Fuzzy nanoassembly of polyelectrolyte and layered clay multicomposite toward a reliable gas barrier.

Flexible and transparent gas-diffusion barriers have played an important role in recent years. The present study describes a flexible barrier film with a tailored architecture of cationic polyelectrolytes and clay/polymer nanoassemblies. Highly oriented and well-aligned barrier films were achieved by the consecutive absorption of flexible cationic polymer and anionic montmorillonite platelets. The experimental results showed that the layer-by-layer deposition of oppositely charged thin films containing self-assembled poly(vinyl alcohol) and montmorillonites improved their gas barrier characteristics based on the Ca degradation test, enhancing their optical transparency. This nanostructure, fabricated using a solution process, is useful in many applications, for example, flexible and moisture-free organic electronics. This simple and fast method is suitable for the mass coating of large surface areas, as required in industry.

White organic light-emitting diodes utilized by near UV-deep blue emitter and exciplex emission.

Numerous investigations have been made into the development of wide color gamut displays for deep-blue OLEDs, including the RGB sub pixels, and white OLEDs (WOLEDs). One of the well known deep-blue emissive dopants, tris(phenyl-methyl-benzimidazolyl)iridium(III) [Ir(pmb)3], successfully introduced its fascinating color coordinate of Commission Internationale de l'Eclairage (CIE) 1931 (0.17, 0.06), however there have been no reports utilizing its accomplishments as WOLEDs. In this report, using only one phosphorescent dopant, the near UV-deep blue emissive Ir(pmb)3, the WOLEDs having the CIE 1931 coordinate of (0.33, 0.38) at 100 cd/m2 with a color rendering index of 85 are demonstrated. The white emission of the fabricated OLEDs are oriented from the near UV-deep blue emission of Ir(pmb)3 and the successfully controlled exciplex emission, between the Ir(pmb)3-host, and the Ir(pmb)3-interfaced material.

Highly conformal SiO2/Al2O3 nanolaminate gas-diffusion barriers for large-area flexible electronics applications.

The present study demonstrates a flexible gas-diffusion barrier film, containing an SiO(2)/Al(2)O(3) nanolaminate on a plastic substrate. Highly uniform and conformal coatings can be made by alternating the exposure of a flexible polyethersulfone surface to vapors of SiO(2) and Al(2)O(3), at nanoscale thickness cycles via RF-magnetron sputtering deposition. The calcium degradation test indicates that 24 cycles of a 10/10 nm inorganic bilayer, top-coated by UV-cured resin, greatly enhance the barrier performance, with a permeation rate of 3.79 × 10(-5) g m(-2) day(-1) based on the change in the ohmic behavior of the calcium sensor at 20 °C and 50% relative humidity. Also, the permeation rate for 30 cycles of an 8/8 nm inorganic bilayer coated with UV resin was beyond the limited measurable range of the Ca test at 60 °C and 95% relative humidity. It has been found that such laminate films can effectively suppress the void defects of a single inorganic layer, and are significantly less sensitive against moisture permeation. This nanostructure, fabricated by an RF-sputtering process at room temperature, is verified as being useful for highly water-sensitive organic electronics fabricated on plastic substrates.

Electroluminescence property of highly soluble Ir(III) complex utilized by various hole blocking layers in polymer light emitting diodes.

The tris(2-phenylpyridine)iridium(III) [Ir(ppy)3] is a well known highly efficient green light-emitting phosphorescent guest dye dopant, but its relatively low solubility has been obstructing it to be used in polymer light-emitting diodes (PLEDs). According to our latest reports the solubility of Ir(ppy)3 complexes with the carbazole ligands, i.e., Ir(Czppy)3, was improved significantly in organic solvents, and was sufficient to be used in soluble process. This highly soluble Ir(Czppy)3 complex showed remarkably higher photoluminescence characteristics than conventional Ir(ppy)3, but it showed similar or comparably better electroluminescence (EL) characteristics, when the PLED was composed by widely used conventional hole blocking layer (HBL) and electron transport layer; 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline and tris(8-hydroxyquinoline)aluminum, respectively. In this report, we applied various HBLs to improve the EL characteristics of soluble Ir(III) complex based phosphorescent PLEDs. The PLEDs utilized by the wide band-gap 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole demonstrated highly improved the current and the external quantum efficiency of 17.61 cd/A and 6.42%, respectively.

Hydrophobic nanopatterning on a flexible gas barrier film by using a poly(dimethylsiloxane) elastomer.

In this work, we fabricated a hydrophobic and transparent gas barrier film via a nanopatterned poly(dimethylsiloxane) elastomer imprinting on an ultraviolet-curable polymer resin. A Ca degradation method (water permeation rate) and surface energy measurements were used to determine the level of modification of the surface characteristics. As a result, the decreased surface energy from 25.8 to 7.29 mN m(-1) led to a lower water vapor transmission rate from 3.06 x 10(-1) to 6.24 x 10(-2) g m(-2) day(-1) according to the degree of decreased Ca height from 100 nm. A tunable wettability is beneficial for application where controlling the direction of moisture flow is important, such as in flexible organic electronics.

UV-Vis absorption and photoluminescence characteristics of doped organic solid depend on its doping concentration.

We've studied the influence of doping concentration with UV-Vis absorption spectra analysis and their photoluminescence (PL) characteristics. With applying variations of doping concentration, co-doped organic solid films were prepared. The host material was Tris-(8-hydroxyquinoline) aluminum and the two dopants were N, N'-dimethyl-quinacridone and 10-(2-Benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7,-tetramethyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one. The PL characteristics showed its dependence on doping concentration, as doping concentration changes the PL changed also, and it showed certain trend in intensity. The trend was in agreement with previous study of single-doped and co-doped organic light-emitting diode (OLED) in previous works. This shows PL could be an effective way for estimate the performance of doped OLED.

Stretchable Electroluminescent Display Enabled by Graphene-Based Hybrid Electrode.

Stretchable alternating-current electroluminescent (ACEL) devices are required due to their potential in wearable, biomedical, e-skin, robotic, lighting, and display applications; however, one of the main hurdles is to achieve uniform electroluminescence with an optimal combination of transparency, conductivity, and stretchability in electrodes. We therefore propose a fabrication scheme involving strategically combining two-dimensional graphene layers with a silver nanowire (Ag NW)-embedded PEDOT:PSS film. The developed hybrid electrode overcomes the limitations of commonly known metallic NWs and ionic conductor-based electrodes for ACEL applications. Furthermore, the potential of the hybrid electrode is realized in demonstrating large-area stretchable ACEL devices composed of an 8 × 8 passive array. The prototype ACEL passive array demonstrates efficient and uniform electroluminescence under high levels of mechanical deformation such as bending, rolling, twisting, and stretching.

Diffusion characteristics and induced electronic channels of magnesium in organic light-emitting diodes.

The alkali and alkali-earth metals doping were widely investigated to improve the electroluminescence characteristics of organic light-emitting diodes (OLED). We study the effects of magnesium (Mg) incorporation in the transport layer, and also the emission layer of the OLED. A thermally deposited Mg has been inserted into the various positions, and the thickness was varied either. By the position and the thickness, the Mg made partially an electronic channel and made a leakage path ways. Resulted difference of initial maximum luminance distribution was observed. On the other hand, with the optimized inserting position and thickness of Mg, the OLED showed the improved EL characteristics.

Evaluation of gas permeation barrier properties using electrical measurements of calcium degradation.

In this work, we developed a thin calcium degradation method introducing sensitive electrical resistance monitoring. We have demonstrated structural models of the inorganic/organic thin films to evaluate barrier properties against water and oxygen permeation. The time-dependent transmission curve of a multibarrier coated on both sides of the polyethersulfone substrate had a linear slope which was measured as 5.17 x 10(-3) gm(2) day at 20 degrees C and 60% relative humidity. This system can measure an accurate permeation rate with a high sensitivity in the measurable range of 10(1)-10(-6) gm(2) day. In addition, the test structure devised is applicable to various fabrication techniques for passivation layers with durability and ultralow permeability for flexible organic light emitting diodes.

Development of Epidural and Paraspinal Abscesses after Insufficient Evaluation and Treatment of Acute Pyelonephritis Caused by Staphylococcus aureus.

Diagnoses of pyelonephritis caused by Staphylococcus aureus should be accompanied by investigations of concomitant bladder obstruction and metastatic infections, especially to the spine or heart. Complicated pyelonephritis due to S. aureus requires more than 2 weeks of antibiotics, which is the typically recommended treatment duration for pyelonephritis. We describe a patient who was diagnosed with complicated epidural and paraspinal abscesses after insufficient evaluation and treatment of acute pyelonephritis due to S. aureus. A 62-year-old man with type 2 diabetes was admitted with fever, increased urinary frequency, and left flank pain. He was diagnosed with acute pyelonephritis caused by S. aureus. His fever and flank pain subsided after 3 days of intravenous antibiotics. Evaluation of bladder obstruction and metastatic infection were not performed, as he declined further evaluation. The patient was discharged with oral antibiotics and was requested to attend weekly appointments but was lost to follow-up. One month later, the patient presented at the outpatient clinic with similar symptoms. Computed tomography showed recurrent pyelonephritis and a distended bladder. His flank pain persisted despite administration of an opioid agent. Therefore, magnetic resonance imaging was performed, revealing epidural and paraspinal abscesses. Ultrasound-guided aspiration of the paraspinal muscle layer was performed, and blood and percutaneous aspirated fluid cultures revealed S. aureus growth. The pattern of antimicrobial sensitivity was identical to that at his first admission. Following more than 4 weeks of antibiotics, magnetic resonance imaging showed the abscesses had decreased in size. The patient was discharged without neurologic sequelae and was provided with oral antibiotics.

Pulmonary edema following laparoscopic bariatric surgery.

Because of the increased intra-abdominal pressure and the physiologic changes in the obese patient, laparoscopic bariatric surgery can aggravate perioperative pulmonary complications. A 23-year-old female with morbid obesity experienced pulmonary edema after laparoscopic adjustable gastric banding surgery. One lung was unintentionally ventilated for approximately 5 minutes during the operation. At the end of the operation, profuse pink frothy sputum emerged from the left lung. The chest roentgenogram showed the atelectasis and severe edema in the left lung superimposed on diffuse interstitial bilateral pulmonary edema. After aspiration of the secretions and oxygen supplementation, the patient recovered uneventfully.

Modification of ascorbic acid using transglycosylation activity of Bacillus stearothermophilus maltogenic amylase to enhance its oxidative stability.

Ascorbic acid (1), a natural antioxidant, was modified by employing transglycosylation activity of Bacillus stearothermophilus maltogenic amylase with maltotriose and acarbose as donor molecules to enhance its oxidative stability. The transglycosylation reaction with maltotriose as donor created mono- and di-glycosyl transfer products with an alpha-(1,6)-glycosidic linkage. In addition, two acarviosine-glucosyl transfer products were generated when transglycosylation was performed with acarbose as a donor. All transfer products were observed by TLC and HPLC, and purified by Q-sepharose anion exchange and Biogel P-2 gel permeation chromatographies. LC/MS and (13)C NMR analyses revealed that the structures of the transfer products were 6-O-alpha-D-glucosyl- (2) and 6-O-alpha-D-maltosyl-ascorbic acids (3) in the reaction of maltotriose, and 6-O-alpha-acarviosine-D-glucosyl- (4) and 2-O-alpha-acarviosine-D-glucosyl ascorbic acids (5) in the reaction of acarbose. The stability of the transglycosylated ascorbic acid derivatives was greatly enhanced against oxidation by Cu(2+) ion and ascorbate oxidase. Among them, compound 3 proved to be the most stable against in vitro oxidation. The antioxidant effects of glycosyl-derivatives of ascorbic acid on the lipid oxidation in cooked chicken breast meat patties indicated that they had antioxidant activities similar to that of ascorbic acid. It is suggested that the transglycosylated ascorbic acids can possibly be applied as effective antioxidants with improved stability in food, cosmetic, and other applications.

Modulation of cyclizing activity and thermostability of cyclodextrin glucanotransferase and its application as an antistaling enzyme.

Cyclodextrin glucanotransferase from Bacillus stearothermophilus ET1 (CGTase ET1) is a potential antistaling enzyme with cyclodextrin (CD)-forming activity. To reduce cyclization activity of CGTase ET1, phenylalanine residues at 191 and 255 were replaced with a glycine (F191G-CGTase ET1) and an isoleucine (F255I-CGTase ET1), respectively. Temperature optima of both mutant enzymes were lower than that of the wild-type. Cyclization activities of both mutants decreased dramatically, but F255I-CGTase ET1 showed a 2-fold higher hydrolytic activity than the wild-type enzyme. CD content of bread loaf treated with F191G-CGTase ET1 was 28.6% of that treated with wild-type, whereas no CD was detected in the loaf treated with F255I-CGTase ET1. Loaves treated with CGTase ET1 or either of the two mutants contained more of the larger maltooligosaccharides such as maltopentaose and maltohexaose than the control and the commercial antistaling enzyme-treated loaves. Retrogradation rates decreased significantly in the loaves treated with either mutant, which indicates the applicability of CGTase ET1 in the bread industry by modulating the cyclizing and hydrolyzing activities of the enzyme.

Three-dimensional evaluation of maxillary anterior alveolar bone for optimal placement of miniscrew implants.

OBJECTIVE: This study aimed to propose clinical guidelines for placing miniscrew implants using the results obtained from 3-dimensional analysis of maxillary anterior interdental alveolar bone by cone-beam computed tomography (CBCT). METHODS: By using CBCT data from 52 adult patients (17 men and 35 women; mean age, 27.9 years), alveolar bone were measured in 3 regions: between the maxillary central incisors (U1-U1), between the maxillary central incisor and maxillary lateral incisor (U1-U2), and between the maxillary lateral incisor and the canine (U2-U3). Cortical bone thickness, labio-palatal thickness, and interdental root distance were measured at 4 mm, 6 mm, and 8 mm apical to the interdental cementoenamel junction (ICEJ). RESULTS: The cortical bone thickness significantly increased from the U1-U1 region to the U2-U3 region (p < 0.05). The labio-palatal thickness was significantly less in the U1-U1 region (p < 0.05), and the interdental root distance was significantly less in the U1-U2 region (p < 0.05). CONCLUSIONS: The results of this study suggest that the interdental root regions U2-U3 and U1-U1 are the best sites for placing miniscrew implants into maxillary anterior alveolar bone.

The flexible Ca-test: an improved performance in a gas permeability measurement system.

A flexible performance permeability measuring test for flexible organic light-emitting diodes is described in this paper. A single thin film layer of gas barriers is constructed on polyethersulfone (PES). The barrier coats the upper and lower surfaces of the PES layer. Two PES samples, one coated with Al(2)O(3) on both surfaces and the other coated on a single surface, were made for comparison. According to this test, the time-dependent transmission curve of the one sided barrier sample had a linear slope which measured 1.65 g∕m(2)∕day at room temperature at a 50% relative humidity. This result shows that the measurement time is about 182% faster than has been achieved with the conventional test structure that uses a glass substrate. In addition, this measurement structure not only reduces the inevitable electrical noise which occurs during measurement but also increases the water vapor permeation signal. These effects improve the sensing reliability of the test. In addition, this structure is flexible, so one can instantly detect barrier performance changes when applying external stress.

Hydrophilic dots on hydrophobic nanopatterned surfaces as a flexible gas barrier.

The present study demonstrates a transparent polymeric gas barrier film mimicking the Namib Desert beetle's back. SiO(2) hydrophilic dots have been deposited on a nanopatterned hydrophobic surface. A nanopatterned surface was fabricated by UV-curable nanoimprinting techniques. The surface energies of the hydrophobic and hydrophilic domains were 7.29 and >73.12 mN/m, respectively. The characteristics of water vapor transfer from hydrophobic to hydrophilic regions due to difference of the attractive force at interfaces are shown to yield the enhanced barrier performance according to the Ca degradation measurements. This strategy is suitable for organic electronics, solar cells, and plastic optics applications requiring moisture-free properties with high transmission.

Anatomic localization of motor points for the neuromuscular blockade of hand intrinsic muscles involved in thumb-in-palm.

OBJECTIVE: To determine the location of the motor points and intramuscular branches for the muscles involved in thumb-in-palm and the abductor pollicis brevis muscle, the latter of which, because of its anatomic proximity, may be inadvertently blocked. DESIGN: Hand intrinsic muscles from 20 fresh cadavers were dissected. The point of nerve entry to the muscle belly and the points where the intramuscular endings were located most proximally and distally were defined in relation to a reference line connecting the hook of hamate and the head of the first metacarpal bone. RESULTS: We were able to define a region, located from 66.08% +/- 8.67% to 70.28% +/- 10.62% of the reference line, with the hook of hamate as starting point, where intramuscular endings for the thumb-in-palm muscles were dense and farther from the intramuscular endings for the abductor pollicis brevis. The region around 40% of the reference line was the point where the intramuscular endings were most dense for the abductor pollicis brevis. CONCLUSION: The results may provide guidelines that could help in localizing the appropriate points for the neuromuscular blockade of thumb-in-palm muscles and, at the same time, help in minimizing the inadvertent block of the abductor pollicis brevis.