34 research outputs found
Measurement of 3D-Shape Preferred Orientation (SPO) Using Synchrotron μ-CT: Applications for Estimation of Fault Motion Sense in a Fault Gouge
We propose a 3D-shape preferred orientation (SPO) measurement method of rigid grains using synchrotron micro-computational tomography (μ-CT). The method includes oriented sampling, 3D μ-CT imaging, image filtering, ellipsoid fitting, and SPO measurement. After CT imaging, all processes are computerized, and the directions of thousands of rigid grains in 3D-space can be automatically measured. This method is optimized for estimating the orientation of the silt-sized rigid grains in fault gouge, which indicates P-shear direction in a fault system. This allows us to successfully deduce fault motion sense and quantify fault movement. Because this method requires a small amount of sample, it can be applied as an alternative to study fault systems, where the shear sense indicators are not distinct in the outcrop and the fault gouge is poorly developed. We applied the newly developed 3D-SPO method for a fault system in the Yangsan fault, one of the major faults in the southeastern Korean Peninsula, and observed the P-shear direction successfully
A Novel Mechanism for Chemical Sensing Based on Solvent-Fluorophore-Substrate Interaction: Highly Selective Alcohol and Water Sensor with Large Fluorescence Signal Contrast
Differentiation of solvents having similar physicochemical properties, such as ethanol and methanol, is an important issue of interest. However, without performing chemical analyses, discrimination between methanol and ethanol is highly challenging due to their similarity in chemical structure as well as properties. Here, we present a novel type of alcohol and water sensor based on the subtle differences in interaction among solvent analytes, fluorescent organic molecules, and a mesoporous silica gel substrate. A gradual change in the chemical structure of the fluorescent diketopyrrolopyrrole (DPP) derivatives alters their interaction with the substrate and solvent analyte, which creates a distinct intermolecular aggregation of the DPP derivatives on the silica gel substrate depending on the solvent environment and produces a change in the fluorescence color and intensity as a sensory signal. The devised sensor device, which is fabricated with simple drop-casting of the DPP derivative solutions onto a silica gel substrate, exhibited a completely reversible fluorescence signal change with large fluorescence signal contrast, which allows selective solvent detection by simple optical observation with the naked eye under UV light. Superior selectivity of the alcohol and water sensor system, which can clearly distinguish among ethanol, methanol, ethylene glycol, and water, is demonstrated.clos
Factors to consider during anesthesia in patients undergoing preemptive kidney transplantation: a propensity-score matched analysis
Abstract Background International guidelines have recommended preemptive kidney transplantation (KT) as the preferred approach, advocating for transplantation before the initiation of dialysis. This approach is advantageous for graft and patient survival by avoiding dialysis-related complications. However, recipients of preemptive KT may undergo anesthesia without the opportunity to optimize volume status or correct metabolic disturbances associated with end-stage renal disease. In these regard, we aimed to investigate the anesthetic events that occur more frequently during preemptive KT compared to nonpreemptive KT. Methods This is a single-center retrospective study. Of the 672 patients who underwent Living donor KT (LDKT), 388 of 519 who underwent nonpreemptive KT were matched with 153 of 153 who underwent preemptive KT using propensity score based on preoperative covariates. The primary outcome was intraoperative hypotension defined as area under the threshold (AUT), with a threshold set at a mean arterial blood pressure below 70 mmHg. The secondary outcomes were intraoperative metabolic acidosis estimated by base excess and serum bicarbonate, electrolyte imbalance, the use of inotropes or vasopressors, intraoperative transfusion, immediate graft function evaluated by the nadir creatinine, and re-operation due to bleeding. Results After propensity score matching, we analyzed 388 and 153 patients in non-preemptive and preemptive groups. The multivariable analysis revealed the AUT of the preemptive group to be significantly greater than that of the nonpreemptive group (mean ± standard deviation, 29.7 ± 61.5 and 14.5 ± 37.7, respectively, P = 0.007). Metabolic acidosis was more severe in the preemptive group compared to the nonpreemptive group. The differences in the nadir creatinine value and times to nadir creatinine were statistically significant, but clinically insignificant. Conclusion Intraoperative hypotension and metabolic acidosis occurred more frequently in the preemptive group during LDKT. These findings highlight the need for anesthesiologists to be prepared and vigilant in managing these events during surgery
Humidifier Disinfectant Consumption and Humidifier Disinfectant-Associated Lung Injury in South Korea: A Nationwide Population-Based Study
Humidifier disinfectant (HD) is a household biocidal product used in humidifier water tanks to prevent the growth of microorganisms. In 2011, a series of lung injury cases of unknown causes emerged in children and pregnant women who had used HD in Korea. This study investigated changes in the nationwide number of cases of humidifier disinfectant-associated lung injury (HDLI) in concordance with nationwide HD consumption using data covering the entire Korean population. More than 25 kinds of HD products were sold between 1994 and 2011. The number of diagnosed HDLI, assessed by S27.3 (other injuries of lungs) of the Korea National Health Insurance Service (NHIS) data, sharply increased by 2005, subsequently decreased after 2005, and almost disappeared after 2011 in concordance with the annual number of HD sales. The number of self-reported HDLIs, assessed using data from all suspected HDLI cases registered in the Korea Ministry of Environment, changed with the annual number of HD sales, with a delay pattern, potentially induced by the late awareness of lung injury diseases. The present study suggests that changes in the nationwide annual consumption of HD products were consistent with changes in the annual number of HDLI cases in Korea
Polyaniline Nanocoating on the Surface of Layered Li[Li0.2Co0.1Mn0.7]O-2 Nanodisks and Enhanced Cyclability as a Cathode Electrode for Rechargeable Lithium-Ion Battery
The surfaces of layer-structured Li[Li0.2Co0.1Mn0.7]O-2 nanodisks were nanocoated with polyaniline and examined by SEM and TEM studies, via the chemical oxidative polymerization of aniline in an acid medium for 10 min-Mn4+ ions in the pristine lithium manganese oxides acted as oxidants. During this reaction, the crystal structure of the pristine nanodisks was retained, and the XRD patterns showed no evidence of H+ exchange with the Li+ located between the manganese oxide layers. The nanocoated polyaniline was in the low molecular weight of base states, and the majority (similar to 70%) was complexed with Li[Li0.2Co0.1Mn0.7]O-2 nanodisks, as shown by UV-vis and FT-IR spectroscopic analysis. By application of nanocoated polyaniline nanodisks as the cathode material, the discharge capacity was improved by about 15%. Furthermore. the cyclability was enhanced with almost no change in discharge capacity being detected at extended cycle numbers, while that of pristine nanodisks showed a tendency to continually decrease as the number of cycles increased. Results from the present Study Suggest that a well-controlled polyaniline nanocoating, particularly formed with the aid of pristine metal oxides as oxidants for polymerization, call act as a potential buffer layer between electrodes and electrolytes, which makes this a promising method for the reducing/protection of Continuous Structural distortion that Occurs during extended charge-discharge cycling.close1
Recipient efficacy and safety of kidney transplantation from older living donor: consideration for using older kidney as a solution to the shortage of organs
Background : As a solution to organ shortages, studies on kidney transplantation (KT) from older donors are being conducted. However, many controversies remain about its safety and efficacy. Methods : In Samsung Medical Center, from January 2000 to May 2015, 1,141 patients underwent living KT. Cases of retransplantation, recipient and donor aged younger than 18 years, and multiorgan transplantation were excluded, and a total of 859 cases were selected. Analysis was performed by dividing the patents into two groups: a younger donor group (donors <60 years old; n=826) and an older donor group (donors ≥60 years old; n=33). Results : There were no significant differences between the two groups in patient death (log-rank P=0.173) or in postoperative complications. The older donor group had a higher acute rejection (P=0.034; hazard ratio [HR], 1.704) and graft failure rate (P=0.029, HR=2.352). There was no significant difference in the trend of estimated glomerular filtration rate over time (P=0.189). Conclusions: KT using kidneys from old-aged donors is safe, but there is room for improvement due to problems with higher acute rejection and graft failure rate
Two-Week Protocol Biopsy in Renal Allograft: Feasibility, Safety, and Outcomes
Background: Protocol biopsy in renal allograft helps to early detect subclinical rejection (SCR) in patients who have no abnormal clinical and laboratory findings. Still, there are rare reports about the techniques and outcomes of two-week protocol biopsy. The aim of this study was to assess two-week protocol biopsy regarding the technical feasibility, procedure safety, and clinical outcomes. Methods: A total of 894 protocol biopsies were performed in adult recipients between 2012 and 2019. Two-week and one-year protocol biopsies were guided with ultrasound in 842 and 399 patients by one of four radiologists with wide range of biopsy experience, respectively. These protocol biopsies were compared in terms of feasibility and safety. Standard references were clinico-laboratory findings and biopsy examinations. Results: The median period of two-week and one-year protocol biopsies were 12 days (10–20 days) and 383 days (302–420 days), respectively. All protocol biopsies were technically successful and there was no difference between radiologists regarding technical success and complications (p = 0.453). Major complication (Clavien–Dindo grading II–IV) rates of two-week and one-year protocol biopsies were 0.3% (3/842) and 0.2% (1/399), respectively (p = 1.000). However, univariate analysis demonstrated that platelet count p 0.001). Conclusion: Two-week protocol biopsy is technically feasible and safe. It contributes to early detecting a substantial number of SCRs. Prior to the biopsy, platelet count and blood urea nitrogen should be carefully checked to predict major complications
Switching to Hidden Metallic Crystal Phase in Phase-Change Materials by Photoenhanced Metavalent Bonding
Copyright © 2022 American Chemical Society©. Metavalent bonding is crucial for the determination of phase transition and improvement of device performance in phase-change materials, which are attracting interest for use in memory devices. Although monitoring dielectric and phononic parameters provides a direct measure of the metavalent bonding, the control of phase-change phenomena and metavalent bonding in the dynamical regime has yet to be demonstrated. This study reports the photoenhanced metavalent bonding and resulting hidden metallic crystalline state of Ti-doped Sb2Te3, a representative phase-change material with ultralong sustainability. Using ultrafast terahertz spectroscopy, Ti0.4Sb2Te3 was discovered to possess ultralong pump-probe dynamics, which is retained over hundreds of picoseconds, unlike the short-lived state of undoped Sb2Te3. Moreover, for Ti0.4Sb2Te3 during the long-lived transmission change, the infrared-active phonon is highly softened, even more than the amount of a thermal phonon shift, indicating the photoenhancement of lattice anharmonicity. Such a long-lived relaxation implies photoinduced transition into a crystalline state of ultrastrong metavalent bonding in Ti0.4Sb2Te3, on the basis of comparisons of the dynamical dielectric constant and temporal phonon shift. Our results show the realization of photoengineering of phase-change materials by tuning electron sharing or transferring.11Nsciescopu
Table1_Long-term outcomes of liver transplantation for biliary atresia and results of policy changes: over 20 years of follow-up experience.docx
ObjectiveBiliary atresia (BA) patients develop chronic liver disease after the Kasai operation and are eventually indicated for liver transplantation (LT). The purposes of this study were to analyze long-term outcomes after LT and risk factors that affect complications to reduce graft failure.Study designOverall, 145 pediatric patients who underwent LT between June 1996 and June 2020 after a diagnosis of BA were included. We performed a retrospective analysis of medical records and evaluated patient and graft survival, cumulative incidence of complications, risk factors, and the results of policy changes.ResultsPatient and graft survival rates in over 20 years were 95.8% and 91.0%, respectively. Post-transplantation lymphoproliferative disease was frequently observed in the early period of immunosuppression within the first 1–2 years after LT. The incidence of cholangitis and rejection steadily increased over time. Weight-to-portal vein size was evaluated as a risk factor for cholangitis and bile duct strictures (OR = 12.82, p = 0.006 and OR = 16.54, p = 0.015, respectively). When evaluated using 2013 as a reference point, the split graft indication was expanded and the group that received LT after 2013 had a significantly lower survival over time compared with that of the group that received LT before 2013 (p = 0.006).ConclusionThis study revealed time differences in prevalence of complications. The evaluation of weight-to-duct or vessel size is a more important factor in considering complications than the graft-to-recipient weight ratio. Survival outcomes may have been altered by a policy change that affects the donor type ratio in transplantation.</p
Bead-Based Microfluidic Sediment Analogues: Fabrication and Colloid Transport
Mobile
colloids can act as carriers for low-solubility contaminants
in the environment. However, the dominant mechanism for this colloid-facilitated
transport of chemicals is unclear. Therefore, we developed a bead-based
microfluidic platform of sediment analogues and measured both single
and population transport of model colloids. The porous medium is assembled
through a bead-by-bead injection method. This approach has the versatility
to build both electrostatically homogeneous and heterogeneous media
at the pore scale. A T-junction at the exit also allowed for encapsulation
and enumeration of colloids effluent at single particle resolution
to give population dynamics. Tortuosity calculated from pore-scale
trajectory analysis and its comparison with lattice Boltzmann simulations
revealed that transport of colloids was influenced by the size exclusion
effect. The porous media packed by positively and negatively charged
beads into two layers showed distinctive colloidal particle retention
and significant remobilization and re-adsorption of particles during
water flushing. We demonstrated the potential of our method to fabricate
porous media with surface heterogeneities at the pore scale. With
both single and population dynamics measurement, our platform has
the potential to connect pore-scale and macroscale colloid transport
on a lab scale and to quantify the impact of grain surface heterogeneities
that are natural in the subsurface environment