Anjar Anggraini Harumningtyas

This study reports a novel cold plasma-assisted glycerolysis process for the synthesis of monoacylglycerols and diacylglycerols in the absence of a catalyst. The studied parameters including molar ratio, plasma power, treatment time, and argon (Ar) gas flow rate were optimized. Parameter optimization was obtained via the Taguchi design method based on signal-to-noise (S/N) ratio analysis. The results revealed that the highest predicted response was achieved as the optimal combination under the conditions of a 1:1 oil to glycerol molar ratio, 30 W plasma power, 45 min treatment time, and 3 L/min Argon gas flow rate. GC-MS analysis showed that the relative abundances of the MAG and DAG components were 22.47% 1-MAG (monoolein), 22.51% 1,2(1,3)-DAG (palmitin, olein), and 47.44% 1,2-DAG (olein, palmitin) in the presence of 1 mL co-solvent (t-butanol). The integration of cold plasma in glycerolysis enabled reactant conversion at a low bulk reaction temperature (50-55 °C) and low power input (30 W), offering a markedly more efficient process compared to conventional processes (typically 220-250 °C). A possible mechanism involving intermediate cleavage and re-esterification is proposed. These findings demonstrate the potential of cold plasma as an applicable strategy to reduce catalyst dependency and produce clean-label ingredients in the food industry, as no catalyst residues remain in the product.

Liquid smoke is a condensate formed from the incomplete burning of lignocellulosic materials, which generates chemical compounds such as acetic acid, phenols, carbonyls, and their derivatives. This study aims to utilize mahang wood (Macaranga pruinosa) as an alternative raw material for generating liquid smoke and to examine the properties of the resulting compounds. A traditional pyrolysis technique was utilized for the production process, with pyrolysis times of 30, 45, and 60 minutes. A simple condensation system was used to collect the combustion vapors. The findings suggest that mahang wood can generate liquid smoke with a fairly good yield, noted for its dark brown color and unique scent. Preliminary analysis revealed that the primary components were organic acids, phenols, furans, and their derivatives, as identified through GC–MS (Gas Chromatography–Mass Spectrometry) analysis. The research shows that increasing pyrolysis duration decreases the total phenolic content in the liquid smoke, with the highest value of 18.65 mg GAE/g identified at 30 minutes through UV–Vis spectrophotometric analysis. Based on FTIR spectra, prolonged pyrolysis of mahang wood decreases oxygenated and aliphatic groups, while increasing aromatic structures, reflecting enhanced aromatization and structural stability in the resulting pyrolysis products. Consequently, mahang wood possesses considerable potential as an affordable and eco-friendly raw material for producing liquid smoke, while also increasing the added value of local forest resources that are not fully utilized.

Nanocoatings for the biomineralization membrane were developed on a gelatin (Gel) and carbonated hydroxyapatite (CHA) composite, namely, Gel/CHA membrane. The membrane, which contains bioactive polymer and a mineral phase, was further modified using plasma to deposit thin functional polymeric films. These surface-tailored nanocoatings improved the membrane's performance by increasing its swelling capacity to better mimic a tissue-like environment, strengthening its mechanical stability during application, and modulating interactions with biological components such as proteins to support tissue engineering and regeneration. Four types of thin films were explored, namely, 2-methyl-2-oxazoline (OX), 1,7-octadiene, acrylic acid (AC), and allylamine (AA). The physicochemical, mechanical, and biological properties of these plasma-functionalized membranes were systematically investigated. Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) confirmed the successful deposition of functional coatings, while scanning electron microscopy (SEM) and atomic force microscopy demonstrated variations in the surface morphology and roughness. Water contact angle and swelling ratio measurements revealed tunable hydrophilicity and water uptake properties, with AC- and OX-coated membranes exhibiting enhanced hydration. Mechanical testing in dry state indicated that the OX-coated membranes achieved an optimal balance between tensile strength and elongation, thereby enhancing their mechanical resilience. Protein adsorption studies highlighted increased biomolecular interactions with hydrophobic surfaces demonstrating higher protein affinity. Cytocompatibility assessments, following ISO 10993-5:2009 standards, confirmed that all plasma-coated membranes were noncytotoxic to osteoblast MC-3T3-E1 cell lines, with cell viability exceeding 80%. The in vitro evaluation of MC-3T3-E1 cell adhesion was confirmed using DAPI staining and SEM observation and revealed that the MC3T3-E1 cells attached on control, AC, and AA membranes with a flatter shape. Additionally, the mineralization potential was assessed via simulated body fluid immersion for up to 360 min. EDX analysis showed time-dependent deposition of calcium and phosphate, with AA-coated membranes exhibiting the highest mineral accumulation. These findings demonstrate that plasma-assisted functionalization can significantly improve the membrane properties, making it a promising candidate for advanced bone tissue engineering applications.

A recent in vivo study [Kodama et al., Sci. Rep. 11, 1 (2021)] showed that porous artificial bones coated with amine-containing polymers deposited by plasma-enhanced chemical vapor deposition (PECVD) significantly enhanced bone regeneration. This article reports the chemical and physical properties of amine plasma polymers (PPs) formed under the same deposition conditions, including the film stability for up to two months, the effects of sterilization on the chemical compositions of the films, and the penetration of amine PPs into the inner surfaces of interconnected microscopic pores of the amine PP-coated porous artificial bone. It was found that, immediately after the plasma polymerization process, approximately 20% of nitrogen atoms on the surface of the deposited amine PP formed primary amines. However, the value decreased to approximately 5% over one month if the sample was exposed to ambient air. The relative concentration of primary amines also decreased to a similar value after the sample was sterilized by autoclaving or ethylene oxide gas. Molecular dynamics simulations were used to examine possible formation mechanisms of nitriles in deposit films under the PECVD conditions and found that ion impact can significantly reduce the nitrile content.

Molecular dynamics simulations were performed to examine the amine formation in carbon-based polymer films deposited by plasma-enhanced chemical vapor deposition (PECVD) with methane (CH4) and nitrogen (N2) gases. In the simulations, the interactions between the deposited film surface and incident precursors were examined, where nitrogen species were assumed to be supplied only as amino radicals (NH2) such that the amount of primary amine (−NH2) could be maximized in the deposited film. Carbon was supplied as CH2 or CH3 radicals as well as CH2+ or CH3+ ions with an ion kinetic energy up to 100 eV, as typical in such PECVD experiments. It has been found that, even under such “ideal” conditions for the maximum primary-amine content, hydrogen (H) atoms of incident NH2 radicals tend to be transferred to surrounding C atoms in the polymerization process, leaving a relatively small amount of primary amine (the concentration ratio of primary amino groups NH2 to nitrogen atoms N ∼10%) in the deposited polymer films. The simulation results indicate that an increase of NH2 radicals in the gas phase of PECVD hardly increases the primary-amine content in the deposited films and, therefore, the primary-amine content may not depend strongly on the plasma conditions as long as a sufficient amount of nitrogen and hydrogen is supplied during the plasma polymerization process. The primary-amine content predicted by the simulations was found to be consistent with earlier experimental observations.

In Indonesia, several procedures have been proposed for the development of artificial bone implant technologies; e.g., the improvement of mechanical properties of artificial bones, the discovery of synthetic artificial bone materials from the local biomaterial industry and the enhancement of biocompatibility of existing artificial bones. However, not much work has been performed on the functionalization of existing artificial bone surfaces. For example, artificial bone surfaces may be functionalized by the formation of amino groups through plasma polymerization. It is known that the surface modification of biomaterial implant surfaces with amino groups has advantages for the immobilization of biomolecules and the stimulation of more rapid healing processes. In this study, amino groups were deposited by low-pressure plasma polymerization with a DC-plasma source that was developed and built at BATAN. Plasma polymerization was performed between the parallel stainless-steel electrodes of the system with a DC power supply. The pressure was maintained below 5 × 10⁻² mbar via a rotary pump. The power, pressure, flow rate, electrode size and shape, and deposition time were varied to examine the film deposition rates and plasma stability. A mixture of hydrocarbon and nitrogen gases was needed in the plasma polymerization processes to form amino groups on biomaterial surfaces. In the mixed gas used in this study for amino-group functionalization, acetylene (C₂H₂), nitrogen (N₂), and argon (Ar) were used as a monomer gas, a reactive gas, and an inert gas, respectively. Furthermore, the formation of functional groups on the surface after a DC-plasma treatment was identified and analyzed by Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR).

We apply particle based kinetic simulations to explore the characteristics of a low-pressure gas discharge driven by high-voltage (∼kV) pulses with alternating polarity, with a duty cycle of ≈ 1% and a repetition rate of 5 kHz. The computations allow tracing the spatio-temporal development of several discharge characteristics, the potential and electric field distributions, charged particle densities and fluxes, the mean ion energy at the electrode surfaces, etc. As such discharges have important surface processing applications, e.g. in the treatment of artificial bones, we analyse the time-dependence of the flux and the mean energy of the ions reaching the electrode surfaces, which can be both conducting and dielectric. Our investigations are conducted for argon buffer gas in the 40–140 Pa pressure range, for 1–5 cm electrode gaps and voltage pulse amplitudes ranging between 600 V and 1200 V.

We have studied a collimator design setup for the Subcritical Assembly for Mo-99 Production (SAMOP) at the Center for Accelerator Sciences and Technology (CAST), Nuclear Energy Agency of Indonesia (BATAN). The main purpose of the project is for providing sufficient neutrons to produce Mo-99, to be used to produce Tc-99m for nuclear medical applications. The modelling of the collimator is based on Monte Carlo simulation using MCNPX version 5 software to determine the variation of the suitable materials. The collimator consists of moderator, filter, and reflector, where we expected that the output of neutron will be thermal neutron with a sufficient neutron flux of about 10 8 neutron/cm 2 .s. The neutron source used is a D-T reaction neutron generator with a mono-energetic neutron energy of 14.1 MeV. The simulation has been conducted in nine variations, with each experiment uses five types of materials. The best result in terms of neutron flux is seem from the material combination of Al, C25H52, LiF, and PbF2, which produces a thermal neutron flux of 1.24×10 7 neutron/cm 2 .s and average energy deposition of 1.88×10 6 MeV/g. This research needs to be developed further for subsequent experiments to optimize the combination of materials and geometry systems to be used.

ELECTRON BEAM EXTRACTION ON PLASMA CATHODE ELECTRON SOURCES SYSTEM. The electron beam extraction through window of Plasma Generator Chamber (PGC) for Pulsed Electron Irradiator (PEI) device and simulation of plasma potential has been studied. Plasma electron beam is extracted to acceleration region for enlarging their power by the external accelerating high voltage (V_ext) and then it is passed foil window of the PEI for being irradiated to any target (atmospheric pressure). Electron beam extraction from plasma surface must be able to overcome potential barrier at the extraction window region which is shown by estimate simulation (Opera program) based on data of plasma surface potential of 150 V with U_eks values are varied by 150 kV, 175 kV and 200 kV respectively. PGC is made of 304 stainless steel with cylindrical shape in 30 cm of diameter, 90 cm length, electrons extraction window as many as 975 holes on the area of (15 × 65) cm² with extraction hole cell in 0.3 mm of radius each other, an cylindrical shape IEP chamber is made of 304 stainless steel in 70 cm diameter and 30 cm length. The research result shown that the acquisition of electron beam extraction current depends on plasma parameters (electron density n_e, temperature T_e), accelerating high voltage V_ext, the value of discharge parameter G, anode area S_a, electron extraction window area S_e and extraction efficiency value α.