Pure Constituents Research Articles

Preparation of Mn-Ce/TiO2 Catalysts and its Selective Catalytic Reduction of NO at Low-temperature

The catalytic performance of NO removal was studied over Mn-Ce/TiO2 catalysts prepared by rheological phase method under different preparation parameters, such as preparation method, manganese precursor, Mn/(Mn + Ce) molar ratio and calcination conditions. It was found that manganese nitrate and manganese acetate were more conducive to high denitration efficiency than manganese chloride. The highest NO conversion of 92% is achieved at the Ce/(Mn + Ce) molar ratio of 0.15, which is much higher than that of the pure manganese constituent. The increase of calcining temperature favored the crystallization of active components and leads to the decline of catalytic activity.

Experimental measurement of carbon dioxide solubility in 1-methylpyrrolidin-2-one (NMP) + 1-butyl-3-methyl-1H-imidazol-3-ium tetrafluoroborate ([bmim][BF4]) mixtures using a new static-synthetic cell

A new experimental setup based on the “static-synthetic” method was designed and commissioned for the measurement of solubility from vacuum to moderates pressures. The new apparatus and experimental method were extensively validated by measuring the solubility of carbon dioxide in three pure solvents, viz., n-hexane, n-methyl-2-pyrrolidone and 1-butyl-3-methylimidazolium tetrafluoroborate. New solubility data for carbon dioxide in hybrid solvents with different mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate + n-methyl-2-pyrrolidone were measured at three temperatures, viz. (298.15, 313.15 and 323.15) K. Additionally, viscosity, density and sound velocity for binary mixtures of n-methyl-2-pyrrolidone + 1-butyl-3-methylimidazolium tetrafluoroborate were measured. The experimental phase equilibrium data were modelled using the Peng-Robinson equation of state and van der Waals mixing rule. In general, the solubility of carbon dioxide in the hybrid solvent was lower than the respective pure constituents. However, the hybrid solvent exhibited a significantly lower viscosity than the pure ionic liquid.

A Compositive Strategy to Study the Pharmacokinetics of TCMs: Taking Coptidis Rhizoma, and Coptidis Rhizoma-Glycyrrhizae Radix et Rhizoma as Examples.

Pharmacokinetic studies are crucial for elucidating the effective constituents and formula compatibility of traditional Chinese medicines (TCMs). However, studies have usually been limited to single dosages and detection of systemic blood concentrations. To obtain comprehensive pharmacokinetic information, here we propose a multi-dosage and multi-sampling (blood from portal vein or systemic circulation, and liver) strategy to comparatively study the pharmacokinetics of multi-form TCMs, i.e., pure constituents, TCMs, or TCM formula extracts. Based on this strategy, we studied the pharmacokinetics of pure berberine, berberine in Coptidis Rhizoma (CRE), and berberine in Coptidis Rhizoma-Glycyrrhizae Radix et Rhizoma extracts (CR-GRE). After simple calculation and comparison of the obtained area under the curve (AUC) values, the results revealed the drastically different pharmacokinetic properties of pure berberine compared to CRE and CR-GRE. The results contribute to explaining the pharmacological loss of berberine activity after purification and the compatibility of the CR-GR drug pair. The results also innovatively showed that it was intestinal absorption that differentiated the pharmacokinetics of CRE and pure berberine, and CRE and CR-GRE. In conclusion, we propose a composite strategy to comparatively study the pharmacokinetics of TCMs, which could provide sufficient information to obtain a comprehensive view, before follow-up mechanism-of-action studies.

Chemical and Cytotoxic Investigation of Non-Polar Extract from Ceiba pentandra (L.) Gaertn.: A Study Supported by Computer Based Screening

Nowadays, the discovery of new drugs from natural sources is increasing dramatically. Recently, the sight is directed toward ornamental plants due to their sustainability. In this study, we are reporting on the gas chromatography profile of fatty acids, other related lipids and hydrocarbons of the non-polar methylene chloride fraction of the extract of the ornamental tree Ceiba pentandra (L.) Gaertn. Chromatographic purification of the same fraction furnished eight pure known constituents, 3β-taraxerol (1), 3β-taraxerol acetate (2), all-trans-squalene (3), oleic acid (4), 1-hexacosanol (5), β-amyrin (6), β-sitosterol (7) and β-sitosterol-3-O-β-D-glucopyranoside (8), which are relatively abundant in the fraction, six of them firstly isolated in the plant. A computer based bio-activity study indicated cancer treatment and/or prevention of the isolated compounds (1‒3 and 6) with pa values higher than for the other predicted effects. The experimental cytotoxicity assessment of the methylene chloride fraction demonstrated prominent cytotoxic effect against the cancer cell lines HepG2 (IC50 = 14.895µg/mL) and MCF-7 (IC50 = 18.859 µg/mL).

A study of Electronic Structure in W–Cu Alloys by using RFA and FE models

In this paper, Compton profile for Tungsten (W) was computed by employing both the RFA and FE models setting several electronic configurations in subset (5d-6s). same were done for copper (Cu) by chosen (3d-4s) subshells, these Results were compared with recent experimental data, these study are extended to the electronic state in (W0.60 Cu0.40, W0.72 Cu0.28) alloys. The superposition are adopted to calculate the total C.P for the two alloys, where the calculated values for W& Cu of the constituent are used, the available measured data on both alloys are in very good agreement with the superposition of Compton profiles of the pure constituent metales .

Lu5Pd4Ge8 and Lu3Pd4Ge4: Two More Germanides among Polar Intermetallics

In this study, two novel Lu5Pd4Ge8 and Lu3Pd4Ge4 polar intermetallics were prepared by direct synthesis of pure constituents. Their crystal structures were determined by single crystal X-ray diffraction analysis: Lu5Pd4Ge8 is monoclinic, P21/m, mP34, a = 5.7406(3), b = 13.7087(7), c = 8.3423(4) Å, β = 107.8(1), Z = 2; Lu3Pd4Ge4 is orthorhombic, Immm, oI22, a = 4.1368(3), b = 6.9192(5), c = 13.8229(9) Å, Z = 2. The Lu5Pd4Ge8 analysed crystal is one more example of non-merohedral twinning among the rare earth containing germanides. Chemical bonding DFT studies were conducted for these polar intermetallics and showing a metallic-like behavior. Gathered results for Lu5Pd4Ge8 and Lu3Pd4Ge4 permit to described both of them as composed by [Pd–Ge]δ– three dimensional networks bonded to positively charged lutetium species. From the structural chemical point of view, the studied compounds manifest some similarities to the Zintl phases, containing well-known covalent fragment i.e., Ge dumbbells as well as unique cis-Ge4 units. A comparative analysis of molecular orbital diagrams for Ge26– and cis-Ge10– anions with COHP results supports the idea of the existence of complex Pd–Ge polyanions hosting covalently bonded partially polarised Ge units. The palladium atoms have an anion like behaviour and being the most electronegative cause the noticeable variation of Ge species charges from site to site. Lutetium charges oscillate around +1.5 for all crystallographic positions. Obtained results explained why the classical Zintl-Klemm concept can’t be applied for the studied polar intermetallics.

A study of Electronic Structure in W–Cu Alloys by using RFA and FE models

In this paper, Compton  profile for Tungsten (W) was computed by  employing both the RFA and FE models setting several electronic configurations in subset (5d-6s). same were done for copper (Cu) by chosen (3d-4s) subshells, these Results were compared with recent experimental data, these study are extended to the electronic state in (W0.60 Cu0.40, W0.72 Cu0.28) alloys. The superposition are adopted to calculate the total C.P for the two alloys, where the calculated values for W& Cu of the constituent are used, the available measured data on both alloys are in very good agreement with the superposition of Compton profiles of the pure constituent metales .   http://dx.doi.org/10.25130/tjps.23.2018.055

Positive influence of Sb doping on properties of di-phase multiferroics based on barium titanate and nickel ferrite

Multiferroic composite materials based on antimony doped barium titanate/nickel ferrite were prepared by a mixing route. In order to obtain fine grained microstructure composite materials, pure constituent phases were prepared via chemical methods. The optimization of processing parameters has been made in order to reduce the chemical reactions at the interfaces between ferroelectric-ferrite phases. XRD data confirmed the presence of both barium titanate and nickel ferrite phases in the ceramic samples. The resistivity data obtained from impedance as well as calculated activation energies indicated the grain boundary contribution as a more influential effect in the total resistivity of ceramics. Dielectric permittivity enhancement in comparison with composites prepared from pure barium titanate was noticed. Well defined hysteresis loops have shown the changes of properties induced by the modification of the barium titanate phase with Sb doping and due to the co-existence of two different phases in the materials. The comparative study of magnetic properties of obtained composite materials was presented. The results on the magnetodielectric properties are understood in terms of the stress induced variations in the polarization and dielectric permittivity.

In vivo antimalarial extracts and constituents of Prosopis juliflora (Fabaceae)

Prosopis juliflora (Fabaceae) is a small perennial tree used as human food and livestock feed for thousands of years in arid and semi-arid regions worldwide. This study was performed to investigate the in vivo antimalarial activity of alkaloid-enriched extracts and pure alkaloidal constituents of Prosopis juliflora in a murine model. Alkaloid-enriched extracts from leaves (FACB) and pods (BCE) of P. juliflora, as well as FACB pure constituents (as formate salts), were obtained and assayed against Plasmodium berghei NK65 infection in mice via oral administration. FACB and BCE exhibited a remarkable in vivo antimalarial activity with little parasitemia inhibition at the 2 mg/kg dose. Additionally, julifloridine was weakly active, but juliprosopine caused a parasitemia inhibition at the 2 mg/kg dose similar to that observed for chloroquine at 50 mg/kg. This study reports for the first time the in vivo antimalarial activity of julifloridine, juliprosopine and alkaloid-enriched extracts from P. juliflora (Fabaceae).

Preparation and Properties of WC-Based Alloy Coatings with Controlled Co and Cr via High Velocity Oxy-Fuel Spray Technique.

WC based alloy coatings included different mass percent of Co and Cr have been synthesized on high carbon steel by using a facile high velocity oxy-fuel spray method. The mechanical nature of the coating films has been investigated by micro vickers hardness and fracture toughness. X-ray diffraction (XRD) and EDX analyses indicate that the three different samples (WC-10Co-4Cr, WC-17Co, and WC-12Co) consist of pure WC, W, Cr, and Co constituents as well as W2C and Co6W6C phases. The SEM and image analysis results show that WC-10Co-4Cr condition has higher porosity than those of WC-17Co, and WC-12Co coatings. WC-17Co coating showed the highest value in the hardness and fracture toughness test among three different samples. The obtained results revealed that the mechanical properties of WC based alloy coatings synthesized by a facile high velocity oxy-fuel spray method is very sensitive to Co content.

Efficient and Selective Photocatalytic Oxidation of Benzylic Alcohols with Hybrid Organic–Inorganic Perovskite Materials

The impressive optoelectronic performance and low production cost of metal halide perovskites have inspired applications well beyond efficient solar cells. Herein, we widen the materials engineering options available for the efficient and selective photocatalytic oxidation of benzylic alcohols, an industrially significant reaction, using formamidinium lead bromide (FAPbBr3) and other perovskite-based materials. The best performance was obtained using a FAPbBr3/TiO2 hybrid photocatalyst under simulated solar illumination. Detailed optical studies reveal the synergetic photophysical pathways arising in FAPbBr3/TiO2 composites. An experimentally supported model rationalizing the large conversion enhancement over the pure constituents shows that this strategy offers new prospects for metal halide perovskites in photocatalytic applications.

Quasi-polymeric construction of stable perovskite-type LaFeO3/g-C3N4 heterostructured photocatalyst for improved Z-scheme photocatalytic activity via solid p-n heterojunction interfacial effect

Materials of perovskite-type structure have attracted considerable attention for their applications in photocatalysis. In this study, a novel composite of p-type LaFeO3 microsphere coated with n-type nanosized graphitic carbon nitride nanosheets was constructed by the quasi-polymeric calcination method with the aid of electrostatic self-assembly interaction. Results indicate that the LaFeO3/g-C3N4p-n heterostructured photocatalyst obtained, in contrast to the pure constituents, enabled improved visible-light absorption, and more efficient separation and migration of charge carriers via solid p-n heterojunction interfacial effect. Correspondingly, the LaFeO3/g-C3N4 composite allowed for higher visible-light-responsive photocatalytic activity for the degradation of Brilliant Blue, which was 16.9 and 7.8 times that of pristine g-C3N4 and LaFeO3, respectively. The photocatalytic degradation of Brilliant Blue was ascribed to the combined contributions of the photogenerated holes (h+), superoxide radicals (O2−) and hydroxyl radicals (OH). Based on solid p-n heterojunction interfacial interaction, a Z-scheme charge carrier transfer pathway integrated with the dye-sensitization effect is proposed as the underlying mechanism of the photocatalytic reaction process. Therefore, we believe that the perovskite-type LaFeO3/g-C3N4 Z-scheme photcatalyst promotes the development of photocatalysis and holds much promise for environmental remediation.

Effect of quality and origin of technical sucrose solutions on the inclusion of colourants into the sugar crystal matrix.

Due to the liberalisation of the European sugar market the pressure to improve factory utilisation is growing. Currently, beet and cane as sucrose sources are produced in isolation, according to geography. Co-production of sugar from beet and cane origin in one stream is a promising option. However, the knowledge base for production sugar is practically non-existent. This paper is part of our contribution to this field and specifically addresses effects of raw material quality. This framework formulated for the colouring of sugars crystallised from mixed syrups is also valid for different raw material qualities: raw cane sugars: colour values 1221 to 2505 IU, dextran levels 50 to 1200 mg kg-1 ; beet syrups: 1509 to 2058 IU. Co-crystallisation is the main colour incorporation mechanism. Colour due to liquid inclusion increases strongly at cane inclusion levels in excess of 60%. The prediction of final sugar colour based on characteristics of pure mixture constituents is verified and indicates significant differences to current recommendations. A first comprehensive description of the colour values in sugars produced from mixed cane and beet syrups is presented. Prediction of colour values from data on sugar colour of single sources marks a major contribution to future applications of co-production. © 2017 Society of Chemical Industry.

Metal Alloys for Superabsorption: Lithography‐Free, Omnidirectional, CMOS‐Compatible AlCu Alloys for Thin‐Film Superabsorbers (Advanced Optical Materials 2/2018)

Complementary metal–oxide–semiconductor (CMOS)-compatible metal alloys formed by earth-abundant materials can enable near-unity absorption (>99%) in the visible to near-infrared spectral region. In article number 1700830, Marina S. Leite and co-workers demonstrate that Si/AlCu produces multi-wavelength, omnidirectional superabsorption in a thin-film configuration, outperforming its pure metal constituents and other metals, such as Ag and Au. Metal alloys can be potentially implemented as active elements in photonic devices.

Nanoscale partitioning of paclitaxel in hybrid lipid-polymer membranes.

Paclitaxel is a powerful drug against restenosis and many forms of cancer. However, its clinical application hinges on the ability to achieve suitable stabilized drug concentrations in an aqueous suspension while hindering drug crystallization. To engineer such formulations, it is imperative to understand paclitaxel's partitioning and crystallization within the carrier matrix. Lipid-polymer hybrid films have been recently shown to accommodate large paclitaxel loads and suppress crystallization. Additionally, such hybrid materials promote synergistic drug release compared to the pure constituents. Here, we leverage the composition sensitive photo-thermal induced resonance (PTIR) technique to study paclitaxel partitioning within hybrid films at the nanoscale. PTIR data reveal that paclitaxel nano-crystals segregate from lipid-only films but are well dispersed in polymer-only films. Remarkably, lipid-polymer hybrid films show enhanced partitioning of paclitaxel at the lipid-polymer phase boundaries, but still stifle crystallization, thus paving the way towards compositional and microstructural engineering of small-drug delivery systems.

THE STUDY OF POROSITY OF SINTERED SAMPLES OF COBALT-CHROMIUM ELECTROEROSION POWDERS

One of the main requirements for powders for additive 3D technologies is the spherical shape of particles. Such particles are most densely fit into a certain space and provide the ‘fluidity’ of powder compositions in the systems of material supply with minimal resistance. In addition, the powder should contain a minimum amount of dissolved gas. The microstructure of the powder should be homogeneous and finely dispersed (with a uniform distribution of phase constituents). Based on the peculiarities of the methods of producing spherical powders in order to obtain spherical granules of regulated granularity, the electroerosion dispersion (EED) technology, which is characterized by relatively low energy costs and environmentally sound process, is proposed. The main advantage of the proposed technology is the use of waste materials as raw stuff which are much cheaper than the pure constituents used in traditional technology. In addition, this technology allows varying the granulometric composition of the resulting powder by changing electrical parameters. The objective of this work is to study the porosity of sintered samples of cobalt-chromium powders obtained for additive technologies by means of electroerosion dispersion. To implement the proposed research, wastes of the cobalt-chromium alloy of KHMS "CELLIT" grade were chosen. Distilled water and isobutyl alcohol were used as the working fluid. Electrical discharge machine to disperse conductive materials was used to produce cobalt-chromium powders. The powders are consolidated by the method of spark plasma sintering using the spark plasma sintering system SPS 25-10 (Thermal Technology, USA). The initial material was put in a graphite matrix placed under a press in a vacuum chamber. Electrodes integrated into the mechanical part of the press feed electric current to the matrix and create spark discharges between the sintered particles of the material, providing intensive interaction. The porosity was determined using Olympus GX51 optical inverted microscope with a software for quantitative image analysis. Prepared samples had no traces of structural components grinding, polishing or dying. The microsection metalographic specimen was made by the cross section (fracture) of the whole product. Based on the results of the conducted experiment aimed at studying the porosity of sintered samples from cobalt-chromium powders obtained for additive technologies by electroerosion dispersion in isobutyl alcohol, it was found that the porosity ranges from 3.19 to 6.15 %.

Methodology for the Absolute Configuration Determination of Epoxythymols Using the Constituents of Ageratina glabrata.

A methodology to determine the enantiomeric excess and the absolute configuration (AC) of natural epoxythymols was developed and tested using five constituents of Ageratina glabrata. The methodology is based on enantiomeric purity determination employing 1,1'-bi-2-naphthol (BINOL) as a chiral solvating agent combined with vibrational circular dichroism (VCD) measurements and calculations. The conformational searching included an extensive Monte Carlo protocol that considered the rotational barriers to cover the whole conformational spaces. (+)-(8S)-10-Benzoyloxy-6-hydroxy-8,9-epoxythymol isobutyrate (1), (+)-(8S)-10-acetoxy-6-methoxy-8,9-epoxythymol isobutyrate (4), and (+)-(8S)-10-benzoyloxy-6-methoxy-8,9-epoxythymol isobutyrate (5) were isolated as enantiomerically pure constituents, while 10-isobutyryloxy-8,9-epoxythymol isobutyrate (2) was obtained as a 75:25 (8S)/(8R) scalemic mixture. In the case of 10-benzoyloxy-8,9-epoxythymol isobutyrate (3), the BINOL methodology revealed a 56:44 scalemic mixture and the VCD measurement was beyond the limit of sensitivity since the enantiomeric excess is only 12%. The racemization process of epoxythymol derivatives was studied using compound 1 and allowed the clarification of some stereochemical aspects of epoxythymol derivatives since their ACs have been scarcely analyzed and a particular behavior in their specific rotations was detected. In more than 30 oxygenated thymol derivatives, including some epoxythymols, the reported specific rotation values fluctuate from -1.6 to +1.4 passing through zero, suggesting the presence of scalemic and close to racemic mixtures, since enantiomerically pure natural constituents showed positive or negative specific rotations greater than 10 units.

Lithography‐Free, Omnidirectional, CMOS‐Compatible AlCu Alloys for Thin‐Film Superabsorbers

AbstractSuperabsorbers based on metasurfaces have recently enabled the control of light at the nanoscale in unprecedented ways. Nevertheless, the sub‐wavelength features needed to modify the absorption band usually require complex fabrication methods, such as electron‐beam lithography. To overcome the scalability limitations associated with the fabrication of metallic nanostructures, engineering the optical response of superabsorbers by metal alloying is proposed, instead of tuning the geometry/size of the nanoscale building blocks. The superior performance of thin film AlCu alloys as the metallic component of planar bilayer superabsorbers is numerically demonstrated. This alloy outperforms its pure constituents as well as other metals, such as Ag, Au, and Cr. As a model system, a Si/AlCu structure is analyzed that presents >99% absorption at selected wavelength ranging from the visible to the near‐infrared regions of the spectrum, depending on the subwavelength thickness of the semiconductor. The multi‐wavelength near‐unity absorption behavior of Si/AlCu persists even for oblique angle of incidence, up to 70°. Additionally, the findings are validated by fabricating and testing a‐Si/AlCu superabsorbers, where good agreement is found between the numerically and experimentally determined optical response. The system investigated here is relevant for integration in complementary metal‐oxide‐semiconductor (CMOS) technologies.

Alternating current conduction mechanisms of RbMgPO4 compound

Rubidium magnesium monophosphate (RbMgPO4) compound was prepared from highly pure constituents by solid state reaction. It was characterized by X-ray powder diffraction, IR, Raman, differential scanning calorimetry (DSC) and impedance spectroscopy. The infrared and Raman spectra were interpreted on the basis of PO43− vibrations. DSC revealed two displacive and reversible phase transitions at T1 = 442/432 K and T2 = 460/445 K (heating/cooling). The electrical conductivity was measured in the frequency and temperature range 200 Hz-5 MHz and 423 K–523 K, respectively. The obtained results were analysed by fitting the experimental data to an equivalent circuit model. The temperature dependence of alternating and direct current conductivities (σac, σdc) confirms the observed transitions in the calorimetric study; they were described in terms of Arrhenius relation. The activation energy’s values were determined in each phase. The AC conductivity behavior is ensured by a single process defined as a hopping transport mechanism. The conductivity frequency dependence was interpreted using the correlated barrier-hopping model (CBH) in all phases.

Determining the effective Wilson coefficient a2 in terms of BR(Bs→ηcϕ) and evaluating BR(Bs→ηcf0(980))

In this work, we investigate decays of $B_s\to \eta_c\phi$ and $B_s\to \eta_cf_0(980)$ in a theoretical framework. The calculation is based on the postulation that $f_0(980)$ and $f_0(500)$ are mixtures of pure quark states ${1\over\sqrt 2} (\bar uu+\bar dd)$ and $\bar ss$. The hadronic matrix elements for $B_s\to \phi$ and $B_s\to f_0(980)$ are calculated in the light-front quark model and the important Wilson coefficient $a_2$ which is closely related to non-perturbative QCD is extracted. However, our numerical results indicate that no matter how to adjust the mixing parameter to reconcile contributions of $f_0(980)$ and $f_0(500)$, one cannot make the theoretical prediction on $B_s\to \eta_c+\pi^+\pi^-$ to meet the data. Moreover, the new measurement of $BR(B_s\to J/\psi+f_0(500))<1.7\times 10^{-6}$ also negates the mixture scenario. Thus, we conclude that the recent data suggest that $f_0(980)$ is a four quark state ( tetraquark or $K\bar K$ molecule ), at least the fraction of its pure quark constituents is small.