A scaling law of particle transport in inkjet-printed particle-laden polymeric drops.

Hydrogels with embedded functional particulates are widely used to create soft materials with innovative functionalities. In order to advance these soft materials to functional devices and machines, critical technical challenges are the precise positioning of particulates within the hydrogels and the construction of the hydrogels into a complex geometry. Inkjet printing is a promising method for addressing these challenges and ultimately achieving hydrogels with voxelized functionalities, so-called digital hydrogels. However, the development of the inkjet printing process primarily relies on empirical optimization of its printing and curing protocol. In this study, a general scaling law is proposed to predict the transport of particulates within the hydrogel during inkjet printing. This scaling law is based on a hypothesis that water-matrix interaction during the curing of inkjet-printed particle-laden polymeric drops determines the intra-drop particle distribution. Based on the hypothesis, a dimensionless similarity parameter of the water-matrix interaction is proposed, determined by the hydrogel's water evaporation coefficient, particle size, and mechanical properties. The hypothesis was tested by correlating the intra-drop particle distribution to the similarity parameter. The results confirmed the scaling law capable of guiding ink formulation and printing and curing protocol.

Effect of laser intensity on the characteristic of inkjet-printed silver nanoparticles during continuous laser sintering.

The variation in electric conductivity was examined for laser irradiation with various beam intensities. A 532-nm continuous wave laser was irradiated onto inkjet-printed silver lines on a glass substrate and the electrical resistance was measured in situ during the irradiation. The results demonstrate that electrical conductivity varies nonlinearly with laser intensity, and has a minimum specific resistance of 3.1 x 10(-8) Ωm at 4 kW/cm2 irradiation. These results are interesting because the specific resistance achieved by the present laser irradiation was approximately 1.9 times lower than the best value obtainable by oven heating, even though it was still higher by 1.9 times than that of bulk silver. It is also demonstrated that the irradiation time required to complete the sintering process decreases with laser intensity. The numerical simulation of laser heating shows that the heating temperature could be as high as 250 degrees C for laser sintering, while it is limited to 250 degrees C for oven sintering. The characteristics of sintering with laser intensity based on the results of field emission scanning electron microscope images are discussed.

Pulsed Laser Ablation Characteristics of Light-Absorbing Mask Layer Based on Coating Thicknesses under Laser Lift-Off Patterning Process.

Thin transparent oxide layers are typically patterned for use in electronic products including semiconductors, displays, and solar cells for applications such as transparent electrodes, insulating films, and encapsulation films. Conventional patterning methods have traditionally been used in photolithography and lift-off processes. Photolithography employs the wet development process, which has disadvantages such as potential undercut effects, swelling, chemical contamination, and high process costs. On the other hand, laser ablation, which has the advantages of high accuracy, high speed, a noncontact nature, and selective processing, can be used to pattern thin films. However, absorption in transparent oxide films is usually low. In this study, experiments were conducted to determine the ablation characteristics of mask layers. The factors affecting ablation, including beam radii, fluences, overlap ratios, and coating thicknesses, were examined; and the parameters characteristic of residue-free ablation, namely the ablation threshold, minimum fluence, and minimum ablation linewidth, were also examined. The experimental results revealed that the beam radius was an important parameter in determining the resolutions of transparent films and substrates.

Physical Characteristics of Sintered Silver Nanoparticle Inks with Different Sizes during Furnace Sintering.

The influence of nanoparticle (NP) size on the physical characteristics of sintered silver NP ink was studied using four different types of inks. The Ag NP inks were spin-coated on glass substrates with an average thickness of 300 nm. Each sample was sintered for 30 min, with temperatures from 50 °C to 400 °C by an interval of 50 °C. After sintering, the specific resistance of each case was obtained using the resistance and surface profile measurements. The minimum specific resistance obtained by the experiment was 2.6 µΩ·cm in the case in which 50 nm-sized Ag NP ink was sintered at 350 °C. The transformed surface morphology and grain size of each case were observed using scanning electron microscopy and atomic force microscopy. The results of this study can be a reference for future manufacturers in selecting the Ag NP size and the sintering temperature.

The characteristic variations of inkjet-printed silver nanoparticle ink during furnace sintering.

In this work, an experiment on furnace thermal sintering with printed silver (Ag) nanoparticle ink was carried out. The Ag nanoparticle ink employed in this study has a particle size of around 50 nm and particles constitute 34 wt% of the ink. The Ag nanoparticle ink was printed by inkjet printing. A thermal sintering process in a furnace was conducted at temperatures of 150, 200, and 250 degrees C for 20 to 3000 seconds. After sintering, electrical conductivities and cross-sectional images were measured. The specific resistance and the cross-sectional area of the sintered ink decrease as the sintering temperature increases. The SEM images indicate that surface premelting caused sintering below the melting temperature of silver, 960 degrees C, which increased neck growth and lowered the electrical resistance. Lastly, the minimum specific resistance of 7.08 microOmgega x cm was obtained after sintering for 3000 s at 250 degrees C. This specific resistance value was 4.4 times larger than that of bulk silver.

[Efficacy of hepatic arterial infusion therapy for advanced hepatocellular carcinoma using 5-fluorouracil, epirubicin and mitomycin-C].

BACKGROUND/AIM: Prognosis of advanced hepatocellular carcinoma (HCC) treated by conventional therapies has been considered to be poor. The aim of this study was to evaluate the efficacy of hepatic arterial infusion therapy (HAIT) using FEM (5-fluorouracil, epirubicin, mitomycin-C) regimen for advanced HCC. METHODS: Eighteen patients received repeated HAIT using an implanted drug delivery system. Of the 18 patients, 8 patients had HCC with portal vein tumor thrombosis, 9 patients had recurrent HCC after transarterial chemoembolization (TACE) and 1 patient after surgical resection. The patients received 5-fluorouracil (330 mg/m(2), every week), epirubicin (30 mg/m(2), every 4 weeks) and mitomycin-C (2.7 mg/m(2), every 2 weeks). RESULTS: Mean age was 51 years. The response rate (complete response+partial response) by tumor size on abdominal CT was 38.9%. Survival ranged from 2 to 24 months and the median survival time was 8 months. The cumulative survival rate of responders group was significantly higher than non-responders group (p=0.0385). The mean levels of serum alpha-FP and PIVKA-II in responders group decreased after HAIT (3,179 ng/mL and 2,850 ng/mL) than before (11,218 ng/mL and 4,396 ng/mL), but not significantly. Chemotherapy-related side effects were nausea, vomiting and alopecia. Three patients had catheter-related complications. One patient developed gastric ulcer. CONCLUSIONS: HAIT using FEM regimen is a useful therapeutic option for patients with advanced HCC with portal vein tumor thrombosis or ineffective response to other therapies.

[Esophageal mucosal desquamation with hemorrhage in bullous pemphigoid: a case report].

Bullous pemphigoid is a subepidermal blistering skin disease, usually occurred in the elderly. It is an autoimmune disease associated with circulating autoantibodies directed against structural components of hemodesmosome. Rarely, it can involve the esophagus, which can be complicated by upper gastrointestinal hemorrhage. We report a case of bullous pemphigoid with esophageal mucosal desquamation and hemorrhage in patient with chronic renal failure.

[A case of primary small cell carcinoma in the common bile duct].

Extrapulmonary primary small cell carcinoma comprises approximately 4% of all small cell carcinoma. In the common bile duct, small cell carcinomas are extremely rare. We experienced a 60-year-old woman with small cell carcinoma arising in the common bile duct. Abdominal CT scan revealed an intraluminal mass in the proximal common bile duct and multiple lymphadenopathies. Microscopic examination of the tumor revealed proliferation of small monotonous anaplastic cells, which were characterized with hyperchromatic nuclei, high nuclear to cytoplasmic ratio, and frequent mitosis. By immunohistochemical stain, the tumor cells were strongly positive for chromogranin, synaptophysin, and CD56. We report this case with a review of literatures.

Segmental groove pancreatitis: report of one case.

Groove pancreatitis is a special form of chronic pancreatitis in which scarring is found mainly in the groove between the pancreatic head, duodenum, and common bile duct. Preoperative differentiation between groove pancreatitis and pancreatic cancer is difficult. Here we report one case of segmental groove pancreatitis diagnosed by clinical and radiological features. The patient was a 46-year old man with severe abdominal pain, weight loss, and a long history of alcohol abuse. Computed tomography revealed swelling of the pancreatic head and a heterogeneously enhanced low-density lesion in the groove. MR images revealed a mass in the groove that had a low signal on T1-weighted images and a low signal relative to the pancreatic head on T2-weighted images. T1-weighted images on dynamic study showed the medial wall thickening of descending duodenum, several small cysts in the groove and thickened duodenal wall. The patient has been under conservative treatment for 2 months and his severe abdominal pain has improved.

Factors associated or related to with pathological severity of nonalcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) has been more and more often regarded as a serious disorder, because nonalcoholic steatohepatitis (NASH), a part of NAFLD, may progress to the end stage of liver disease. Though an advanced age, obesity, diabetes mellitus (DM) etc. being not infrequent conditions in Korea, are known to exacerbate the severity of this disease, there are only a few Korean reports on this subject. The purpose of this study is to identify possible factors that might add up to the pathological severity of this disorder in Korean patients. METHODS: Of 60 patients with steatosis found at liver biopsy, 43 NAFLD patients were reviewed retrospectively after exclusion of other liver diseases. RESULTS: The cases of steatosis were mild, moderate, and severe in 9. 10, and 24 patients, respectively. The degree of necroinflammatory activity was mild, moderate, and severe in 33, 9, and 1 patients, respectively. There were no established factors directly related to these classes. As to fibrosis, the cases were classified as none, mild, moderate, severe, and cirrhotic in 9, 11, 16, 7, and 0 patients, respectively. The stage of fibrosis correlated with the age (p < 0.001), BMI (body mass index) (p = 0.032), and the platelet count (p = 0.009), but the presence of NASH was associated only with BMI (p = 0.002) and obesity (p = 0.001). CONCLUSION: It seems that there are no factors that are directly related to the degree of steatosis or necroinflammatory activity. BMI seems to be a unique factor directly related to both the severity of fibrosis and the presence of NASH. The age and the platelet count are factors that are directly related to the degree of fibrosis but not to the presence of NASH.

[A case of intraluminal gallbladder hematoma after percutaneous liver biopsy].

Percutaneous liver biopsy is valued in the diagnosis of diffuse or localized liver disease. Serious complications after ultrasonography-guided liver biopsy are rare. We report a case of a 69-year-old man who underwent a percutaneous liver biopsy for the evaluation of his underlying liver disease with subsequent late complication of intraluminal gallbladder hematoma.