Computational Estimation of the Acidities of Pyrimidines and Related Compounds

Pyrimidines are key components in the genetic code of living organisms and the pyrimidine scaffold is also found in many bioactive and medicinal compounds. The acidities of these compounds, as represented by their pKas, are of special interest since they determine the species that will prevail under different pH conditions. Here, a quantum chemical quantitative structure–activity relationship (QSAR) approach was employed to estimate these acidities. Density-functional theory calculations at the B3LYP/6-31+G(d,p) level and the SM8 aqueous solvent model were employed, and the energy difference ∆EH2O between the parent compound and its dissociation product was used as a variation parameter. Excellent estimates for both the cation → neutral (pKa1, R2 = 0.965) and neutral → anion (pKa2, R2 = 0.962) dissociations were obtained. A commercial package from Advanced Chemical Design also yielded excellent results for these acidities.

Thermal Properties of Copper Matrix-Ceramic Filler Composite Prepared by Polymer Solution Method

A copper (Cu) metal-ceramic filler composite with high thermal conductivity and a suitable thermal expansion coefficient was designed for application as a high-performance heat dissipation material. The purpose of the designed material was to utilize the high thermal conductivity of Cu while lowering its high coefficient of thermal expansion by using a ceramic filler. In this study, a Cu-sol containing a certain amount of AlN or SiC ceramic filler was prepared using a non-aqueous solvent. A complex was produced by applying a PVB polymer to prepare a homogeneous precursor. The composite sintered without pressure in a reducing atmosphere showed low thermal conductivity due to residual pores, but the hot press sintered composite exhibited improved thermal conductivity. The Cu composite with 30 wt% AlN filler added exhibited a thermal conductivity of 290 W/m·K and a thermal expansion coefficient of 9.2 × 10-6/oC. Due to the pores in the composite, the thermal conductivity showed some difference from the theoretical value calculated from the rule of mixture. However, the thermal expansion coefficient did not show any significant difference.

Amine-Ionic Liquid Blends in CO2 Capture Process for Sustainable Energy and Environment

In the present work, an experiment for CO2 capture process were performed by absorption using various aqueous solvent blends of amine and ionic liquids. The solvent blends were prepared for various compositions by mixing TetraButylAmmonium Acetate [TBA][OAC] and TetraButylAmmonium Bromide [TBA][Br] ionic liquids with Monoethanolamine (MEA). The obtained results were compared with baseline MEA. It was observed that capture efficiency of CO2, absorption rate of CO2 and CO2 diffusion coefficient of MEA-[TBA][OAC] and MEA-[TBA][Br] solvent blends were comparatively higher than baseline 30%MEA. Moreover, the parameters such as density, viscosity, pH, carbon loading and surface tension of all the solvent blends were measured for before and after absorption process. The carbon loading of solvent blends MEA-[TBA][Br] (0.405 mole of CO2/mole of solvent) and MEA-[TBA][OAC](0.459 mole of CO2/mole of solvent) was slightly lower than baseline MEA (0.494 mole of CO2/mole of solvent). However, the viscosity of MEA-[TBA][Br] blends were remarkably lower than MEA-[TBA][OAC] blend and baseline MEA. This might be an important key factor in solvent recovery process with lesser energy demand for sustainable energy and environment.

Rapid meniscus-guided printing of stable semi-solid-state liquid metal microgranular-particle for soft electronics

Liquid metal (LM) is being regarded as the most feasible material for soft electronics owing to its distinct combination of high conductivity comparable to that of metals and exceptional deformability derived from its liquid state. However, the applicability of LM is still limited due to the difficulty of achieving its mechanical stability and intrinsic conductivity. Furthermore, reliable and rapid patterning of stable LM directly on various soft substrates at high-resolution remains a formidable challenge. In this work, meniscus-guided printing of ink containing polyelectrolyte-attached LM microgranular-particle (PaLMP) in an aqueous solvent to generate semi-solid-state LM is presented. PaLMP printed in the evaporative regime is mechanically stable, intrinsically conductive, and patternable down to 50 µm on various substrates. Demonstrations of the ultrastretchable (~500% strain) electrical circuit, customized e-skin, and zero-waste ECG sensor validate the simplicity, versatility, and reliability of this manufacturing strategy, enabling broad utility in the development of advanced soft electronics.

Preliminary Phytochemical analysis of Andrographis paniculata Leaf extract

Andrographis paniculata is a traditional medicinal plant widely used in Ayurveda and Siddha treatment. The extract from this plant is used to prevent and cure certain diseases. Phytochemical analysis of this leaf extract would identify the compounds in it and through this, new medicine could be formulated. In this study, three different solvent systems (Solvent A-100% aqueous, Solvent B-100% methanol and Solvent C- 50% aqueous and 50% methanol) were used to extract the compounds from leaves with three different time period of 24hrs, 48 hrs and 72 hrs. When compared to other conditions, the majority of the compounds were discovered in analyses with solvent C at 24hrs. The major compounds such as alkaloid, terpenoid, flavonoid, tannin and saponin were identified in the leaf extract. This study reveals that; with better extraction conditions, the presence of most of the phytochemicals from the leaf extract could pave a way to formulate new medication.

Dense Phases of γ-Gliadins in Confined Geometries

The binary phase diagram of γ-gliadin, a wheat storage protein, in water was explored thanks to the microevaporator, an original PDMS microfluidic device. This protein, usually qualified as insoluble in aqueous environments, displayed a partial solubility in water. Two liquid phases, a very dilute and a dense phase, were identified after a few hours of accumulation time in the microevaporator. This liquid–liquid phase separation (LLPS) was further characterized through in situ micro-Raman spectroscopy of the dilute and dense protein phases. Micro-Raman spectroscopy showed a specific orientation of phenylalanine residues perpendicular to the PDMS surfaces only for the diluted phase. This orientation was ascribed to the protein adsorption at interfaces, which would act as nuclei for the growth of dense phase in bulk. This study, thanks to the use of both aqueous solvent and a microevaporator, would provide some evidence for a possible physicochemical origin of the gliadin assembly in the endoplasmic reticulum of albumen cells, leading to the formation of dense phases called protein bodies. The microfluidic tool could be used also in food science to probe protein–protein interactions in order to build up phase diagrams.

Antimicrobial Hydrophilic Membrane Formed by Incorporation of Polymeric Surfactant and Patchouli Oil

Membrane properties are highly affected by the composition of the polymer solutions that make up the membrane material and their influence in the filtration performance on the separation or purification process. This paper studies the effects of the addition of pluronic (Plu) and patchouli oil (PO) in a polyethersulfone (PES) solution on the membrane morphology, membrane hydrophilicity, and filtration performance in the pesticide removal compound in the water sample. Three types of membranes with the composition of PES, PES + Plu, and PES + Plu + patchouli oil were prepared through a polymer phase inversion technique in an aqueous solvent. The resulting membranes were then analyzed and tested for their mechanical properties, hydrophilicity, antimicrobial properties, and filtration performance (cross-flow ultrafiltration). The results show that all of the prepared membranes could reject 75% of the pesticide. The modification of the PES membrane with Plu was shown to increase the overall pore size by altering the pore morphology of the pristine PES, which eventually increased the permeation flux of the ultrafiltration process. Furthermore, patchouli oil added antimicrobial properties, potentially minimizing the biofilm formation on the membrane surface.