Synthesis and Characterization of Polystyrene Sulfonic Acid from Expanded Polystyrene Foam as a Catalyst in the Synthesis of Triacetin

In Indonesia, the composition of waste has gradually changed over time. To reduce expanded polystyrene (EPS) foam waste, we converted it into a heterogeneous acid catalyst, namely Polystyrene Sulfonic Acid (PSSA). The catalyst was then used in an esterification reaction to generate triacetin. In this research, the synthesis of PSSA was performed using a sulfonation reaction with silver sulfate (Ag2SO4) as the catalyst. Based on FTIR analysis, the sulfonation reaction was successful. The use of 0.5% and 1% catalysts led to a significant increase in the degree of sulfonation of PSSA, while there was a relatively constant increase when using 1.5–2.5% catalysts. The highest degree of sulfonation (78.63%) was achieved when the reaction was performed using 2% Ag2SO4 catalyst for 25 min. The PSSA with the highest degree of sulfonation was characterized using X-Ray Diffraction (XRD), SEM-EDX, and BET-BJH. This PSSA had a semi-crystalline structure with a crystallinity of 73.83%, a particle size of 1.75 nm, mesoporous pores with a radius of 16.984 Å, and a sulfur content of 15% (% mass).

In vitro testing of silver-containing spacer in periprosthetic infection management

Deep infection is a serious complication in endoprosthetic surgery. In correlation to the patient local or systemic compromising factors conservative and surgical proceedings has to be evaluated. Systemic antibiotic therapy is the gold standard in infection management. Implanted silver-coated or silver-containing medical devices have been proven to their antimicrobial effectiveness since the 1990s by several investigators. The outcomes showed that long time implantation could cause damaging of the surrounding tissues, especially of adjacent nerves. The aim of our study was to evaluate the release of silver (I) ions from bone cement mixed with either nanosilver particles (AgNPs), different concentrations of silver sulfate (Ag2SO4) or from pure metallic silver strips. Therefore, we choose two methods: the first, called “static model”, was chosen to evaluate the maximal accumulative concentration of silver (I) ions, with the second, called “dynamic model”, we simulated a continuous reduction of the ions. In an additional test design, the different materials were evaluated for their antimicrobial activity using an agar gel diffusion assay. The outcome showed that neither the addition of 1% (w/w) nanosilver nor 0.1% silver sulfate (w/w) to polymethylmethacrylat bone cement has the ability to release silver (I) ions in a bactericidal/antifungal concentration. However, the results also showed that the addition of 0.5% (w/w) and 1% (w/w) silver sulfate (Ag2SO4) to bone cement is an effective amount of silver for use as a temporary spacer.

Synthesis of new bimetallic phosphate (Al/Ag3PO4) and study for its Catalytic performance in the synthesis of 1,2-dihydro-l-phenyl-3H-naphth [1,2-e]-[1,3] oxazin-3-one derivatives

<p>This work aims to prepare a new bimetallic phosphate catalyst using a new simple and effective method. This new catalyst was ready for the first time by a modification of Triple Super Phosphate (TSP) fertilizer with silver sulfate (AgSO₄), followed by the impregnation of the aluminum atoms using aluminum nitrate (Al(NO₃)₃). The use of Al/Ag₃PO₄, for the first time as a heterogeneous catalyst in organic chemistry, offers a new, efficient, and green pathway for synthesizing 1,2-dihydro-l-phenyl-3H-naphth[1,2-e]-[1,3]oxazin-3-one derivatives by one-pot three-component cyclocondensation of b-naphthol, aryl aldehyde, and urea. The structure and the morphology of the prepared catalyst were characterized by spectroscopic methods such as X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), and dispersive X-ray spectrometry coupled with a scanning electron microscope (EDX-SEM). In addition, the optimization of the reaction parameters was carried out considering the effect of catalyst amount, the temperature, and the solvent. The procedure described herein allowed a comfortable preparation of oxazine derivatives with excellent yields, short reaction times, and in the absence of organic solvent.</p>

Factors affecting synthesis of silver-nanoparticles and antimicrobial applications

Silver nanoparticles were synthesized from silver sulfate by using the chemical reduction method with dextran as both a reducing agent and a protective agent. The influence of reaction temperature, time, and initial pH on the synthesis was investigated. The formation of Ag nano-particles (AgNPs) and their morphology were characterized with UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and Fourier transform-infrared spectroscopy. The antifungal and antibacterial effects of AgNPs/dextran on Xanthomonas oryzae and Pyricularia oryzae were tested.

Effect of Treatment with Silver Sulfate on the Physiological Effects of Natural Mineral Water

The treatment of mineral water with silver allows to significantly extend its shelf life without deteriorating its organoleptic properties, which makes it possible to use mineral water away from the natural deposit and is critical for business and the end consumer. However, possible changes in the physiological properties of mineral waters when treated with silver have not been studied until now. We have carried out a preclinical double-blind randomized placebo-controlled, experimental study, during which the effect of treatment with silver sulfate at a dose of 0.02 mg / liter (according to the EAEU tR 044–2017 regulation) of natural mineral water of sulphate-hydrocarbonate calcium-sodium (Russia, Stavropol territory, deposit “Slavyanovskaya”, well No. 69 bis) for cellular metabolism, microcirculation and micro-lymphocyte when applied externally to the area of the inner surface of the forearm. A comparison of the effect on cell metabolism and microcirculation has been made for applications with native mineral water “Slavyanovskaya”, “Slavyanovskaya, enriched with silver sulfate” and placebo (tap water) after 30 minutes and after 24 hours. Number of patients: 15. Number of studies by location: 45. the results were monitored using the LAZMA St device. the study carried out simultaneous registration of diagnostic parameters of blood microcirculation, lymph microcirculation, as well as fluorescence amplitudes of coenzymes participating in oxidative metabolism - reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavin adenine dinucleotide (FAD). It was revealed that the mineral water “Slavyanovskaya enriched with silver” differs in its physiological effect on cellular metabolism, microcirculation and micro-lymph flow from the physiological effect of the mineral water “Slavyanovskaya”, namely that, compared to “Slavyanovskaya”, the mineral water “Slavyanovskaya enriched with silver” has a more pronounced positive effect on cellular metabolism, metabolic reserves of the cell, promotes the activation of microcirculation and micro-lymphatic flow. Mineral water “Slavyanovskaya, enriched with silver” has a longer effect on cellular metabolism, microcirculation and micro-lymphatic flow than mineral water “Slavyanovskaya”. A statistically significant positive effect of cell metabolism activation was detected both 30 minutes and 24 hours after exposure. Thus, this method of processing mineral water with silver sulfate not only does not decrease its positive physiological effect, but also improves it, prolonging its action, which makes further use of silver preparations in the processing of mineral water justified.

Identifying water availability in the Atacama Desert (Chile) by triple oxygen isotope analyses of sulfates

&lt;p&gt;Ca-Sulfates (Gypsum and Anhydrite) are the most common salts accumulating in the soil of the Chilean Atacama Desert. Sulfate sources include sea spray, redeposition of playa sediments, terrestrial weathering, and deposition of sulfate formed in the atmosphere (secondary atmospheric sulfate = SAS). Sulfate from sea spray, playa lakes, and terrestrial weathering have a triple oxygen isotope composition (&amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt;) at or slightly below zero reflecting reaction with water and oxygen. Positive &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; are generally the result of atmospheric SO&lt;sub&gt;2&lt;/sub&gt; oxidation by ozone or hydrogen peroxide. Sulfate oxygen is only altered with ambient water by cycling through biological activity resulting in &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; &amp;#8776; 0&amp;#8240;. Therefore, &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; aids in quantifying the relative contribution of SAS to the desert soil and in identifying bioactivity and water availability in the hyperarid Atacama Desert. The spatial quantification of different sulfate sources may serve to improve the understanding of sulfate deposition in this region.&lt;/p&gt;&lt;p&gt;Samples were analysed by continuous flow IRMS using the pyrolysis of Ag&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt; to determine &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; from O&lt;sub&gt;2&lt;/sub&gt;. An optimized sample preparation to form clean silver sulfate and intra-day calibration against two in-house standards resulted in an external reproducibility of 0.12&amp;#8240;. An inter laboratory comparison including data derived from the laser-fluorination method confirmed the accuracy of our analyses.&lt;/p&gt;&lt;p&gt;We analyzed desert soil surface samples from four E-W transects in the Atacama Desert reaching from the Pacific coast across the Coastal Cordillera, the Central Depression, and up the alluvial fans protruding from the Pre-Andean Cordillera. Transects begin at Pisagua (19.5&amp;#176;S), Salar Grande (21.0&amp;#176;S), Antofagasta (24.0&amp;#176;S), and Paposo (25.0&amp;#176;S). Values of &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; vary between 0.3 and 1.1&amp;#8240;. The lowest &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4 &lt;/sub&gt;values were measured near Salar Grande and on the Pre-Andean alluvial fans. The highest &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4 &lt;/sub&gt;values are observed at the highest altitudes in the Coastal Cordillera - east of Paposo - well above the coastal fog zone (&gt; 1200 m). At similar or higher altitudes on the Pre-Andean fans, &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; converge towards zero.&lt;/p&gt;&lt;p&gt;The spatial distribution is the result of source contributions and subsequent biological reset. Positive &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; values throughout suggest a significant contribution from SAS. We quantified sea spray contributions using Cl-&amp;#160;concentration, which drop dramatically above the fog-zone [1]. Furthermore, salt distribution suggests minimal weathering and redistribution in recent times. The lowest contribution from such near zero &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; sulfate sources are expected in the Coastal Cordillera, which is consistent with our data. Within the Coastal Cordillera there is a north to south &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4 &lt;/sub&gt;trend, which is also an elevation trend. Increased water availability from fog at lower elevations facilitates more efficient resetting of &amp;#916;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;SO4&lt;/sub&gt; via microbial activity. These observations suggest that the driest place in the Atacama Desert is situated within the Coastal Cordillera above the fog zone.&lt;/p&gt;&lt;p&gt;[1] Voigt et al. (2020) Global and Planetary Change &lt;strong&gt;184&lt;/strong&gt;&lt;/p&gt;

Morphological comparative assessment of in vivo 2-week oral exposure of silver nanoparticles and silver sulfate on the mice liver

Currently the problem of the impact of nanoparticles and nanomaterials on human health remains to be poorly understood. As in our studies of the impact of silver nanoparticles on rats liver as well in works of other researchers there were investigated morphofunctional indices under peroral exposure. Although all researchers took different sizes, doses and concentrations of silver nanoparticles, various exposure time and different stabilizers, the same effects had been obtained, which, however, were occurred under both different doses and time of exposure. However, it was interesting to compare the impact of silver nanoparticles with reference substance - silver sulfate on the mice liver with the previously evaluated effect produced on the rats ’ liver. By ourselves there was executed the morphological comparative evaluation of in vivo oral 2-weeks exposure of 4 concentrations (0.1; 5; 50 and 500 mg/l) of silver nanoparticles with size of 14 nm, stable arabian gum 1:7 by weight, and of 4 similar concentrations of silver sulfate on the liver of male mice СВАхС57В1/6 weighing 25-35g. 2 groups were considered as control: intact mice and mice received gum in water. Results of the exposure were assessed according to 10 morphological and functional indices. The impact of nanosilver was shown to initiate from its concentration of 50 mg/l and to express in the gain of the index of alteration of the cytoplasm of hepatocytes with the increasing in both severity of steatosis and the number of micronecroses, persisting at the same level at concentrations of 500 mg/l and with the elevation of the index of alteration of nuclei of hepatocytes, while the similar effect develops under the influence of silver sulfate at a concentration of 500 mg/l only. The remaining investigated morphofunctional indices did not differ significantly in all groups of mice. Unlike previously executed studies on rats, mice appeared to be sensitive to the effects of nano-silver more than to silver sulfate.