Publications by authors named "Yoojin Kim"

30 Publications

  • Page 1 of 1

Chitosan-Alginate-Pectin-coated Suspended-Liquid-Encapsulating (CAPSuLE) marbles for therapeutic agent storage and delivery.

Biomater Sci 2021 Mar;9(5):1639-1651

Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, 03722, Korea.

Developing a cutting-edge system capable of ensuring long-lasting functionality of therapeutic agents and implementing diverse delivery modes is challenging. A quasi-spherical triple-layered capsule containing suspended liquid droplets and allowing multi-modal delivery of therapeutic agents in the aqueous phase was developed, primarily by adopting the core principles for creating liquid marbles. A naturally derived wettable polysaccharide-pectin-was utilized as a liquid-air interfacial barrier to keep the liquid droplets in the core zone. To tailor the pectin-coated droplet as a therapeutic agent carrier, anionic alginate and cationic chitosan layers were sequentially formed via additional interactions: physically stacking substances with structural chirality (pectin-alginate) and inducing electrostatic association to create the reversible complex coacervates (alginate-chitosan). The resulting system, which is called a Chitosan-Alginate-Pectin-coated Suspended-Liquid-Encapsulating (CAPSuLE) marble, had sufficient mechanical strength to resist external harsh environments and exhibited unique features: ecofriendly sustainability, responsiveness to external stimuli, coacervate-driven coalescence for linking adjacent marbles, and a self-repairing ability. The proposed CAPSuLE system can facilitate the adoption of the liquid-marble concept to biomedical fields, extending its applicability in the fields of biology and applied engineering.
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http://dx.doi.org/10.1039/d0bm01504kDOI Listing
March 2021

Exploration of hybrid nanocarbon composite with polylactic acid for packaging applications.

Int J Biol Macromol 2020 Feb 2;144:135-142. Epub 2019 Dec 2.

Department of Sustainable Biomaterials, Virginia Tech, Blacksburg, VA 24061, United States. Electronic address:

Polylactic acid (PLA) nanocomposite films were fabricated with graphene oxide (GO) and single-walled carbon nanotubes (CNT) as a hybrid-co-filler with GOCNT fraction varying from 0.05 to 0.4% by weight. The effect of the GOCNT on the physical, thermal, morphological, gas permeation, and optical properties was investigated. The X-ray diffraction test reveals no restacking and coagulation of GOCNT in the composite films. Differential Scanning Calorimetry analysis shows an insignificant shift of glass transition and melting temperature but enhanced crystallization resulting from the existence of GOCNT as a nucleating agent. Scanning Electron Microscope scans indicate GOCNT embedded homogeneously without considerable aggregates in the PLA. Transmission of ultraviolet-visible radiation decreases to 30% with increasing fraction of GOCNT while Oxygen Transmission Rate diminishes to 67% in the film. These are attributed to the tortuous pathways provided by the well-dispersed hybrid GOCNT in the PLA. Compared to the pristine PLA film, the composite film shows an increase of 75% and 130% in the tensile strength and Young's modulus, respectively. Taken together, all of these improvements observed in the hybrid GOCNT-PLA composites should provide useful guidelines in customizing designs for applications across a range of fields including packaging, life sciences, cosmetics, and conventional synthetic plastics.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.11.239DOI Listing
February 2020

Rare Occurrence of Prosthetic Knee Septic Arthritis Due to Streptococcus viridans in the Background of a Dental Procedure.

Cureus 2019 Oct 24;11(10):e5980. Epub 2019 Oct 24.

Internal Medicine, New York Medical College - Metropolitan Hospital Center, New York, USA.

The American Academy of Oral Medicine, American Dental Association (ADA), in conjunction with the American Academy of Orthopedic Surgeons (AAOS) and the British Society for Antimicrobial Chemotherapy, advises against the universal use of antimicrobial prophylaxis prior to dental procedures for the prevention of prosthetic joint infection (PJI). Here, we discuss the case of a patient with PJI in the background of periodontal scaling, which was done a week prior to presentation to the hospital. The PJI occurred with Streptococcus (S.) viridans, a rare organism for PJI but a common oral commensal. As the number of prosthetic joint surgeries are increasing and more data become available, prophylactic antibiotics might be considered to prevent PJI, especially in high-risk patients.
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http://dx.doi.org/10.7759/cureus.5980DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6874422PMC
October 2019

Urinary neutrophil gelatinase-associated lipocalin in dogs with stable or progressive kidney disease.

J Vet Intern Med 2019 Mar 14;33(2):654-661. Epub 2019 Feb 14.

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, Minnesota.

Background: Active kidney injury may play a role in chronic kidney disease (CKD) progression in dogs. Neutrophil gelatinase-associated lipocalin (NGAL), a novel tubular kidney injury biomarker, may help differentiate progressive CKD from stable CKD in dogs.

Objectives: To determine if urinary NGAL : creatinine ratio (UNCR) differentiates stable and progressive CKD in dogs. We hypothesized that UNCR would be higher in dogs with progressive CKD versus stable CKD.

Animals: Twenty-one healthy control dogs, 22 with prerenal azotemia, 19 with stable CKD, 30 with progressive CKD, and 27 with acute kidney injury (AKI).

Methods: Prospective study. Azotemic (serum creatinine concentration >1.6 mg/dL) dogs or nonazotemic AKI dogs were enrolled and classified into 4 groups: (1) prerenal azotemia, (2) stable CKD, (3) progressive CKD, and (4) AKI. Urinary NGAL was measured by ELISA and UNCR compared among groups. Urine protein : creatinine ratio (UPC) in dogs with stable and progressive CKD was compared to UNCR for differentiating CKD groups.

Results: UNCR was significantly higher in dogs with progressive CKD than stable CKD. UNCR of the prerenal azotemia group was significantly lower than that of the progressive CKD and AKI groups. No significant difference was found in UNCR between stable CKD and prerenal azotemia groups. ROC curve analysis of UNCR for differentiating progressive CKD from stable CKD resulted in an AUC of 0.816 (95% confidence interval [CI], 0.673-0.959), greater than that of UPC (0.696; 95% CI, 0.529-0.863).

Conclusions And Clinical Importance: Urinary NGAL could be helpful to predict the risk of progression in dogs with CKD.
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http://dx.doi.org/10.1111/jvim.15428DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6430932PMC
March 2019

Biogenic Hematite from Bacteria: Facile Synthesis of Secondary Nanoclusters for Lithium Storage Capacity.

ACS Appl Mater Interfaces 2019 Feb 6;11(7):6948-6957. Epub 2019 Feb 6.

School of Earth Sciences and Environmental Engineering , Gwangju Institute of Science and Technology , Gwangju 61005 , Republic of Korea.

Ferrihydrite, or iron(III) (oxyhydr)oxide (Fe(OH)), a representative scavenger of environmentally relevant toxic elements, has been repurposed as a low-cost and scalable precursor of well-developed hematite (α-FeO) secondary nanoclusters with a hierarchically structured morphology for lithium-ion anode materials. Here, we report that the bacteria Clostridium sp. C8, isolated from a methane-gas-producing consortium, can synthesize self-assembled secondary hematite nanoclusters (∼150 nm) composed of small nanoparticles (∼15 nm) through the molecular structural rearrangement of amorphous ferrihydrite under mild conditions. The biogenic hematite particles, wrapped with graphene oxide reduced in situ by the reducing bacteria Shewanella sp. HN-41 via one-pot synthesis, deliver an excellent reversible capacity of ∼1000 mA h g after 100 cycles at a current density of 1 A g. Furthermore, the heat-treated hematite/rGO exhibits a capacity of 820 mA h g at a high current density of 5 A g and a reversible capacity of up to 1635 mA h g at a current density of 100 mA g. This study provides an easy, eco-efficient, and scalable microbiological synthetic route to produce hierarchical hematite/rGO secondary nanoclusters with potential as high-performance Li-ion anode materials.
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http://dx.doi.org/10.1021/acsami.8b18894DOI Listing
February 2019

Simulation Experiences in Canadian Physiotherapy Programmes: A Description of Current Practices.

Physiother Can 2018 ;70(3):262-271

Department of Physical Therapy.

Although health care professional education programmes around the world are increasingly using sophisticated simulation technology, the scope of simulation use in Canadian physiotherapy programmes is currently undefined. The current study explores the definitions of simulation, its current use, and the perceived benefits and barriers in Canadian entry-to-practice physiotherapy programmes. Using a qualitative, descriptive study approach, we contacted Canadian physiotherapy programmes to identify faculty members with simulation experience. Using a semi-structured interview format, we asked participants to discuss their perspectives of simulation in their physiotherapy programmes. Interviews were audio recorded, transcribed, and analyzed for themes. Of 13 eligible Canadian physiotherapy programmes, participants from 8 were interviewed. The interviews revealed three major themes: (1) variability in the definition of in simulation, (2) variability in simulation use, and (3) the benefits of and barriers to the use of simulation. Variability in the definition of in simulation among Canadian physiotherapy programmes is consistent with the current literature, highlighting a spectrum of complexity from low fidelity to high fidelity. Physiotherapy programmes are using a variety of simulations, with the aim of creating a bridge from theoretical knowledge to clinical practice. This study describes the starting point for characterizing simulation implementation in Canadian physiotherapy programmes and reflects the diversity that exists across the country.
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http://dx.doi.org/10.3138/ptc.2017-11.eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158570PMC
January 2018

The complete chloroplast genome of (Ranunculaceae).

Mitochondrial DNA B Resour 2018 Oct 3;3(2):1090-1091. Epub 2018 Oct 3.

Genome Analysis Center at National Instrumentation Center for Environmental Management, Seoul National University, Seoul, Republic of Korea.

The complete chloroplast genome sequence of , a species of the family, was characterized from the assembly of HiSeq (Illumina Co.) paired-end sequencing data. The chloroplast genome of was 155,292 bp in length, with a large single-copy (LSC) region of 84,120 bp, a small single-copy (SSC) region of 18,342 bp, and a pair of identical inverted repeat regions (IRs) of 26,415 bp. The genome contained a total of 114 genes, including 80 protein-coding genes, 30 transfer RNA (tRNA) genes, and 4 ribosomal RNA (rRNA) genes. The phylogenetic analysis of with 14 related species revealed the closest taxonomical relationship with in the family.
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http://dx.doi.org/10.1080/23802359.2018.1508383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7799707PMC
October 2018

Evaluation of Color and Structure of -Fe₂O₃ Nanocapsules by Tuning of the SiO₂ Morphology.

J Nanosci Nanotechnol 2018 09;18(9):6133-6136

Engineering Ceramic Center, Korea Institute of Ceramic Engineering and Technology, Icheon 17303, South Korea.

In this study, we synthesized a core/yolk-shell α[email protected] structure by treatment of SiO2 shell with mild basic solution. Spindle shaped α-Fe2O3 nanoparticles were initially prepared as core materials and subsequently coated with silica via sol-gel method. The yolk shell of α-Fe2O3 was produced by dissolution of silica shell from core-shell type hematite in NH4OH solution. In addition, the correlation between the density and morphology of the silica coating layer and the chromaticity according to the NH4OH concentration and the etching time was confirmed. We found that, after the conversion, the spindle shapes of the composite colloids were retained for both the hematite core and the silica shell, but the physical properties had a median value.
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http://dx.doi.org/10.1166/jnn.2018.15617DOI Listing
September 2018

Efficiency-limiting processes in cyclopentadithiophene-bridged donor-acceptor-type dyes for solid-state dye-sensitized solar cells.

J Chem Phys 2018 Jan;148(4):044703

King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), Material Science and Engineering Program (MSE), Thuwal 23955-6900, Kingdom of Saudi Arabia.

The charge generation and recombination processes in three novel push-pull photosensitizers for dye-sensitized solar cells (DSSCs) are studied by ps-μs transient absorption (TA) and quasi-steady-state photoinduced absorption (PIA) spectroscopy. The three cyclopentadithiophene-based photosensitizer dye molecules exhibit comparably low power conversion efficiencies ranging from 0.8% to 1.7% in solid-state DSSCs. We find that the photocurrents increase in the presence of Li-salt additives. Both TA and PIA measurements observe long-lived dye cations created by electron injection from the dyes' excited state for two dyes from the series. However, the third dye shows significantly lower performance as a consequence of the less efficient electron injection even after the addition of Li-salts and faster electron-hole recombination on the ns-μs time scale. In essence, the prerequisites for this class of donor-π bridge-acceptor photosensitizers to reach higher charge generation efficiencies are a combination of strong dipole moments and fine tuning of the electronic landscape at the titania-dye interface by Li-salt addition.
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http://dx.doi.org/10.1063/1.4999136DOI Listing
January 2018

BiFACIAL ( Biomimetic Freestanding Anisotropic Catechol- Interfaces with Asymmetrically Layered) Films as Versatile Extracellular Matrix Substitutes.

ACS Appl Mater Interfaces 2018 Mar 14;10(9):7602-7613. Epub 2017 Sep 14.

Department of Chemical and Biomolecular Engineering , Yonsei University , 50 Yonsei-ro , Seodaemun-gu , Seoul 120-749 , Korea.

Biological naïve extracellular matrices (ECMs) exhibit anisotropic functions in their physical, chemical, and morphological properties. Representative examples include anisotropic skin layers or blood vessels simultaneously facing multiphasic environments. Here, anisotropically multifunctional structures called BiFACIAL ( biomimetic freestanding anisotropic catechol- interfaces with asymmetrically layered) films were developed simply by contacting two polysaccharide solutions of heparin-catechol (Hep-C) and chitosan-catechol (Chi-C). Such anisotropic characters were due to controlling catechol cross-linking by alkaline pH, resulting in a trimodular structure: a rigid yet porous Hep-C exterior, nonporous interfacial zone, and soft/highly porous Chi-C interior. The anisotropic features of each layer, including the porosity, rigidity, rheology, composition, and ionic strength, caused the BiFACIAL films to show spontaneously biased stimuli responses and differential behaviors against biological substances (e.g., blood plasma). The films could be created in situ in live animals and imitated the structural/functional aspects of the representative anisotropic tissues (e.g., skin and blood vessels), providing valuable ECM-like platforms for the creation of favorable environments or for tissue regeneration or disease treatment by effectively manipulating cellular behaviors.
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http://dx.doi.org/10.1021/acsami.7b10023DOI Listing
March 2018

Characterization and Control of Nanoparticle Emission during 3D Printing.

Environ Sci Technol 2017 Sep 30;51(18):10357-10368. Epub 2017 Aug 30.

Department of Environmental Health and ‡Institute of Health and Environment, School of Public Health, Seoul National University , 1, Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.

This study aimed to evaluate particle emission characteristics and to evaluate several control methods used to reduce particle emissions during three-dimensional (3D) printing. Experiments for particle characterization were conducted to measure particle number concentrations, emission rates, morphology, and chemical compositions under manufacturer-recommended and consistent-temperature conditions with seven different thermoplastic materials in an exposure chamber. Eight different combinations of the different control methods were tested, including an enclosure, an extruder suction fan, an enclosure ventilation fan, and several types of filter media. We classified the thermoplastic materials as high emitter (>10 #/min), medium emitters (10 #/min -10 #/min), and low emitters (<10 #/min) based on nanoparticle emissions. The nanoparticle emission rate was at least 1 order of magnitude higher for all seven filaments at the higher consistent extruder temperature than at the lower manufacturer-recommended temperature. Among the eight control methods tested, the enclosure with a high-efficiency particulate air (HEPA) filter had the highest removal effectiveness (99.95%) of nanoparticles. Our recommendations for reducing particle emissions include applying a low temperature, using low-emitting materials, and instituting control measures like using an enclosure around the printer in conjunction with an appropriate filter (e.g., HEPA filter) during 3D printing.
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http://dx.doi.org/10.1021/acs.est.7b01454DOI Listing
September 2017

Mutagenic Analysis of an Adeno-Associated Virus Variant Capable of Simultaneously Promoting Immune Resistance and Robust Gene Delivery.

Hum Gene Ther 2018 01 23;29(1):25-41. Epub 2017 Jun 23.

1 Department of Chemical and Biomolecular Engineering, Yonsei University , Seoul, Korea.

In addition to the ability to boost gene delivery efficiency in many therapeutically relevant cells, the capability of circumventing neutralizing antibody (NAb) inactivation is a key prerequisite that gene carriers must fulfill for their extensive applications as therapeutic agents in many gene therapy trials, especially for cancer treatments. This study revealed that a genetically engineered adeno-associated virus (AAV) variant, AAVr3.45, inherently possesses dual beneficial properties as a gene carrier: (i) efficiently delivering therapeutic genes to many clinically valuable cells (e.g., stem or cancer cells) and (ii) effectively bypassing immunoglobulin (IgG) neutralization. Detailed interpretation of the structural features of AAVr3.45, which was previously engineered from AAV2, demonstrated that the LATQVGQKTA peptide at the heparan sulfate proteoglycan binding domain, especially the presence of cationic lysine on the peptide, served as a key motif for dramatically enhancing its gene delivery capabilities, ultimately broadening its tropisms for many cancer cell lines. Furthermore, the substitution of valine on the AAV2 capsid at the amino acid 719 site to methionine functioned as a coordinator for promoting viral resistance against IgG inactivation. The NAb-resistant characteristics of AAVr3.45 were possibly associated with the LATQVGQKTA sequence itself, indicating that its synergistic cooperation with the point mutation (V719M) is required for maximizing its ability to evade NAb inactivation. The potential of AAVr3.45 as a cancer gene therapy agent was confirmed by provoking apoptosis in breast adenocarcinoma by efficiently delivering a pro-apoptotic gene, BIM (Bcl-2-like protein 11), under high titers of human IgG. Thus, the superior aspects of the NAb-resistant AAVr3.45 as a potential therapeutic agent for systemic injection approaches, especially for cancer gene therapy, were highlighted in this study.
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http://dx.doi.org/10.1089/hum.2017.034DOI Listing
January 2018

Development of efficient adeno-associated virus (AAV)-mediated gene delivery system with a phytoactive material for targeting human melanoma cells.

N Biotechnol 2017 Jul 5;37(Pt B):194-199. Epub 2017 Feb 5.

Department of Chemical and Biomolecular Engineering, Yonsei University, 50, Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea; Skin Research Division, R&D Unit, AmorePacific Corporation, 1920, Yonggu-daero, Giheung-gu, Yongin-si, Gyeonggi-do, Republic of Korea. Electronic address:

We exploited the emerging potential of gene therapy strategies to design a powerful therapeutic system that combines two key components-AAV vector and [6]-gingerol. In this study, we created an AAV2 construct expressing the proapoptotic protein BIM, which uses HSPG as its primary receptor, to target HSPG-overexpressing melanoma cells. This combination treatment showed promising results in vitro, inducing apoptosis in human melanoma cells. This new platform technology will make a significant contribution to numerous therapeutic applications, most notably for melanoma, including overcoming resistance to conventional anticancer therapies.
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http://dx.doi.org/10.1016/j.nbt.2017.02.001DOI Listing
July 2017

The cutoff values of indirect indices for measuring insulin resistance for metabolic syndrome in Korean children and adolescents.

Ann Pediatr Endocrinol Metab 2016 Sep 30;21(3):143-148. Epub 2016 Sep 30.

Department of Pediatrics, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Korea.

Purpose: The prevalence rates of metabolic syndrome (MetS) and percentile distribution of insulin resistance (IR) among Korean children and adolescents were investigated. The cutoff values of IR were calculated to identify high-risk MetS groups.

Methods: Data from 3,313 Korean subjects (1,756 boys and 1,557 girls, aged 10-18 years) were included from the Korean National Health and Nutrition Examination Survey conducted during 2007-2010. Three different sets of criteria for MetS were used. Indirect measures of IR were homeostasis model assessment (HOMA-IR) and triglyceride and glucose (TyG) index. The cutoff values of the HOMA-IR and TyG index were obtained from the receiver operation characteristic curves.

Results: According to the MetS criteria of de Ferranti el al., Cook et al., and the International Diabetes Federation, the prevalence rates in males and females were 13.9% and 12.3%, 4.6% and 3.6%, and 1.4% and 1.8%, respectively. Uses these 3 criteria, the cutoff values of the HOMA-IR and TyG index were 2.94 and 8.41, 3.29 and 8.38, and 3.54 and 8.66, respectively. The cutoff values using each of the 3 criteria approximately corresponds to the 50th-75th, 75th, and 75th-90th percentiles of normal HOMA-IR and TyG index levels.

Conclusion: This study describes the prevalence rates of MetS in Korean children and adolescents, an index of IR, and the cutoff values for MetS with the aim of detecting high-risk groups. The usefulness of these criteria needs to be verified by further evaluation.
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http://dx.doi.org/10.6065/apem.2016.21.3.143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5073160PMC
September 2016

Water as an agent for the morphology modification of metal oxalate materials on the nanoscale: from sheets to rods.

Sci Rep 2016 Jan 14;6:19282. Epub 2016 Jan 14.

Department of Bio &Nano Chemistry, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702, Republic of Korea.

A number of approaches have been used to control the shape of metal oxalates, which often used as precursors for metal oxide nanomaterials. However, attempts to use water as a regulator have not been reported. Here in we report systematic studies on related topics: nanosheets, composed of 1-dimensional [M(C2O4)(EG)] (M = Zn or Co) polymeric structure, could be transformed into nanorods by using water as a shape-shifting agent because water can readily substitute EG ligand, leading alternation of inter-chain hydrogen bonding interactions. In addition, heat-treatment of these nanomaterials with diverse morphologies resulted in porous metal oxides with high degrees of shape retention.
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http://dx.doi.org/10.1038/srep19282DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4725861PMC
January 2016

Synthesis and characterization of multi-functional ZnO nano ceramic phosphor.

Authors:
Ri Yu YooJin Kim

J Nanosci Nanotechnol 2014 Nov;14(11):8711-4

This manuscript reports on the synthesis and characterization of a multi-functional ZnO core-shell structure with CoFe2O4 as magnetic materials. To form a combination between optical (ZnO) and magnetic (CoFe2O4) materials, the surfaces of both materials were modified by amine and silica. First, ZnO raw mertials were coated silica using sol-gel methods and -OH group of their surface were modified using amines. Hydrophobic CoFe2O4 nanoparticle was coated with silica and was found to have hydrophilic properties. CoFe2O4 attached silica-coated ZnO core-shell structures were prepared by self-assembly technique and have blue luminescence and magnetic properties.
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http://dx.doi.org/10.1166/jnn.2014.9968DOI Listing
November 2014

The association between glycemic control and clinical outcomes after kidney transplantation.

Endocr Pract 2014 Sep;20(9):894-900

Section of Endocrinology, Diabetes and Metabolism, University of Illinois at Chicago, Chicago, Illinois.

Objective: To analyze the relationship between glycemic control after renal transplantation and subsequent graft function and complications.

Methods: We conducted a retrospective chart review of 202 consecutive patients undergoing kidney transplantation to analyze the association between perioperative and chronic glycemic control and clinical outcomes of rejection, infection, and hospital readmission during the first year after kidney transplantation.

Results: Mean in-hospital blood glucose (BG) was 157 ± 34.5 mg/dL. Mean hemoglobin A1c (HbA1c) during the first 12 months posttransplantation was 6.84 ± 1.46%. Fiftyfour patients (27%) were treated for acute or chronic rejection, 88 (44%) for infection, and 149 (74%) patients were readmitted at least once within the first year after transplantation. There were no significant differences in the risks for rejection, infection, or readmission across the 5 mean initial inpatient BG or subsequent HbA1c quintiles. In addition, there was no significant relationship between the percentage of BG measurements that fell in the "tight control" range of 80 to 110 mg/dL for each patient and any of the outcomes.

Conclusion: We did not find an association between glycemic control (perioperative or chronic) and the outcomes of graft rejection, infection, or hospital readmission in the first 12 months after renal transplantation. Our results suggest that "near normal" glycemic targets are not necessary for managing hyperglycemia after renal transplantation.
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http://dx.doi.org/10.4158/EP13463.ORDOI Listing
September 2014

Impact of glycemic variability and hypoglycemia on adverse hospital outcomes in non-critically ill patients.

Diabetes Res Clin Pract 2014 Mar 3;103(3):437-43. Epub 2014 Jan 3.

Section of Endocrinology, Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA; Division of Endocrinology and Metabolism, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. Electronic address:

Aims: To determine if glycemic variability is associated with hospitalization outcomes in non-critically ill patients, and if this association remains after controlling for hypoglycemia.

Methods: A retrospective review was performed on 1276 medical admissions (801 patients) in which insulin was given, ≥6 point of care glucose (POCG) measurements and length of stay (LOS) 2-30 days. Coefficient of variation (%CV) was used to measure glycemic variability. Outcomes included LOS and a composite outcome based on ICU transfer, hospital acquired infections, and acute renal failure (ARF).

Results: There were a median of 18.5 POCG measurements per admission with a mean %CV 34.2 ± 11.1. Hypoglycemia (POCG ≤70 mg/dl [3.9 mmol/l]) occurred in 35.0% of admissions. ICU transfer occurred in 3.3%, hospital acquired infections 4.8%, ARF 8.3%, and composite outcome 13.5%. Adjusting for age, sex, race and Charlson score, every 10 unit increase in %CV was associated with an increase in LOS of 0.27 days (p=0.004), while there was no association between %CV and the composite outcome. For LOS, there was a significant interaction between %CV and hypoglycemia (p=0.07). While there was a non-significant correlation in patients without hypoglycemia, LOS correlated negatively with %CV in patients with hypoglycemia. When considered simultaneously with %CV, hypoglycemia was associated with increased odds of the composite outcome [OR 2.03 (95% CI 1.36-3.01), p=<0.001] and an increase of 2 days in LOS for those with average %CV.

Conclusions: Hypoglycemia, compared to glycemic variability, is more strongly associated with adverse outcomes in hospitalized, non-critically ill patients.
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http://dx.doi.org/10.1016/j.diabres.2013.11.026DOI Listing
March 2014

Clinical potential of sodium-glucose cotransporter 2 inhibitors in the management of type 2 diabetes.

Diabetes Metab Syndr Obes 2012 31;5:313-27. Epub 2012 Aug 31.

Division of Endocrinology, John, Stroger Jr Hospital of Cook County and Rush University, Chicago, IL, USA.

Background: The kidney plays an important role in glucose metabolism, and has been considered a target for therapeutic intervention. The sodium-glucose cotransporter type 2 (SGLT2) mediates most of the glucose reabsorption from the proximal renal tubule. Inhibition of SGLT2 leads to glucosuria and provides a unique mechanism to lower elevated blood glucose levels in diabetes. The purpose of this review is to explore the physiology of SGLT2 and discuss several SGLT2 inhibitors which have clinical data in patients with type 2 diabetes.

Methods: We performed a PubMed search using the terms "SGLT2" and "SGLT2 inhibitor" through April 10, 2012. Published articles, press releases, and abstracts presented at national and international meetings were considered.

Results: SGLT2 inhibitors correct a novel pathophysiological defect, have an insulin-independent action, are efficacious with glycosylated hemoglobin reduction ranging from 0.5% to 1.5%, promote weight loss, have a low incidence of hypoglycemia, complement the action of other antidiabetic agents, and can be used at any stage of diabetes. They are generally well tolerated. However, due to side effects, such as repeated urinary tract and genital infections, increased hematocrit, and decreased blood pressure, appropriate patient selection for drug initiation and close monitoring after initiation will be important. Results of ongoing clinical studies of the effect of SGLT2 inhibitors on diabetic complications and cardiovascular safety are crucial to determine the risk-benefit ratio. A recent decision by the Committee for Medicinal Products for Human Use of the European Medicines Agency has recommended approval of dapagliflozin for the treatment of type 2 diabetes as an adjunct to diet and exercise, in combination with other glucose-lowering medicinal products, including insulin, and as a monotherapy for metformin-intolerant patients. Clinical research also remains to be carried out on the long-term effects of glucosuria and other potential effects of SGLT2 inhibitors, especially in view of the observed increase in the incidence of bladder and breast cancer. SGLT2 inhibitors represent a promising approach for the treatment of diabetes, and could potentially be an addition to existing therapies.
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http://dx.doi.org/10.2147/DMSO.S22545DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437808PMC
October 2012

Thermal behavior and coloration study of silica-coated alpha-Fe2O3 and beta-FeOOH nanocapsules.

J Nanosci Nanotechnol 2011 Jul;11(7):6283-6

Engineering Ceramic Center Korea Institute of Ceramic Engineering and Technology, Icheon 467-843, Korea.

This manuscript reports characterization of the colorations and thermal behaviors of the silica-coated alpha-Fe2O3 and beta-FeOOH nanocapsules. Prepared beta-FeOOH and alpha-Fe2O3 nanoparticles were coated with silica using tetraethylorthosilicate (TEOS) and cetyltrimethyl-ammonium bromide (CTAB) as a surface modifier for the comparison of physical properties of both samples. XRD patterns of the silica-coated beta-FeOOH and alpha-Fe2O3 nanoparticles were heated to 1000 degrees C, show a hematite (alpha-Fe2O3) structure. The silica-coated beta-FeOOH nanoparticles became almost entirely hollow at 1000 degrees C due to their volume reduction. In addition, the coloration values of the transformation nano capsule alpha-Fe2O3 are lower than those of the silica-coated alpha-Fe2O3 nanostructures. On the other hand, the silica-coated alpha-Fe2O3 nanoparticles retained their colorations and shapes after being heated to 1000 degrees C. The morphologies, crystal structures and colorations of the as prepared samples were analyzed by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction and CIE colorimeter.
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http://dx.doi.org/10.1166/jnn.2011.4379DOI Listing
July 2011

One-step silica coating of cetyltrimethyl ammonium bromide-stabilized alpha-Fe2O3.

J Nanosci Nanotechnol 2010 Jan;10(1):380-2

Advanced Industrial Ceramic Team, Icheon Center, Korea Institute of Ceramic Engineering and Technology, Icheon, 467-843, Korea.

The alpha-Fe2O3 nanoparticles were coated with silica using intermediated surfactant such as cetyltrimethyl ammonium bromide (CTAB). After the formation of a thin intermediate layer in basic solution without any purification, TEOS was added directly to the solution for further silica growing. Silica thickness can be controlled through the various synthetic conditions (5 to 50 nm). The synthesized powder was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and UV-visible spectroscopy. XRD and UV-visible spectroscopy of silica coated alpha-Fe2O3 is preserved constant after coating silica, suggesting that the SiO2 layers can be regarded as protecting layers without destroying the properties of the alpha-Fe2O3 nanoparticles.
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http://dx.doi.org/10.1166/jnn.2010.1508DOI Listing
January 2010

Interfacial assembly of nanoparticles in discrete block-copolymer aggregates.

Angew Chem Int Ed Engl 2007 ;46(48):9235-8

Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.

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http://dx.doi.org/10.1002/anie.200703032DOI Listing
February 2008

Synthesis, structure, and properties of a mixed-valent triiron complex of tetramethyl reductic acid, an ascorbic acid analogue, and its relationship to a functional non-heme iron oxidation catalyst system.

Inorg Chem 2007 Jul 19;46(15):6099-107. Epub 2007 Jun 19.

Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

The purple triiron(II,III,III) complex, [Fe(3)Cl(2)(TMRASQ)(4)(HTMRA)(2)] x C(5)H(12) (1 x C(5)H(12)), where H(2)TMRA is a tetramethyl reductic acid, 4,4,5,5-tetramethyl-2,3-dihydroxy-2-cyclopenten-1-one, and HTMRASQ is the semiquinone form of this ligand, was prepared from (Et(4)N)(2)[Fe(2)OCl(6)] and H(2)TMRA and characterized by X-ray crystallography, Mössbauer spectroscopy, and redox titrations. The physical properties of the complex in solution are consistent with its mixed-valent character, as delineated by a solid-state structure analysis. Assignments of the iron and ligand oxidation states in the crystal were made on the basis of a valence bond sum analysis and the internal ligand geometry. As the first well-characterized iron complex of an ascorbic acid H(2)AA analogue, 1 provides insight into the possible coordination geometry of the family of complexes containing H(2)AA and its analogues. In the presence of air and H(2)TMRA, 1 is able to catalyze the oxidation of cyclohexane to cyclohexanol with remarkable selectivity, but the nature of the true catalyst remains unknown.
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http://dx.doi.org/10.1021/ic700622aDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3236675PMC
July 2007

The dramatic effect of architecture on the self-assembly of block copolymers at interfaces.

Langmuir 2005 Nov;21(23):10444-58

Department of Chemical Engineering, Stanford University, California 94305-5025, USA.

Dramatic morphological changes are observed in the Langmuir-Blodgett (LB) film assemblies of poly(ethylene glycol)-b-(styrene-r-benzocyclobutene) block copolymer (PEG-b-(S-r-BCB)) after intramolecular cross-linking of the S-r-BCB block to form a linear-nanoparticle structure. To isolate architectural effects and allow direct comparison, the linear block copolymer precursor and the linear-nanoparticle block copolymer resulting from selective intramolecular cross-linking of the BCB units were designed to have exactly the same molecular weight and chemical composition but different architecture. It was found that the effect of architecture is pronounced with these macromolecular isomers, which self-assemble into dramatically different surface aggregates. The linear block copolymer forms disklike surface assemblies over the range of compression states, while the linear-nanoparticle block copolymer exhibits long (>10 microm) wormlike aggregates whose length increases as a function of increasing cross-linking density. It is shown that the driving force behind the morphological change is a combination of the altered molecular geometry and the restricted degree of stretching of the nanoparticle block because of the intramolecular cross-linking. A modified approach to interpret the pi-A isotherm, which includes presence of the block copolymer aggregates, is also presented, while the surface rheological properties of the block copolymers at the air-water interface provide in-situ evidence of the aggregates' presence at the air-water interface.
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http://dx.doi.org/10.1021/la047122fDOI Listing
November 2005

Two-dimensional carboxylate bridged network of europium(III)-transition metal(II) glutarate compounds.

Dalton Trans 2005 Aug 4(15):2603-8. Epub 2005 Jul 4.

Department of Chemistry-BK21 and the Institute of Basic Sciences, Sungkyunkwan University, Suwon 440-746, Korea.

Four new heterometallic glutarate coordination polymers, [Eu2M(H2O)4][O2C(CH2)3CO2]4.2H2O (M = Mn (1), Fe (2), Co (3) and Ni (4)) have been obtained under hydrothermal synthesis. The single-crystal X-ray diffraction analyses showed that they have two-dimensional frameworks based on the linear polyhedral chains consisting of two nine-coordinated Eu(III)O9 and a six-coordinated M(II)O6. These 1-D MO6-Eu2O16 chains are cross-linked by glutarate ligands as an interchain pillared architecture, whose conformations vary depending upon the transition metals. The magnetic behavior of the compounds show a weak antiferromagnetic interaction, in which shielding of the 4f electrons by the outer shell electrons effectively precludes significant coupling interactions between the Eu-4f electrons and transition metal (M)-3d electrons.
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http://dx.doi.org/10.1039/b505384fDOI Listing
August 2005

Interaction among Btn1p, Btn2p, and Ist2p reveals potential interplay among the vacuole, amino acid levels, and ion homeostasis in the yeast Saccharomyces cerevisiae.

Eukaryot Cell 2005 Feb;4(2):281-8

Center for Aging and Developmental Biology, Ann Institute of Biomedical Sciences, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA.

Btn2p, a novel cytosolic coiled-coil protein in Saccharomyces cerevisiae, was previously shown to interact with and to be necessary for the correct localization of Rhb1p, a regulator of arginine uptake, and Yif1p, a Golgi protein. We now report the biochemical and physical interactions of Btn2p with Ist2p, a plasma membrane protein that is thought to have a function in salt tolerance. A deletion in Btn2p (btn2Delta strains) results in a failure to correctly localize Ist2p, and strains lacking Btn2p and Ist2p (btn2Delta ist2Delta strains) are unable to grow in the presence of 0.5 or 1.0 M NaCl. Btn2p was originally identified as being up-regulated in a btn1Delta strain, which lacks the vacuolar-lysosomal membrane protein, Btn1p, and serves as a model for Batten disease. This up-regulation of Btn2p was shown to contribute to the maintenance of a stable vacuolar pH in the btn1Delta strain. Btn1p was subsequently shown to be required for the optimal transport of arginine into the vacuole. Interestingly, btn1Delta ist2Delta strains are also unable to grow in the presence of 0.5 or 1.0 M NaCl, and ist2Delta suppresses the vacuolar arginine transport defect in btn1Delta strains. Although further investigation is required, we speculate that altered vacuolar arginine transport in btn1Delta strains represents a mechanism for maintaining or balancing cellular ion homeostasis. Btn2p interacts with at least three proteins that are seemingly involved in different biological functions in different subcellular locations. Due to these multiple interactions, we conclude that Btn2p may play a regulatory role across the cell in response to alterations in the intracellular environment that may be caused by changes in amino acid levels or pH, a disruption in protein trafficking, or imbalances in ion homeostasis resulting from either genetic or environmental manipulation.
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http://dx.doi.org/10.1128/EC.4.2.281-288.2005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC549324PMC
February 2005

Crystal structure and spectroscopic study of novel two- and three-dimensional photoluminescent Eu(III)-adipate compounds.

Inorg Chem 2004 Jan;43(1):245-50

Department of Chemistry-BK21 and the Institute of Basic Sciences, Sungkyunkwan University, Suwon 440-746, Korea.

Two new photoluminescent compounds with the formulas of [Eu(2)(adipate)(3)(H(2)O)].H(2)O (1) and [Eu(2)(adipate)(3)(4H(2)O)] (2) were synthesized by using Eu(III) chloride and adipic acid under hydrothermal reaction conditions in aqueous solution. Compound 1, a 3-D layered framework, possesses infinite Eu-O-Eu polyhedral chains and self-assembled adipate ligands between Eu-O layers. Compound 2 has dimeric Eu(2)O(16) units interconnected by adipate ligand, resulting in 2-D open frameworks with a cavity among the ligands. Crystal data 1: monoclinic space group C2/c, with a = 14.2486(12) A, b = 8.2733(7) A, c = 39.298(2) A, beta = 99.530(6) degrees, and Z = 8. 2: monoclinic space group P2(1)/c, with a = 11.661(4) A, b = 14.011(3) A, c = 9.013(4) A, beta = 110.87(3) degrees, and Z = 2. The ligand conformations of two Eu(III)-adipate (1 and 2) compounds present anti/anti/anti, gauche/anti/gauche, and intermediate forms. Both compounds 1 and 2 showed strong red luminescence upon excitation, and their luminescence decay involves the multiphonon relaxation mechanism.
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http://dx.doi.org/10.1021/ic034418kDOI Listing
January 2004

A role in vacuolar arginine transport for yeast Btn1p and for human CLN3, the protein defective in Batten disease.

Proc Natl Acad Sci U S A 2003 Dec 5;100(26):15458-62. Epub 2003 Dec 5.

Center for Aging and Developmental Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.

In Saccharomyces cerevisiae, transport of arginine into the vacuole has previously been shown to be facilitated by a putative H+/arginine antiport. We confirm that transport of arginine into isolated yeast vacuoles requires ATP and we demonstrate a requirement for a functional vacuolar H+-ATPase. We previously reported that deletion of BTN1 (btn1-delta), an ortholog of the human Batten disease gene CLN3, resulted in a decrease in vacuolar pH during early growth. We report that this altered vacuolar pH in btn1-delta strains underlies a lack of arginine transport into the vacuole, which results in a depletion of endogenous vacuolar arginine levels. This arginine transport defect in btn1-delta is complemented by expression of either BTN1 or the human CLN3 gene and strongly suggests a function for transport of, or regulation of the transport of, basic amino acids into the vacuole or lysosome for yeast Btn1p, and human CLN3 protein, respectively. We propose that defective transport at the lysosomal membrane caused by an absence of functional CLN3 is the primary biochemical defect that results in Batten disease.
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http://dx.doi.org/10.1073/pnas.2136651100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC307589PMC
December 2003

Conformation change of the cyclohexanedicarboxylate ligand toward 2D and 3D La(III)-organic coordination networks.

Chem Commun (Camb) 2002 Apr(8):908-9

Department of Chemistry-BK21, Institute of Basic Sciences, Sungkyunkwan University, Suwon 440-746, Korea.

2D and 3D structures of La-1,4-cyclohexanedicarboxylates (chdc) coordination networks, have been constructed using flexible chdc ligands which can have cis and trans conformations of two dicarboxylate groups, controlled by the solution pH in hydrothermal reaction conditions.
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http://dx.doi.org/10.1039/b200658hDOI Listing
April 2002

A coordination polymer of cobalt(II)-glutarate: two-dimensional interlocking structure by dicarboxylate ligands with two different conformations.

Inorg Chem 2002 Feb;41(3):501-6

Department of Chemistry-BK21, Institute of Basic Science, Sungkyunkwan University, Suwon 440-746, Korea.

A novel Co-glutarate, Co[O(2)C(CH(2))(3)CO(2)] (1), was synthesized as single crystals by the hydrothermal reaction of CoCl(2) with glutaric acid in the presence of KOH and characterized by single-crystal X-ray diffraction analysis, TGA, IR, UV-vis reflectance spectrometry, and SQUID measurements. The dark purple Co-glutarate crystallizes in the monoclinic system in the space group P2/c, with a = 14.002(3) A, b = 4.8064(10) A, c = 9.274(3) A, beta = 90.5(2)degrees, and Z = 4. The Co(2+) centers are tetrahedrally coordinated to four oxygen atoms from the dicarboxylate ligands. The anhydrous-pillared three-dimensional structure consists of infinite Co-CO(2)-Co inorganic layers, which are stacked by the coordinated glutarate alkyl chain along the a-axis. There are two different conformations for glutarate ligands, i.e., the gauche- and the anti-forms. These ligands reside between the inorganic layers alternatively to separate each layer by 7.01 A (gauche) and 6.99 A (anti). Magnetic measurement reveals that the predominant magnetic interactions are antiferromagnetic below 14 K.
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http://dx.doi.org/10.1021/ic010861oDOI Listing
February 2002
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