Organic integrated circuits using room-temperature sintered silver nanoparticles as printed electrodes

Organic integrated circuits based on organic thin-film transistor (TFT) devices are fabricated with solution-based electrodes by using dense inks of silver nanoparticles, which can be sintered at room-temperature. The TFT devices fabricated at a sintering temperature of 30 °C exhibit good electrical characteristics. There is a strong relation between the sintering temperature of silver nanoparticle inks and transistor characteristics. A work function of silver electrodes can be controlled by changing the sintering temperature of silver nanoparticle inks, thereby threshold voltage of fabricated TFT devices are shifted accordingly. Fabricated pseudo-CMOS inverter circuits are successfully operated at low voltage with small hysteresis, and large gains are obtained. These results suggest that printed organic TFT devices fabricated with a low-temperature process enable large-area and low-cost integrated circuits by using these techniques in future applications.     

All-digital A/D converter TAD with high-resolution and low-power for sensor/RF digitization

For achieving both high resolution and low power of a sensor/RF interface, time-domain processing using full-digital circuits, which deals with only two voltage levels (i.e., V _in-supply-voltage and ground-level), is presented. In a much broader sense, digital circuits can be used for time-domain processing instead of conventional analog signal processing. In this study, an all-digital 6- to 16-bit adaptive sensor-interface ADC is experimentally evaluated for high-resolution and low-power operation along with high scalability. The circuit architecture is completely digital, using a ring-delay-line (RDL) driven by an input voltage V _in as its power supply. Resolutions can be controlled by setting its conversion time T _cv, resulting in 16 bit (1 kS/s, 34 μW) and 6 bit (1 MS/s, 48 μW) with a prototype IC in a low-cost 0.65-μm (650-nm) digital CMOS, achieving the sensor digitizer (sensor-digitization product) of a pressure sensor ASIC. The all-digital structure has been scaled into a 0.18-μm technology, and the test IC presented a higher performance with 28 μV/LSB (160-kS/s). Finally, as an RF digitization application, the circuit is demonstrated to realize the time-domain processing of an RF signal, working as both mixer and ADC, achieving minimum/maximum detectable sensitivity of 0.7-μVrms/100-mVrms, respectively, for a 40-kHz sine wave at the LNA input terminal of a 0.18-μm digital CMOS one-chip radio-controlled clock receiver IC.     

Intravenous injection of tridihomo-γ-linolenoyl-glycerol into mice and its effects on delayed-type hypersensitivity

Highly purified tridihomo-γ-linolenoyl-glycerol (DGLA-TG) was emulsified with egg yolk lecithin as a 10% (wt/vol) DGLA-TG emulsion. We injected 0.05 or 0.5 mL of the emulsion into mice through the tail vein and investigated its effects on the fatty acid composition of spleen cells and on delayed-type hypersensitivity (DTH) response. At 1 h after the injection, dihomo-γ-linolenic acid (DGLA) concentrations were increased significantly in the total phospholipid fraction of spleen cells from 1.21±0.13 mol% to 2.09 ±0.74 mol% (P<0.02) and 7.95±1.25 mol% (P<0.001) in the 0.05-mL and 0.05-mL groups respectively. Mice, which had already been immunized with sheep red blood cells (SRBC), were challenged by the injection of SRBC into the right-hind footpad. Intravenous injection into mice with 0.5 mL of the emulsion immediately before the challenge almost completely suppressed DTH response measured by the swelling of the right-hind footpads 24 h thereafter. This inhibitory effect on the DTH response was significant with as little as 0.05 mL of the emulsion, whereas a soybean oil emulsion was not effective at all. In conclusion, intravenous injection of a DGLA emulsion increased DGLA concentrations in immune cells within 1 h and suppressed the DTH reaction.     

Effect of a phase-transfer catalyst on the chemical modification of poly(vinyl chloride) by substitution with thiocyanate as a nucleophile

This study examined the effect of the phase-transfer catalysts tetrabutylammonium bromide (TBAB) and tetrabutylammonium hydrogen sulfate (TBAHS) on the chemical modification of poly(vinyl chloride) (PVC) by substitution with thiocyanate as a nucleophile. TBAB accelerated the dechlorination of PVC in SCN/ethylene glycol (EG) solution. Furthermore, the addition of TBAB to SCN/EG solution improved the substitution of the Cl in PVC with SCN in solution. The addition of TBAB or TBAHS to SCN/H₂O solution promoted the dechlorination of PVC, whereas dechlorination did not occur without the catalyst. The catalysts preferred substitution to the elimination of HCl in SCN/H₂O solution, and TBAB was slightly superior to TBAHS in terms of the degree and selectivity of the substitution. The addition of nitrobenzene to SCN/H₂O solution with TBAB increased the degree of substitution. Consequently, phase-transfer catalysts, particularly TBAB, were very effective at promoting the substitution of Cl in PVC with SCN in solution.     

Molecular dynamics simulation analyses on injection angle dependence of SiO2 sputtering yields by fluorocarbon beams

Angular dependence of sputtering yields of SiO₂ substrates subject to CF₃ beam injections is evaluated with the use of molecular dynamics simulations. The obtained sputtering yield data are in reasonable agreement with experimental observations. Atomic compositions in the SiO₂-CF mixing layer as well as kinetic energies and atomic compositions of sputtered species also exhibit strong dependence of the injection angle.     

Hybrid inorganic/organic composites of Mg-Al layered double hydroxides intercalated with citrate, malate, and tartrate prepared by co-precipitation

Inorganic/organic composite materials composed of Mg-Al layered double hydroxides (Mg-Al LDHs) intercalated with citrate (C₆H₅O₇³⁻), malate (C₄H₄O₅²⁻), or tartrate (C₄H₄O₆²⁻) anions were prepared by a co-precipitation technique and characterized by X-ray diffraction and compositional analyses. The molecular orientation of the organic component in the interlayer space was determined. At low intercalation levels, citrate ion was inclined at an angle of 26° relative to the brucite-like layers of Mg-Al LDH. At higher solution concentrations, both the Mg(C₆H₅O₇)⁻ complex and free C₆H₅O₇³⁻ were isotropically oriented in the interlayer space. For both malate·Mg-Al LDH and tartrate·Mg-Al LDH, the organic anions were inclined at 26° relative to the Mg-Al LDH layers regardless of anion concentration.     

Inverse association between docosahexaenoic acid and mortality in patients on hemodialysis during over 10 years

We have previously conducted a cohort study to investigate n‐3 polyunsaturated fatty acids (PUFAs) in red blood cells (RBCs) and risk of all‐cause mortality in hemodialysis (HD) patients over 5 years and found that n‐3 PUFAs, especially docosahexaenoic acid (DHA), might be an independent predictor of all‐cause mortality. In the present study, we extended the study for another 5 years to determine whether DHA levels in RBCs still predict the mortality of HD patients during a 10‐year study period. The study cohort consisted of 176 patients (64.1 ± 12.0 [mean ± standard deviation] years of age, 96 men and 80 women) under HD treatment. The fatty acid composition of patients' RBCs was analyzed by gas chromatography. During the study period of 10 years, 97 deaths occurred. After adjustment for 10 confounding factors, the hazard ratio of all‐cause mortality of the HD patients in the highest DHA tertile (>8.1%) was 0.52 (95% confidence interval 0.30–0.91) compared with those in the lowest DHA tertile (<7.2%). However, other n‐3 PUFAs such as eicosapentaenoic acid and docosapentaenoic acid (n‐3) did not reveal any significant correlations. The level of DHA in RBCs could be an independent predictor of all‐cause mortality in HD patients even during a long period of follow‐up.     

Large photocurrent-response observed at Pt/InP Schottky interface formed on anodic porous structure

A photoelectric-conversion device—based on an InP porous structure utilizing the large surface area inside pores and the low reflectance on the porous surface—is proposed. The InP walls inside the pores are covered with thin platinum films that form a Schottky barrier yielding an electric field that separates photo carriers generated under illumination. The coverage of the platinum film and its optical reflectance depended largely on the surface morphology of the porous structure. Removal of the irregular top layer formed at the initial stage of the pore formation effectively improved the coverage of the platinum film, which showed a very low optical reflectance (i.e., below 3.2%). According to current-voltage measurements under illumination, the platinum/porous InP showed larger photocurrents and higher responsivity than those of a reference planar sample.     

Thermodynamic study of the effect of calcium on removal of phosphorus from silicon by acid leaching treatment

The interaction between calcium and phosphorus in molten silicon was investigated for predicting the removal of phosphorus from silicon by an acid leaching treatment with calcium addition. In the present study, two immiscible liquids of silicon and lead were equilibrated, and the interaction parameter between calcium and phosphorus and the self-interaction parameter of phosphorus in molten silicon at 1723 K were determined.