7 research outputs found
Hematopoietic Stem Cell Transplantation after Posttransplant Lymphoproliferative Disorder
A 16-yr-old girl received liver transplantation for fulminant hepatitis. Aplastic anemia developed, and she received hematopoietic stem cell transplantation (HSCT). Eleven months after liver transplantation, abdominal lymph node enlargement and colon ulcers were observed, and colon biopsy showed posttransplant lymphoproliferative disorder (PTLD). Immunosuppression reduction was attempted, but it produced no therapeutic effect. Fourteen months after liver transplantation, she received a second HSCT due to engraftment failure, and PTLD resolved completely. The second HSCT can serve as cellular therapy for PTLD
A Case of Swallow Syncope Associated With Cold Beverage Ingestion
Swallow syncope (also known as deglutition syncope) is a relatively rare type of syncope that is treatable if diagnosed correctly. We report a case of a 39-year-old man with recurrent swallow syncope. The patient did not have structural heart disease. He developed a complete atrioventricular block upon drinking a cold beverage (Chilsung cider) while undergoing a repeated head-up tilt test. The patient was advised to avoid cold beverages and has been symptom free for 5 months
An adaptive hybrid filter for practical WiFi-based positioning systems
AbstractThis paper proposes an adaptive hybrid filter for WiFi-based indoor positioning systems. The hybrid filter adopts the notion of particle filters within the prediction framework of the basic Kalman filter. Restricting the predicts of a moving object to a small number of particles on a way network, and replacing the Kalman gain with a dynamic weighting scheme are the key features of the hybrid filter. The adaptive hybrid filter significantly outperformed the basic Kalman filter, and a particle filter in the performance evaluation at three test places: a Library and N5 building, KAIST, Daejeon, and an E-mart mall, Seoul
Synthesis of Hapten for Indirect Competitive Immunoassay for Measuring 3,5,6-trichloro-2-pyridinol
BACKGROUND: In this study, we have attempted to identify a urinary biomarker to assess chlorpyrifos exposure in farmers. The major metabolite and the excretion pathway of chlorpyrifos is 3,5,6-trichloro-2- pyridinol (TCP) in urine. Herein, we describe an adequate synthetic method for TCP hapten for measuring urinary TCP of farmers. METHODS AND RESULTS: First, TCP was prepared by spacer attachment through hydrolysis of thiophosphate ester from chlorpyrifos. After reaction with benzyl bromide, the TCP was transformed into 2,3,5-trichloro-6- benzyloxypyridine. Next, the chlorine in the 2nd position of the pyridyl ring was substituted into 3-mercaptopropanoic acid spacer arm. Finally, the phenyl group attached to the 6th position in pyridyl ring was removed for producing the targeted product, 3-(3,5-Dichloro-6-hydroxy-2-pyridyl) thiopropanoic acid. CONCLUSION: Henceforth, this TCP hapten would be used in developing immunoassay studies for the detection and quantitation of urinary TCP of farmers
Covalent-Frameworked 2D Crown Ether with Chemical Multifunctionality
Here,
we present the synthesis and characterization of a novel
2D crystalline framework, named C2O, which mainly consists of carbon and oxygen in a 2:1
molar ratio and features crown ether holes in its skeletal structure.
The covalent-frameworked 2D crown ether can be synthesized on a gram-scale
and exhibits fine chemical stability in various environments, including
acid, base, and different organic solvents. The C2O efficiently activates KI through
the strong coordination of K+ with crown ether holes in
a rigid framework, which enhances the nucleophilicity of I– and significantly improves its catalytic activity for CO2 fixation with epoxides. The presence of C2O with KI results in remarkable increases
in CO2 conversion from 5.7% to 99.9% and from 2.9% to 74.2%
for epichlorohydrin and allyl glycidyl ether, respectively. Moreover, C2O possesses both electrophilic
and nucleophilic sites at the edge of its framework, allowing for
the customization of physicochemical properties by a diverse range
of chemical modifications. Specifically, incorporating allyl glycidyl
ether (AGE) as an electrophile or ethoxyethylamine (EEA) as a nucleophile
into C2O enables
the synthesis of C2O-AGE or C2O-EEA, respectively.
These modified frameworks exhibit improved conversions of 97.2% and
99.9% for CO2 fixation with allyl glycidyl ether, outperforming
unmodified C2O showing
a conversion of 74.2%. This newly developed scalable, durable, and
customizable covalent framework holds tremendous potential for the
design and preparation of outstanding materials with versatile functionalities,
rendering them highly attractive for a wide range of applications
Critical roles of metal–ligand complexes in the controlled synthesis of various metal nanoclusters
Abstract Metal nanoclusters (NCs), an important class of nanoparticles (NPs), are extremely small in size and possess quasi-molecular properties. Due to accurate stoichiometry of constituent atoms and ligands, NCs have strong structure-property relationship. The synthesis of NCs is seemingly similar to that of NPs as both are formed by colloidal phase transitions. However, they are considerably different because of metal-ligand complexes in NC synthesis. Reactive ligands can convert metal salts to complexes, actual precursors to metal NCs. During the complex formation, various metal species occur, having different reactivity and fraction depending on synthetic conditions. It can alter their degree of participation in NC synthesis and the homogeneity of final products. Herein, we investigate the effects of complex formation on the entire NC synthesis. By controlling the fraction of various Au species showing different reactivity, we find that the extent of complex formation alters reduction kinetics and the uniformity of Au NCs. We demonstrate that this concept can be universally applied to synthesize Ag, Pt, Pd, and Rh NCs