Effects of particle size on the pretreatment efficiency and subsequent biogas potential of polylactic acid.

The fragmentation of bioplastics (BPs) before pretreatment and anaerobic digestion is conducted for higher efficiency; however, based on the literature, the size reduction varies widely. In this study, initially, various combinations of thermal-alkaline pretreatments were applied at different strengths to the polylactic acid (PLA) in three groups (<0.5, 0.5 < size < 1.0, and 1.0 < size < 2.0 mm). After pretreatment, the solubilization of PLA was increased to 11.5-40.0 % using alkaline dosage and temperature ranging from 50 to 200 g OH-/kg BP, 60-100 °C, respectively, in a 1-10 h timeframe. The results were statistically proved using a 3D response surface graph, where the pretreatment was more effective for smaller particle sizes. The reduction in particle size also increased the CH4 production, which was more pronounced at the strong pretreatment (24 % increment vs. 10-15 %). Computed results indicated 44-86 % conversion of pretreated PLA particles to CH4, supported by Fourier transform infrared spectroscopy analysis, especially focusing on the intensity of -OH bands.

Air pollution and mortality in patients with chronic obstructive pulmonary disease: a cohort study in South Korea.

Background: Evidence on whether long-term exposure to air pollution increases the mortality risk in patients with chronic obstructive pulmonary disease (COPD) is limited. Objectives: We aimed to investigate the associations of long-term exposure to particulate matter with diameter <10 µm (PM10) and nitrogen dioxide (NO2) with overall and disease-specific mortality in COPD patients. Design: We conducted a nationwide retrospective cohort study of 121,423 adults ⩾40 years diagnosed with COPD during 1 January to 31 December 2009. Methods: Exposure to PM10 and NO2 was estimated for residential location using the ordinary kriging method. We estimated the risk of overall mortality associated with 1-, 3-, and 5-years average concentrations of PM10 and NO2 using Cox proportional hazards models and disease-specific mortality using the Fine and Gray method adjusted for age, sex, income, body mass index, smoking, comorbidities, and exacerbation history. Results: The adjusted hazard ratios (HRs) for overall mortality associated with a 10 µg/m3 increase in 1-year PM10 and NO2 exposures were 1.004 [95% confidence interval (CI) = 0.985, 1.023] and 0.993 (95% CI = 0.984, 1.002), respectively. The results were similar for 3- and 5-year exposures. For a 10-µg/m3 increase in 1-year PM10 and NO2 exposures, the adjusted HRs for chronic lower airway disease mortality were 1.068 (95% CI = 1.024, 1.113) and 1.029 (95% CI = 1.009, 1.050), respectively. In stratified analyses, exposures to PM10 and NO2 were associated with overall mortality in patients who were underweight and had a history of severe exacerbation. Conclusion: In this large population-based study of patients with COPD, long-term PM10 and NO2 exposures were not associated with overall mortality but were associated with chronic lower airway disease mortality. PM10 and NO2 exposures were both associated with an increased risk of overall mortality, and with overall mortality in underweight individuals and those with a history of severe exacerbation.

Use of reverse osmosis concentrate for mitigating greenhouse gas emissions from pig slurry.

Due to the high global warming potential (GWP) in a short time scale (GWP100 = 28 vs. GWP20 = 86), mitigating CH4 emissions could have an early impact on reducing current global warming effects. The manure storage tank emits a significant amount of CH4, which can diminish the environmental benefit resulting from the anaerobic digestion of manure that can generate renewable energy. In the present study, we added the reverse osmosis concentrate (ROC) rich in salt to the pig slurry (PS) storage tank to reduce CH4 emissions. Simultaneously, pure NaCl was tested at the same concentration to compare and verify the performance of ROC addition. During 40 days of storage, 1.83 kg CH4/ton PS was emitted, which was reduced by 7-75% by the addition of ROC at 1-9 g Na+/L. This decrease was found to be more intensive than that found upon adding pure sodium, which was caused by the presence of sulfate rich in ROC, resulting in synergistic inhibition. The results of the microbial community and activity test showed that sodium directly inhibited methanogenic activity rather than acidogenic activity. In the subsequent biogas production from the stored PS, more CH4 was obtained by ROC addition due to the preservation of organic matter during storage. Overall, 51.2 kg CO2 eq./ton PS was emitted during the storage, while 8 kg CO2 eq./ton PS was reduced by biogas production in the case of control, resulting in a total of 43.2 kg CO2 eq./ton PS. This amount of greenhouse gas emissions was reduced by ROC addition at 5 g Na+/L by 22 and 65 kg CO2 eq./ton PS, considering GWP100 and GWP20 of CH4, respectively, where most of the reduction was achieved during the storage process. To the best of our knowledge, this was the first report using salty waste to reduce GHG emissions in a proper place, e.g., a manure storage tank.

Effect of Nanoparticles in LiFePO4 Cathode Material Using Organic/Inorganic Composite Solid Electrolyte for All-Solid-State Batteries.

Herein, we report the effect of using nanoparticles of LiFePO4 on the electrochemical properties of all-solid-state batteries (ASSBs) with a solid electrolyte. LiFePO4 (LFP) cathode materials are promising cathode materials in polymer-based composite solid electrolytes because of their limited electrochemical window range. However, LFP cathodes exhibit poor electric conductivity and sluggish lithium ion diffusion. In addition, there is a disadvantage in that the interfacial resistance increases due to poor contact between the LFP cathode material and the solid electrolyte when composing the composite cathode. The nano-sized LFP cathode material increases the contact area between solid electrolyte in the positive electrode and enhances lithium ion diffusion. Therefore, the structural differences and electrochemical performance of these nanoscale LFP cathode materials in the ASSB were studied by X-ray diffraction, scanning electron microscopy, and electrochemical analysis.

PM10 and PM2.5 real-time prediction models using an interpolated convolutional neural network.

In this paper, we propose a real-time prediction model that can respond to particulate matters (PM) in the air, which are an indication of poor air quality. The model applies interpolation to air quality and weather data and then uses a Convolutional Neural Network (CNN) to predict PM concentrations. The interpolation transforms the irregular spatial data into an equally spaced grid, which the model requires. This combination creates the interpolated CNN (ICNN) model that we use to predict PM10 and PM2.5 concentrations. The PM10 and PM2.5 evaluation results show an effective prediction performance with an R-squared higher than 0.97 and a root mean square error (RMSE) of approximately 16% of the standard deviation. Furthermore, both PM10 and PM2.5 prediction models forecast high concentrations with high reliability, with a probability of detection higher than 0.90 and a critical success index exceeding 0.85. The proposed ICNN prediction model achieves a high prediction performance using spatio-temporal information and presents a new direction in the prediction field.

Enhanced immobilization of Prussian blue through hydrogel formation by polymerization of acrylic acid for radioactive cesium adsorption.

In this study, a hydrogel impregnated with powder activated carbon (PAC), MAA-PAC, was synthesized through the polymerization of acrylic acid (AA) and PB was immobilized using the carboxyl group of AA. In this process, an adsorbent with an enhancement of PB content and stability of immobilization was developed through the additional supply of Fe3+ ions by the layer by layer (LBL) assembly. XRD, FT-IR, SEM (EDS), TEM (EDS, mapping), and TG analyzes of the LBL and non-LBL groups were performed to confirm the change of PB content in the adsorbent as the LBL assembly was applied. The stability of PB immobilization was confirmed during the washing process after the synthesis of the adsorbent. When the LBL assembly process was applied as a PB immobilization strategy, the PB content in the adsorbent was improved and PB leakage was not observed during the washing process. The maximum adsorption (qm) for cesium in the MAA-PAC-PB LBL group that showed high PB content was 40.03 mg/g, and the adsorption isotherm was more suitable for the Langmuir model than the Freundlich model. The LBL group showed a high removal efficiency of 99.81% and a high DF value (525.88) for radioactive cesium (120 Bq/g). These results demonstrate the potential efficiency of the MAA-PAC-PB LBL group for the decontamination of radioactive cesium-contaminated water systems. Furthermore, it was verified that the LBL group of MAA-PAC-PB could be used as an adsorbent without an additional design of the existing water treatment facility. This can an economical decontamination method for removing radioactive cesium.

Prussian blue immobilized cellulosic filter for the removal of aqueous cesium.

Cesium is a typical radioisotope that has a long half-life and is dangerous and can be emitted in the event of a nuclear accident. Prussian blue (PB), which is known to effectively adsorb cesium, is difficult to separate when it is dissolved in an aqueous system. In this study, PB was immobilized on a filter type support media, cellulose filter (CF), for use as a selective material for cesium adsorption. The commercially available CF was functionalized by the addition of acrylic acid (AA) (i.e., CF-AA) to enhance the PB immobilization, which increased both PB loading and binding strength. The AA functionalization changed the major functional groups from hydroxyl to carboxylic, as confirmed by Fourier-transform infrared spectroscopy. As a result of the surface modification, the PB immobilization increased 1.5 times and reduced detachment of PB during washing. The prepared adsorbent, CF-AA-PB, was tested for its cesium adsorption capability. Cesium adsorption equilibrated within 3 h, and the maximum cesium adsorption capacity was 16.66 mg/g. The observed decrease in the solution pH during cesium adsorption inhibited the overall cesium uptake; however, this was minimized by buffering. The prepared CF-AA-PB was used as a filter material and its potential use as a countermeasure for removing radioactive cesium from a contaminated water stream was demonstrated.

Yield and physicochemical properties of low fat tofu prepared using supercritical carbon dioxide treated soy flours with different fat levels.

The consumer demands for low fat foods are increasing to reduce obesity and chronic diseases. Low-fat tofu (LFT) was prepared using soy flours treated with supercritical CO2 (SC-CO2) at pressures of 10, 20, and 30 MPa. After SC-CO2 treatment, the residual oil contents of the soy flours were 12.07, 8.12, and 1.64%, respectively, whereas that of the control soy flour was 18.20%. The objective of this study was to investigate the yield and quality characteristics of LFTs, compared to the control tofu. All SC-CO2-treated LFTs had significantly higher protein and moisture contents than the control tofu. The yields (g/100 g soy flour) of SC-CO2-treated tofu were 442.69, 507.44, and 535.47 g, respectively, at three fat levels, whereas the yield was 385.23 g in case of the control tofu. The SC-CO2-treated LFTs had softer textural attributes due to increasing moisture contents. In addition, the LFTs obtained higher sensory scores owing to softer texture and lower beany flavor than control sample. SC-CO2-treated soy flours showed higher solubility in soy milk, leading to higher yield, produced softer texture of tofu, and increased nutritional value with low fat and high protein content.

The Development of an IMU Integrated Clothes for Postural Monitoring Using Conductive Yarn and Interconnecting Technology.

Spinal disease is a common yet important condition that occurs because of inappropriate posture. Prevention could be achieved by continuous posture monitoring, but most measurement systems cannot be used in daily life due to factors such as burdensome wires and large sensing modules. To improve upon these weaknesses, we developed comfortable "smart wear" for posture measurement using conductive yarn for circuit patterning and a flexible printed circuit board (FPCB) for interconnections. The conductive yarn was made by twisting polyester yarn and metal filaments, and the resistance per unit length was about 0.05 Ω/cm. An embroidered circuit was made using the conductive yarn, which showed increased yield strength and uniform electrical resistance per unit length. Circuit networks of sensors and FPCBs for interconnection were integrated into clothes using a computer numerical control (CNC) embroidery process. The system was calibrated and verified by comparing the values measured by the smart wear with those measured by a motion capture camera system. Six subjects performed fixed movements and free computer work, and, with this system, we were able to measure the anterior/posterior direction tilt angle with an error of less than 4°. The smart wear does not have excessive wires, and its structure will be optimized for better posture estimation in a later study.

Comparative study of the quality characteristics of defatted soy flour treated by supercritical carbon dioxide and organic solvent.

Defatted soy flour is a potential source of food protein, amino acids, ash and isoflavones. The supercritical carbon dioxide (SC-CO2) and a traditional organic solvent extraction methods were used to remove fat from soy flour, and the quality characteristics of a control soy flour (CSF), defatted soy flour by SC-CO2 (DSFSC-CO2) and defatted soy flour by an organic solvent (DSF-OS) were compared. The SC-CO2 process was carried out at a constant temperature of 45 °C, and a pressure of 40 MPa for 3 h with a CO2 flow rate of 30 g/min. The DSFSC-CO2 had significantly higher protein, ash, and amino acids content than CSF and DSF-OS. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated that CSF and DSFSC-CO2 had protein bands of similar intensity and area that indicated no denaturation of protein, whereas DSF-OS showed diffuse bands or no bands due to protein denaturation. In addition to higher nutritional value and protein contents, DSFSC-CO2 showed superior functional properties in terms of total soluble solids content, water and oil absorption, emulsifying and foaming capacity. The SC-CO2 method offers a nutritionally and environmentally friendly alternative extraction processing approach for the removal of oil from high-protein food sources. It has a great potential for producing high-protein fat-free, and low-calorie content diet than the traditional organic solvent extraction method.

Nutritional Quality and Physicochemical Characteristics of Defatted Bovine Liver Treated by Supercritical Carbon Dioxide and Organic Solvent.

Defatted bovine liver (DBL) is a potential source of protein and minerals. Supercritical carbon dioxide (SC-CO2) and a traditional organic solvent method were used to remove lipid from bovine liver, and the quality characteristics of a control bovine liver (CBL), bovine liver defatted by SC-CO2 (DBLSC-CO2) at different pressures, and bovine liver defatted by organic solvent (DBL-OS) were compared. The DBLSC-CO2 samples had significantly higher (p<0.05) protein, amino acid, carbohydrate, and fiber contents than CBL and DBL-OS. There was a higher yield of lipid from CBL when using SC-CO2 than the organic solvent method. SDS-PAGE analysis demonstrated that the CBL and DBLSC-CO2 had protein bands of a similar intensity and area, whereas DBL-OS appeared extremely poor bands or no bands due to the degradation of proteins, particularly in the 50 to 75 kDa and 20 to 25 kDa molecular weight ranges. In addition, DBLSC-CO2 was shown to have superior functional properties in terms of total soluble content, water and oil absorption, and foaming and emulsification properties. Therefore, SC-CO2 treatment offers a nutritionally and environmentally friendly approach for the removal of lipid from high protein food sources. In addition, SC-CO2 may be a better substitute of traditional organic solvent extraction for producing more stable and high quality foods with high-protein, fat-free, and low calorie contents.

An Upflow-Type Filtration Device Using Expanded Polypropylene Media (EPM) to Treat First Flush of Rainwater.

The first flush of rainwater in urban areas is highly contaminated and causes adverse effects on both the water environment and ecosystem. In this study, a novel filtration device using expanded polypropylene media (EPM) was developed for efficient control of pollutants in first flush of urban runoff. The effect of foaming ratio on EPM for filtration efficiency and clogging potential was examined under various operating conditions. Experimental results using a laboratory-scale filtration device indicated that the removal efficiencies of suspended solids were initially high (>90% removal until 60 minutes) and decreased with filtration time (60% for EPM15 at 180 minutes and less than 10% for EPM45). Similarly, more than 90% of Cr, Pb, and Zn were removed for EPM15 within 30 minutes and decreased with filtration time. The surface area and specific hydraulic resistance of EPM were sensitive to foaming ratio. Optimum conditions for foaming ratio increased pollutant removal and minimized head loss. A simple model was derived and applied for theoretical analysis of the filtration device with EPM.

Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation.

PURPOSE: We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). MATERIALS AND METHODS: The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. RESULTS: VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). CONCLUSION: It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

Separation of fine particles at different frequencies and HRTs using acoustic standing waves.

The objective of this study was to evaluate the separation of fine particles using several frequencies and hydraulic retention times (HRTs) in an acoustic standing wave reactor without any separate cooling devices. The acoustic standing wave reactor consisted of sufficient space (over 100 mm) between the transducer and reflector, resulting in a slight increase in temperature. However, the increase in temperature did not affect the formation of standing waves and particle aggregations in our experiments. The results indicated that the turbidity removal efficiencies of fine kaolin particles, when using frequencies of 580 kHz, 1, and 2 MHz, increased with longer standing wave operation time. Especially, the turbidity removal efficiencies for 1 and 2 MHz were higher than that for 580 kHz because the wavelength (λ) of the 580 kHz wave was longer than that of the 1 and 2 MHz waves. Furthermore, the turbidity removal efficiency of kaolin in a continuous reactor improved with increasing hydraulic retention times (HRTs), and the reactor was more effective with 1 and 2 MHz used in parallel instead of 1 and 2 MHz used individually under the same HRT conditions with the entrance length (EL) having no adverse effect.

Surgical outcome and cost comparison between total vaginal hysterectomy and laparoscopic hysterectomy for uteri weighing >500 g.

STUDY OBJECTIVE: To compare surgical outcomes and overall costs of less invasive methods of hysterectomy to treat benign disease including total vaginal hysterectomy (TVH) and total laparoscopic hysterectomy (TLH) in women with a uterus weighing >500 g. DESIGN: Retrospective review of medical records (Canadian Task Force classification III). SETTING: University-associated hospital. PATIENTS: One hundred three women with a uterus weighing >500 g who had undergone either total vaginal hysterectomy (TVH) (n = 52) or total laparoscopic hysterectomy (TLH) (n = 51). MEASUREMENTS AND MAIN RESULTS: Cost data were extracted from the hospital billing system. Patient characteristics, surgical outcomes, and hospital costs were compared between the 2 groups. Patient characteristics were similar in both groups except for a history of surgery (TVH 11.5%, and TLH 37.3%; p = .01). Insofar as surgical outcomes, mean (SD) operative time was shorter in the TVH group compared with the TLH group (110.00 [28.68] minutes vs 180.47 [51.32] minutes; p < .001), and hospital stay was longer (8.08 [0.68] days vs 7.45 [1.03] days; p < .001). Other surgical outcomes including estimated blood loss (p = .20) and decrease in hemoglobin (p = .12) did not differ between the 2 groups. Total hospital costs (converted from Korean won to US dollars) were significantly lower in the TVH group than in the TLH group ($2076.59 [$666.58] vs $2744.03 [$715.76]; p < .001). CONCLUSION: Our data suggest that TVH is a safe and economic procedure even in women with a uterus weighing >500 g. Skilled surgeons should preferentially consider TVH for treatment of benign uterine disease, regardless of uterine size.

Prophylactic adnexectomy along with vaginal hysterectomy for benign pathology.

OBJECTIVE: This study was designed to evaluate the safety and feasibility of prophylactic adnexectomy during vaginal hysterectomy for benign pathology. METHODS: We retrospectively reviewed medical records of all patients who underwent vaginal hysterectomy (VH) between 2008 and 2010. Clinical comparison of patients who underwent VH with adnexectomy (n = 92) and VH only (n = 686) was performed. Clinical characteristics (age, parity, body mass index, and previous pelvic surgery), surgical outcomes (uterine weight, operative time, estimated blood loss, pelvic adhesion, hemoglobin change and hospital stay) and intra- and postoperative complications (transfusion, bladder injury and fever) were evaluated. RESULTS: Clinical characteristics except for age (45.44 years for VH only vs. 47.15 years for VH with adnexectomy, P = 0.007) were not different between the two groups. Similarly, surgical outcomes and complication rates were not different between the two groups. CONCLUSION: Prophylactic bilateral adnexectomy can be performed safely during VH.

Low-temperature synthesis of LiFePO4 nanocrystals by solvothermal route.

LiFePO4 nanocrystals were synthesized at a very low temperature of 170°C using carbon nanoparticles by a solvothermal process in a polyol medium, namely diethylene glycol without any heat treatment as a post procedure. The powder X-ray diffraction pattern of the LiFePO4 was indexed well to a pure orthorhombic system of olivine structure (space group: Pnma) with no undesirable impurities. The LiFePO4 nanocrystals synthesized at low temperature exhibited mono-dispersed and carbon-mixed plate-type LiFePO4 nanoparticles with average length, width, and thickness of approximately 100 to 300 nm, 100 to 200 nm, and 50 nm, respectively. It also appeared to reveal considerably enhanced electrochemical properties when compared to those of pristine LiFePO4. These observed results clearly indicate the effect of carbon in improving the reactivity and synthesis of LiFePO4 nanoparticles at a significantly lower temperature.

When do we need to perform laparotomy for benign uterine disease? Factors involved with conversion in vaginal hysterectomy.

AIM: To identify the preoperative risk factors affecting the conversion to laparotomy during vaginal hysterectomy (VH) for benign uterine conditions. MATERIAL AND METHODS: The charts were reviewed for all patients who underwent VH between 1 January 2003 and 31 December 2008 at Hallym University Hospital, Seoul. RESULTS: The rate of conversion to laparotomy was 3.7% (32 cases). Factors that were independently associated with the risk of conversion to laparotomy were found to be low parity (conversion 1.43 vs VH 1.92, P=0.021), previous abdominal surgery (conversion 0.71 vs, VH 0.26, P=0.012), pelvic adhesion (conversion 1.25 vs VH 0.04, P=0.000), and large uterine weight (conversion 345.15g vs VH 222.38g, P=0.005). In the conversion group, the operative time was longer (conversion 144.84min vs VH 77.67min, P=0.000), and estimated blood loss was also greater (conversion 656.25mL vs VH 358.47mL, P=0.00). Postoperative hemoglobin change (conversion 1.65g/dL vs VH 1.23g/dL, P=0.046) and transfusion rate were also greater in the conversion group (conversion 0.75 vs VH 0.01, P=0.001). CONCLUSION: VH is the main procedure for benign uterine disease and is successfully performed in most cases. But several factors, including low parity, previous abdominal surgery, pelvic adhesion and large uterine weight can affect the risk of conversion to laparotomy.

Material depth reconstruction method of multi-energy X-ray images using neural network.

With the advent of technology, multi-energy X-ray imaging is promising technique that can reduce the patient's dose and provide functional imaging. Two-dimensional photon-counting detector to provide multi-energy imaging is under development. In this work, we present a material decomposition method using multi-energy images. To acquire multi-energy images, Monte Carlo simulation was performed. The X-ray spectrum was modeled and ripple effect was considered. Using the dissimilar characteristics in energy-dependent X-ray attenuation of each material, multiple energy X-ray images were decomposed into material depth images. Feedforward neural network was used to fit multi-energy images to material depth images. In order to use the neural network, step wedge phantom images were used for training neuron. Finally, neural network decomposed multi-energy X-ray images into material depth image. To demonstrate the concept of this method, we applied it to simulated images of a 3D head phantom. The results show that neural network method performed effectively material depth reconstruction.

Enhancement of bioremediation by Ralstonia sp. HM-1 in sediment polluted by Cd and Zn.

In this study, the potential for the application of the bioaugmentation to Cd and Zn contaminated sediment was investigated. A batch experiment was performed in the lake sediments augmented with Ralstonia sp. HM-1. The degradation capacity of 18.7 mg-DOC/l/day in the treatment group was bigger than that of the blank group (4.4 mg-DOC/l/day). It can be regarded as the result of the reduction of the metal concentration in the liquid phase due to adsorption into the sediments, with the increased alkalinity resulting from the reduction of sulfate by sulfate reducing bacteria (SRB). The removal efficiency of cadmium and zinc in the treatment group was both 99.7% after 35 days. Restrain of elution to water phase from sediment in the Ralstonia sp. HM-1 added treatment group was also shown. In particular, the observed reduction of the exchangeable fraction and an increase in the bound to organics or sulfide fraction in the treatment group indicate its role in the prevention of metal elution from the sediment. Therefore, for bioremediation and restrain of elution from the sediment polluted by metal, Ralstonia sp. augmentation with indigenous microorganism including SRB, sediment stabilization and restrain of elution to surface water is recommended.