Amphiphilic Magnetic Particles Dispersed in Water and Oil for the Removal of Hydrophilic and Hydrophobic Microplastics.

The study explores the synthesis and versatile properties of amphiphilic magnetic particles (AMPs) achieved through sequential coatings. Modulating the hydrophobic content in the synthesis process allows for the formation of hydrophilic, amphiphilic, and hydrophobic magnetic particles, with stable AMPs synthesis achieved at a ratio of hydrophilic to hydrophobic portions of approximately 71 to 29%. These AMPs exhibited outstanding dispersion in both oil and water within an oil/water mixture. Polyethylenimine in the AMP primarily enhances the removal of hydrophilic microparticles and facilitates dispersion in water. On the other hand, octadecylamine is specifically designed for the effective elimination of hydrophobic microparticles and their dispersion in oil. AMPs demonstrated effective removal capabilities for both hydrophilic and hydrophobic microparticles in water as well as hydrophobic microparticles in 100% oil. Our approach is also suited for eliminating hydrophobic microparticles dispersed in small quantities of oil floating on large bodies of water in real-world situations.

Physical Properties of Paste Synthesized from Wet- and Dry-Processed Silver Powders.

This study compares the characteristics and low-temperature curing properties of pastes prepared from silver (Ag) powders synthesized by either wet powder (WP) or dry powder (DP) processing. The WP synthesis of electrode particles has the advantage of controlling the average particle size and particle size distribution but the disadvantage of producing low-purity, crystalline particles because they are synthesized through chemical reduction at less than 100 °C. Conversely, the DP synthesis of electrode particles has the advantage of producing pure, highly crystalline particles (due to synthesis at high temperatures) but the disadvantage of a high processing cost. WP and DP were used to manufacture pastes for low-temperature curing, and the physical properties of the pastes and the electrode characteristics after low-temperature curing were compared between powder types. Shear stress as a function of the shear rate shows that the WP paste is a plastic fluid, whereas the DP paste is a pseudoplastic fluid, closer to a Newtonian fluid. Screen printing the Ag pastes and curing for 30 min at 130 °C produces a nonconductive WP paste, whereas it produces a DP paste with a conductivity of 61 mΩ/sq, indicating that the highly crystalline DP paste is advantageous for low-temperature curing.

Hybrid Bead Air Filters with Low Pressure Drops at a High Flow Rate for the Removal of Particulate Matter and HCHO.

A tower air filtration system was designed in which bead air filters (BAFs) were actively rotated by a fan motor to remove particulate matter (PM) or HCHO gas. Three types of BAF, hydrophilic, hydrophobic, and hybrid, were prepared and compared for the removal of PM and HCHO gas. A tower air filtration system loaded with hybrid BAFs purified 3.73 L of PM (2500 µg/m3 PM2.5) at a high flow rate of 3.4 m/s with high removal efficiency (99.4% for PM2.5) and a low pressure drop (19 Pa) in 6 min. Against our expectations, the PM2.5 removal efficiency slightly increased as the air velocity increased. The hybrid BAF-200 showed excellent recyclability up to 50 cycles with high removal efficiencies (99.4-93.4% for PM2.5). Furthermore, hydrophilic BAF-200 could permanently remove 3.73 L of HCHO gas (4.87 ppm) and return the atmosphere to safe levels (0.41-0.31 ppm) within 60 min without any desorption of HCHO gas.

Solar-Driven Unmanned Hazardous and Noxious Substance Trapping Devices Equipped with Reverse Piloti Structures and Cooling Systems.

A solar-driven unmanned hazardous and noxious substance (HNS) trapping device that can absorb, evaporate, condense, and collect HNSs was prepared. The HNS trapping device was composed of three parts: a reverse piloti structure (RPS) for absorption and evaporation of HNSs, Al mirrors with optimized angles for focusing light, and a cooling line system for the condensation of HNSs. The RPS was fabricated by assembling a lower rectangle structure and an upper hollow column. The lower rectangular structure showed a toluene evaporation rate of 6.31 kg/m2 h, which was significantly increased by the installation of the upper hollow column (11.21 kg/m2 h) and led to the formation of the RPS. The installation of Al mirrors on the RPS could further enhance the evaporation rate by 9.1% (12.28 kg/m2 h). The RPS system equipped with an Al mirror could rapidly remove toluene, xylene, and toluene-xylene with high evaporation rates (12.28-8.37 kg/m2 h) and could effectively collect these substances with high efficiencies (81-65%) in an unmanned HNS trapping device. This prototype HNS trapping device works perfectly without human involvement, does not need electricity, and thus is suitable for fast cleanup and collection of HNSs in the ocean.

Characterization of Bi-Te p-Type Thermoelectric Materials Produced by Uniaxial and Hydrostatic Sintering Technologies.

The anisotropic structure of Bi2Te3-type thermoelectric materials makes them prone to mechanical vulnerabilities and inconsistent electrical and thermal properties according to microstructural orientation. In this study, sintered BiSbTe bodies were synthesized by spark plasma sintering (SPS), hot pressing (HP), and hot isostatic pressing (HIP) using p-type thermoelectric powders produced through oxide reduction. Changes in the microstructure and thermoelectric properties were investigated according to the sintering process. The thermoelectric properties of the samples produced by uniaxial methods (SPS and HP) were affected by the direction of pressing during sintering; the electrical and thermal conductivities differed by up to 30% depending on the orientation. In contrast, the hydrostatic HIP process did not impart such directionality; the difference in thermoelectric properties according to orientation was significantly reduced to less than 4%. Moreover, the sintered Bi2Te3 body produced by HIP showed outstanding thermoelectric performance at a much lower temperature than the samples produced by SPS or HP, with a maximum figure-of-merit (ZT) of 1.42 at 373 K.

Remote-Controlled Magnetic Sponge Balls and Threads for Oil/Water Separation in a Confined Space and Anaerobic Reactions.

Magnetic sponges (MSs) and magnetic threads with hydrophilic and hydrophobic characteristics that can perform remote-controlled oil/water separation in a confined space and anaerobic reactions were prepared. For large amounts of water or oil, trainlike hydrophilic or hydrophobic MSs composed of more than three sponge balls moved as a group and quickly absorbed the water or oil droplets in oil or water by magnetic manipulation from outside of the tube. For the removal of heavy oils below the water in three-liquid multiphase solutions, the hydrophobic MS balls were moved to the heavy oil below the water, absorbed some of the heavy oil, and returned to the light oil layer to deliver the heavy oil by means of an external magnetic field. The mixed oils floating on the water were easily removed by a suction pump once the heavy oil had been completely delivered to the light oil layer via the round-trip process. Furthermore, our approach was demonstrated for use in an anaerobic reaction system due to the strong magnetic property that transfers the reactants/products, the porous structure providing a reaction site, and the prewetting ability containing the reactants/products of the MSs and the oil layer prohibiting oxygen contact.

An Active Absorbent for Cleanup of High-Concentration Strong Acid and Base Solutions.

There is significant interest in developing novel absorbents for hazardous material cleanup. Iron oxide-coated melamine formaldehyde sponge (MFS/IO) absorbents with various IO layer thicknesses were synthesized. Various other absorbents were also synthesized and compared to evaluate the absorption capability of the MFS/IO absorbents for strong acid (15%, v/v) and base (50%, m/m) solutions. Specifically, absorbent and solution drop tests, dust tests, and droplet fragment tests were performed. Among the various absorbents, MFS/IO absorbents possessing a needlelike surface morphology showed several unique characteristics not observed in other absorbents. The MFS/IO absorbents naturally absorbed a strong base solution (absorption time: 0.71-0.5 s, absorption capacity: 10,000-34,000%) without an additional external force and immediately absorbed a strong acid solution (0.31-0.43 s, 9830-10,810%) without absorption delay/overflow during absorbent and solution drop tests, respectively. The MFS/IO absorbents were also demonstrated to be ideal absorbents that generated fewer dust particles (semiclass 1 (ISO 3) level of 280 piece/L) than the level of a clean room (class 100). Furthermore, the MFS/IO absorbents were able to prevent the formation of droplet fragments and solution overflow during the solution drop test due to their unique surface morphology and extremely high absorption speed/capacity, respectively.

NiCo2S4 Nanotrees Directly Grown on the Nickel NP-Doped Reduced Graphene Oxides for Efficient Supercapacitors.

In this work, we report a feasible fabrication of NiCo2S4 nanotree-like structures grown from the Ni nanoparticle (NP)-doped reduced graphene oxides (Ni-rGO) by a simple hydrothermal method. It is found that the presence of Ni NPs on the surface of the rGOs initiates growth of the NiCo2S4 nanotree flocks with enhanced interfacial compatibility, providing excellent cyclic stability and rate performance. The resulting NiCo2S4/Ni-rGO nanocomposites exhibit a superior rate performance, demonstrating 91.6% capacity retention even after 10,000 cycles of charge/discharge tests.

Effect of Potassium Ions on the Formation of Mixed-Valence Manganese Oxide/Graphene Nanocomposites.

One-pot synthesis of mixed-valence manganese oxide (MnOx)/potassium ion-doped reduced graphene oxide (rGO) composites for efficient electrochemical supercapacitors is introduced. Using manganese nitrate and potassium permanganate as co-precursors for the MnOx and by directly annealing the rGO without tedious purification steps, as described herein, MnOx/rGO composites with a high specific capacitance of 1955.6 F g-1 at a current density of 1 A g-1 are achieved. It is found that the presence of potassium ions helps in the development of mixed-valence MnOx on the surface of the rGO.

Surface Design of Separators for Oil/Water Separation with High Separation Capacity and Mechanical Stability.

A convection heat treatment that can replace existing chemical oxidation methods was developed for the preparation of hierarchically oxidized Cu meshes with various surface morphologies, representing a very simple and green route that does not involve toxic chemicals. Three types of Cu meshes [bumpy-like (BL) and short and long needle-like (NL) structures] exhibited similar separation efficiencies of 95-99% over 20 separation cycles, as indicated by their similar water contact angles (WCAs; 147-150°). However, these Cu meshes exhibited different flux behaviors. Excessively rough and excessively smooth surfaces of the Cu mesh resulted in increased resistance to flow and to a decrease of the penetration of oil. A surface with intermediate smoothness, such as the BL-Cu mesh, was necessary for high flux over a broad range of oil viscosities. Furthermore, a less rough surface was more suitable for the separation of highly viscous oil. Computational fluid dynamics (CFD) simulations were carried out to support our experimental results. The BL-Cu meshes also showed outstanding mechanical stability because of their low resistance to the flow of fluids.

Simultaneous Nitrogen Doping and Pore Generation in Thermo-Insulating Graphene Films via Colloidal Templating.

We report a simple method for preparing highly efficient thermoelectric materials through the fabrication of nitrogen-doped reduced graphene oxide (GO) with a porous structure. The samples were produced by thermal annealing of GO/nitrogen-rich polystyrene (N-PS) particle composite films using a colloidal templating method. N-PS particles served as a nitrogen dopant source for the nitrogen-doped thermally reduced graphene oxide (TrGO) as well as sacrificial particles for the porous structure. The S values of the porous TrGO films were negative, indicating that the samples were transformed into n-type materials. Their porous structures simultaneously resulted in materials with high σ values and low in-plane κ values by providing numerous air cavities for phonon scattering and destruction of the anisotropic structure, maintaining an interconnected structure for an electron transport path. Thus, the porous TrGO films exhibited enhanced power factors and low κ values. The highest ZT value of 1.39 × 10-4 was attained for a porous TrGO film annealed at 1100 °C, which was 1200 times higher than that of a nonporous TrGO film. This study emphasizes that an isotropic orientation of two-dimensional materials has a significant effect on the suppression of in-plane κ, leading to their enhanced thermoelectric performance.

Analgesic efficacy of ropivacaine wound infusion after laparoscopic colorectal surgery.

PURPOSE: Local anesthetic wound infusion has been previously investigated in postoperative pain management. However, a limited number of studies have evaluated its use in laparoscopic colorectal surgery. This study aims to evaluate whether ropivacaine wound infusion is effective for postoperative pain management after laparoscopic surgery in patients with colorectal cancer. METHODS: This prospective study included 184 patients who underwent laparoscopic surgery for colorectal cancer between July 2012 and June 2013. The patients were grouped as the combined group (intravenous patient-controlled analgesia [IV-PCA] plus continuous wound infusion with ropivacaine, n = 92) and the PCA group (IV-PCA only, n = 92). Efficacy and safety were assessed in terms of numeric rating scale (NRS) pain score, opioid consumption, postoperative recovery, and complications. RESULTS: The total quantity of PCA fentanyl was significantly less in the combined group than in the PCA group (P < 0.001). The NRS score of the combined group was not higher than in the PCA group, despite less opioid consumption. There were no differences between groups for postoperative recovery and most complications, including wound complications. However, the rate of nausea and vomiting was significantly lower in the combined group (P = 0.022). CONCLUSION: Ropivacaine wound infusion significantly reduced postoperative opioid requirements and the rate of nausea/vomiting. This study showed clinical efficacy of ropivacaine wound infusion for postoperative pain control in colorectal cancer patients undergoing laparoscopic surgery.

A remote-controlled generation of gold@polydopamine (core@shell) nanoparticles via physical-chemical stimuli of polydopamine/gold composites.

We present the synthesis of polydopamine particle-gold composites (PdopP-Au) and unique release of Au@Pdop core@shell nanoparticles (NPs) from the PdopP-Au upon external stimuli. The PdopP-Au was prepared by controlled synthesis of AuNPs on the Pdop particles. Upon near infrared (NIR) irradiation or NaBH4 treatment on the PdopP-Au, the synthesized AuNPs within the PdopPs could be burst-released as a form of Au@Pdop NPs. The PdopP-Au composite showed outstanding photothermal conversion ability under NIR irradiation due to the ultrahigh loading of the AuNPs within the PdopPs, leading to a remote-controlled explosion of the PdopP-Au and rapid formation of numerous Au@Pdop NPs. The release of the Au@Pdop NPs could be instantly stopped or re-started by off or reboot of NIR, respectively. The structure of the released Au@Pdop NPs is suitable for a catalyst or adsorbent, thus we demonstrated that the PdopP-Au composite exhibited excellent and sustained performances for environmental remediation due to its capability of the continuous production of fresh catalysts or adsorbents during the reuse.

Hierarchical porous carbon by ultrasonic spray pyrolysis yields stable cycling in lithium-sulfur battery.

Utilizing the unparalleled theoretical capacity of sulfur reaching 1675 mAh/g, lithium-sulfur (Li-S) batteries have been counted as promising enablers of future lithium ion battery (LIB) applications requiring high energy densities. Nevertheless, most sulfur electrodes suffer from insufficient cycle lives originating from dissolution of lithium polysulfides. As a fundamental solution to this chronic shortcoming, herein, we introduce a hierarchical porous carbon structure in which meso- and macropores are surrounded by outer micropores. Sulfur was infiltrated mainly into the inner meso- and macropores, while the outer micropores remained empty, thus serving as a "barricade" against outward dissolution of long-chain lithium polysulfides. On the basis of this systematic design, the sulfur electrode delivered 1412 mAh/g sulfur with excellent capacity retention of 77% after 500 cycles. Also, a control study suggests that even when sulfur is loaded into the outer micropores, the robust cycling performance is preserved by engaging small sulfur crystal structures (S2-4). Furthermore, the hierarchical porous carbon was produced in ultrahigh speed by scalable spray pyrolysis. Each porous carbon particle was synthesized through 5 s of carrier gas flow in a reaction tube.

Investigation of clinical manifestations in korean colorectal cancer patients.

PURPOSE: Early diagnostic work-up in patients with clinical symptoms of colorectal cancer (CRC) is important to achieve good treatment results. In this study, we investigated clinical symptoms when a diagnosis of CRC was made in patients who had a surgical resection, especially focusing on the relevance of constipation to CRC. METHODS: The clinical symptoms of 17,415 CRC patients who had curative surgery from January 2010 to December 2012 were collected from 24 training hospitals of surgery. RESULTS: The number of symptomatic patients before the diagnosis of CRC was 11,085 (63.7%). Hematochezia or melena, abdominal pain, anemia, and constipation were more often found in female than male patients while bowel habit change was more common in male patients. Considering age, bowel habit change and hematochezia or melena were more common in patients younger than 60. Anemia and constipation, however, were more common in patients older than 60. According to the group classification based on age, patients older than 60 had experienced more constipation (P = 0.049). Moreover, patients with constipation tended to have a more advanced disease status (P < 0.001). CONCLUSION: In patients who had surgery due to CRC, bleeding, abdominal pain, bowel habit change and constipation were the most frequent symptoms before diagnosis. Although whether or not constipation is a cause of CRC is unclear, it is one of the important clinical symptoms that presents in patients with CRC, and patients with a symptom of constipation tend to present with a more advanced CRC stage.

Defect healing of reduced graphene oxide via intramolecular cross-dehydrogenative coupling.

A chemical defect healing of reduced graphene oxide (RGO) was carried out via intramolecular cross-dehydrogenative coupling (ICDC) with FeCl3 at room temperature. The Raman intensity ratio of the G-band to the D-band, the IG/ID ratio, of the RGO was increased from 0.77 to 1.64 after the ICDC reaction. From XPS measurements, the AC=C/AC-C ratio, where the peak intensities from the C=C and C-C bonds are abbreviated as AC=C and AC-C, of the RGO was increased from 2.88 to 3.79. These results demonstrate that the relative amount of sp(2)-hybridized carbon atoms is increased by the ICDC reaction. It is of great interest that after the ICDC reaction the electrical conductivity of the RGO was improved to 71 S cm(-1), which is 14 times higher than that of as-prepared RGO (5 S cm(-1)).

Graphene-based multifunctional iron oxide nanosheets with tunable properties.

We report the synthesis of graphenes with tunable properties due to the growth of needlelike iron oxide (IO) nanoparticles on their surfaces. The electrical conductivity, flexibility, and magnetic properties of graphene nanosheets (GNSs) could be tuned on demand by fine controlling both the surface coverage and the length of the IO nanoneedles. The degree of coverage of the IO nanoparticles on the surface of the GNSs made it possible to control the resulting properties of the IO/GNSs on demand. As examples of their utility, paperlike materials were generated by simple filtration, and the resulting IO/GNS nanocomposites showed extraordinary removal capacity and fast adsorption rates for As(V) and Cr(VI) ions in water. Another possible application is the preparation of multifunctional films equipped with conductivity, flexibility, and magnetic properties. The fabrication process is easy to scale up at a low cost. In addition, both the colloidal solution and film forms of the resulting IO/GNSs were effective for removal of heavy metal ions, meaning this material could be utilized for actual industrial applications.

Synthesis of nano-sized biphasic calcium phosphate ceramics with spherical shape by flame spray pyrolysis.

Nanometer size biphasic calcium phosphate (BCP) powders with various Ca/P molar ratios satisfied with appropriate phase ratios of HA/beta-TCP were prepared by high temperature flame spray pyrolysis process. The BCP powders had spherical shapes and narrow size distributions irrespective of the ratios of Ca/P. The mean size of the BCP powders measured from the TEM image was 38 nm. The composition ratio of Ca/P was controlled from 1.500 to 1.723 in the spray solution, and required phase ratios of HA/TCP are controlled systematically. The calcium dissolution of the pellets obtained from the BCP powders directly prepared by flame spray pyrolysis in buffer solution increased with the decrease of Ca/P ratios except with the Ca/P ratio of 1.713. The pellet surface with Ca/P ratio of 1.500, which consisted of beta-TCP, was eroded dramatically for 7 days. On the other hand, the pellet surface with Ca/P ratio of 1.667 was stable and did not disintegrate after immersion in Tris-HCl buffer solution based on the SEM observation.

Facile fabrication of core-in-shell particles by the slow removal of the core and its use in the encapsulation of metal nanoparticles.

Core-in-shell particles with controllable core size have been fabricated from core-shell particles by means of the controlled core-dissolution method. These cores in inorganic shells were employed as scaffolds for the synthesis of metal nanoparticles. After dissolution of the cores, metal nanoparticles embedded in cores were encapsulated into the interior of shell, without any damage or change. This article describes a very simple method for deriving core-in-shell particles with controllable core size and encapsulation of nanoparticles into the interior of shell.