001). Three of the LA positive patients suffered from type 2 diabetes and all of them had been under dialysis for less obtained by than 6 months. Vascular access was catheterization which means that 57.1% of patients with this type of procedure were positive for LA. The present results show a strong relationship between the presence of LA and thrombotic episodes in patients with TCRF, under hemodialysis with the use of catheter, instead of a permanent vascular access. Due to the fact that prolonged use of catheters for hemodialysis has been related to positive LA, it is advisable to screen patients under dialysis for the presence of this antibody, and to promote the prompt availability of a permanent vascular access, in order to prevent complications, such as thrombosis.