Batch Cooling Crystallization in Non-Isothermal Taylor Vortex Flow: Effective Method for Controlling Crystal Size Distribution

A non-isothermal Taylor vortex fluid motion was applied for effective control of the crystal size distribution (CSD) in batch cooling crystallization without seed crystals. The non-isothermal Taylor vortex fluid motion was generated using different cylinder temperatures, i.e., a hot inner cylinder and cold outer cylinder, in a Couette–Taylor (CT) crystallizer. Thus, an internal loop of heating dissolution of crystals on the inner cylinder and cooling recrystallization on the outer cylinder was created in the gap between the two cylinders by the Taylor vortex fluid motion. As a result, the crystal size distribution can be effectively controlled by adjusting the operating parameters, including the temperature difference between the inner and outer cylinders, rotation speed of the inner cylinder, and cooling rate in the CT crystallizer. When increasing the temperature difference, the mean crystal size becomes larger and the CSD becomes narrower. Meanwhile, increasing the rotation speed enlarges the mean crystal size and broadens the CSD. Conversely, a fast cooling rate reduces the mean crystal size and narrows the CSD. The mean crystal size and CSD in the non-isothermal CT crystallizer are 3–4 times larger and 30–40% narrower, respectively, when compared with those in the isothermal CT crystallizer and mixing tank crystallizer

Chiral Symmetry Breaking and Deracemization of Sodium Chlorate in Turbulent Flow

The chiral symmetry breaking and deracemization of sodium chlorate were investigated when varying the agitation speed and cooling rate in cooling crystallization. At a low agitation speed, almost zero crystal enantiomeric excess occurred at the induction period. When increasing the agitation speed, the crystal enantiomeric excess at the induction period (called the “initial CEE”) increased due to the promotion of chiral symmetry breaking. The chiral symmetry breaking at the induction period (called the “initial chiral symmetry breaking”) also varied with the cooling rate. At a low cooling rate of 0.0738 °C/min, the initial CEE reached up to about 90% and was rapidly reduced when increasing the cooling rate. The experiments also showed enhanced deracemization of the chiral crystals when increasing the initial CEE. Thus, complete deracemization was achieved when the initial CEE was over 60%. The influence of the agitation speed and cooling rate on the initial CEE originated from secondary nucleation depending on the supersaturation at the induction period (called the “induction supersaturation”). Using a nucleation rate equation, the initial CEE was found to correlate well with the induction supersaturation. Also, varying the final setting temperature and agitator confirmed that secondary nucleation was significantly involved in the chiral symmetry breaking at the induction period

Control of Crystal Size Distribution using Non-Isothermal Taylor Vortex Flow

Using a Couette-Taylor (CT) crystallizer, a non-isothermal technique was developed for effective control of the crystal size distribution (CSD) of the suspension. The proposed technique is based on the internal heating–cooling cycle in a non-isothermal CT crystallizer, consisting of a hot cylinder (<i>T</i>_h) and cold cylinder (<i>T</i>_c). Thus, an internal loop of fines destruction of the suspension in the heating boundary layer of the hot cylinder and recrystallization in the cooling boundary layer of the cold cylinder is formed by the periodic circulating flow of the Taylor vortex in the non-isothermal CT crystallizer. The efficiency of the heating–cooling cycle for improving the CSD depends on the non-isothermal mode and non-isothermal parameters. When the inner cylinder temperature is hot and the outer cylinder temperature is cold (Mode-I), this is more efficient for improving the mean crystal size and dispersity of the CSD than when the cylinder temperatures are reversed (Mode-II). In addition, the efficiency of the heating–cooling cycle is optimized using the temperature difference between hot and cold cylinders (Δ<i>T</i> = <i>T</i>_h – <i>T</i>_c) and saturated bulk temperature. The Taylor vortex fluid motion is always found to enhance the internal cycle efficiency. Thus, the initially small crystal size and broad CSD of the seed suspension (230 μm of mean crystal size and 81% of coefficient of variation) are improved to a large crystal size and narrow CSD of the product suspension (1020 μm of mean crystal size and 31% of coefficient of variation) at a non-isothermality of 8.7 ± 0.1 °C, saturated bulk temperature of 24.0 °C, and rotation speed of 800 rpm. The variation of the cycle efficiency is explained in terms of the driving forces for heating dissolution and cooling recrystallization

sj-docx-2-ajr-10.1177_19458924241251387 - Supplemental material for Predictive Value of Nasal Nitric Oxide for Diagnosing Eosinophilic Chronic Rhinosinusitis: A Systematic Review and Meta-Analysis

Supplemental material, sj-docx-2-ajr-10.1177_19458924241251387 for Predictive Value of Nasal Nitric Oxide for Diagnosing Eosinophilic Chronic Rhinosinusitis: A Systematic Review and Meta-Analysis by Do Hyun Kim, Hyesoo Shin, Gulnaz Stybayeva and Se Hwan Hwang in American Journal of Rhinology & Allergy</p

sj-docx-1-ajr-10.1177_19458924241251387 - Supplemental material for Predictive Value of Nasal Nitric Oxide for Diagnosing Eosinophilic Chronic Rhinosinusitis: A Systematic Review and Meta-Analysis

Supplemental material, sj-docx-1-ajr-10.1177_19458924241251387 for Predictive Value of Nasal Nitric Oxide for Diagnosing Eosinophilic Chronic Rhinosinusitis: A Systematic Review and Meta-Analysis by Do Hyun Kim, Hyesoo Shin, Gulnaz Stybayeva and Se Hwan Hwang in American Journal of Rhinology & Allergy</p

sj-docx-4-ajr-10.1177_19458924221150977 - Supplemental material for The Efficacy of Olfactory Training as a Treatment for Olfactory Disorders Caused by Coronavirus Disease-2019: A Systematic Review and Meta-Analysis

Supplemental material, sj-docx-4-ajr-10.1177_19458924221150977 for The Efficacy of Olfactory Training as a Treatment for Olfactory Disorders Caused by Coronavirus Disease-2019: A Systematic Review and Meta-Analysis by Se Hwan Hwang, Sung Won Kim, Mohammed Abdullah Basurrah and Do Hyun Kim in American Journal of Rhinology & Allergy</p

Strain-Induced Large Exciton Energy Shifts in Buckled CdS Nanowires

Strain engineering can be utilized to tune the fundamental properties of semiconductor materials for applications in advanced electronic and photonic devices. Recently, the effects of large strain on the properties of nanostructures are being intensely investigated to further expand our insights into the physics and applications of such materials. In this Letter, we present results on controllable buckled cadmium-sulfide (CdS) optical nanowires (NWs), which show extremely large energy bandgap tuning by >250 meV with applied strains within the elastic deformation limit. Polarization and spatially resolved optical measurements reveal characteristics related to both compressive and tensile regimes, while microreflectance spectroscopy clearly demonstrates the effect of strain on the different types of excitons in CdS. Our results may enable strained NWs-based optoelectronic devices with tunable optical responses

Fabrication of Microcapsules for Dye-Doped Polymer-Dispersed Liquid Crystal-Based Smart Windows

A dye-doped polymer-dispersed liquid crystal (PDLC) is an attractive material for application in smart windows. Smart windows using a PDLC can be operated simply and have a high contrast ratio compared to those of other devices that employed photochromic or thermochromic material. However, in conventional dye-doped PDLC methods, dye contamination can cause problems and has a limited degree of commercialization of electric smart windows. Here, we report on an approach to resolve dye-related problems by encapsulating the dye in monodispersed capsules. By encapsulation, a fabricated dye-doped PDLC had a contrast ratio of >120 at 600 nm. This fabrication method of encapsulating the dye in a core–shell structured microcapsule in a dye-doped PDLC device provides a practical platform for dye-doped PDLC-based smart windows

Exogenous Gene Integration for Microalgal Cell Transformation Using a Nanowire-Incorporated Microdevice

Superior green algal cells showing high lipid production and rapid growth rate are considered as an alternative for the next generation green energy resources. To achieve the biomass based energy generation, transformed microalgae with superlative properties should be developed through genetic engineering. Contrary to the normal cells, microalgae have rigid cell walls, so that target gene delivery into cells is challengeable. In this study, we report a ZnO nanowire-incorporated microdevice for a high throughput microalgal transformation. The proposed microdevice was equipped with not only a ZnO nanowire in the microchannel for gene delivery into cells but also a pneumatic polydimethylsiloxane (PDMS) microvalve to modulate the cellular attachment and detachment from the nanowire. As a model, hygromycin B resistance gene cassette (Hyg3) was functionalized on the hydrothermally grown ZnO nanowires through a disulfide bond and released into green algal cells, <i>Chlamydomonas reinhardtii</i>, by reductive cleavage. During Hyg3 gene delivery, a monolithic PDMS membrane was bent down, so that algal cells were pushed down toward ZnO nanowires. The supply of vacuum in the pneumatic line made the PDMS membrane bend up, enabling the gene delivered algal cells to be recovered from the outlet of the microchannel. We successfully confirmed Hyg3 gene integrated in microalgae by amplifying the inserted gene through polymerase chain reaction (PCR) and DNA sequencing. The efficiency of the gene delivery to algal cells using the ZnO nanowire-incorporated microdevice was 6.52 × 10⁴- and 9.66 × 10⁴-fold higher than that of a traditional glass bead beating and electroporation

<i>In Vitro</i> Biosynthesis of Metal Nanoparticles in Microdroplets

We report the use of a hydrogel polymer, recombinant <i>Escherichia coli</i> cell extracts, and a microdroplet-based microfluidic device to fabricate artificial cellular bioreactors which act as reactors to synthesize diverse metal nanoparticles (NPs). The combination of cell extracts, microdroplet-based microfluidic device, and hydrogel was able to produce a mass amount of artificial cellular bioreactors with uniform size and shape. For the first time, we report the alternating generation of microdroplets through one orifice for the fabrication of the artificial cellular reactors using the cell extract as inner cellular components and hydrogel as an artificial cellular membrane. Notably, the hydrogels were able to protect the encapsulated cell extracts from the surrounding environment and maintain the functionality of cellular component for the further cellular bioreactor applications. Furthermore, the successful applications of the fabricated artificial cellular bioreactors to synthesize various NPs including quantum dots, iron, and gold was demonstrated. By employing this microfluidic technique, the artificial cellular bioreactors could be applicable for the synthesis of diverse metal NPs through simple dipping of the reactors to the metal precursor solutions. Thus, the different size of NPs can be synthesized through controlling the concentration of metal precursors. This artificial cellular bioreactors offer promising abilities to biofriendly ways to synthesis diverse NPs and can be applicable in chemical, biomedical, and bioengineering applications