Pure Constituents Research Articles

Impact of the Force Field on the Calculation of Density and Surface Tension of Epoxy-Resins.

The molecular simulation of interfacial systems is a matter of debate because of the choice of many input parameters that can affect significantly the performance of the force field of reproducing the surface tension and the coexisting densities. After developing a robust methodology for the calculation of the surface tension on a Lennard-Jones fluid, we apply it with different force fields to calculate the density and surface tension of pure constituents of epoxy resins. By using the model that best reproduces the experimental density and surface tension, we investigate the impact of composition in mass fraction on uncured epoxy resins and the effects of degree of cross-linking on cured resins.

Modeling the viscosity of binary eutectic systems at different compositions and temperatures

Deep eutectic solvents (DESs) are considered as promising green alternatives to common organic solvents in various applications. For utilizing DESs in process applications, it is essential to study their viscosity. In this work, the modified Adam-Gibbs (AG) and Vogel-Fulcher-Tammann (VFT) models were combined with 12 mixing rules to calculate the viscosity of 11 L-menthol-based binary eutectic systems (ESs) at various temperatures and compositions. The modified AG and VFT models were adopted to predict the viscosity of pure constituents below their melting temperatures, while the mixing rules were used to estimate the viscosity of ESs. It was found that the VFT model predictions for the viscosity of pure constituents below their melting temperatures were generally higher than those predicted by the modified AG model. Accordingly, when combined with the 12 mixing rules, the modified AG model gave better predictions for the viscosity of ESs than the VFT model. The Grunberg-Nissan mixing rule with one adjustable parameter provided the lowest average absolute relative deviation between the calculated and experimental viscosity.

Insecticidal Potential of α-Pinene and β-Caryophyllene against Myzus persicae and Their Impacts on Gene Expression

<i>Myzus persicae</i> (<i>M. persicae</i>) is now considered a threat to agricultural crops due to economic losses. Numerous synthetic insecticides applied every year against <i>M. persicae</i>, are reported to be unsafe for environment, humans, and beneficial insects. Furthermore, several species of <i>Myzus</i> have been found to develop resistance due to over application of these insecticides. Therefore, it is required to find some novel insecticide that would be safe for the environment as well as for humans. In the current study, two major pure constituents α-pinene and β-caryophyllene were evaluated for their insecticidal potential against <i>M. persicae</i> using a fumigant toxicity assay. Furthermore, impact of α-pinene and β-caryophyllene on expression of five different genes, e.g., HSP 60, FPPS I, OSD, TOL and ANT responsible for reproduction, dispersion, and growth of <i>M. persicae</i> has also been investigated. To perform fumigant toxicity assay, five different concentrations (3.5, 4, 4.5, 5 and 6 μL L⁻¹) of α-pinene and β-caryophyllene were prepared. Lethal concentration (LC) was calculated, and gene expression studies were executed through qRT PCR at LC₃₀ of α-pinene and β-caryophyllene. Both constituents demonstrated excellent fumigant toxicity effects against <i>M. persicae</i> at all five concentrations. However, α-pinene shows significantly better results (98%) as compared to β-caryophyllene (80%) after 72 h at 6 μL L⁻¹ of dose. The highest upregulation in expression was demonstrated at LC₃₀ dose of α-pinene in five in three out of five genes understudy (TOL, ANT, and FPPS I). Conversely, two genes HSP 60 and OSD demonstrated downregulation at LC₃₀ dose of β-caryophyllene. Conclusively, our results highlighted the promising insecticidal potential of both compounds α-pinene and β-caryophylleneby interfering with the reproduction and development related processes in <i>M. persicae</i>, allowing us to recommend the phytoconstituents under investigation as an ecofriendly alternative to synthetic insecticides.

Phyto-exclusion of Pb and Cd by different genotypes of Andrographis paniculata (Burm. F.) nees: A novel approach for safe cultivation

Pb and Cd are ubiquitous heavy metals (HMs) in the environment and their accumulation in medicinal herbs poses a serious threat due to health hazards. The genetic selection of high-yielding and low Pb and Cd accumulating genotypes known as phtyoexclusion is a cost-effective and promising phytotechnology. In the present study, phtyoexclusion method was used for the selection of low Pb and Cd accumulating genotypes of Andrographis paniculata (Burm.F.) Nees with minimum alteration in their pharmacological important constituents in three application rates of Pb and Cd. The performance of genotypes of A. paniculata was evaluated by uptake and translocation of Pb and Cd, biomass yield, shoot-to-root ratio, metabolite content, oxidative enzymes, and mineral content for their safe production and commercial viability. The bio-concentration factor (BCF) and translocation factor (TF) of Pb among the genotypes ranged from 0.09-3.6 and 0.006–0.045, respectively. However, variations in BCF and TF of Cd were 0.05–3.36 and 0.001–0.150 respectively. The differential expression of the metal accumulation in genotypes of A. paniculata was majorly associated with ionomics and biomass. Four genotypes of A. paniculata were screened out and were divided in the three categories. One, genotypes that accumulated Pb and Cd below the prescribed limits with high productivity and tolerance could be used for safer herb production. In the second category, genotypes having high accumulation in roots and low translocation could be used for phytostabilization of the soil. The above-ground material of the plant can be used for the extraction of pure constituents. The third one is genotypes with high accumulators and low productivity. • Fifteen genotypes of A. paniculata were screened for Pb and Cd accumulation. • Four genotypes demostrated the phytoexcluder potential for Pb and Cd. • Biomass and mineral contents were the main drivers for low accumulating genotypes. • Some high accumulating genotypes can be good candidate for phytostabilization.

Physics-Based Fusion of Sentinel-2 and Sentinel-3 for Higher Resolution Vegetation Monitoring

Monitoring vegetation growth, phenology and health in agriculture requires very high spatial and spectral resolution sensors. Sentinel-2 is among the spaceborne sensors that tried to meet these requirements. However, due to physical constraints, few visible bands are present with relatively large spectral responses which limits the leaf pigment content estimation. In this work, we propose to fuse Sentinel-2 bands with a Sentinel-3 image which has a lower spatial resolution but contains several spectral narrower bands in both the visible and near-infrared domains. The fusion procedure consists in sharpening the Sentinel-3 bands to match the Sentinel-2 spatial resolution leading to a higher spatial resolution Sentinel-3 image. The proposed fusion technique follows a physics-based approach based on the use of a radiative transfer model for establishing a correspondence between Sentinel-2 and Sentinel-3 images. In greater details, the main spectrally pure constituent of each high resolution Sentinel-2 pixel is identified for each pixel and it is then related to the corresponding low resolution Sentinel-3 pixel. Pure materials are the barycenters of clusters obtained by an unsupervised classification of the Sentinel-2 image. Sentinel-3 signatures are obtained using coarse resolution pixel matching with the Sentinel-2 image. The latter result is then corrected using radiative transfer modeling allowing the production of more realistic signatures. Validation was done using real Sentinel-2/Sentinel-3 images taken with a delay of only one day or less and by comparing the sharpened Sentinel-3 bands Oa04, Oa06, Oa08, and Oa17 with the corresponding Sentinel-2 bands B2, B3, B4, and B8A, as they are respectively spectrally close. For all the bands, the RMS is lower than 0.007, and compared to the state-of-the-art techniques it shows competitive results and robustness against scene heterogeneity. Besides, our findings prove that the retrieved Sentinel-3 signatures at full resolution are physically consistent and in good agreement with the Sentinel-2 data.

INSECTICIDAL PROPERTY OF TERPENES AGAINST MAIZE WEEVIL, SITOPHILUS ZEAMAIS (MOTSCHULSKY)

Synthetic pesticides are used indiscriminately in insect pest management, which damages the ozone layer and causes resistance in target organisms as well as neurotoxicity, carcinogenicity, teratogenicity and mutagenesis in non-target organisms. Due to these negative consequences, research is now focused on using plant-based techniques to control insect pests. The maize weevil, Sitophilus zeamais (Coleoptera: Curculionidae), was tested in the laboratory to determine the insecticidal effects of two pure essential oil constituents, namely α-pinene and β-caryophyllene. These two terpenes were tested against S. zeamais for their toxic, ovipositional, developmental, and feeding inhibitory effects. When S. zeamais adults were fumigated for 24 and 48hrs, the median lethal concentrations (LC50) of α-pinene and β-caryophyllene were 0.412 and 0.305 μlcm-3 and 0.486 and 0.315 μlcm-3 air respectively. When S. zeamais adults were exposed for 24 and 48hrs in a contact toxicity assay, the LC50 values for α-pinene and β-caryophyllene were 0.388 and 0.256 μlcm-2 and 0.308 and 0.216 μlcm-2 area respectively. Adults exposed to sub-lethal concentrations of both terpenes experienced decreased acetylcholine esterase (AChE) enzyme activity. In S. zeamais, α-pinene and β-caryophyllene decreased oviposition, progeny output and eating. According to this study, α-pinene and β-caryophyllene can be used to make environmentally acceptable formulations and as a substitute for synthetic insecticides.

Ethanol in Aqueous Solution Studied by Microjet Photoelectron Spectroscopy and Theory.

By combining results and analysis from cylindrical microjet photoelectron spectroscopy (cMJ-PES) and theoretical simulations, we unravel the microscopic properties of ethanol-water solutions with respect to structure and intermolecular bonding patterns following the full concentration scale from 0 to 100% ethanol content. In particular, we highlight the salient differences between bulk and surface. Like for the pure water and alcohol constituents, alcohol-water mixtures have attracted much interest in applications of X-ray spectroscopies owing to their potential of combining electronic and geometric structure probing. The water mixtures of the two simplest alcohols, methanol and ethanol, have generated particular attention due to their delicate hydrogen bonding networks that underlie their structural and thermodynamic properties. Macroscopically ethanol-water seems to mix very well, however microscopically this is not true. The aberrant thermodynamics of water-alcohol mixtures have been suggested to be caused by energy differences of hydrogen bonding between water-water, alcohol-alcohol and alcohol-water molecules. These networks may perturb the local character of the interaction between X-rays and matter, calling for analysis that go beyond the normally applied local selection and building block rules and that can combine the effects of light-matter, intra- and intermolecular interactions. However, despite decades of ongoing research there are still controversies of the precise nature of hydrogen bonding networks that underlie the mixing of these simple molecules. Our combined analysis indicates that at low concentration ethanol molecules form a film at the surface since ethanol at the surface can expose its hydrophobic part to the vacuum retaining its two (or three) possible hydrogen bonds, while water at the surface cannot retain all its four possible hydrogen bonds. Thus, ethanol at the surface becomes energetically favorable. Ethanol molecules show a tilting angle variation of the C-C axis with respect to the surface normal as large as 60° at very low concentration. In bulk, around ca. ten %, the ethanol oxygen atoms tend to make a third acceptor hydrogen bond to water molecules. At ca. 20 %, there is a U-shaped change in the CH3 to CH2OH binding energy (BE) shift indicating the presence of ring-like agglomerates called clathrate structures. At the surface, between 5 and 25%, ethanol forms a closely packed layer with the smallest C-C tilting angle variation down to ∼20°. Above 25% and below the azeotrope at the surface, ethanol shows an increase in the tilting angle variation, while at very high ethanol concentrations water tends to move to the surface so giving a microscopic explanation of the azeotrope effect. This migration is connected to the presence of longer (shorter) ethanol chains in the bulk (surface). A brief comparison with discussions and predictions from other spectroscopic techniques is also given. We emphasize the execution of an integrated approach that combines molecular structural dynamics with quantum predictions of the core electronic chemical shift, so establishing a protocol with considerable interpretative as well as predictive power for cMJ-PES measurements. We believe that this protocol can valorize cMJ-PES for studies of properties of other alcohol mixtures as well as of binary solutions in general.

Active Blood Pressure Lowering Fractions from the Aqueous Extract of the Leaves of Phyllanthus amarus Schum and Thonn (Euphorbiaceae)

Background: The blood pressure-lowering effffect of aqueous leaves extract of Phyllanthus amarus&nbsp;has been reported in earlier work in normotensive albino rabbits. The effffects of organic solvent&nbsp;fractions were evaluated in Wistar rats. Methods: The aqueous fraction obtained from the crude extract of the leaves was evaluated for blood pressure-lowering effffect in anaesthetized normotensive Wistar rats, at the graded doses of 2.5-40&nbsp;mg/kg after which it was subjected to vacuum liquid chromatography (VLC) using combinations of chloroform, ethyl acetate, methanol and water. This yielded eleven fractions which were bulked into six samples (A-F) after thin layer chromatograph analysis, and samples A, B and C were evaluated for&nbsp;activities on the blood pressure of hypertensive Wistar rats at the graded doses of 5 to 20 mg/kg.&nbsp;Fraction “C” showed the highest blood pressure lowering effffect and was further subjected to column&nbsp;chromatographic and VLC analysis, to obtain fraction (BVLC2) which was evaluated for possible blood&nbsp;pressure lowering effffect in hypertensive Wistar rats. Results: The aqueous fraction caused a dose de pendent decrease in the blood pressure of normotensive Wistar rats, decreasing the mean arterial blood pressure (MAP) from a basal level of 104.58 ± 8.29 mmHg to 45.22 ± 6.71 mmHg (p&lt;0.0001; 66.4%) at the dose of 40 mg/kg. Fraction “C” caused signifificant decrease in the MAPfrom 116.99 ± 10.28 mmHg to 68.33 ± 6.78 mmHg (p &lt; 0.001;&nbsp;0.01%) at the dose of 20 mg/kg, while the fraction BVLC2 decreased the MAPfrom 146.11 ± 8.29 mmHg&nbsp;to 79.33 ± 6.18 mmHg (***p&lt; 0.001) at the dose of 10 mg/kg, indicating a trend of increasing potency&nbsp;along the course of purifification. Conclusion: The aqueous fraction of the leaves of Phyllanthus amarus yielded column&nbsp;chromatographic sample (BVLC2), that might possibly serve as a lead sample from which pure active&nbsp;hypotensive constituent(s) could be isolated.&nbsp;

Design of Deep Eutectic Systems: Plastic Crystalline Materials as Constituents.

Deep eutectic solvents (DESs) are a class of green and tunable solvents that can be formed by mixing constituents having very low melting entropies and enthalpies. As types of materials that meet these requirements, plastic crystalline materials (PCs) with highly symmetrical and disordered crystal structures can be envisaged as promising DES constituents. In this work, three PCs, namely, neopentyl alcohol, pivalic acid, and neopentyl glycol, were studied as DES constituents. The solid–plastic transitions and melting properties of the pure PCs were studied using differential scanning calorimetry. The solid–liquid equilibrium phase diagrams of four eutectic systems containing the three PCs, i.e., L-menthol/neopentyl alcohol, L-menthol/pivalic acid, L-menthol/neopentyl glycol, and choline chloride/neopentyl glycol, were measured. Despite showing near-ideal behavior, the four studied eutectic systems exhibited depressions at the eutectic points, relative to the melting temperatures of the pure constituents, that were similar to or even larger than those of strongly nonideal eutectic systems. These findings highlight that a DES can be formed when PCs are used as constituents, even if the eutectic system is ideal.

The anti-oxidative potential of ginger extract and its constituent on meat protein isolate under induced Fenton oxidation

Ginger extract has been reported to possess antioxidant properties. However, components isolated from ginger have been rarely reported to inhibit oxidation. Herein, the antioxidant properties of ginger and purified components derived from it (6-gingerol, zingerone, rutin, quercetin, and kaempferol) were confirmed by using HPLC and were further used to investigate its effect on lamb meat. Myofibrillar proteins isolated (MPI) from lamb meat were incubated with ginger and its constituents under induced Fenton oxidation (1.0 mmol/L FeCl3, 0.1 mmol/L Asc, and 20 mmol/L H2O2) for 1, 3,5, and 7 h. Incubating meat protein isolate in the absence of ginger extract or its components resulted in a substantial drop in sulfhydryl groups, an increase in protein carbonyl content, and a corresponding increase in TBARS content. However, ginger extract and its constituents demonstrated antioxidant properties, which might be attributed to their hydroxyl groups and suitable solubilizing side chains. Overall, ginger extract exhibited the highest antioxidant capabilities of all treated samples, suggesting that ginger extracts may be used as a natural antioxidant in meat and lipid/protein-containing processed products. Significance of the studyGinger extract is also frequently used as a herbal medicine due to its anti-inflammatory, anti-cancer, and antibacterial qualities. Nonvolatile pungent chemicals found in ginger, such as gingerol, shogaols, paradols, and zingerone, as well as kaempferol, rutin, and other phenolic compounds, have been confirmed in ginger extract and have been shown to have antioxidant action driven by free radical elimination. Despite these findings, ginger extract and its pure constituent components have seldom been shown to have the ability to slow protein and lipid oxidation in meat and meat-related products. The effect of ginger extracts on the oxidative stability of myofibriller protein isolate has never been investigated. Exploiting the phenolic content of ginger extract may result in a discovery that would have a huge influence on both the ginger and meat industries as well as other food processing sectors. The first aim of our study was to confirm the presence of six selected phenolic compounds (rutin, kaempferol, 6-gingerol, zingerone, naringenin, and quercetin) in ginger as reported by literature, and the second objective was to determine the efficacy of ginger extracts and its purified constituents on myofibrillar protein isolate treated under induced Fenton oxidation.

Dynamics of type V menthol-thymol deep eutectic solvents: Do they reveal non-ideality?

We have established a comprehensive study of the molecular dynamics of the menthol-thymol mixture, the prototype of the new class of type V deep eutectic solvents. Dielectric spectroscopy and differential scanning calorimetry were combined to assess the dipolar relaxation and glassy dynamics over an extended range of timescales (10-6 – 102 s) and for eleven different compositions including the two pure constituents. Positive deviations from ideal mixing approximation were demonstrated for both the solvent dielectric strength and the glass transition. They support the idea that preferential H-bond interactions between unlike molecules induce structural rearrangements in the DES mixtures. Excellent glassforming capability of the DES mixtures was demonstrated for a broad range of compositions (xThymol = 0.4–0.7). In this case, the dipolar dynamics could be assessed from the normal liquid to the deeply supercooled state. Many salient parameters of the relaxation functions, including fragility, non-Debye character and rotation-translation decoupling point to the development of dynamic heterogeneities.

Magnetic Fe3O4 nanoparticles in melamine-based ternary deep eutectic solvent as a novel eco-compatible system for green synthesis of pyrido[2,3-d]pyrimidine derivatives

Deep eutectic solvents (DESs) are among novel and more eco-friendly alternatives to ionic liquids (ILs) prepared by combining the components and the hydrogen bonds developed between them. The strong hydrogen bond interactions between the constituents of DESs make a considerable decline in the melting points in comparison to pure constituents. These green solvents have unique properties, making them a reliable and safe alternative to ILs and conventional organic solvents. In this study, we investigate the role of Fe3O4 nanoparticles (NPs) in Lactic acid:Melamine:NH4Cl (as a novel deep eutectic solvent) in the green synthesis of pyrido[2,3-d] pyrimidine derivatives. The prepared DES was characterized using FT-IR, 1H NMR, 13C NMR, TGA/DTA, DSC and physical properties, including viscosity, acidity, refractive index, surface tension, and density. The DES used during the experiments plays both catalytic roles and serves as a green environment for this reaction. In addition, magnetic DES can operate under very mild reaction conditions and be recycled easily with no significant catalytic activity loss. The fast and complete synthesis and high yield of the desired product are the remarkable benefits of this catalytic system.

English

Refractive index is a characteristic parameter of fluids with numerous industrial uses. The values of refractive indices of many pure liquids are known or can be found in the literature. However, when experimental values of the liquid mixtures are not available then refractive indices of binary mixtures and multi-component liquids are frequently assessed from the pure constituents using mixing rules. The refractive indices &nbsp;of binary mixture and pure liquids methyl laurate (M.L) and pentan -2-ol (P) over the entire mole fraction range at five temperatures (298.15, 303.15, 308.15, 313.15, and 318.15K) were measured using an Anton-Paar Abbemat 3200 refractometer and were tested with the traditional equations, viz Gladstone-Dale (G.D), Lorentz-Lorentz (L.L), Weiner-relation (W.R) and Heller-relation (H.R). The excess refractive indices&nbsp;&nbsp;were calculated using measured experimental refractive indices&nbsp;&nbsp;and&nbsp; ideal refractive indices. The values of excess refractive indices were found to be negative at low mole fractions and positive over the high mole fractions. The experimental data for binary mixture involving methyl laurate + Pentan-2-ol authenticate the mixing rules. Key words: Excess refractive index, binary mixture, mixing rules, methyl laurate.

Antioxidant, antibacterial, antitumor, antifungal, antiviral, anti-inflammatory, and nevro-protective activity of Ganoderma lucidum: An overview.

Ganoderma lucidum is a very medicinal mushroom that has been utilized in Oriental medicine for many years. It has a wide range of pharmacological and therapeutic properties, and has been used for many years as a health promoter. It contains various biologically active compounds that improve the immune system and have antioxidant, antitumor, anti-inflammatory, antifungal, and antimicrobial properties. Active compounds include triterpenoids and polysaccharides, as well as proteins, lipids, phenolics, sterols, etc. In the following review, we summarize briefly their biological activities, such as antioxidant, anti-bacterial, anti-fungal, antitumor, anti-viral, and anti-inflammatory activity. Although Ganoderma has a number of medicinal effects that have been confirmed by the in vitro and in vivo studies summarised in this review, there are some limitations. Clinical trials face mainly a lack of pure constituents. Accurate identification of the compounds obtained is also problematic. In addition, most of the included studies were small, and there were concerns about the methodological quality of each study. Studies have shown that Ganoderma has valuable potential for the prevention and treatment of cancer. In any case, G. lucidum cannot be used as first-line therapy for cancer.

In-situ fabrication of 3D/1D p-NiO/p-ZrO2 heterojunction composites with enhanced photo-degradation activity towards methyl orange and benzimidazole

In current work, p-p type NiO/ZrO2 composites (NZO-1 and NZO-2) were fabricated with the help of single step co-precipitation route. NiO to ZrO2 ratio was kept 9:1 and 8:2 for NZO-1 and NZO-2, respectively. As prepared composites were characterized by different physiochemical techniques. XRD data confirmed that cubic and monoclinic crystal phases of NiO and ZrO2 were present in both NZO-1 and NZO-2 composites. With the increase in concentration of ZrO2, crystallite size of NiO/ZrO2 was decreased from 16 nm to 14 nm. SEM analysis showed the formation of 3D quasi spherical particles of NiO and 1D nanoneedles of ZrO2. With FT-IR investigations different M − O bonds related to Ni–O and Zr–O were observed in NZO-1 and NZO-2. When used for photocatalytic activities, NZO-2 outperformed as compared to NZO-1 and pure constituents (NiO and ZrO2). In brief, NZO-2, NZO-1, NiO and ZrO2 removed 93, 80, 62 and 45% of Methyl orange (MO) dye in presence of natural sunlight within 120 min. Clearly, NZO-2 hold optimum concentrations of NiO and ZrO2 with a kinetic rate constant value of 0.019 min−1. Scavenging experiments disclosed electrons, superoxide radicals and holes were the main species involved in the photo-removal of MO. For benzimidazole, sufficient photo-degradation activity (57%) was observed in presence of NZO-2. Photo-catalytic investigations suggested that NZO-2 can be used as efficient photocatalyst for the treatment of multiple pollutants from contaminated water.

Computational studies of structural, energetic, and electronic properties of pure Pt and Mo and mixed Pt/Mo clusters: Comparative analysis of characteristics and trends.

The added technological potential of bimetallic clusters and nanoparticles, as compared to their pure (i.e., one-component) counterparts, stems from the ability to further fine-tune their properties and, consequently, functionalities through a simultaneous use of the "knobs" of size and composition. The practical realization of this potential can be greatly advanced by the knowledge of the correlations and relationships between the various characteristics of bimetallic nanosystems on the one hand and those of their pure counterparts as well as pure constituent components on the other hand. Here, we present results of a density functional theory based study of pure Ptn and Mon clusters aimed at revisiting and exploring further their structural, electronic, and energetic properties. These are then used as a basis for analysis and characterization of the results of calculations on two-component Ptn-mMom clusters. The analysis also includes establishing relationships between the properties of the Ptn-mMom clusters and those of their Ptn-m and Mom components. One of the particularly intriguing findings suggested by the calculated data is a linear dependence of the average binding energy per atom in sets of Ptn-mMom clusters that have the same fixed number m of Mo atoms and different number n-m of Pt atoms on the fractional content (n-m)/n of Pt atoms. We derive an analytical model that establishes the fundamental basis for this linearity and expresses its parameters-the m-dependent slope and intercept-in terms of characteristic properties of the constituent components, such as the average binding energy per atom of Mom and the average per-atom adsorption energy of the Pt atoms on Mom. The conditions of validity and degree of robustness of this model and of the linear relationship predicted by it are discussed.

Modeling atomically mixed graded density impactors

Graded density impactors (GDIs) are multi-material composite impactors used in gas gun experiments to tailor the drive conditions imparted to a sample test material. Previous graded density impactors generally rely on thin, but discrete, layers of different materials. The thinner and the greater number of layers will result in smoother compression. Taken to the limit of very thin layers would be pure material 1 at one surface, such as the front surface of an impactor, smoothly transitioning at the atomic scale to pure material 2 on the back surface. Such an impactor can initially shock, then smoothly compresses a material during a dynamic experiment. This type of experiment can serve to explore a larger region of thermodynamic space than a single or even multi-shock experiments. An overview of how graded density impactors are made is reviewed and sample results are given. A strategy for modeling these kinds of impactors is presented. The length scales of constituent mixing are given from the experimental build through electrochemical-deposition. Equation of state models for pure constituents and their subsequent mixtures are presented. It is demonstrated that the time scales for pressure and temperature equilibration, for atomically mixed GDIs, are short enough to be a justifiable closure for the resulting multiphase flow. Furthermore, we present simulation results of dynamic shock followed by a ramp compression, utilizing a silver/gold graded density impactor, onto a tantalum sample.

Performance of binary zeotropic mixtures in organic Rankine cycles (ORCs)

Compared to pure fluids, zeotropic mixtures have the potential to lower the irreversibilities in low temperature Rankine cycles by better temperature profile matching of the working fluid with the heat source/sink. However, having a gliding temperature does not guarantee performance boost over pure fluids, as many factors influence the exergy efficiency of the cycle. In this study, 25 pure fluids and 104 binary mixtures of natural working fluids are analyzed in subcritical ORCs with heat source temperature range of 125–300 ℃ and different condensing conditions and the results are investigated within two frameworks: (1) comparing the mixtures to their pure constituents, (2) comparing the mixtures to the best performing pure fluid. In one behavior type, the performance of the mixture falls between the performance of its pure constituents for all evaporator pressure range, and the mixture provides no benefit. However, some mixtures could provide performance boost in a specific evaporator range. Therefore, the maximum allowable evaporator pressure plays an important role in the performance comparison of zeotropic mixtures to their pure constituents. Mixtures which outperform their pure constituents in the first perspective, are further analyzed in the second perspective. Finally, a screening method is presented to map the binary mixtures with performance boost compared to their pure constituents and high absolute exergy efficiency. This method is based on the key thermophysical properties of the fluids including critical temperature and normal boiling point, as well as working conditions such as heat source and heat sink temperature and PPTD in the evaporator and the condenser.

Anti-SARS-CoV-2 potential of Cissampelos pareira L. identified by connectivity map-based analysis and in vitro studies

BackgroundViral infections have a history of abrupt and severe eruptions through the years in the form of pandemics. And yet, definitive therapies or preventive measures are not present. Herbal medicines have been a source of various antiviral compounds such as Oseltamivir, extracted using shikimic acid from star anise (Illicium verum) and Acyclovir from Carissa edulis are FDA (Food and Drug Administration) approved antiviral drugs. In this study, we dissect the anti-coronavirus infection activity of Cissampelos pareira L (Cipa) extract using an integrative approach.MethodsWe analysed the signature similarities between predicted antiviral agents and Cipa using the connectivity map (https://clue.io/). Next, we tested the anti-SARS-COV-2 activity of Cipa in vitro. Molecular docking analyses of constituents of with key targets of SARS-CoV2 protein viz. spike protein, RNA‑dependent RNA‑polymerase (RdRp) and 3C‑like proteinase. was also performed. A three-way comparative analysis of Cipa transcriptome, COVID-19 BALF transcriptome and CMAP signatures of small compounds was also performed.ResultsSeveral predicted antivirals showed a high positive connectivity score with Cipa such as apcidin, emetine, homoharringtonine etc. We also observed 98% inhibition of SARS-COV-2 replication in infected Vero cell cultures with the whole extract. Some of its prominent pure constituents e.g. pareirarine, cissamine, magnoflorine exhibited 40–80% inhibition. Comparison of genes between BALF and Cipa showed an enrichment of biological processes like transcription regulation and response to lipids, to be downregulated in Cipa while being upregulated in COVID-19. CMAP also showed that Triciribine, torin-1 and VU-0365114–2 had positive connectivity with BALF 1 and 2, and negative connectivity with Cipa. Amongst all the tested compounds, Magnoflorine and Salutaridine exhibited the most potent and consistent strong in silico binding profiles with SARS-CoV2 therapeutic targets.

Cytotoxicity of Cymbopogon citratus (DC) Stapf fractions, essential oil, citral, and geraniol in human leukocytes and erythrocytes

Ethnopharmacology relevanceOur recently published paper demonstrated that ethyl acetate fractions obtained from Cymbopogon citratus (DC.) Stapf (C. citratus) leaves, which are consumed as infusion in folk medicine due to their therapeutic properties, are rich in polyphenols and exhibit promising antioxidant activity by acting through different mechanisms in vitro. However, studies regarding the toxicity of these fractions are necessary to investigate their safe use in future biomedical applications. Aim of the studyThis study aimed to investigate the toxicity of ethyl acetate (obtained in acidic and basic conditions and after the essential oil removal from the leaves) and chloroform fractions, essential oil, and its pure constituents, citral and geraniol. Materials and methodsThe toxicity of C. citratus samples was evaluated by using Artemia salina (A. salina) and human blood cells (leukocytes and erythrocytes). ResultsThe A. salina lethality assay demonstrated that C. citratus fractions were moderately toxic with LC50 values ranging from 146.12 to 433.15 μg mL−1, whereas the essential oil and isolated compounds were highly toxic with LC50 lower than 100 μg mL−1. Leukocyte viability decreased after incubation in the presence of the fractions obtained after the essential oil removal from the plant leaves, as well as in the presence of essential oil, citral and geraniol. The same samples increased the osmotic fragility of erythrocytes, and field emission gun scanning electron microscopy (FESEM) analysis revealed significant changes in cell morphology. Interestingly, our results suggest that the previous removal of essential oil from plant leaves facilitated the extraction of cytotoxic compounds from C. citratus. ConclusionsIt was demonstrated that C. citratus ethyl acetate and chloroform fractions, essential oil, as well citral and geraniol were considered toxic to A. salina, cytotoxic to human blood cells and showed to induce alterations in the erythrocyte membrane at higher concentrations. These fractions will be further investigated to identify the phytochemicals involved in the observed cytotoxic effects and explored using in vivo models.