Recrystallization Of Water Research Articles

Psilocybin: Characterization of the Metastable Zone Width (MSZW), Control of Anhydrous Polymorphs, and Particle Size Distribution (PSD).

Psilocybin, a serotonergic agonist, was granted a “breakthrough therapy” status by the Food and Drug Administration for clinical trials involving major depressive disorder and treatment-resistant depression. The direct phosphorylation of psilocin to psilocybin that uses a fast crystallization associated with a kinetically controlled process resulted in a smaller particle size distribution. Herein, the measurement of the metastable zone width (MSZW) and nucleation induction enabled a thermodynamically controlled crystallization process, which leads to the formation of a crystal structure with stronger interactions, controlled particle size distribution (PSD), and improved impurity profile. Employing a high-resolution inline microscopy viewer allowed the real-time monitoring of the crystallization process and the measurement of the particle size. We also present a comprehensive study of the formation of polymorph B (trihydrate), polymorph A (anhydrate), and polymorph H (anhydrate) using water recrystallization, which indicates that the formation of polymorph B (trihydrate) is independent of the crystallization method. However, polymorphs A and H are dependent on the mode of drying: drying at room temperature under vacuum gives rise to mainly polymorph A, and when heated even at relatively low temperatures, a mixture of polymorphs A and H beings to form.

Luminescence Change from Orange to Blue for Zero-Dimensional Cs2 InCl5 (H2 O) Metal Halides in Water and a New Post-doping Method.

Zero-dimensional metal halides have attracted much attention due to their attractive photoelectric properties. Here, we propose a new strategy of synthesizing metal halides crystals by recrystallization in water. The as-synthesized Cs2 InCl5 (H2 O)-orange crystals are dissolved and recrystallized in water (Cs2 InCl5 (H2 O)-blue), with its photoluminescence (PL) changing from orange to blue, both of which are derived from self-trapping excitons (STEs). The time-resolved photoluminescence (TRPL) spectrum of Cs2 InCl5 (H2 O)-blue shows that it has an ultralong lifetime up to milliseconds (τ=52.98 ms), which is expected to be applied in biological sensors. The photoluminescence quantum yield (PLQY) increases from 2.25% to 11.61% in the self-assembly process. By using a post-doping method, the PL of crystals turns into red when we introduce Mn2+ as dopant while there is no obvious change upon using a traditional solvent-thermal method. Recrystallization in water and post-doping provide a new perspective for the synthesis and doping of metal halides.

Biodegradable cellulose I (II) nanofibrils/poly(vinyl alcohol) composite films with high mechanical properties, improved thermal stability and excellent transparency

Cellulose nanofibrils (CNFs) with cellulose I and II allomorphs were efficiently prepared by sulfuric acid hydrolysis of eucalyptus cellulose under three different conditions followed by mechanical treatments: (i) classical sulfuric acid hydrolysis of cellulose I (CNF-I), (ii) sulfuric acid hydrolysis of mercerized cellulose II (MNF-II), and (iii) solubilization and hydrolysis of cellulose I by concentrated sulfuric acid and subsequent recrystallization in water (RNF-II). Crystal structure, surface chemistry, morphology and thermal properties of three CNFs were investigated and compared. Three CNFs of 2–10 wt% were mixed with PVA to prepare biodegradable composite films. CNF allomorph had significant impact on crystal structure, mechanical and thermal properties of the PVA composites. The maximum Young's modulus of CNF-I/PVA, RNF-II/PVA and MNF-II/PVA were increased by 62, 32 and 44%, respectively. Addition of CNFs raised onset degradation temperature (Tonset) and thermal decomposition temperature (Tmax) of PVA nanocomposite, while decreased the melting temperature (Tm). Temperature window (Tonset − Tm) for the melt processing of nanocomposites (10 wt% CNF loading) were increased 2.8, 3.2 and 2.5 times for CNF-I/PVA, RNF-II/PVA and MNF-II/PVA, respectively. All composite films remained excellent transparency with addition of CNFs. This comparative study provided important knowledge of selecting CNF allomorph for fabrication of high-performance CNF/PVA composites.

Reversible Colloidal Crystallization

We report 3D colloidal self-assembly (crystallization) of poly(ionic liquid) latexes to produce crystals that exhibit reversible melting and recrystallization in water, due to “classical” interparticle interactions, typical of multifunctional polymers. These new materials are derived from an ionic liquid monomer that is polymerized at room temperature by redox-initiated polymerization. Particle synthesis, self-assembly, thermal properties, and introductory light diffraction effects are reported with a focus on melting. These crystals are distinguishable from classical colloidal crystalline arrays, and are the first such crystals to exhibit thermal melting. This new hydrogel offers promise for engineering large volume production of photonic crystals active in the visible and proximal spectral regions, by crystallization from suspension (solution), characteristic of most useful chemical compounds.

Rheological evaluation of gelation during thermal treatments in block freeze concentration of coffee extract

Block freeze concentration (BFC) is a promising technique to concentrate coffee extract in the freeze-dried coffee industry. The application of thermal treatments (the use of different cooling/heating ramps and isothermal stages) to BFC lab-scale operations has increased the process's efficiency but has simultaneously led to the formation of gels that reduce the recovery of solids. In this work, we present a methodology to monitor the rheological behavior of coffee extract when subjected to temperature profiles similar to those presented during lab-scale BFC processes. It was revealed that cryogelation occurs at the early stages of the isothermal step (annealing) of a multi-stage temperature profile. For gelation to occur, the annealing temperature should be close to the water's equilibrium melting temperature. Phenomena leading to more efficient BFC processes (solids elution and water recrystallization during isothermal thawing) also promote cryogelation.

Solvent-dependent chirality transformation: Construction of a helical homochiral silver(I) MOF using the V-shaped ligand 3-Aminobenzoate

Less attention has been paid to the solvent-dependent chirality transformation behavior of coordination compounds when using achiral precursors. We have successfully prepared one known helical achiral compound (α-[AgL]n∙nH2O, 1) using water or DMSO as a solvent, one new helical homochiral MOF (β-[AgL]n∙nH2O, 2) using DMF, dimethyl acetamide or ethanol as a solvent, and one new non-helical achiral compound ([Ag2L(NO3)]n, 3) using n-propyl alchohol or cyclohexanol as a solvent, with the V-shaped achiral ligand 3-aminobenzoic acid (HL) as a ligand. Achiral 1 can be converted from chiral isomeric 2 through recrystallization in water. Such successive chirality transformation (achirality→chirality→achirality) behavior is probably proportional the polarity of the used solvent: cyclohexanol (3)<n-propyl alchohol (3)<ethanol (2)<dimethyl acetamide (2)<DMF (2)<DMSO (1)<water (1). A preliminary study revealed that the isomeric compounds 1 and 2 displayed significantly different photoluminescence.

ChemInform Abstract: A Ta/W Mixed Addenda Heteropolyacid with Excellent Acid Catalytic Activity and Proton‐Conducting Property.

AbstractYellow crystals of H20 [P8W60Ta12(H2O)4 (OH)8O236]·125H2O are obtained from an aqueous solution of K8Na8H4 [P8W60Ta12(H2O)4 (OH)8O236]·42H2O by ion exchange (HCl‐loaded Amberlite IR120B, 95% yield) followed by recrystallization in water (91% yield).

Heat Capacity Prediction During Pork Meat Thawing: Application of Artificial Neural Network

AbstractCurrent models based on artificial neural networks (ANNs) constitute an application for recognizing nonlinear patterns in biological processes and are useful tools for process control. A property that is used to evaluate the behavior of solid foods exposed to heating or cooling processes is their heat capacity (Cp), which is estimated through empirical or semi‐theoretical equations. The aim of this study is to develop an ANN model that is based on backpropagation error, to determine Cp during the pork meat thawing with frost formation. Two neural networks were trained with nonassociated variables, such as statistical texture parameters, image analysis, color parameters for tristimulus space and surface temperature. The Cp supervising agent was obtained through modulated differential scanning calorimetry (MDSC). The observed error for the neural network with five variables was 0.0082 (R2 = 0.9992), and the error with seven variables was 0.00079 (R2 = 0.9989) when predicting the Cp.Practical ApplicationsTemperature variations during transportation or even storage can cause changes in the final product due to continued thawing and water recrystallization. This uncontrolled condition, which is common in the meat industry, affects thermodynamic properties, such as heat capacity (Cp), structure and meat product quality. Cp is typically estimated using empirical data or by expensive equipment such as modulated differential scanning calorimetry; it represents the structural changes that are caused by the formation, growth and size of ice crystals that damage meat muscle fibers. In this study, the Cp was predicted with an unusual methodology while thawing meat, based on easily measurable variables, such as changes in the color and texture, measurements obtained by image analysis, and temperature, using a trained artificial neural network. Frost formation on the meat surface during thawing is a variable that has not been studied in depth in the food area.

Water outburst activity in Comet 17P/Holmes

Cometary outbursts are sporadic events whose mechanisms are not well known where the activity and consequently the brightness can increase hundreds of thousands of times within a few hours to several days. This indicates a dramatic departure from thermal equilibrium between the comet and interplanetary space and is usually documented by “light curves”. In a typical cometary outburst, the brightness can increase by 2–5 magnitudes (Whitney, 1955; Gronkowski and Wesolowski, 2015). In only 42h, Comet 17P/Holmes was reported to brighten from a magnitude of about 17 to about 2.4 at the height of the burst, representing the largest known outburst by a comet. We present the H2O production rate of Holmes for the megaburst occurring between 23 and 24 October 2007. For this, we selected more than 1900 photometric observations from the International Comet Quarterly Archive of Photometric Data (Green, 2007) and use the Semi-Empirical Method of Visual Magnitudes (SEMVM; de Almeida et al., 2007). We clearly show that the comet achieved an average water production rate of 5×1029 moleculess−1, corresponding to a water gas loss rate of 14,960kgs−1, in very good agreement with Schleicher (2009) who derived the water production rate using OH measurements on 1 Nov 2007 (about 8days after the outburst). We discuss possible physical processes that might cause cometary outbursts and propose a new qualitative mechanism, the Pressurized Obstructed Pore (POP) model. The key feature of POP is the recrystallization of water in the surface regolith as it cools, plugging pores and blocking the release of subsurface gas flow. As the interior gas pressure increases, an outburst is eventually triggered. POP is consistent with current observations and can be tested in the future with observations (e.g., Rosetta in situ measurements) and detailed simulations.

Comprehensive morphological and structural investigation of cellulose I and II nanocrystals prepared by sulphuric acid hydrolysis

CNCs were produced from eucalyptus wood pulp by (i) classical sulphuric acid hydrolysis, (ii) acid hydrolysis of cellulose previously mercerized by alkali, (iii) solubilization of cellulose in sulphuric acid and subsequent recrystallization in water.

Mid-infrared spectroscopic investigation of the perfect vitrification of poly(ethylene glycol) aqueous solutions.

Crystallization/recrystallization behaviors of poly(ethylene glycol) (PEG) aqueous solutions with water contents (WC's) of ∼36-51 wt % were investigated by temperature-variable mid-infrared spectroscopy. At a WC of 43.2 wt %, crystallization and recrystallization of water and PEG were not observed. At this specific WC value (WCPV), perfect vitrification occurred. Below and above the WCPV value, crystallization/recrystallization behaviors changed drastically. The crystallization temperature below WCPV (237 K) was ∼10 K greater than that above WCPV (226 K). Recrystallization above and below WCPV occurred in one (213 K) and two (198 and 210 K) steps, respectively. These findings resulted from the difference in the (re)crystallization behaviors of water molecules associated with PEG chains with helical and random-coil conformations. These two types of water molecules might have limiting concentrations for their (re)crystallization, indicating that perfect vitrification might have occurred when the concentrations of the two types of water molecules were less than the limiting concentrations of their (re)crystallization.

The influence of amorphization methods on the apparent solubility and dissolution rate of tadalafil

This study for the first time investigates the solubility and dissolution rate of amorphous tadalafil (Td) – a poorly water soluble chemical compound which is commonly used for treating the erectile dysfunction. To convert the crystalline form of Td drug to its amorphous counterpart we have employed most of the commercially available amorphization techniques i.e. vitrification, cryogenic grinding, ball milling, spray drying, freeze drying and antisolvent precipitation. Among the mentioned methods only quenched cooling of the molten sample was found to be an inappropriate method of Td amorphization. This is due to the thermal decomposition of Td above 200°C, as proved by the thermogravimetric analysis (TGA). Disordered character of all examined samples was confirmed using differential scanning calorimetry (DSC) and X-ray powder diffraction (PXRD). In the case of most amorphous powders, the largest 3-fold increase of apparent solubility was observed after 5min, indicating their fast recrystallization in water. On the other hand, the partially amorphous precipitate of Td and hypromellose enhanced the solubility of Td approximately 14 times, as compared with a crystalline substance, which remained constant for half an hour. Finally, disk intrinsic dissolution rate (DIDR) of amorphous forms of Td was also examined.

Chemical evolution of a gas-capped deep aquifer, southwest of Iran

The Kangan Aquifer (KA) is located below a gas reservoir in the crest of the Kangan Anticline, southwest of Iran. This aquifer is composed of Permo-Triassic limestone, dolomite, sandstone, anhydrite and shale. It is characterized by a total dissolved solid of about 332,000 mg/L and Na–Ca–Cl-type water. A previous study showed that the source of the KA waters is evaporated seawater. Chemical evolution of the KA is the main objective of this study. The major, minor and trace element concentrations of the KA waters were measured. The chemical evolution of KA waters occurred by three different processes: evaporation of seawater, water–rock and water–gas interactions. Due to the seawater evaporation process, the concentration of all ions in the KA waters increased up to saturation levels. In comparison to the evaporated seawater, the higher concentrations of Ca, Li, Sr, I, Mn and B and lower concentrations of Mg, SO4 and Na and no changes in concentrations of Cl and K ions are observed in the KA waters. Based on the chemical evolution after seawater evaporation, the KA waters are classified into four groups: (1) no evolution (Cl, K ions), (2) water–rock interaction (Na, Ca, Mg, Li and Sr ions), (3) water–gas interaction (SO4 and I ions) and (4) both water–rock and water–gas interactions (Mn and B ions). The chemical evolution processes of the KA waters include dolomitization, precipitation, ion exchange and recrystallization in water–rock interaction. Bacterial reduction and diagenesis of organic material in water–gas interaction also occur. A new type of chart, Caexcess versus Mgdeficit, is proposed to evaluate the dolomitization process.

Effect of Milling on Particle Shape and Surface Energy Heterogeneity of Needle-Shaped Crystals

Milling and micronization of particles are routinely employed in the pharmaceutical industry to obtain small particles with desired particle size characteristics. The aim of this study is to demonstrate that particle shape is an important factor affecting the fracture mechanism in milling. Needle-shaped crystals of the β polymorph of D-mannitol were prepared from recrystallization in water. A portion of the recrystallized materials was ball-milled. Unmilled and milled sieved fractions of recrystallized D-mannitol were analyzed by dynamic image analysis (DIA) and inverse gas chromatography (IGC) at finite concentration to explain the breakage/fracture behavior. In the process of ball-milling, D-mannitol preferentially fractured along their shortest axis, exposing (011) plane with increased hydrophilicity and increased bounding rectangular aspect ratio. This is in contrary to attachment energy modeling which predicts a fracture mechanism across the (010) plane with increased hydrophobicity, and small change in particle shape. Crystal size, and more importantly, crystal shape and facet-specific mechanical properties, can dictate the fracture/cleavage behavior of organic crystalline materials. Thorough understanding of the crystal slip systems, combining attachment energy prediction with particle shape and surface characterization using DIA and IGC, are important in understanding fracture behavior of organic crystalline solids in milling and micronization.

Recrystallization of Water in Non-Water-Soluble (Meth)Acrylate Polymers Is Not Rare and Is Not Devitrification

Change in the state of water sorbed into four kinds of non-water-soluble poly(meth)acrylates with low water content by temperature (T) perturbation was examined on the basis of T variable mid-infrared (MIR) spectroscopy. Many studies using differential scanning calorimetry suggested that there was no change in the state. T dependence of their MIR spectra, however, clearly demonstrated various changes in the state. Furthermore, recrystallization, which was crystallization during heating, was observed in all four polymers. The recrystallization observed in this study was not devitrification, which is the change in the state from glassy water to crystalline water, but vapor deposition during heating (vapor re-deposition). There were only two reports about recrystallization of water in a non-water-soluble polymer before this report; therefore, it might be considered to be a rare phenomenon. However, as demonstrated in this study, it is not a rare phenomenon. Recrystallization (vapor re-deposition) of water in the polymer matrices is related to a balance between flexibility and strength of the electrostatic interaction sites of polymer matrices but might not be related to the biocompatibility of polymers.

Recrystallization of Water in a Non-Water-Soluble Polymer Examined by Fourier Transform Infrared Spectroscopy: Poly(2-methoxyethylacrylate) with Low Water Content

Crystallization of water during heating, the so-called "recrystallization of water", in poly(2-methoxyethylacrylate) (PMEA) was investigated by temperature-variable Fourier transform infrared spectroscopy. Recrystallization in a polymer-water system is generally understood to be a phase transition from glassy water (condensed water) to crystalline water. However, infrared spectral changes of the PMEA-water system with low water content indicated that the formation of ice I h during heating occurred by a vapor deposition process rather than by a crystallization process.

Comment on vibrational spectral investigation on xanthine and its derivatives—theophylline, caffeine and theobromine

these pharmacologically active molecules. However, some care should be taken in the sample preparation, since sample handling may affect the water content of samples. This is a very relevant issue, since it has been shown that water causes pseudopolymorphic transformations on both theophylline and caffeine, which affect their bioavailability and stability [2–5]. Both caffeine and theophylline can be crystallized under the dehydrated [6,7] and monohydrated forms [6,8]. The dehydrated form can be obtained commercially, while monohydrated forms are currently prepared from recrystallization in water. However, our studies show that anhydrous crystals can turn into the monohydrated ones by simple exposure to the humidity from surrounding atmosphere over a few days. A similar effect has already been described for -cyclodextrin [9] and glucose [10], for instance. The dehydrated and monohydrated forms have quite difcorrespond to two different samples. In fact, the FT-IR spectrum (Fig. 3 [1], top) clearly refers to the monohydrated form, while the Raman spectrum (Fig. 3 [1], bottom) corresponds to the anhydrous sample. Since the authors state that the samples had been obtained commercially with high grade purity and used as such [1], it can be assumed that the Raman spectra was obtained from a “fresh” sample, while the sample for FT-IR was left in contact with atmosphere humidity for a few days before recording the spectrum. The description of IR and Raman spectra of different samples as “vibrational spectra of theophylline”, and their use as such, has two main effects: it can be misleading for future readers and it has been misleading to the authors themselves. In fact, there are several relevant changes in the positions and intensities of the vibrational bands from one form to another, which were not detected by the authors. The assignments present in Table 4 of [1], as well as the proposed correspon-

Immunogold localization of glucanase-like antifreeze protein in cold acclimated winter rye

Apoplastic antifreeze proteins (AFPs) accumulate in winter rye (Secale cereale L. cv. Musketeer) leaves during cold acclimation. Two of the rye AFPs with molecular masses of 32 and 35 kDa are similar in their amino acid sequences and epitopes to β-1, 3-endoglucanase. Localization of these AFPs, which we refer to as glucanase-like proteins (GLPs), was carried out with antiserum raised against the 32 kDa AFP. Specimens from leaves and roots of non-acclimated (NA) plants and cold acclimated (CA) plants were prepared by freeze-substitution for high resolution immunoelectron microscopy. In CA leaves, high levels of GLPs were observed in cell walls of mesophyll cells adjacent to intercellular spaces and in secondary thickenings of xylem vessels. Taken together with the absence of GLPs in vacuoles, these results confirm the apoplastic accumulation of AFPs in CA winter rye. Within the cells of CA leaves, GLPs were localized in cisternae of the rough endoplasmic reticulum, the Golgi apparatus and the plasma membrane, which indicates that GLPs are secreted via an exocytic bulk-flow pathway. The occurrence of high levels of GLPs in CA leaves, their low presence in NA leaves and the lack of GLPs in roots all suggest that there is a correlation between increased accumulation of GLPs and increased freezing tolerance of these plant materials. Furthermore, the localization of GLPs in the immediate vicinity of pathways for free water within the tissues supports the view that these proteins have an important role in the crystallization and/or recrystallization of water when the leaves of CA winter rye are exposed to freezing temperatures.

Efficiency of Recrystallization Methods for the Purification of β‐Cyclodextrin

AbstractCyclodextrins are an important class of products made from starch, and have many applications in the food and other industries. Among the cyclodextrins, β‐cyclodextrin (β‐CD) is the most important and is produced in the largest amount. Some commercial preparations of β‐CD contain contaminants which must be eliminated to enhance the purity of the product. The purity of β‐CD was increased by four different methods, i.e. recrystallization in water, and purification with isopropanol, cyclohexane, or isopropanol and cyclohexane. Purity of β‐CD following the isopropanol method was over 99%, but the yield was only 40%. After cyclohexane treatment or the combined treatment with isopropanol and cyclohexane, purity was also over 99%, but yield was over 60%. Contaminants in commercial β‐CD may be soluble or insoluble. Some contaminants would be bound in the inclusion cavity, and elimination of such contaminants by recrystallization in water was not successful. The purity and endothermic energy changes of β‐CD were also determined by differential scanning calorimetry.

Cryosputtering—a combined freeze‐drying and sputtering method for high‐resolution electron microscopy

Preparing cellular structures for visualization by high-resolution scanning electron microscopy (SEM) is a multi-step process which includes fixation, dehydration, drying and metal coating. Drying and metal coating are limiting for high-resolution work. Commonly, the dried samples are exposed to the air before they are inserted into a metal coating apparatus, thereby exposing them to moisture and the accompanying risk of rehydration, which may cause changes in the supramolecular structure. We have modified a freeze-dryer to accommodate a magnetron sputtering head, in order to sputter-coat the frozen-dried samples while still in the drying chamber in the cold, a process we call cryosputtering. A layer of 1.5 nm of tungsten was cryosputtered onto whole mounts of cytoskeletons from detergent-extracted human glioma cells or fibroblasts and the specimens were examined by high-resolution SEM and transmission electron microscopy (TEM). To reduce the effects of backstreaming oil from the vacuum system, a turbomolecular pump backed by a two-stage rotary vane pump was connected to the drying-coating chamber. This pump system provides a high vacuum, making it possible to dry the specimens at -90 degrees C/183 K, thus reducing the risk for recrystallization of water. Furthermore, the high vacuum minimizes the negative effects of contaminants, which can be deposited onto the specimen surface and affect the quality of the metal coat formed during sputtering.