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1.
ACS Appl Mater Interfaces ; 15(20): 24366-24376, 2023 May 24.
Article in English | MEDLINE | ID: mdl-37186545

ABSTRACT

Aqueous zinc-ion batteries (ZIBs) provide a safer and cost-effective energy storage solution by utilizing nonflammable water-based electrolytes. Although many research efforts are focused on optimizing zinc anode materials, developing suitable cathode materials is still challenging. In this study, one-dimensional, mixed-phase MnO2 nanorods are synthesized using ionic liquid (IL). Here, the IL acts as a structure-directing agent that modifies MnO2 morphology and introduces mixed phases, as confirmed by morphological, structural, and X-ray photoelectron spectroscopy (XPS) studies. The MnO2 nanorods developed by this method are utilized as a cathode material for ZIB application in the coin-cell configuration. As expected, Zn//MnO2 nanorods show a significant increase in their capacity to 347 Wh kg-1 at 100 mA g-1, which is better than bare MnO2 nanowires (207.1 Wh kg-1) synthesized by the chemical precipitation method. The battery is highly rechargeable and maintains good retention of 86% of the initial capacity and 99% Coulombic efficiency after 800 cycles at 1000 mA g-1. The ex situ XPS, X-ray diffraction, and in-depth electrochemical analysis confirm that MnO6 octahedra experience insertion/extraction of Zn2+ with high reversibility. This study suggests the potential use of MnO2 nanorods to develop high-performance and durable battery electrode materials suitable for large-scale applications.

2.
Sci Rep ; 13(1): 5776, 2023 Apr 08.
Article in English | MEDLINE | ID: mdl-37031237

ABSTRACT

A heterojunction photocathode of CuO and CuBi2O4 grown on an FTO substrate (FTO/CuO/CuBi2O4) was synthesized using hydrothermal method followed by spin coating and annealing to overcome the bottlenecks encountered by CuO in photoelectrochemical (PEC) water splitting application. The synthesis methods, morphological, structural properties, and composition of each sample under each synthesis condition are discussed in detail. The photocathode with 15 coating layers annealed at 450 °C exhibited the best PEC performance. Moreover, its current density reached 1.23 mA/cm2 under an applied voltage of - 0.6 V versus Ag/AgCl in a neutral electrolyte. Additionally, it exhibited higher stability than the bare CuO thin film. The bonding of CuBi2O4 on CuO resulted in close contact between the two semiconductors, helping the semiconductors support each other to increase the PEC efficiency of the photocathode. CuO acted as the electron-generating layer, and the CuBi2O4 layer helped minimize photocorrosion as well as transport the carriers to the electrode/electrolyte interface to accomplish the hydrogen evolution reaction.

3.
World J Gastroenterol ; 21(3): 1020-3, 2015 Jan 21.
Article in English | MEDLINE | ID: mdl-25624740

ABSTRACT

Leptomeningeal carcinomatosis occurs very rarely in patients with pancreatic cancer. Leptomeningeal carcinomatosis is characterized by multifocal seeding of the leptomeninges by malignant cells that originate from a solid tumor. To the best of our knowledge, brain metastasis from pancreatic cancer is extremely rare. Leptomeningeal carcinomatosis is estimated to occur in 3% to 8% of cases of solid tumors. The clinical manifestation usually involves neurological symptoms, including dizziness, headache, vomiting, nausea, and hemiparesis, symptoms similar to those of meningitis or brain tumors. Diagnostic methods for leptomeningeal carcinomatosis include brain magnetic resonance imaging and cerebrospinal fluid examination. Here, we describe a case of leptomeningeal carcinomatosis in which the primary tumor was later determined to be pancreatic cancer. Brain magnetic resonance imaging findings showed mild enhancement of the leptomeninges, and cerebrospinal fluid cytology was negative at first. However, after repeated spinal taps, atypical cells were observed on cerebrospinal fluid analysis and levels of tumor markers such as carbohydrate antigen 19-9 in cerebrospinal fluid were elevated. Abdominal computed tomography, performed to determine the presence of extracerebral tumors, revealed pancreatic cancer. Pancreatic cancer was confirmed histopathologically on examination of an endoscopic ultrasound-guided fine needle aspiration specimen.


Subject(s)
Adenocarcinoma/secondary , Meningeal Carcinomatosis/secondary , Pancreatic Neoplasms/pathology , Adenocarcinoma/cerebrospinal fluid , Adenocarcinoma/complications , Adenocarcinoma/radiotherapy , Aged, 80 and over , CA-19-9 Antigen/cerebrospinal fluid , Cranial Irradiation , Headache/etiology , Humans , Magnetic Resonance Imaging , Male , Meningeal Carcinomatosis/cerebrospinal fluid , Meningeal Carcinomatosis/complications , Meningeal Carcinomatosis/radiotherapy , Palliative Care , Predictive Value of Tests , Seizures/etiology , Tomography, X-Ray Computed
4.
Korean J Gastroenterol ; 52(5): 281-5, 2008 Nov.
Article in Korean | MEDLINE | ID: mdl-19077473

ABSTRACT

BACKGROUND/AIMS: Natural orifice transluminal endoscopic surgery (NOTES) is a new era of minimally invasive surgery which has the potential to offer scarless surgery. So far, numerous reports on various routes to peritoneal organs in NOTES have been published. In case of transgastric approach, it is more inconvenient than transcolonic approach to access upper abdominal organs because of retroflexion. However, most data were subjective and there was no report examining the best access route for the exploration of peritoneal organs. The aim of this study was to evaluate the best access route according to the abdominal organs objectively. METHODS: Six female pigs weighing 30 to 35 kg were placed under general anesthesia. Incisions were made on both anterior wall of stomach body and rectosigmoid colon 15 to 20 cm above anal verge, respectively. Then, via each incision site, we evaluated the endoscopic visibility and checked the elapsed time to access abdominal organs in sequence [(gallbladder (GB), spleen, bladder, uterus, and ovary)]. RESULTS: On comparison of the mean time to approach each organs, GB and ovary showed statistical difference in the mean time to approach between transgastric and transcolonic approaches. It took relatively shorter time to access GB via transcolonic route than transgastric route (352.3+/-80.1 sec vs. 222.2+/-82.0 sec, p=0.021). Next, we evaluated the time to access upper organs (GB and spleen) and lower organs (bladder, uterus and ovary). In case of lower organs, it showed no difference in time between transgastric and transcolonic approaches. However, to explore upper organs, transcolonic route was more favorable than transgastric route (351.8+/-80.7 sec vs. 273.3+/-110.3 sec, p=0.002). CONCLUSIONS: For exploration of lower organs, there is statistically no significant difference in time between transgastric and transcolonic approaches. But, in case of upper organs, transcolonic approach is superior to transgastric approach.


Subject(s)
Laparoscopy , Peritoneal Cavity/surgery , Animals , Feasibility Studies , Female , Minimally Invasive Surgical Procedures , Models, Animal , Statistics, Nonparametric , Swine , Time
5.
J Invest Dermatol ; 124(2): 291-7, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15675945

ABSTRACT

The diverse functions of microtubules (MT) in different cells and tissues may be facilitated by compositional changes in tubulin isotypes. We obtained partial cDNA clones of class II beta-tubulin from a library of differentiating normal human epidermal keratinocytes (NHEK) cells, whereas screening via subtractive hybridization for genes involved in calcium-induced keratinocyte differentiation. Analysis of the isotypic composition of beta-tubulin from NHEK cells revealed elevations in class II beta-tubulin concentrations at both protein and message levels during cell differentiation, resulting in increased rates of incorporation of class II beta-tubulin into MT. Immunohistochemistry of normal and pathologic skin tissues showed that class II beta-tubulin occurred in the granular layer of the epidermis and in differentiated areas of carcinomas. Class II beta-tubulin was, however, not observed in the uppermost granular and cornified layers of normal epidermis. Further experiments showed that MT were likely to decay in the final stage of terminal differentiation during formation of the cornified envelope. Our results suggest that there is differential modulation of MT composition and stability during keratinocyte differentiation.


Subject(s)
Keratinocytes/cytology , Keratinocytes/physiology , Tubulin/genetics , Acetylation , Cell Differentiation/physiology , Cells, Cultured , Gene Expression/physiology , Humans , Microtubules/physiology , Skin/cytology , Skin/metabolism , Tubulin/metabolism , Up-Regulation/physiology
6.
Korean J Gastroenterol ; 43(2): 125-8, 2004 Feb.
Article in Korean | MEDLINE | ID: mdl-14978370

ABSTRACT

Meckel's diverticulum is an embryonic derivative of the omphalomesenteric duct and the most commonly encountered congenital anomaly of the gastrointestinal tract. Its incidence records about 2%. Among them, only 5% are symptomatic with complications-bleeding, intestinal obstruction, inflammation, and perforation. In particular, bleeding is a common complication and has always been caused by an ulceration of the ileal mucosa adjacent to the acid-producing ectopic mucosa in a Meckel's diverticulum. Wireless capsule endoscopy is a new method enabling non-invasive diagnostic endoscopy of the entire small intestine. We experienced a case of Meckel's diverticulum detected by wireless capsule endoscopy in a 34 year-old man who presented with chronic obscure gastrointestinal bleeding.


Subject(s)
Endoscopy, Gastrointestinal , Gastrointestinal Hemorrhage/diagnosis , Gastrointestinal Hemorrhage/etiology , Meckel Diverticulum/complications , Adult , Chronic Disease , Humans , Male , Meckel Diverticulum/diagnosis
7.
Gastrointest Endosc ; 57(6): 679-82, 2003 May.
Article in English | MEDLINE | ID: mdl-12709696

ABSTRACT

BACKGROUND: An ectopic opening of the common bile duct in the duodenal bulb is extremely rare, and the clinical significance of this anomaly has not been clarified. This study analyzed the clinical implications and cholangiographic findings of this anomaly. METHODS: A total of 18 patients (15 men, 3 women; median age, 51 years) with an ectopic opening of the common bile duct in the duodenal bulb were studied. Medical records, endoscopic findings, and cholangiographic and other radiographic findings were reviewed. RESULTS: All 18 patients had biliary pain; 7 had fever and chills. Fifteen (83%) had diffuse dilatation of the extrahepatic bile ducts with or without intrahepatic bile duct dilation. Associated bile duct stones were found in 10 (56%) patients. The papilla in the bulb had an orifice stained with bile at endoscopy, which was associated with duodenal ulcer disease found in 13 (72%) patients. The distal end of the common bile duct was tapered and narrowed and had a hook shape in all patients. CONCLUSION: An ectopic opening of the common bile duct in the duodenal bulb may be associated with clinical entities such as recurrent or intractable duodenal ulcer, choledocholithiasis, or acute cholangitis. Although these openings are rare, knowledge of the endoscopic and radiographic findings of an ectopic opening of the common bile duct in the duodenal bulb may help to clarify the cause of chronic recurrent duodenal ulcer disease in some patients and prevent damage to the bile duct during surgery.


Subject(s)
Common Bile Duct/abnormalities , Duodenum/abnormalities , Adult , Aged , Bile Ducts, Extrahepatic/pathology , Cholangiography , Dilatation, Pathologic , Duodenoscopy , Female , Humans , Male , Middle Aged , Retrospective Studies
8.
Nanotechnology ; 14(12): 1269-71, 2003 Dec.
Article in English | MEDLINE | ID: mdl-21444980

ABSTRACT

Regular arrays of freestanding single carbon nanotubes (CNTs) were prepared on Ni dot arrays by dc plasma-enhanced chemical vapour deposition. The size of the Ni dot was reduced for single CNT growth by means of conventional photolithography and a lateral wet-etch process. The vertical alignment of a single CNT was directly dependent on the location of the catalyst metals. Using this method, well-separated and well-defined regular arrays of freestanding CNTs can be fabricated and the process can be scaled up at a lower cost than electron beam lithography, which is encouraging for applications in field emitters and nanoelectrodes.

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