Solid Inclusions Research Articles

Experimental and computational modeling of thermal conductivity of cementitious syntactic foams filled with hollow glass microspheres

Insulating cementitious syntactic foams (CSFs) reinforced hollow glass microspheres (HGMs) have been paid much attention for the growing requirement of energy savings. In this paper, the CSF plates with different volume contents of HGMs are manufactured by a novel three-step manufacturing process and then they are tested by transient plane source (TPS) method to investigate their heat insulation performance. The filler volume content is in the range of 0–56 vol%. The experimental results reveal that the effective value of thermal conductivity of the foam decreases roughly linearly with increasing the HGM volume content. The addition of 56 vol% HGMs brings over 47% decrease of the thermal conductivity of the foam, in contrast to the pure cement material. In addition, the heat transfer mechanisms in the CSFs are further investigated by the developed computational model with randomly dispersed HGMs to approximate the real arrangement of microspheres in the foam. The experimental data are in good agreement with the numerical estimations. Moreover, the resulting numerical predictions demonstrate that the effective thermal conductivity coefficient of the foam increases as the constituent thermal conductivity increases. However, compared to the core and solid wall material, the matrix material gives significant influence to the foam. Finally, a two-phase composite model with equivalent solid spherical inclusion is presented based on Eshelby’s equivalent inclusion theory to indirectly determine the thermal conductivity of pure HGM, which are important for guiding the predesign of syntactic foams with desired low thermal conductivity.

Dependence of the Clogging Possibility of the Submerged Entry Nozzle during Steel Continuous Casting Process on the Liquid Fraction of Non-Metallic Inclusions in the Molten Al-Killed Ca-Treated Steel

In the current study, the nozzle clogging behavior and inclusion composition in Al-killed Ca-treated steels were observed to investigate the relationship between the liquid fraction of non-metallic inclusions and the clogging possibility of the submerged entry nozzle. Clogging materials were mainly MgO-Al2O3 with less than 20% liquid phases, while most of the inclusions were full liquid CaO-Al2O3-MgO in tundish at the casting temperature. Thus, it was proposed that the nozzle clogging can be effectively avoided by modification of solid inclusions to partial liquid ones rather than full liquid ones. There was a critical value of liquid fraction of inclusions causing the nozzle clogging. A critical condition of the inclusion attachment on the nozzle wall was a function of cosθN−S+cosθI−S<0. With the increase of T.Ca content in steel, the evolution route of inclusions was solid MgO-Al2O3→liquid CaO-Al2O3-MgO→solid CaS and CaO. To avoid the clogging of the submerged entry nozzle (SEN) under the current casting condition, the appropriate T.Ca concentration range in Al-killed Ca-treated steels can be enlarged from the 100% liquid inclusion zone of 10–14 ppm to the 20% liquid inclusion zone of 4–38 ppm.

Quality and safety of dry protein and carbohydrate composite based on HACCP principles

Creating complete feed for cattle especially during the period of indoor housing is an important task of feed production. This determines the increase in milk yield and live weight, and the profitability of all production. Biotechnology of obtaining a combined feed additive in the form of a dry protein and carbohydrate composite for animals from plant raw materials and secondary raw materials allows us to solve this problem. At the same time, the quality and safety of the composite is an extremely relevant topic. In the course of research the influence of technological factors control, based on the principles of HACCP, on the quality and safety indicators of the combined feed additive has been established. The resulting product according to organoleptic indicators is a loose mixture of no more than 5–8 mm in size, without solid inclusions, foreign impurities and fumes; color is from gray to brown; smell is characteristic of the set of components included in the recipe, without musty, mold and other odors. Physical and chemical parameters are as follows: mass fraction of moisture no more than 14 %; mass fraction of sugars is at least 27–30 %; mass fraction of protein is 17,6–18,4 %, fiber content is 7,0–7,3 %. Safety indicators: total number of fungi (CFU/g) no more than 5×10[sup]4[/sup] ; total microbial number (CFU/g) no more than 5×10[sup]5[/sup] . The presence of Salmonella in 25 g is not allowed; the presence of pathogenic Escherichia in 1,0 g is not allowed. The remaining safety indicators, due to their invariability in the process of technological operations, must comply with the indicators provided for in the normative documents for raw materials. Five control critical points in the technology of proteincarbohydrate composite production that pose a threat to its quality and safety have been identified. It has been shown that the preliminary assessment and proposed corrective actions for managing hazards at all stages of the production process, which significantly affect the safety of products, can prevent the appearance of a danger of deviations from the parameters of the technological process at each stage of production.

Studies on the supramolecular complex of a guanosine with beta-cyclodextrin and evaluation of its anti-proliferative activity

The behavior of the inclusion behavior of guanosine (GU) with beta-cyclodextrin (β-CD) in the liquid, solid and virtual state were investigated. The absorption and fluorescence spectral were used to determine the inclusion behavior in liquid state. FT-IR, NMR, TGA, DSC, PXRD and FESEM techniques were used to investigate the inclusion behavior in solid-state, meanwhile the virtual state studies are done by molecular docking. The solid inclusion complex (GU: β-CD) was prepared by using the co-precipitation method. The binding constant (K) of (GU: β-CD) was calculated by using Benesi-Hildebrand. Besides that, the 1:1 stoichiometric ratio of inclusion complex was confirmed by using the Benesi-Hildebrand plot and Job's plot of continuous variation method. The most preferable model of GU: β-CD that suggested via molecular docking studies was in good agreement with experimental results. The inclusion complex of GU: β-CD exerted its toxicity effects towards HepG2 cell lines based on the reduced number of cell viability and lowest IC50 value compared to the GU and β-CD viability.

Development and Characterization of Orally Disintegrating Tablets Containing a Captopril-Cyclodextrin Complex.

Captopril is the first angiotensin I-converting enzyme inhibitor widely used for the treatment of hypertension. Based on the well-known benefits of cyclodextrin inclusion complexes, the present study investigated the ability of β-cyclodextrin to include captopril. Solid inclusion complexes of captopril with β–cyclodextrin in a 1:2 molar ratio were prepared by using the paste method of complexation. For comparison purposes, a simple physical mixture with the same molar ratio was also prepared. Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and simultaneous thermal analysis were used to characterize the raw materials, physical mixture and solid inclusion complex. In order to provide the drug in a more accessible and patient-compliant form following masking its bitter taste, as well as ensuring the appropriate release kinetics, the investigated complex was formulated as orally disintegrating tablets. The study of captopril dissolution in both compendial and simulated saliva media suggested the Noyes Whitney model as the best mathematical model to describe the release phenomena. A clinical study on healthy volunteers also highlighted the taste improvement of the new formulation as compared to conventional tablets.

Comparative studies of directly loaded and cyclodextrin-mediated release of Theophylline and evaluation of biodegradation studies of HPNs

Theophylline, also known as 1,3-dimethylxanthine, is a bronchodilator used to cure respiratory problems. With a view to improve drug solubility, therapeutic index, stability and controlled drug delivery of Theophylline, the Host–Guest, solid inclusion compounds of Theophylline and beta-cyclodextrin were prepared through traditional methods and microwave-prompted technique. All the characterization techniques like FESEM, FTIR, PXRD 1HNMR and DSC confirmed the MW irradiation method is the best method to form true inclusion complexes of beta-cyclodextrin and drug Theophylline. The drug release of directly loaded TP was compared with inclusion loaded hybrid polymer networks (HPNs) of chitosan and gelatin synthesized in air conditions. It was found that TP was released in a controlled manner as compare to the HPNs loaded with TP directly. Secondly, the drug release through the differently prepared ICs was also compared and found that the microwave-triggered synthesis of ICs is a brilliant method for the sustained release of the TP. It is a competent, green, quick and environment friendly in comparison to the traditional methods. In drug release kinetics, the values of n were found as 1.143, 0.501 and 0.797 at pH of 2, 7 and 7.4, respectively, which confirmed the non-Fickian diffusion at pH of 7 and 7.4, but at acidic pH conditions, the value of diffusion exponent was found to be greater than one, and it is the non-Fickian super case II diffusion. The continuous development of biodegradation at diverse steps was inspected by weight loss and with different characterization techniques like FTIR and FESEM, which revealed the hydrogel networks prepared in air conditions are biodegradable and the composting process of biodegradation was established as a more efficient method than soil burial approach.

Electrohydraulic pretreatment method for the purpose of complex enrichment of fine clay ores of weathering crust

The paper substantiates the possibility of applying the technology based on the use of electrohydraulic effect for the preliminary preparation of clay ores with fine mineral phases. The technology was developed in the laboratory by conducting experimental studies on samples of several types of clay rocks and ores that differ in the composition of inclusions of solid fractions in them. Experiments have confirmed that with the optimal selection of operating modes of a specially created electrohydraulic unit, high selectivity is achieved for crushing and dispersing different strength minerals and mineral phases of sample materials, which ensures the destruction of the clay component while maintaining the integrity of solid fractions. Removal of water-soluble clay fraction with the pulp and washing of the resulting intermediate product provides a high degree of cleaning of solid inclusions from clay. This makes it possible to recommend the use of electrohydraulic technology for cleaning solid fractions of fine clay ores from clay at the initial stage of ore preparation, followed by the extraction of valuable minerals from the resulting intermediate product of enrichment by traditional methods.

Path of a solid inclusion embedded in a soft matrix subject to finger palpation

A solid inclusion is embedded in a soft matrix supported by a rigid substrate. To simulate finger palpation, a spherical indenter exerts a vertical load on the matrix surface, followed by a lateral motion. A deep inclusion first rises close to the surface, dives under the indenter, and emerges from the leeside of the traversing indenter. The inclusion trajectory is essentially symmetric about the axis where the inclusion lies. A shallow inclusion is first pushed sideways, but an instability causes it to jump spontaneously to the rear following an asymmetric path. Such instability is a specific feature in hyperelastic materials.

STUDY OF THE TACTICAL AND TECHNICAL CHARACTERISTICS OF A SPECIAL FIRE BARREL FOR EXTINGUISHING UNDERGROUND FIRES IN PEAT-FOREST ECOSYSTEMS

One of the promising methods of extinguishing fire is to extinguish with water or solutions of extinguishing agents. This method is relevant for extinguishing underground fires in peat-forest ecosystems, in particular litter and peat. For this, a special fire barrel was developed to extinguish underground fires using water extinguishing agents with the addition of surfactants. In the work, the tactical and technical characteristics of a special fire barrel for extinguishing underground fires are established and a method for extinguishing them with fire extinguishing agents using surfactants is developed.A special fire barrel equipped with auger blades has been developed, which perform a number of functions: cut solid inclusions when deepening, the trunk, hold the trunk in peat layers, open free channels to withdraw excess water to the surface without erosion of the soil.Based on the studies, it is possible to select the optimal parameters of pressure and fluid flow for specific conditions of quenching of peat and litter in the peat-forest ecosystem. In addition, it should be noted that the developed special fire barrelFire Safety, №36, 2020 109 has a more than 3 times greater consumption of extinguishing agent than existing analogues, such as TS-1, TS-2, SPT-70. This suggests that in practice such trunks will be needed less, and their extinguishing efficiency will be higher. As a fire extinguishing agent, it is recommended to use not water, but aqueous solutions of Bars S-1, Bars S-1m blowing agents containing surfactants that reduce the surface tension of water and increase the wetting ability of bedding, peat and are one of the most effective ways to combat peat fires.The fluid flow rate of a special fire barrel for extinguishing underground fires in peat-forest ecosystems was determined at pressures of 0.4 and 0.7 MPa, which are respectively 13.24 and 15.98 l/s.The fluid flow rate was calculated at 0.5 and 0.6 MPa, which is 14.26 and 15.40 l/s, respectively.Based on experimental and calculated data, it was found that the increase in fluid flow at pressures of 0.4 – 0.6 MPa occurs almost uniformly, and significantly slows down in the range of 0.6 – 0.7 MPa.

Petrogenesis and Lu–Hf Dating of (Ultra)Mafic Rocks from the Kutná Hora Crystalline Complex: Implications for the Devonian Evolution of the Bohemian Massif

Abstract The Lu–Hf isotope system and Sr–Nd–Hf–Os isotope systematics of mantle rocks are capable of unravelling the early processes in collision belts, especially in a hot subduction context where the Sm–Nd and U–Pb systems in crustal rocks are prone to resetting owing to high temperatures and interaction with melts during exhumation. To improve models of the Devonian–Carboniferous evolution of the Bohemian Massif, we investigated in detail mafic and ultramafic rocks (eclogite, pyroxenite, and peridotite) from the ultrahigh-pressure and ultrahigh-temperature Kutná Hora Crystalline Complex (KHCC: Úhrov, Bečváry, Doubrava, and Spačice localities). Petrography, multiphase solid inclusions, major and trace element compositions of rocks and minerals, and radiogenic isotopic data document contrasting sources and protoliths as well as effects of subduction-related processes for these rocks. The Úhrov peridotite has a depleted composition corresponding to the suboceanic asthenospheric mantle, whereas Bečváry and Doubrava peridotites represent lithospheric mantle that underwent melt refertilization by basaltic and SiO2-undersaturated melts, respectively. Multiphase solid inclusions enclosed in garnet from Úhrov and Bečváry peridotites represent trapped H2O ± CO2-bearing metasomatizing agents and Fe–Ti-rich melts. The KHCC eclogites either formed by high-pressure crystal accumulation from mantle-derived basaltic melts (Úhrov) or represent a fragment of mid-ocean ridge basalt-like gabbroic cumulate (Spačice) and crustal-derived material (Doubrava) both metamorphosed at high P–T conditions. The Lu–Hf age of 395 ± 23 Ma obtained for the Úhrov peridotite reflects garnet growth related to burial of the asthenospheric mantle during subduction of the oceanic slab. By contrast, Spačice and Doubrava eclogites yield younger Lu–Hf ages of ∼350 and 330 Ma, respectively, representing mixed ages as demonstrated by the strong granulite-facies overprint and trace element zoning in garnet grains. We propose a refined model for the Early Variscan evolution of the Bohemian Massif starting with the subduction of the oceanic crust (Saxothuringian ocean) and associated oceanic asthenospheric mantle (Úhrov) beneath the Teplá–Barrandian at ≥380 Ma, which was responsible for melt refertilization of the associated mantle wedge (Bečváry, Doubrava). This was followed by continental subduction (∼370–360 Ma?) accompanied by the oceanic slab break-off and incorporation of the upwelling asthenospheric mantle into the Moldanubian lithospheric mantle and subsequent coeval exhumation of mantle and crustal rocks at ∼350–330 Ma.

Development of food grade 3D printable ink based on pectin containing cannabidiol/cyclodextrin inclusion complexes

In the current study a 3D-printable system was developed, based on natural, food-grade and nontoxic materials that may be used as a platform technology to host cannabinoids, and more specifically CBD for medicinal purposes. Pectin and honey were combined toward the fabrication of 3D printable inks that form solid structures upon drying. This model food-grade 3D-printed system was evaluated as a host matrix for the incorporation of CBD, in the form of inclusion complexes with β-cyclodextrins. The prepared solid inclusion complexes were characterized by means of Differential Scanning Calorimetry (DSC), Fourier-Transform Infrared (FTIR) and Thermogravimetric Analysis (TGA) complemented with phase solubility studies and in vitro release of the β-CD/CBD complex. The release behavior of CBD from the 3D printed formulations was assessed in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and simulated colonic fluid (SCF). The results shown that that the highest release rates of CBD were obtained in SCF medium, with minor release in SGF and SIF media.

Mixing of carbonatitic into saline fluid during panda diamond formation

Diamonds containing fluid inclusions provide invaluable samples of upper mantle fluids, the study of which illuminates not only diamond formation but also the long-term evolution of the subcratonic, lithospheric mantle. The very large range of inclusion compositions worldwide has been interpreted to represent four end-member fluids: saline (rich in Na + K + Cl); silicic (rich in Si + Al); and carbonatitic (rich in Ca + Mg + Fe, with low-Mg and high-Mg end members). However, the sources and evolution of these fluids and the processes involved in diamond formation are still unclear.We used an unusual study of diamonds from the Panda kimberlite (Ekati Mine, Northwest Territories, Canada) in which both mineral and fluid inclusions in the diamonds were analyzed (Tomlinson et al., 2006) to develop models of the saline, silicic, and low-Mg carbonatitic fluids present in the Panda fluid inclusions. The models used aqueous speciation and solubility calculations to link the solid and fluid inclusion chemistry with model upper mantle rock types. We used the extended Deep Earth Water model to calculate equilibrium constants previously calibrated with experimental rock solubilities referring to upper mantle temperatures and pressures (Huang and Sverjensky, 2019). Our results at 950 °C and 4.5 GPa suggest that the saline fluid could originate from peridotite, the silicic fluid from eclogite, and the low-Mg carbonatitic fluid from carbonated dunite.The fluid models were then used to predict the irreversible, chemical mass transfer when the carbonatitic fluid infiltrated a harzburgite containing a saline fluid. Simultaneous reduction of formate and bicarbonate in the carbonatitic fluid and oxidation of aqueous hydrocarbons from the peridotitic fluid during mixing and reaction with harzburgite resulted in the formation of diamond, olivine, garnet, and clinopyroxene, and increases in the logfO2 and pH. Olivine was predicted to become more Fe-rich and garnet more Ca and Fe-rich with reaction progress, in agreement with reported temporal trends (core-to-rim) in the Panda mineral inclusions. The fluid at the site of diamond formation became more saline with reaction progress and the predicted aqueous phase concentrations of all elements changed consistent with trends in Panda fluid inclusions. In contrast, a prediction for a saline fluid infiltrating a harzburgite containing a carbonatitic fluid resulted in trends of the silicate minerals and the salinity with reaction progress that were in the opposite direction to data from the Panda diamonds. Overall, our study strongly supports the notion that fluids from subducting slabs could mix and precipitate diamonds containing carbon from both oxidized and reduced sources, while adding Ca and Fe to the sub-lithospheric cratonic mantle through metasomatic reactions.

Commensurate Growth of Magnetite Microinclusions in Olivine under Mantle Conditions

Magnetite-bearing multiphase solid inclusions hosted in metamorphic olivine have been interpreted as final products of the trapping of the aqueous fluid produced by the subduction-zone dehydration ...

An evolutionary system of mineralogy. Part II: Interstellar and solar nebula primary condensation mineralogy (>4.565 Ga).

(1)Varied crystalline and amorphous molecular solids containing primarily H, C, O, and N are observed to condense in cold, dense molecular clouds in the interstellar medium (10 < T < 20 K; P < 10-13 atm). With the possible exception of some nanoscale organic condensates preserved in carbonaceous meteorites, the existence of these phases is documented primarily by telescopic observations of absorption and emission spectra of interstellar molecules in radio, microwave, or infrared wavelengths. (2)Evidence from infrared observations and laboratory experiments suggest that cubic H2O ("cubic ice") condenses as thin crystalline mantles on oxide and silicate dust grains in cool, distant nebular and circumstellar regions where T ~100 K. (3)The earliest phase of nebular mineralogy saw the formation of primary refractory minerals that solidified through high-temperature condensation (1100 < T < 1800 K; 10-6 < P < 10-2 atm) in the solar nebula more than 4.565 billion years ago. These earliest mineral phases originating in our solar system formed prior to the accretion of planetesimals and are preserved in calcium-aluminum-rich inclusions, ultra-refractory inclusions, and amoeboid olivine aggregates.

Computation of acoustic properties and design guidelines of periodic Biot-modeled foams

This paper aims at consolidating research dealing with vibroacoustics of periodic media. The main goal of this work is to develop and to validate tools for the design of global vibroacoustic treatments based on periodic patterns, allowing passive control of acoustic paths in layered concepts. To this aim, some enhancements are introduced to the state of the art on the study and the design of Biot-modeled foams, in order to obtain desired acoustics performances through embedded periodic inclusions. At first, the properties of the studied acoustic package, constituted by a poro-elastic 3D unit cell, is introduced. Successively, through the use of the acoustic-structure coupling that comes from the implementation of Biot model, a non-rigid inclusion test campaign is carried out by considering some solid (but still non-perfectly-rigid) inclusions in a 3D-modeled unit cell; in particular, six setups are discussed herein. Then, some design guidelines are provided in order to predict at which frequency the first performance peak appears, together with its amplitude, as functions of unit cell dimensions, airflow resistivity, tortuosity, viscous and thermal characteristic lengths, frame density, Young modulus and loss factor; conversely, it is shown also the link between the unit cell dimensions and the first performance peak amplitude as functions of the design frequency.

Experimental Studies on Durability of PVD-Based CrCN/CrN-Coated Cutting Blade of Planer Knives Used in the Pine Wood Planing Process.

The condition of the cutting tool is one of the most important factors as it directly affects the technological and economic efficiencies of the woodworking process. The large variety of raw materials of wood combined with possible impurities and inclusion of solids puts high demands on planing machines. One of the methods to modify their operational properties is to apply antiwear coating on their working surfaces using vacuum deposition methods, such as physical vapor deposition (PVD). The use of such coatings reduces the adhesion of planing products to the surface of industrial planer knives, reduces the friction between the cutting tool and the workpiece, and limits the penetration of heat into the tool, thereby contributing to extending its effective working life. This study examines the impact of PVD-based CrCN/CrN coating on the operational durability and intensity of wear of planer knives operating in production conditions compared to unmodified knives (typically used in the wood processing industry for pine wood planing). For the unmodified and CrCN/CrN-coated planing blades (before and after processing), detailed analyses were carried out. These analyses included determining the rounding radius and profile along the blade (worn edge displacement), calculating surface texture parameters of the rake face of planer knives, and carrying out visual microscopic analysis of its condition. The results of the experiments indicated an increase in durability of up to 142% for the CrCN/CrN-coated tools. It was also found that the use of PVD-based modified industrial planer knives turned out to be more beneficial in each analyzed area of analysis.

Production of a potential collagenolytic protease by nejayote fermentation with Aspergillus oryzae

SummaryNejayote is the wastewater obtained from maize lime cooking. It was used for Aspergillus oryzae growth and enzyme production. Protein production and collagenolytic activity were evaluated to test the effects of pH, spore inoculum and nejayote content in a 33 factorial design. No collagenolytic activity was observed in the supernatant of the fermentation without nejayote. Using nejayote at 5% increased 1.5 times the fungus growth in comparison with nejayote 1% and 3%; and the maximum collagenolytic activity was reached after 3 days at pH 8 (P &lt; 0.05). After sequencing, a 32 kDa alkaline protease was identified. Along with the alkaline conditions produced by the inclusion of nejayote solids, this waste is an important source of carbohydrates that improved the growth of A. oryzae to produce a protease that has the potential to break collagen. This permits a prospective revalorisation of a waste material to get a product with multiple biotechnological uses.

Methods for assessing the strength of the blades of soil-cutting parts of forestry machines

One way of increasing the wear resistance of working bodies of forestry machines is the use of strengthening technologies. Working tools of tillage machines used in forestry are dampened as a result of edge damage during multiple strike impacts of solid soil inclusions along blade edge. The purpose is to identify the pattern of damage of the blade edge of the of soil-cutting parts of forestry machines and theoretically justify the algorithm of strength evaluation in order to determine the rational thickness of the wear-resistant coating during strengthening. Instrumental and analytical studies were carried out on the damage of the reinforced blade edges as a result of multiple impacts on the pendulum copra. Mathematically described is the process of blade edge failure. In the course of multiple strike impacts of soil solid inclusions on the blade edge, there will be accumulation of volumetric damage because of plastic crumpling or chipping. The sharpness of the self-sealing reinforced blade is determined by the thickness of the reinforcing layer and its ability to resist collapse under strike impactsize.

An evolutionary system of mineralogy. Part I: Stellar mineralogy (>13 to 4.6 Ga).

Minerals preserve records of the physical, chemical, and biological histories of their origins and subsequent alteration, and thus provide a vivid narrative of the evolution of Earth and other worlds through billions of years of cosmic history. Mineral properties, including trace and minor elements, ratios of isotopes, solid and fluid inclusions, external morphologies, and other idiosyncratic attributes, represent information that points to specific modes of formation and subsequent environmental histories-information essential to understanding the co-evolving geosphere and biosphere. This perspective suggests an opportunity to amplify the existing system of mineral classification, by which minerals are defined solely on idealized end-member chemical compositions and crystal structures. Here we present the first in a series of contributions to explore a complementary evolutionary system of mineralogy-a classification scheme that links mineral species to their paragenetic modes. The earliest stage of mineral evolution commenced with the appearance of the first crystals in the universe at >13 Ga and continues today in the expanding, cooling atmospheres of countless evolved stars, which host the high-temperature (T > 1000 K), low-pressure (P < 10-2 atm) condensation of refractory minerals and amorphous phases. Most stardust is thought to originate in three distinct processes in carbon- and/or oxygen-rich mineral-forming stars: (1) condensation in the cooling, expanding atmospheres of asymptotic giant branch stars; (2) during the catastrophic explosions of supernovae, most commonly core collapse (Type II) supernovae; and (3) classical novae explosions, the consequence of runaway fusion reactions at the surface of a binary white dwarf star. Each stellar environment imparts distinctive isotopic and trace element signatures to the micro- and nanoscale stardust grains that are recovered from meteorites and micrometeorites collected on Earth's surface, by atmospheric sampling, and from asteroids and comets. Although our understanding of the diverse mineral-forming environments of stars is as yet incomplete, we present a preliminary catalog of 41 distinct natural kinds of stellar minerals, representing 22 official International Mineralogical Association (IMA) mineral species, as well as 2 as yet unapproved crystalline phases and 3 kinds of non-crystalline condensed phases not codified by the IMA.

Applying Different Techniques to Improve the Bioavailability of Candesartan Cilexetil Antihypertensive Drug.

PurposeThe objective of this study was to compare different techniques to enhance the solubility and dissolution rate, and hence the bioavailability of candesartan cilexetil.MethodsTo achieve this target, various techniques were employed such as solid dispersions, inclusion complexes, and preparation of candesartan nanoparticles. Following the preparations, all samples were characterized for their physicochemical properties, and the samples of the best results were subjected to further bioavailability studies.ResultsResults of dissolution studies revealed an increase in the dissolution rate of all samples. The highest dissolution rate was achieved using solid dispersion of the drug with PVP K-90 (1:4). Physicochemical investigations (XR, DSC, and FT-IR) suggested formation of hydrogen bonding and changing in the crystalline structure of the drug. Regarding the inclusion complexes, more stable complex was formed between HP-β-CD and CC compared to β-CD, as indicated by phase solubility diagrams. Antisolvent method resulted in the preparation of stable nanoparticles, as indicated by ζ potential, with average particle size of 238.9 ± 19.25 nm using PVP K-90 as a hydrophilic polymer. The best sample that gave the highest dissolution rate (CC/PVP K-90 1:4) was allowed for further pharmacokinetic studies using UPLC MS/MS assay of rabbit plasma. Results showed a significant increase in the bioavailability of CC from ~15% to ~48%.ConclusionThe bioavailability of CC was significantly improved from ~15% to ~48% when formulated as SDs with PVP K-90 with 1:4 drug:polymer ratio.