Optimasi Sintesis Ligan Diheksilditiofosfat (DHDTP) Menggunakan Response Surface Method (RSM)

Dihexyldithiophosphate (DHDTP) ligand is one of the homologues of dialkyldithiophosphate which is potentially better as an extractant in solvent extraction. The longer the chain in the dialkyldithophosphate compound, ability to dissolve into the organic phase is increasing compared to the shorter chain. The purpose of this study is to synthesize DHDTP ligands and find out the optimum reaction conditions to produce DHDTP ligands with optimal purity using the BoxBehnken (BBD) response surface method (RSM). DHDTP ligands are synthesized from P2S5 by reflux after addition of n-hexanol under a nitrogen gas environment. Ammonium carbonate is added to the reflux to pH 7, then evaporated to remove the solvent. The synthesized DHDTP ligand was then purified by column chromatography with a mobile phase methanol : aquadest (2.5% gradient). DHDTP ligands were examined for purity using a reverse phase HPLC with a mobile phase methanol: aquadest 3: 2. The purity of the best DHDTP synthesis results obtained was 87.34%. The DHDTP ligand formed was characterized to confirm the structure of its ligand compound by using a UV spectrophotometer in which the synthesis product showed maximum absorption at a wavelength of 212 nm and mass spectroscopy ES- with m / z 297.1687.

Radiation synthesis of poly(acrylic acid) nanogels for drug delivery applications – post-synthesis product colloidal stability

Synthesis of polymer nanogels (NGs) for biomedical applications is considered to be a very promising application in radiation engineering. Under high-dose pulse irradiation of dilute aqueous polymer solution, reactive species generated by water radiolysis can create multiple radicals on each macromolecule and consequently induce intramolecular cross-linking of polymer chains, resulting in NG formation. The obtained products are free from harmful monomers, initiators, and cross-linking agents, which makes them potentially applicable for drug delivery applications. One of the biggest challenges in handling and use of nanoparticles, however, is the colloidal stability, when aqueous suspensions are stored for prolonged periods. Therefore, development of the best protocols for the particular nanocarrier storage is key. To address this need, we have performed the prospective study in which we systematically assessed the influence of various processing and storage scenarios feasible in our lab, on the colloidal stability of the radiation-synthesized poly(acrylic acid) (PAA) NG particles in suspension. This allowed us to choose the optimal way of handling the product after its synthesis. We confirmed that none of the strategies we used and tested are substantially detrimental to our product. Filtration with 0.2-μm filters was proven sufficient for sample purification and prolonged storage in aqueous suspension did not exert a negative effect on the colloidal stability of particles suspension. We have also demonstrated that lyoprotectant-free lyophilization was suitable for our polymer nanoparticles. This is an important fact for further application of particles as nanocarriers for biologically active compounds such as targeting ligands or therapeutic moieties.

Study of particles of plasma dynamic synthesis product in the Ti-O system by high-resolution transmission electron microscopy

The paper demonstrates the possibility of obtaining a dispersed product in the Ti-O system by the method of plasma dynamic synthesis. It was revealed that the product consists of two modifications of TiO2: anatase and rutile. The degree of crystallinity is at a level of ~ 98.0%, which indicates the practical absence of an amorphous component. The predominant phase is anatase, which is confirmed by the results of quantitative X-ray phase analysis and high-resolution transmission electron microscopy.

Electrosynthesis of HKUST-1 with Flow-Reactor Post-Processing

Electrochemical synthesis has been proposed as an efficient method for cost-effective and large-scale production of metal-organic frameworks (MOFs). This work investigates the combined electrochemical synthesis with flow synthesis post-treatment for the production of high surface area HKUST-1. The electrochemical synthesis process used in the experimental work did not require additional electrolytes or washing of the synthesis product. Batch electrosynthesis and electrosynthesis with flow synthesis were compared for the quality of the product using Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), and scanning electron microscopy (EIS). Batch electrosynthesis in 0.01 M benzene-1,3,5-tricarboxylic acid (H3BTC) solution produced HKUST-1 with BET surface area of 1550 m2/g which was increased further to 1716 m2/g with post-flow-synthesis treatment. The greatest change in surface area after flow processing was observed when using 0.78 M H3BTC, with corresponding surface areas of 481 m2/g and 1531 m2/g. According to SEM and BET results, the product purity improved during the post-flow-synthesis treatment. The proposed method enables continuous flow synthesis of high-quality MOFs with minimal purification steps.

Advanced Arc Plasma Synthesis of Biomorphic Silicon Carbide Using Charcoal and Silicon Dioxide in Air

The paper presents the results of experimental studies on the advanced synthesis method for a cubic phase of silicon carbide using charcoal and silicon dioxide as precursors. The charcoal used for the synthesis was obtained by steam pyrolysis of wood wastes (sawdust). It was found that the arc synthesis could be executed in air due to the protective CO and CO2 environment formation by charcoal oxidation. With an increase of the amount of supplied energy by direct current arc plasma synthesis, the products of two crystalline phases were formed: graphite and cubic phase of silicon carbide. The phase of silicon carbide was extracted from the synthesis product by its annealing in air at 850 °C. The resulting cubic SiC phase was characterized by an elementary cell parameter of 4.359 Å. According to the data of scanning electron microscopy, the morphology of crystals obtained is common for the biomorphic silicon carbide which was identified in the synthesis product. The ceramics synthesized by spark plasma sintering from the obtained material was characterized by a density of ~2.0 g/cm3.

Synthesis of Glucopyranosyl Acetic from Sago Flour as Raw Material for the Synthetic Polymers

Synthesis of glucopyranosyl acetic from sago flour as raw material for the synthetic polymers has been successfully carried out. The synthesis product is obtained through two reaction stages, namely the hydrolysis and esterification reactions. Sago flour is hydrolyzed with 25% HCl and neutralized with 45% NaOH. Glucose hydrolysis of sago starch and acetic anhydride was esterified using a zinc chloride catalyst. Synthesis product was obtained as a white solid substance (57.31% recovery), a melting point of 110 - 111oC, and Rf 0.79 on TLC (SiO2, n-hexane: ethyl acetate = 9:1 v/v). The results of the analysis of synthesis products with FTIR and GC-MS spectrometers showed that the synthesis product was glucopyranosyl acetic or 2,3,4,6-tetra-O-acetyl glucopyranose.

Synthesis of Biomaterial Hydroxyapatite from Limestone by Using Two-Step Conversion

Hydroxyapatite [Ca10(PO4)6(OH)2] is natural ceramic material which is often used for artificial bone reconstruction. In this research, hydroxyapatite was synthesized from mineral of Calcite (CaCO3) which obtained from the Campurdarat, Tulungagung. The hydroxyapatite synthesis steps are encompassed by the preparation of precursors and the synthesis process by using wet chemical manipulation or routes. The XRF characterization shows that the percentage of calcium from the raw material is around 99%. This study succesfully obtains the compound of Ca(OH)2as a source of hydroxyapatite. The concentration of H3PO4 in hydroxyapatite synthesis process influences the synthesis results. For the concentration of H3PO4 0.6 M is still found the compound of Ca(OH)2. The difference result is shown H3PO4 with concentration 0.8 M which the total synthesis product is hydroxyapatite.

Regulation of Autophagic Signaling by Mechanical Loading and Inflammation in Human PDL Fibroblasts

Autophagy (cellular self-consumption) is a crucial adaptation mechanism during cellular stress conditions. This study aimed to examine how this important process is regulated in human periodontal ligament (PDL) fibroblasts by mechanical and inflammatory stress conditions and whether the mammalian target of rapamycin (mTOR) signaling pathway is involved. Autophagy was quantified by flow cytometry. Qualitative protein phosphorylation profiling of the mTOR pathway was carried out. Effects of mTOR regulation were assessed by quantification of important synthesis product collagen 1, cell proliferation and cell death with real-time PCR and flow cytometry. Autophagy as a response to mechanical or inflammatory treatment in PDL fibroblasts was dose and time dependent. In general, autophagy was induced by stress stimulation. Phosphorylation analysis of mTOR showed regulatory influences of mechanical and inflammatory stimulation on crucial target proteins. Regulation of mTOR was also detectable via changes in protein synthesis and cell proliferation. Physiological pressure had cell-protective effects (p = 0.025), whereas overload increased cell death (p = 0.003), which was also promoted in long-term inflammatory treatment (p < 0.001). Our data provide novel insights about autophagy regulation by mechanical and inflammatory stress conditions in human PDL fibroblasts. Our results suggest some involvement of the mTOR pathway in autophagy and cell fate regulation under the named conditions.