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1.
Polymers (Basel) ; 15(1)2022 Dec 28.
Article in English | MEDLINE | ID: mdl-36616487

ABSTRACT

The superior chemical and electrical properties of TiO2 are considered to be suitable material for various applications, such as photoelectrodes, photocatalysts, and semiconductor gas sensors; however, it is difficult to commercialize the applications due to their low photoelectric conversion efficiency. Various solutions have been suggested and among them, the increase of active sites through surface modification is one of the most studied methods. A porous nanostructure with a large specific surface area is an attractive solution to increasing active sites, and in the electrospinning process, mesoporous nanofibers can be obtained by controlling the composition of the precursor solution. This study successfully carried out surface modification of TiO2 nanofibers by mixing polyvinylpyrrolidone with different molecular weights and using diisopropyl azodicarboxylate (DIPA). The morphology and crystallographic properties of the TiO2 samples were analyzed using a field emission electron microscope and X-ray diffraction method. The specific surface area and pore properties of the nanofiber samples were compared using the Brunauer-Emmett-Teller method. The TiO2 nanofibers fabricated by the precursor with K-30 polyvinyl pyrrolidone and diisopropyl azodicarboxylate were more porous than the TiO2 nanofibers without them. The modified nanofibers with K-30 and DIPA had a photocatalytic efficiency of 150% compared to TiO2 nanofibers. Their X-ray diffraction patterns revealed anatase peaks. The average crystallite size of the modified nanofibers was calculated to be 6.27-9.27 nm, and the specific surface area was 23.5-27.4 m2/g, which was more than 150% larger than the 17.2 m2/g of ordinary TiO2 nanofibers.

3.
Korean J Gastroenterol ; 63(1): 25-31, 2014 Jan 25.
Article in English | MEDLINE | ID: mdl-24463285

ABSTRACT

BACKGROUND/AIMS: The frequency of symptomatic acute HAV infections in adulthood are increasing in Korea. This study analyzes the clinical severity in patients with acute HAV infection and investigates risk factors associated with three severe complications: prolonged cholestasis, acute kidney injury, and acute liver failure. METHODS: We performed a retrospective analysis of 726 patients diagnosed from January 2006 to December 2010 at three tertiary hospitals in Jeonbuk Province, Republic of Korea with acute HAV infection. RESULTS: In the group of 726 patients, the mean age was 30.3 years, 426 (58.6%) were male, and 34 (4.7%) were HBsAg positive. Severe complications from acute HAV infection occurred as follows: prolonged cholestasis in 33 (4.6%), acute kidney injury in 17 (2.3%), and acute liver failure in 16 (2.2%). Through multivariate analysis, age ≥40 years (OR 2.63, p=0.024) and peak PT (INR) ≥1.5 (OR 5.81, p=0.035) were found to be significant risk factors for prolonged cholestasis. Age ≥40 years (OR 5.24, p=0.002) and female gender (OR 3.11, p=0.036) were significant risk factors for acute kidney injury. Age ≥40 years (OR 6.91, p=0.002), HBsAg positivity (OR 5.02, p=0.049), and peak total bilirubin (OR 1.11, p=0.001) were significant risk factors for acute liver failure. CONCLUSIONS: Age ≥40 years, female gender, HBsAg positivity, peak PT (INR) ≥1.5, and peak total bilirubin were significant risk factors for severe complications in acute HAV infections.


Subject(s)
Hepatitis A/diagnosis , Acute Disease , Acute Kidney Injury/complications , Adult , Cholestasis/complications , Female , Hepatitis A/complications , Hepatitis B Surface Antigens/blood , Humans , Liver Failure, Acute/complications , Male , Middle Aged , Odds Ratio , Republic of Korea , Retrospective Studies , Risk Factors , Tertiary Care Centers
4.
Gut Liver ; 7(6): 712-8, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24312713

ABSTRACT

BACKGROUND/AIMS: We investigated the efficacy of continuous long-term entecavir 0.5 mg treatment in naïve chronic hepatitis B patients showing a partial virologic response (PVR). METHODS: A total of 227 patients were included. PVR was defined as a more than 1 log10 IU/mL decline in detectable serum hepatitis B virus (HBV) DNA by polymerase chain reaction (PCR; ≥20 IU/mL) at week 48. A complete virologic response (CVR) was defined as undetectable serum HBV DNA by PCR (<20 IU/mL) at week 48. RESULTS: At week 48, the rate of the PVR was 64/227 (28.2%). Among patients with PVR, the cumulative rates of virologic response (serum HBV DNA <20 IU/mL) at weeks 96 and 144 were 45.2% and 73.8%, respectively. The cumulative rates of genotypic resistance were not significantly different between patients with a PVR and patients with a CVR (p=0.057). However, the cumulative rates of virologic breakthrough were higher in patients with PVR than in patients with CVR (4% vs 0% and 11.2% vs 0% at weeks 96 and 144, respectively; p<0.001). CONCLUSIONS: Long-term continuous entecavir 0.5 mg treatment in patients with a PVR resulted in an additional virologic response without a significant increase in genotypic resistance. However, the rate of virologic breakthrough was higher in the partial responders.


Subject(s)
Antiviral Agents/administration & dosage , DNA, Viral/blood , Guanine/analogs & derivatives , Hepatitis B virus , Hepatitis B, Chronic/drug therapy , Adult , Alanine Transaminase/blood , Drug Resistance, Viral/genetics , Female , Guanine/administration & dosage , Hepatitis B e Antigens/blood , Hepatitis B virus/genetics , Humans , Male , Middle Aged , Retrospective Studies , Time Factors , Viral Load
5.
Gut Liver ; 7(4): 500-3, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23898395

ABSTRACT

Wilson's disease (WD) is an autosomal recessive inherited disorder of copper metabolism that results in the accumulation of copper in the body and primarily in the liver, brain, and cornea. Copper is a toxic metal and might be associated with cancer induction. Most malignancies associated with WD are hepatocellular carcinoma and cholangiocarcinoma. Other intra-abdominal malignancies have been only rarely reported. To our knowledge, this is the first report to suggest that patients with WD may be vulnerable to a malignant change in the colonic mucosa during long-term copper chelating therapy. We report a case of colonic adenocarcinoma in a patient with WD and review the related literature.

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