Cellulose nanocrystals as support nanomaterials for dual droplet-based freeform 3D printing.

The selection of sacrificial support materials is important in the fabrication of complex freeform structures. In this study, a dual droplet-based, freeform 3D printing method for pseudoplastic alginate biomaterial inks was developed using Bingham plastic cellulose nanocrystals (CNCs) as support nanomaterials. CNCs-CaCl2 mixture compositions and alginate concentrations were varied to enhance printability with rheological properties of shape fidelity and structural stability. The mixtures supported the shape of alginate and allowed CaCl2 diffusion-based cross-linking during 3D printing. The hydrogels showed rheological and physicochemical properties similar to those of pure alginate hydrogel, as CNCs were removed during post-printing processing. BSA-loaded multi-layered spheres, freeform 3D-printed for oral protein drug delivery, protected BSA in the gastric environment and provided controlled and sustained release of BSA into the intestinal environment as layer width and alginate concentration increased. This method can facilitate freeform 3D printing of diverse pseudoplastic biomaterial inks for biomedical applications.

Characteristics of High Content Steel Briquettes Using Nanosized Solid Binders.

In this study, we investigated the characteristics of high-content steel briquettes produced using various nanoscale solid binders and steel byproducts (SS, SCS, SLD, and BSD). The average particle size was 0.171 nm for S5, 0.065 nm for S1, 0.058 nm for S4, and 0.040 nm for S2 and S3. The SEM-EDS analysis of the solid power binder resulted in mostly rectangular images. The compressive strength of the high-content steel briquettes was 120 kgf/cm², with the highest HSL1 using S4 binders. The compressive strength of the high-content steel briquettes was in the order of HSS4 > HSS1 > HSS3 > HSS5 > HSS2.

Oxidation of Acetaldehyde Over Cobalt Supported on Nanosized Carbon Black Catalysts.

In this study, we investigated the oxidation of acetaldehyde over Co/carbon black catalysts. All experiments were conducted in the temperature range of 200-440 °C, at an acetaldehyde concentration of 0.94 mol% in air, and using Co loading amounts in the range of 2-60 wt%. The nanosized carbon black and Co/carbon black catalysts were characterized using thermogravimetric analysis (TGA) and X-ray diffraction (XRD) analysis. The TGA data revealed that the nanosized carbon black was stable at high temperatures (600 °C), and the XRD results indicated that Co/carbon black was deteriorated and Co oxides, such as Co3O4, were formed. The addition of Co3O4 crystallites on the catalyst surface provided the greatest increase in catalytic activity. The catalytic activity of the supports used in this study for the acetaldehyde oxidation reaction increased as follows: SiO2 < TiO2 < carbon black < SiO2-Al2O3. The experimental results and economic considerations revealed that nanosized carbon black could be effectively used as catalyst support for the oxidation of acetaldehyde. The activity of the Co/carbon black catalysts varied with the Co loading amount, and the optimum Co loading amount was 10 wt%.

Effect of Cobalt Oxides on the Catalytic Combustion of Odor.

The catalytic combustion of acetaldehyde was studied using various types of Co oxides and Co-PC. The Co oxides and Co-PC were characterized using an X-ray diffractometer (XRD), X-ray photo-electron spectroscopy (XPS), and a particle sizing analyzer. The Co-PC and CoO were converted into Co3O4 under an air atmosphere at 450 °C, and the results were confirmed using the XRD and XPS. According to the pretreatment of the Co-PC and Co oxides, the conversion of acetaldehyde increased. The order of particle size for both fresh and pretreated samples is summarized as follows: CoO < Co-PC < Co3O4 powder < Co3O4 (99.995%). For all samples, acetaldehyde was not observed at temperatures above 320 °C owing to complete combustion. The conversion of acetaldehyde in the samples was affected by the fresh state of the Co oxides and the space velocity. The catalytic activity depended on the chemical state of the Co oxides and the surface concentrations of Co, O, and N.

Reduction of Fluoride in Water Phase by Micro-Nano Bubble Pretreatment Process.

Fluoride is important to aquatic environment and health aspects, and the optimal fluoride concentration in water is below 1 mg/L. In this study, the micro-nano bubble pretreatment was applied to remove fluoride ions in the water phase. The pH control by calcium hydroxide (Ca(OH)2), and coagulation processes with poly aluminum chloride (PAC), aluminum sulfate (Alum), F900 and two kinds of polymer named as A-polymer and A430P polymer were applied for the pretreated wastewater. In results, the combination of PAC and A430P polymer with micro-nano bubble pretreated wastewater showed a higher fluoride removal than the case of other combinations. In chemical oxygen demand (COD) removal, the combination of Alum and A430P polymer with micro-nano bubble pretreated wastewater showed the best removal efficiency (64.6%) while the COD removal without pretreatment was 71.4% for fluoride and 57.2% for COD.

Nano-Sized Fume Biogas Production from Food Waster Using Semi-Continuous Anaerobic Digester.

In this study, the nano-sized fume biogas production from food waste was investigated using lab scale semi-continuous stirred tank reactor (SCSTR) at 35 °C with 30d HRT and 30L working volume. The mesophilic digestion test was performed with three different feed materials (food waste) and food to microorganism (F/M) ratios (0.13, 0.34, and 0.27) in the same experiment. The results showed that the F/M ratios significantly affected the biogas production rate. The highest production rate was obtained at F/M ratio of 0.13. Nano-sized fume biogas produced in anaerobic digestion consists of 68.7% CH4, 31.2% CO2 and 30~200 nm particle. The average nano-sized fume biogas and methane production of digester were 29.96 L/Kg versus day-1 and 20.58 L/Kg versus day-1, respectively. The CH4 could be calculated as the heat energy 1.85 Kcal/Kg VS day-1. The digestion was operated without addition of chemicals or nutrients into the system.

Environmental Applications of Nano-Sized Recycled Aggregates: The Effect of Sterilization and Adsorption.

To evaluate the sterilize efficiency of nano-sized recycled aggregates (RAs), several types of RAs were examined for the purpose of environmental stamping out procedure. The poultry (e.g., chicken) was selected as a target livestock of epidemic disease, and the blast furnace slag (BFS), fly ash (FA), slaked lime (SL), nano-cerium (n-Ce) and shell (Sh) were used as the RAs materials. The fermented solution of effective microorganisms (EM) was added to decompose the target livestock. Various kinds of lab-scale reactor were operated to examine the effects of RAs volume; high and low volume of RAs (e.g., 1.89 w/v% and 1.14 w/v% of RA in solution, respectively), and the effects of EM concentration (e.g., concentrated solution (100%) and diluted solution (12.5%)) with tested in different reaction time. The number of microorganisms after batch tests was counted for the sterilized effects of RAs, and organic matters (e.g., chemical oxygen demand (COD)) and inorganic matters (e.g., suspended solids (SS), heavy metals and potential ions) were analyzed before and after adsorption process. The cases of SL and n-Ce showed high removal of microorganism in the batch of high concentrated EM for 20 days. However the other RA materials were less effective on the sterilization especially in lower volume of RAs. In diluted EM (e.g., 12.5%) tests, most RAs have high sterilization efficiencies in the short periods of batch reaction regardless of RAs types, and it was more effective with longer reaction time. The BFS and n-Ce exhibited higher surface area than others and they adsorbed highly heavy metals in water. The results suggested that the concentration of target organism was the most important to determine sterilization and adsorption properties of RAs.

The Effects of Pore Volume and Compressive Strength on the Nano-Sized Recycling Material Mixtures.

In this study, the effect on pore volume and compressive strength was investigated using nano-sized blast furnace slag (BFS), fly ash (FA), and desulfurized gypsum (DG). In the chemical compositions of BFS and FA, the sum of the four ingredients, CaO, SiO2, A12O3, and MgO were shown to account for 97% and 87%, respectively. Particles smaller than 50 nm were shown to be distributed in the range of 47.9% to 50.7%, particles larger than 50 nm but smaller than 100 nm were distributed in the range of 19.0% to 29.1%, and particles sized 100 nm or larger were shown to be distributed in the range of 21.3% to 23.2%. As a result of analysis carried out using an scanning electron microscope (SEM), it was found that BFS, FA, and DS are mixtures of smooth spherical particles and unevenly shaped materials. As to the dependence of pore volume, which depends on pore size and compressive strength, the volume of pores of sizes between 3 and 10 nm showed a proportional trend where volume increases and, as a result, compressive strength also increases as the material age increases. Moreover, the volume of pores sized between 10 and 100 nm showed an inversely proportional trend where volume decreases and, as a result, compressive strength also decreases as the material age increases.

Adsorption of Magnesium Sulfate from Desulfurization Industrial Wastewater by Nano-Cerium Loaded Recycled Aggregates.

In this research, the recycled aggregates (RAs) from blast furnace were solidified with nano-cerium (Ce), and applied to reduce the ionic species (e.g., magnesium sulfate) in the desulfurization industrial wastewater. Static batch experiments were performed based on different loading of recycled aggregates. Sulfate sorption isotherm studies were performed by Langmuir adsorption model. The physical morphologies were determined using scanning electron microscope. The results presented that the partial ions were captured with the different loading of the recycled aggregates during the batch tests. It was observed that 8 hr batch reaction equilibrated the electrical conductivity reduction, and 13% mass loading was estimated an optimal dosage of adsorbent. This study showed the nano-Ce loaded RAs could reduce ionic species in wastewater, and expected to be an economical adsorbent for wastewater treatment process.

Brazilein Suppresses Inflammation through Inactivation of IRAK4-NF-κB Pathway in LPS-Induced Raw264.7 Macrophage Cells.

The medicinal herbal plant has been commonly used for prevention and intervention of disease and health promotions worldwide. Brazilein is a bioactive compound extracted from Caesalpinia sappan Linn. Several studies have showed that brazilein exhibited the immune suppressive effect and anti-oxidative function. However, the molecular targets of brazilein for inflammation prevention have remained elusive. Here, we investigated the mechanism underlying the inhibitory effect of brazilein on LPS-induced inflammatory response in Raw264.7 macrophage cells. We demonstrated that brazilein decreased the expression of IRAK4 protein led to the suppression of MAPK signaling and IKKß, and subsequent inactivation of NF-κB and COX2 thus promoting the expression of the downstream target pro-inflammatory cytokines such as IL-1ß, MCP-1, MIP-2, and IL-6 in LPS-induced Raw264.7 macrophage cells. Moreover, we observed that brazilein reduced the production of nitrite compared to the control in LPS-induced Raw264.7. Thus, we suggest that brazilein might be a useful bioactive compound for the prevention of IRAK-NF-κB pathway associated chronic diseases.

Impact of Nano-Pore Structure in Harden Non-Sintering Cement.

This study investigates the nano pore structure of non-sintering cement (NSC) matrix. The result of pore structure properties showed no considerable difference in the total pore volume, but presented a large distinction in distribution of pore diameter by cement mixing ratio. The pore-diameter of NSC paste shows that occupation ratio of pore diameter below 10 nm was larger and was smaller than ordinary Portland cement (OPC) and blast-furnace slag cement (BSC) at pore diameter of over 10 nm. The reasons are due to the hydrate such as C-S-H gel and ettringite which formed dense nano pore structure of NSC matrix.

Clinicopathological characteristics of colon cancer diagnosed at primary health care institutions.

BACKGROUND/AIMS: The purpose of this study was to evaluate the clinicopathologic characteristics of colon cancers detected at the SOK Sokpeynhan Internal Medical Network, a nationwide system of primary health care institutions. METHODS: We analyzed 579 colon cancer patients diagnosed using colonoscopy at the SOK network from January 2011 through December 2012. Cancers from the rectum to the splenic flexure were classified as left colon cancer. Patients over 65 were classified as senior. RESULTS: The mean age (±SD) of subjects was 60.9±10.5 years and 61.1% were men. More than one quarter (28.2%) of patients were asymptomatic. The prevalence of left colon cancer was higher (77.9%) than that for right colon cancer. The most frequent macroscopic and histologic types were depressed (58.9%) and moderately differentiated adenocarcinoma (52.2%), respectively. Asymptomatic subjects displayed protruding or well differentiated adenocarcinoma, while symptomatic patients were more likely to display depressed or moderately differentiated adenocarcinoma (P<0.05). The mean age of the right colon cancer group was higher than that for the left colon cancer group (P<0.05). Among symptomatic patients, the most frequent symptoms were bloody stool for patients with left colon cancer and abdominal discomfort for patients with right colon cancer (P<0.05). The prevalence of depressed cancer was higher in older subjects as compared to younger subjects (P<0.05). The prevalence of right colon cancer tended to increase with age, although this difference did not achieve statistical significance (P>0.05). CONCLUSIONS: Study results indicated an increase of colon cancer amongst younger demographics in recent years. The effectiveness of colonoscopy screening was also evident, as asymptomatic patients demonstrated frequent findings of well differentiated adenocarcinomas. Study results also suggested a need for closer examination of older patients, as right colon cancer tended to increase with age.

[Clinicopathologic characteristics of superficial gastric cancer diagnosed at primary health care institutions in 2011].

BACKGROUND/AIMS: Stomach cancer is prevalent in Korea. The purpose of this study was to evaluate the characteristics of superficial gastric cancers detected at SOK Sokpeynhan Internal Medical Network, the nationwide primary health care institutions. METHODS: We prospectively analysed the clinicopathologic and endoscopic characteristics of 218 superficial gastric cancer patients diagnosed using gastric endoscopy at SOK network from January 2011 through December 2011. RESULTS: The mean age was 58.5 years old and male to female ratio was 1.7 : 1. Asymptomatic patients were most common (45.0%). The macroscopic classification revealed that simple types (63.8%) were more common than complex types (36.2%). The most common type was IIc (28.4%) and other types were as follows; IIb (16.1%), IIb+IIc (13.3%), IIa (10.6%), III (9.2%), IIa+IIc (7.3%), IIc+IIa (6.0%), IIc+IIb (5.0%). The most commonly involved sites were the body (53.1%) and greater curvature (32.6%) of the stomach. The size of lesion was less than 1 cm (69.3%) and less than 5 mm (33.5%) in diameter. The most common pathologic type was tubular adenocarcinoma (75.7%). Helicobacter pylori infection rate was 50.2%. Fifty five percent of the cases were diagnosed via endoscopy of National Health Insurance Corporation screenings. CONCLUSIONS: Superficial gastric cancers in 2011 at primary health care SOK network were different from those of previous reports. Type IIc was most common but type IIb was more prevalent and the body and greater curvature of the stomach were the most commonly involved sites. Therefore, careful observation of the proximal gastric mucosa and mucosal color change is needed.