Water-soluble Crystals Research Articles

Model-based design for water-soluble crystals with anti-caking function by the feedback between caking prediction and crystallization control

Water-soluble crystals with anti-caking function have become high-end products, whereas they are prepared by trial and error due to the lack of quantitative correlation between particle size and caking tendency, as well as the absence of the models for global consideration between caking and crystallization. This work presents a coupled Caking-Size-Crystallization (CSC) model, which connects the front-end crystallization process and the post-end caking process to achieve the closed-loop design of the anti-caking function for the first time. The CSC model can directly generate the optimal cooling trajectory to crystallize the product free of caking. The introduction of the caking constant term, the mean particle size and the Mullin-Nyvlt’s theory improve the design efficiency by an order of magnitude with the precision guaranteed. This model-based approach presents an opportunity to find optimal crystallization operating profiles with diverse crystal seed loading strategies that meet both product function and manufacturability demands.

Surface anchoring controls orientation of a microswimmer in nematic liquid crystal

Microscopic swimmers, both living and synthetic, often dwell in anisotropic viscoelastic environments. The most representative realization of such an environment is water-soluble liquid crystals. Here, we study how the local orientation order of liquid crystal affects the motion of a prototypical elliptical microswimmer. In the framework of well-validated Beris-Edwards model, we show that the microswimmer’s shape and its surface anchoring strength affect the swimming direction and can lead to reorientation transition. Furthermore, there exists a critical surface anchoring strength for non-spherical bacteria-like microswimmers, such that swimming occurs perpendicular in a sub-critical case and parallel in super-critical case. Finally, we demonstrate that for large propulsion speeds active microswimmers generate topological defects in the bulk of the liquid crystal. We show that the location of these defects elucidates how a microswimmer chooses its swimming direction. Our results can guide experimental works on control of bacteria transport in complex anisotropic environments.

Multifunctional and recyclable TiO2 hybrid sponges for efficient sorption, detection, and photocatalytic decomposition of organic pollutants

Developing techniques for monitoring and removing organic pollutants such as solvents and dyes in environmental media is a very important task nowadays. To get rid of the pollutants, efficient materials that can sorb, detect, and decompose such compounds have been consistently sought after. Herein, we demonstrate a simple and inexpensive method to fabricate eco-friendly multifunctional and recyclable TiO2 hybrid sponges composed of a polydimethylsiloxane (PDMS) network and functional nanoparticles. Water-soluble crystals were used to construct porous templates and TiO2 nanoparticles were additionally integrated into the templates where liquid PDMS was filled. After curing the PDMS, the TiO2 integrated hybrid sponges were finally obtained by dissolving the templates with water. By using the fabricated hybrid sponges, sorbed organic pollutants were qualitatively detected via molecular-specific Raman signals. Furthermore, we showed the recyclability by achieving photocatalytic decomposition of the sorbed pollutants induced by the TiO2 nanoparticles. These results are instructive for further applications and also contribute toward solving problems relating to environmental pollution.

リン酸二水素カリウム単結晶の飽和水溶液中におけるレーザビーム走査による研磨

Potassium dihydrogen phosphate (KDP) is a non-linear optical and water-soluble crystal. However, since KDP is brittle material, it takes a large cost to obtain the surface roughness required in generating harmonics. Therefore, a new polishing method using YAG laser beam is developed and verified the method by experiments in our research work. The method developed in this paper is as follows. A YAG laser beam is focused at an edge of an end face of a single crystal in a saturated solution. The laser beam is scanned along the edge of the end surface. It is possible to polish the scanned surface by the solution of the crystal and the other portions are not removed in a saturated solution. In this paper, the surface of the crystal polished by our laser beam scanning method was compared with that polished by sandpapers. The surface polished by laser beam scanning is smoother than that polished by sandpapers when the both surface roughness were same. The crystallinity of both crystals after polishing were same degree by X-ray diffraction analysis. The second harmonic generation were performed using KDP crystals before polishing, after laser beam polishing and after sandpaper polishing. The intensity of the light from the crystal by the laser beam polishing was the best of these three crystals.

Transparent and Dense Ladder-Like Alkylene-Bridged Polymethylsiloxane Coating with Enhanced Water Vapor Barrier Property.

Organic-inorganic hybrid composites have been well-studied as water vapor barrier materials for their long diffusion length of water vapor in coatings which can be realized by improving the aspect ratio of inorganic components and regularity of nanostructure in coatings. In this paper, dense organic-inorganic hybrid coating based on ladder-like alkylene-bridged polymethylsiloxane (ABPMS) was successfully fabricated through the hydrosilylation reaction between polymethylhydrosiloxane and diene (1,5-hexadiene or 1,7-octadiene) in toluene under Pt/C catalysis. Its ladder-like structure was verified by 29Si magic angle spinning (MAS) NMR, 13C MAS NMR, and in-plane and out-of-plane glance-incident X-ray diffraction (GIXRD) techniques. Its corresponding coating showed excellent water vapor barrier ability for a typical water-soluble crystal, potassium dihydrogen phosphate (KDP). When treated in 50% relative humidity (RH) condition at 25 °C for 8 months, the ABPMS coating with 100 nm thickness displayed a very low transmittance loss of 1.6% compared with the high transmittance loss of 10% for uncoated KDP. Moreover, the ABPMS coating showed good ultraviolet radiation resistance, thermal stability, low mechanical property, and excellent compatibility with hydrophobic antireflective (AR) coatings.

Evaluation of kinetic parameters for water soluble crystals by thermo gravimetric analysis

This work elevates the relevance of kinetic parameters of nucleation and thermal decomposition for water soluble crystals. The positive soluble Potassium Dihydrogen Phosphate (KDP) and negative soluble Lithium Sulfate Monohydrate (LSMH) materials were chosen for the kinetic evaluation. The results obtained from the classical nucleation theory are verified with the kinetic parameters which are evaluated from thermo gravimetric analysis. Nucleation parameters of a crystallization process such as interfacial energy (σ), volume free energy (ΔGv), critical energy barrier for nucleation (ΔG⁎), radius of the critical nucleus (r⁎) and nucleation rate (J) of the positive (KDP) and negative solubility (LSMH) crystals are determined from the classical nucleation theory of solubility–enthalpy relation. The kinetic parameters viz. the order of reaction, enthalpy, Gibbs free energy of activation, frequency factor, and entropy of activation are obtained from the TG based models viz. Horowitz–Metzger, Coats–Redfern and Piloyan–Novikova. The effect of varying temperature with relative variation on Gibbs free energy for both positive and negative solubility crystals is also discussed. The developed model holds good for both positive and negative solubility crystals.

A scanning electron microscope technique for identifying the mineralogy of dust in ice cores

AbstractDust particles in an ice core from East Rongbuk Glacier on the northern slope of Qomolangma (Mount Everest; 28°01′ N, 86°58′ E; 6518 m a.s.l.), central Himalaya, have been identified as mica using a combination of scanning electron microscope-based techniques and energy-dispersive X-ray spectroscopy to identify the elements present, and electron backscatter diffraction to identify the crystal type. This technique for identifying individual crystalline dust particles in samples of glacial ice could be especially useful in the future for identifying water-soluble crystals in ice, for studying the strain history (glaciotectonics) of basal ice or in studies of ice–mica composites used as analogs of quartz-mica rocks.

Application of solution techniques for rapid growth of organic crystals

Single crystals of a pure hydrocarbon, 1,3,5-triphenylbenzene, with properties suitable for high-energy neutron detection were grown from toluene solutions using slow evaporation and temperature reduction methods with growth rates up to 10 mm/day. Application of the rapid growth technique developed earlier for growth of large water-soluble crystals shows that crystals of aromatic compounds can be successfully grown from solutions in large volumes required for their use as scintillator materials for radiation detection.

Fluid flows induced by focused ultrasound and their use in single-crystal growth

Particle image velocimetry was used to study the structure of stationary acoustic flows on a solid surface subjected to acoustic radiation along the normal to the prefocal and postfocal planes of a spherical concentrator. The results of model experiments were used for rapid growth of water-soluble single crystals.

Extraction of caesium from mosses and incorporation into an oxalate crystalline lattice

The ratios of stable and radioactive isotopes in the environment are not constant and their effects on living organisms are not the same. Whilst radionuclides can be monitored by measuring their radioactivity levels, it is also important to determine the stable isotopes. The method described in this paper represents a simple and cheap process by which to extract caesium from moss, without significant destruction of the plant, and to incorporate the isolated caesium into a water-soluble crystal. Ammonium oxalate and phosphoric acid are water-soluble substances at 5% concentration but, when the solutions are combined, crystallisation occurs. Crystals were estimated to contain 68.30% O, 20.98% C, 4.68% H, 6.04% N and less than 0.01% P, corresponding to NH4HC2O4 x H2C2O4 x 2H2O (C4H11NO10). The crystal mass did not vary with the species of moss, although the effectiveness of caesium extraction did. Typically, 73.0 +/- 6.1% of the solubilised caesium was entrapped within the crystals.

Shidham’s Staining Method: Evaluating Water-Soluble Crystals in Tissue Sections

Shidham’s Staining Method: Evaluating Water-Soluble Crystals in Tissue Sections

Formation of macropores in calcium phosphate cement implants.

A calcium phosphate cement (CPC) was shown to harden at ambient temperatures and form hydroxyapatite as the only end-product. Animal study results showed that CPC resorbed slowly and was replaced by new bone. For some clinical applications, it would be desirable to have macropores built into the CPC implant to obtain a more rapid resorption and concomitant osseointegration of the implant. The present study investigated the feasibility of a new method for producing macropores in CPC. Sucrose granules, NaHCO3, and Na2HPO4 were sieved to obtain particle sizes in the range of 125 microm to 250 microm. The following mixtures of CPC powder (an equimolar mixture of tetracalcium phosphate, Ca4(PO4)2O, and dicalcium phosphate anhydrous, CaHPO4) and one of the above additive granules were prepared: control-no additive; mixture A-0.25 mass fraction of sucrose; mixture B-0.25 mass fraction of NaHCO3; mixture C-0.25 mass fraction of Na2HPO4, and mixture D-0.33 mass fraction of Na2HPO4. Cement samples were prepared by mixing 0.3 g of the above mixtures with 0.075 ml of the cement liquid (1 mol/l Na2HPO4). After hardening, the specimens were placed in water for 20 h at about 60 degrees C to completely dissolve the additive crystals. Well-formed macropores in the shapes of the entrapped crystals were observed by scanning electron microscope (SEM). The macroporosities (mean+/-standard deviation; n = 6) expressed as volume fraction in % were 0, 18.9 +/- 1.7, 26.9 +/- 1.6, 38.3 +/- 4.4 and 50.3 +/- 2.7 for the control, A, B, C and D, respectively. The diametral tensile strengths (mean+/-standard deviation; n = 3) expressed in MPa were 10.1 +/- 0.7, 3.7 +/- 0.3, 2.4 +/- 0.2, 1.5 +/- 0.5 and 0.4 +/- 0.1, respectively, for the five groups. The results showed that macropores can readily be formed in CPC implants with the use of water-soluble crystals. The mechanical strength of CPC decreased with increasing macroporosity.

Synthesis of polyHEMA hydrogels for using as biomaterials. Bulk and solution radical-initiated polymerization techniques

Dense and porous polyHEMA hydrogels were synthesized by bulk and solution radical-initiated polymerization techniques. The morphologic analysis (SEM) of obtained hydrogels showed an amorphous dense structure for the samples obtained by bulk polymerization and a porous structure with non connected porous as a result of bulk polymerization in the presence of water soluble crystals (sucrose/NaCl). The use of solution polymerization technique using different amounts of water as diluent resulted in the formation of a sponge-like structure with connected microporous in case of using water amount equal or higher than 57.5%. The saline solution uptake and dynamic mechanical behavior of dense hydrogels were influenced by the amount of crosslinking between the polymer chains.

Rapid growth of deuterated L-Alanine-doped Triglycine Sulfate crystal and its pyroelectric property

The higher supersaturation was achieved by means of the over-heating of growth solution. This method was applied to watersoluble crystal, Deuterated L-A lanine-doped TGS (dLATGS). The dLATGS crystalis a pyroelectric material for the infrared detector which, in general, exhibits one of the highest pyroelectric response of all such materials. The over-heating enlarges the metastable zone during temperature-reducing growing process as a result of eliminating the initial clusters in the mother solution.A dLATGS crystal (9×2×7cm) was grown with an average rate of 2×2×0.6mm/day (24g/day) in direction of a, -b and c axe s, respectively. This growth rate was several times larger than that of the conventional growth method. The internal bias shown in D-E curves depends on the growth rate of L-Alanine doped crystal of which an uniformity was enough fine to use as an electronic device.The distribution coefficient of L-Alanine molecule increased with increasing the growth rate.

Dielectric properties of triglycine sulfate crystals with a periodic stratified impurity distribution

Problems associated with the influence of a nonuniform impurity distribution on the properties of ferroelectric water-soluble crystals are studied. Triglycine sulfate crystals with a specially created periodically stratified distribution of chromium impurity ions are used to show that the properties of these crystals (permittivity, spontaneous polarization, pyrocoefficient) differ from those of triglycine sulfate crystals with randomly distributed impurities and also depend on the period of the structure of the inhomogeneous crystals.

Development of Controlled-Release SK&F 82526-J Buffer Bead Formulations with Tartaric Acid as the Buffer

ABSTRACTThe purpose of this research was to design and develop a novel controlled-release bead formulation for oral administration with buffer crystals as a carrier for loading offenoldopam mesylate, an intravenous antihypertensive agent, which provides an in vitro release rate of 30–50 mg/hr for 6–8 hr. Buffer crystals were coated in a jluid-bed granulator with a blend of gastrointestinal (GI) insoluble/ enteric Eudragit® polymers (such as RSPM/S100 polymer blend), drug was layered on these polymer-subcoated buffer beads by a slurry coating process, and the drug-layered beads were subsequently overcoated using a blend of GI insoluble/enteric polymers. The release offenoldopam and tartaric acid was monitored by a two-stage dissolution procedure using USP Apparatus 2 (paddles at 50 rpm) and HPLC methodologies. The overcoating of drug-layered tartaric acid crystals with Eudragit polymers with different permeabilities significantly affected the release offenoldopam. However, even the least permeable polymer, Eudragit RS, could not sustain the release of tartaric acid beyond 2 hr, suggesting the need to subcoat freely water-soluble tartaric acid crystals prior to drug layering. By varying the typehatios of the GI insoluble/enteric polymers for subcoat and overcoat, capsule formulations were developed, which released fenoldopam and tartaric acid at different rates. The use of Eudragit polymer blends at the optimized ratios for both subcoat and overcoat resulted in a significant retardation in the release of tartaric acid; still, the tartaric acid release was faster than that of fenoldopam, suggesting the need to use a less water-soluble fumaric or succinic acid crystals as the buffer. However, the technology described using tartaric acid crystals as the buffer will be highly useful for weakly basic drug substances with less stringent pH-dependent solubility profiles.

Automatic Rapid Growth of Nonlinear Optic Crystal KDP.

The automatic and rapid crystal growth method was developed for water-soluble crystal, KDP. Theover-heating of the water solution of crystal enlarges the metastable zone during the temperature reducingprocess as a result of eliminating an initial cluster density. The higher level of supersaturation up to 200% onKDP crystal was achieved resulting in an average growth rate of 54 mm/day at supersaturation of 38%. Theconcentration of the growth solution was measured by the conductivity of the solution. The supersaturationwas controlled with the dependency of conductivity on temperature by the computer. The 60-mm class KDP single crystal was grown automatically by the method with an average growth rate of 30 mm/day. The spectraltransmittance and laser damage threshold of the rapidly grown crystals were measured. The lower laserdamage threshold of the rapidly grown crystal was improved completely by a thermal conditioning to be 17J/cm2 of 1 ns pulse at 1-μm wavelength.

Augmentation of monocyte chemotactic protein-1 and mRNA transcript in chronic inflammatory states induced by potassium permanganate (KMnO4) in vivo.

Monocyte chemotactic protein-1 (MCP-1) is a proinflammatory cytokine that attracts and activates specific types of leucocytes. The purpose of this work was to analyse the generation of MCP-1 and mRNA transcript in a model of chronic inflammation using a granulomatous tissue induced by potassium permanganate (KMnO4; water soluble crystals). The data presented here shows that MCP-1 is generated in granuloma tissue and its level was strongly increased by i.p. injections of lipopolysaccharide (LPS) and inhibited in rats treated with injections of dexamethasone, 18 hr before the animals were killed. In histological studies LPS and dexamethasone increased and decreased, respectively, the recruitment of mononuclear cells in the granuloma tissue compared with the control granulomas from phosphate-buffered saline (PBS)-treated animals. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used for mRNA extraction and cDNA synthesis. mRNA MCP-1 was significantly produced in the granuloma tissue of untreated animals, an effect increased by LPS and inhibited by dexamethasone, compared with the controls. Moreover, MCP-1 protein was found in the supernatant from homogenized granuloma tissues and the levels of MCP-1 were higher in the LPS-treated animals, while they were lower in the dexamethasone group, compared with the granulomas from the PBS-treated groups (control). The generation of MCP-1 was also found in minced granuloma tissue incubated for 18 hr (overnight) from treated (LPS or dexamethasone) and untreated (PBS) rats. When LPS was added in vitro for 18 hr to the controls and treated animals the production of MCP-1 was further increased except in the dexamethasone group (P > 0.05). Analysing blood serum from LPS, dexamethasone or PBS-treated rats, we found that MCP-1 was also present. The level was higher in the LPS group and lower in the dexamethasone group, compared with the control (PBS). In these studies we show for the first time that MCP-1 transcript and translation is generated in chronic experimental inflammatory tissue, an effect inhibited by dexamethasone.

Rapid growth of water-Soluble crystals

Rapid growth of water-Soluble crystals

Crystalline Precipitates in Bay Scallops (Argopecten irradians) Imported from China

Macroscopic evaluations documented uncharacterized white spots in bay scallops (Argopecten irradians) to be a surface phenomenon, occupying scallop tissue only to a depth demarcated by translucent tissue, which is associated with salt solution penetration. Light microscopy characterized the white material to be crystalline in nature. Scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) identified two types of crystals, the crystal presents in scallops as imported from China, and a second precipitate resulting form reprocessing scallops with sodium tripolyphosphate (STP). The crystal present in scallops as imported were largely water insoluble, did not dissociate upon heating, and contained phosphorous and magnesium as major elements with sodium present only in trace amounts. Crystals resulting form STP reprocessing contained P, Mg, and Na as major or minor elements. This slight compositional alteration affected crystal stability, producing a more water soluble crystal which dissociated upon heating. Both crystals share similar attributes with struvite crystals (Magnesium ammonium phosphate) but are considered to be different precipitates. Dissociation of crystalline precipitates in imported bay scallops was demonstrated during phosphate processing using alternatives to the alkaline STP. Sodium hexametaphosphate (SHMP, pH 7.0) provided total dissociation of scallop precipitates during processing, while a phosphate blend (pH 7.2) containing STP, SHMP, and acid pyrophosphate provided partial precipitate dissociation. STP solutions with pH adjusted to 5.0, 6.3, and 7.0, had no effect on precipitate dissociation.