Publications by authors named "Sang J Park"

An easy and environmentally friendly method was developed for the preparation of a stabilized carbon nanotube-crystalline nanocellulose (CNT-CNC) dispersion and for its deposition to generate self-standing CNT-CNC composite films. The composite films were carbonized at different temperatures of 70 °C, 800 °C, and 1300 °C. Structural and morphological characteristics of the CNT-CNC films were investigated by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM), which revealed that the sample annealed at 800 °C (CNT-CNC) formed nano-tree networks of CNTs with a high surface area (1180 m·g) and generated a conductive CNC matrix due to the effective carbonization.

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Background: To investigate the effects of dipeptidyl peptidase-4 inhibitor (DPP4i) as add-on medications to metformin on progression of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus, compared with sulfonylurea (SU) or thiazolidinedione (TZD).

Methods: We identified 4,447 patients with DPP4i, 6,136 with SU, and 617 with TZD in addition to metformin therapy from the database of Korean National Health Insurance Service between January 2013 and December 2015. Cox proportional hazards regression models were used to calculate hazard ratios (HRs) for DR progression.

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Background: Donor organ quality is a key determinant of graft outcomes in deceased donor kidney transplantation (DDKT). The predictive values of baseline histopathology and several clinical scoring systems for long-term graft outcomes have been evaluated, but the results remain controversial.

Materials And Methods: We screened 167 patients who underwent DDKT at Ulsan University Hospital from April 2003 to June 2016.

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A paramagnetic NiTi substrate was coated with diamagnetic carbon materials, i.e., graphene, graphene oxide (GO), and carbon nanotubes (CNTs), in order to reduce magnetic resonance (MR) image artifacts of NiTi implants.

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Objective: To retrospectively evaluate the value of computerized 3D texture analysis for differentiating pulmonary metastases from non-metastatic lesions in pediatric patients with osteosarcoma.

Materials And Methods: This retrospective study was approved by the institutional review board. The study comprised 42 pathologically confirmed pulmonary nodules in 16 children with osteosarcoma who had undergone preoperative computed tomography between January 2009 and December 2014.

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Though the overall incidence of occupational injuries and accidents has decreased, they continue to happen. Many associated factors are known and managing them with limited resources is difficult. This study evaluates related risk factors and prioritizes their management for reducing occupational injuries and accidents at the workplace.

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Background/aims: To estimate the incidence and demographics of macular hole (MH) requiring surgery in Korea.

Methods: Patients who underwent surgery for MH in Korea from 2011 to 2015 with the diagnostic code for MH and the surgical code for vitrectomy were retrospectively identified using the Korean national health claims database. The average incidence rate of MH during the 5-year study period was estimated by applying the direct method of standardisation using the 2015 census data as a reference population.

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Owing to the extreme toxicity of mercury, methods for its selective and sensitive sensing in solutions, and in live cells and tissues are in great demand. In this study, we developed a naphthalimide-based diphenylphosphinothioyl group-containing fluorescent and colorimetric probe that selectively detects mercury (Hg2+). Upon addition of mercury (Hg2+) to a solution of the probe, both a colorimetric change from colorless to yellow and a fluorescence change from blue to green (under a 365 nm hand-held UV lamp) occur, both of which can be observed using the "naked-eye".

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Background: The graft used in living donor liver transplantation (LDLT) sometimes has two hepatic arteries. This study aimed to introduce arterial-blood gas (ABG) test on the decision on whether to reconstruct a single or both arteries in LDLT.

Methods: Patients with a right lobe graft with two hepatic arteries were enrolled from the prospectively maintained database of our institution.

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Purpose: To determine whether nonarteritic ischemic optic neuropathy (NAION) raises the risk of subsequent stroke in the general population.

Design: Population-based, retrospective cohort study.

Methods: Setting: Nationwide, population-based, retrospective cohort study.

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Radiotherapy in patients with cancer can kill cancer cells but also damage normal cells or tissues. During the treatment of patients with head and neck cancer or thyroid cancer, hyposalivation is a representative chronic side effect of radio-damaged salivary glands (SGs). The major symptom of hyposalivation is mouth dryness, resulting in several subsequent long-term complications.

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Purpose: To predict the rate of liver regeneration after living donor liver transplantation (LDLT) using pre-operative computed tomography (CT) texture analysis.

Materials And Methods: 112 living donors who performed right hepatectomy for LDLT were included retrospectively. We measured the volume of future remnant liver (FLR) on pre-operative CT and the volume of remnant liver (LR) on follow-up CT, taken at a median of 123 days after transplantation.

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Background: Recently, innovative attempts have been made to identify moyamoya disease (MMD) by focusing on the morphological differences in the head of MMD patients. Following the recent revolution in the development of deep learning (DL) algorithms, we designed this study to determine whether DL can distinguish MMD in plain skull radiograph images.

Methods: Three hundred forty-five skull images were collected as an MMD-labeled dataset from patients aged 18 to 50 years with definite MMD.

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Objective: Although evidence and guidelines recommend appropriate rehabilitation from the beginning of diagnosis in patients with Parkinson's disease (PD), there is a lack of data addressing the utilization of rehabilitation therapies for these patients in practice. The aim of this study is to investigate the rate of rehabilitation therapy utilization over time in patients with PD using a nationwide cohort in Korea.

Methods: Patients were identified using the registration code for PD in the program for rare, intractable disease from the National Health Insurance Service-National Sample Cohort database, which consists of 979,390 Korean residents.

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Background: A caudal epidural steroid injection (CESI) is a commonly used method to improve symptoms of lumbosacral pain. We compared the achievement of successful epidurograms and patient-reported clinical outcomes following different needle-insertion depths during CESI.

Methods: For the conventional method group, the needle was advanced into the sacral canal.

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Mitochondrial targeting is a promising approach for solving current issues in clinical application of chemotherapy and diagnosis of several disorders. Here, we discuss direct conjugation of mitochondrial-targeting moieties to anticancer drugs, antioxidants and sensor molecules. Among them, the most widely applied mitochondrial targeting moiety is triphenylphosphonium (TPP), which is a delocalized cationic lipid that readily accumulates and penetrates through the mitochondrial membrane due to the highly negative mitochondrial membrane potential.

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Periodontitis is a common disease characterized by chronic inflammation and tissue destruction of gums. Human periodontal ligament stem cells (PDLSCs), derived from the periodontium, have stem cell properties similar to those of mesenchymal stem cells. PDLSCs possess not only the potential to differentiate into other tissues, but also immunomodulatory abilities.

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Purpose: To determine the effects of different reconstruction algorithms on histogram and texture features in different targets.

Materials And Methods: Among 3620 patients, 480 had normal liver parenchyma, 494 had focal solid liver lesions (metastases = 259; hepatocellular carcinoma = 99; hemangioma = 78; abscess = 32; and cholangiocarcinoma = 26), and 488 had renal cysts. CT images were reconstructed with filtered back-projection (FBP), hybrid iterative reconstruction (HIR), and iterative model reconstruction (IMR) algorithms.

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Purpose: To study the association between the risk of massive submacular hemorrhage (SMH) and polyp regression after initial treatment of polypoidal choroidal vasculopathy using long-term follow-up data.

Methods: Retrospective study of 223 patients who were diagnosed with polypoidal choroidal vasculopathy and were followed up for up to 11 years. Subjects were categorized into "regression" and "no regression" groups, according to their polyp status after the initial treatment.

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Background/aims: To determine whether the development of non-arteritic anterior ischaemic optic neuropathy (NAION) is increased among patients newly diagnosed with obstructive sleep apnoea (OSA) in a large general population.

Methods: A 12-year nationwide, population-based, retrospective cohort study including 1 025 340 beneficiaries in the 2002-2013 Korean National Health Insurance Service database was performed. We identified 919 patients newly diagnosed with OSA aged ≥40 years and matched 9190 non-OSA controls using estimated propensity scores in reference to age, sex, demographics, comorbidities and co-medications.

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Background: The guidelines for applying individual adjustments to macaques according to the severity of behavioral symptoms during 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment were provided to reproduce stable chronic Parkinsonism in a recent study (Potts et al., 2014). But, since there are insufficient guidelines regarding objective severity criteria of individual symptoms for adjustments of MPTP treatment, it is difficult to develop MPTP-induced chronic non-human primate (NHP) models with stable symptoms.

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Purpose: The aim of this study was to investigate the usefulness of a personalized, 3-dimensional (3D)-printed, transparent liver model with focal liver lesions (FLLs) for lesion-by-lesion imaging-pathologic matching.

Materials And Methods: This preliminary, prospective study was approved by our institutional review board, and written informed consent was obtained. Twenty patients (male-to-female ratio, 13:7; mean age, 56 years) with multiple FLLs, including at least one presumed malignant, or an indeterminate lesion 10 mm or less on the preoperative gadoxetic acid-enhanced magnetic resonance imaging (MRI), were included.

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Chitosan, a deacetylated chitin, is one of the few natural polymers similar to glycosaminoglycans (GAGs) widely distributed throughout connective tissues. It has been believed that the excellent biocompatibility of chitosan is largely attributed to this structural similarity. Chitosan is also known to possess biodegradability, antimicrobial activity and low toxicity and immunogenicity which are essential for scaffolds.

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Three-dimensional (3D) printing (rapid prototyping or additive manufacturing) technologies have received significant attention in various fields over the past several decades. Tissue engineering applications of 3D bioprinting, in particular, have attracted the attention of many researchers. 3D scaffolds produced by the 3D bioprinting of biomaterials (bio-inks) enable the regeneration and restoration of various tissues and organs.

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