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.

Inappropriate use of proton pump inhibitors in hospitalized patients with lower gastrointestinal bleeding.

OBJECTIVES: Use of proton pump inhibitors (PPIs) is a mainstay in treating upper gastrointestinal bleeding (UGIB). However, the beneficial effects of PPIs are not anticipated to extend beyond the duodenum and may actually contribute to the risk of lower gastrointestinal bleeding (LGIB). However, in practice, PPIs are often used for inpatients with LGIB where no benefit exists. METHODS: A retrospective chart review was performed on inpatients during a 2-year period at an urban academic teaching hospital. Inpatients with consults to the gastroenterology (GI) service with confirmed or highly suspected LGIB were included. Outcomes regarding PPI use and the GI consulting service recommendations in these 225 patients were evaluated. RESULTS: About 37.8% of patients were started on a PPI during their inpatient course. Of those, 46% patients started on a PPI had no indication for PPI and 85% had no recommendation by the GI consultants to start a PPI. Of the 85 patients started on PPI, the GI consultants recommended stopping it in two (2.3%) patients. Lastly, 20 patients (9%) were discharged on PPI without an indication for PPI. CONCLUSION: To our knowledge, this is the first study that looked at the inappropriate utilization of PPIs in patients admitted for LGIBs utilizing GI consultant recommendations. Given the large proportion of patients started on PPI without a clinical indication and continued at discharge and the paucity of GI recommendations to discontinue inappropriate use, we found that clinical care may be improved with formal GI recommendations regarding use of PPI.

Integrated Water-Level Sensor Using Thin-Film Transistor Technology.

A low-cost water-level sensor was developed utilizing a capacitive sensor design with only one thin-film transistor (TFT). The integration of the a-IGZO TFT process facilitated the complete integration of the water-level sensor on a substrate, including essential components, such as the transistor, capacitor, wires, and sensing electrode. This integration eliminates the need for a separate mounting process, resulting in a robust sensor assembly. To comprehensively assess the performance of the developed water-level sensor, rigorous evaluations were conducted using both MOSFET and TFT integration. In the case of the water-level sensor featuring a-IGZO TFT integration, a voltage output of 4.2 V was measured when the tank was empty, while a voltage output of 0.9 V was measured when the tank was full. Notably, the integrated sensor system demonstrated a higher output voltage compared with the MOSFET sensor, primarily due to the significantly reduced parasitic capacitance of the TFT. The use of a-IGZO TFT in the integrated sensor system contributes to enhanced sensitivity and accuracy. The lower parasitic capacitance inherent in TFT technology allows for improved voltage measurement precision, resulting in more reliable and precise water-level sensing capability. The development of this integrated water-level sensor holds immense potential for a wide range of applications that require a combination of cost-effectiveness, accurate monitoring, and flexibility in form factor. With its affordability, the sensor is accessible for various industries and applications.

Fluorine-Containing, Self-Assembled Graft Copolymer for Tuning the Hydrophilicity and Antifouling Properties of PVDF Ultrafiltration Membranes.

Neat poly(vinylidene fluoride) (PVDF) ultrafiltration (UF) membranes exhibit poor water permeance and surface hydrophobicity, resulting in poor antifouling properties. Herein, we report the synthesis of a fluorine-containing amphiphilic graft copolymer, poly(2,2,2-trifluoroethyl methacrylate)-g-poly(ethylene glycol) behenyl ether methacrylate (PTFEMA-g-PEGBEM), hereafter referred to as PTF, and its effect on the structure, morphology, and properties of PVDF membranes. The PTF graft copolymer formed a self-assembled nanostructure with a size of 7-8 nm, benefiting from its amphiphilic nature and microphase separation ability. During the nonsolvent-induced phase separation (NIPS) process, the hydrophilic PEGBEM chains were preferentially oriented towards the membrane surface, whereas the superhydrophobic PTFEMA chains were confined in the hydrophobic PVDF matrix. The PTF graft copolymer not only increased the pore size and porosity but also significantly improved the surface hydrophilicity, flux recovery ratio (FRR), and antifouling properties of the membrane. The membrane performance was optimal at 5 wt.% PTF loading, with a water permeance of 45 L m-2 h-1 bar-1, a BSA rejection of 98.6%, and an FRR of 83.0%, which were much greater than those of the neat PVDF membrane. Notably, the tensile strength of the membrane reached 6.34 MPa, which indicated much better mechanical properties than those reported in the literature. These results highlight the effectiveness of surface modification via the rational design of polymer additives and the precise adjustment of the components for preparing membranes with high performance and excellent mechanical properties.

Assessment of Cardiovascular Disease Among Predominantly Black Gout Patients.

INTRODUCTION: Although the association between gout and cardiovascular disease (CVD) has been extensively studied, scarce data are available for the Black population. We aimed to assess the association between gout and CVD in a predominantly Black urban population with gout. METHODS: A cross-sectional analysis was performed between a gout cohort and an age-/sex-matched control group. Clinical parameters and 2D echocardiograms were reviewed for the patients with gout and heart failure (HF). The primary outcome studied includes the prevalence and strength of association between gout and CVD. Secondary outcomes studied includes strength of association of gout and HF categorized by ejection fraction, mortality, and HF readmissions. RESULTS: Four hundred seventy-one patients with gout had a mean age of 63.7 ± 0.5 years; 89% were Black, 63% were men, and mean body mass index was 31.3 ± 0.4 kg/m 2 . Hypertension, diabetes mellitus, and dyslipidemia were present in 89%, 46%, and 52%, respectively. Compared with controls, patients with gout had significantly higher rates of angina, arrhythmia, coronary artery disease/stents, myocardial infarction, coronary artery bypass graft surgery, cerebrovascular accident, and peripheral vascular disease. The adjusted odds ratio for CVD was 2.9 (95% confidence interval, 1.9-4.5; p < 0.001). Gout patients had a higher prevalence of HF with 45% (n = 212) compared with controls with 9.4% (n = 44). Adjusted odds ratio for HF risk was 7.1 (95% confidence interval, 4.7-10.6; p < 0.01). CONCLUSIONS: Gout in a predominantly Black population confers 3 times the CVD risk and 7 times HF-specific risk compared with age- and sex-matched cohort. Further research is needed to confirm our findings and to develop interventions to reduce morbidity associated with gout.

Experimental and Computational Approaches to Sulfonated Poly(arylene ether sulfone) Synthesis Using Different Halogen Atoms at the Reactive Site.

Engineering thermoplastics, such as poly(arylene ether sulfone), are more often synthesized using F-containing monomers rather than Cl-containing monomers because the F atom is considered more electronegative than Cl, leading to a better condensation polymerization reaction. In this study, the reaction's spontaneity improved when Cl atoms were used compared to the case using F atoms. Specifically, sulfonated poly(arylene ether sulfone) was synthesized by reacting 4,4'-dihydroxybiphenyl with two types of biphenyl sulfone monomers containing Cl and F atoms. No significant difference was observed in the structural, elemental, and chemical properties of the two copolymers based on nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and electrochemical impedance spectroscopy. However, the solution viscosity and mechanical strength of the copolymer synthesized with the Cl-terminal monomers were slightly higher than those of the copolymer synthesized with the F-terminal monomers due to higher reaction spontaneity. The first-principle study was employed to elucidate the underlying mechanisms of these reactions.

Improving the application of laser-induced breakdown spectroscopy for the determination of total carbon in soils.

The increase of atmospheric greenhouse gases such as CO2 has caused noticeable climate change. Since increased CO2 may contribute to carbon storage in terrestrial ecosystems through the CO2 cycle between the atmosphere and vegetation, it is necessary to improve methods for measuring C in soil. In this study, we determined the total carbon concentrations of soils using a highly sensitive and rapid method, laser-induced breakdown spectroscopy. The presence of C has been measured by detecting signal at the wavelength of 247.86 nm. The obstacle of Fe interference at the C measurement wavelength of 247.86 nm was reduced by selecting the optimal delay time of 1.4 µs. The ratio of peak intensities (areas) at 247.86 nm for C and 248.20 nm for Fe was then successfully applied to the calibration curve. In addition, to dismiss the problem of measuring the C lines at 247.86 nm, 193.03 nm has been used to observe C emission. Both the 193.03- and 247.86-nm lines provided significant linear calibrations. The 193.03-nm lines presented stronger relative accuracies in predicting the lower C concentrations of the unknown samples than that one at 247.86 nm.

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.

Estimation of the properties of silver nanoparticle ink during laser sintering via in-situ electrical resistance measurement.

In this work, the in-situ properties of silver nanoparticle ink were estimated during laser sintering process. The silver nanoparticle ink was composed of 34 wt% silver nanoparticles with an average size of approximately 50 nm, and was deposited on a glass substrate via inkjet printing technology. A 532 nm continuous-wave laser was irradiated to the printed ink for 60 s under various laser intensities. During the laser irradiation, the in-situ electrical conductance of the sintered ink was measured to obtain the transient thermal conductivity of the silver nanoparticle ink using the Wiedemann Franz law. The 2-dimensional, transient heat-conduction equation was calculated to obtain the transient temperature of the silver nanoparticle ink. By coupling the calculated temperature with the measured, transient electrical conductance, the transient thermal conductivity of the ink during the laser sintering process was derived in the calculation. The calculated thermal conductivity of the ink sintered at a laser intensity of 467.9 W/cm2 with 598 K is 355.5 W/mK, which is 86.4% of the thermal conductivity of bulk silver, 411.4 W/mK, at that tempearture. The difference resulting from the porosity of the sintered ink has an effect on the thermal conductivity of the sintered ink.

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.

The effect of temperature on the electrical properties of inkjet-printed silver nanoparticle ink during electrical sintering.

In this work, the thermal behavior of ink-jet-printed nanoparticle ink during electrical sintering was demonstrated. The ink consisting of silver nanoparticles approximately 50 nm in size and 34 wt% was used. Constant currents of 0.11, 0.22, and 0.31 A were applied to Joule-heat the inkjet-printed silver nanoparticles. During the sintering process, in-situ voltage and current measurements were taken to calculate the heat source and thermal conductivity. In order to estimate the temperature during the electrical sintering process, numerical modeling of the two-dimensional heat conduction equation was adopted. Thermal conductivity was obtained from the in-situ electrical conductivity measurement and coupled to the numerical model using the Wiedemann Franz law. From these numerical modeling results, the relationship between the specific resistance of the ink and the temperature was determined. During the electrical sintering process, the specific resistance of the ink was strongly related to the sintering temperature. The specific resistance of the ink decreases as the process temperature rises.

Estimation of thermal conductivity of amorphous silicon thin films from the optical reflectivity measurement.

Amorphous silicon (a-Si) thin film material is widely used in liquid crystal display and solar cell applications. Knowledge of its properties is important in enhancing device performance. The properties of a-Si thin film have not been well understood due to the lack of periodicity of the structure. Furthermore, thermal conductivity of a-Si thin film is a key parameter to understand the complex phase transformation mechanism from a-Si thin film to polysilicon thin film by analyzing the transient temperature during the laser recrystallization process. In this work, thermal conductivity of a-Si thin film was determined by measuring optical reflectivity. A-Si thin film was irradiated with a KrF excimer laser beam to raise its temperature. The raised film temperature affects temperature-dependent optical properties such as refractive indices and extinction coefficients. The temperature-dependent optical properties of refractive indices and extinction coefficients of a-Si thin film were measured by ellipsometry. In-situ transient reflectivity at the wavelength of 633 nm was obtained during the excimer laser irradiation. The numerical simulation of one-dimensional conduction equation was solved so that transient reflectivities were calculated with temperature-dependent optical properties combined with thin film optics. Therefore, a well-fitted thermal conductivity was determined by comparing the numerically obtained transient reflectivity with the experimentally measured reflectivity data. The determined thermal conductivity of a-Si thin films was 1.5 W/mK.

Catalytic conversion of 1,2-dichlorobenzene using V2O5/TiO2 catalysts by a thermal decomposition process.

This study examined the catalytic oxidation of 1,2-dichlorobenzene on V(2)O(5)/TiO(2) nanoparticles. The V(2)O(5)/TiO(2) nanoparticles were synthesized by the thermal decomposition of vanadium oxytripropoxide and titanium tetraisopropoxide. The effects of the synthesis conditions, such as the synthesis temperature and precursor heating temperature, were investigated. The specific surface areas of V(2)O(5)/TiO(2) nanoparticles increased with increasing synthesis temperature and decreasing precursor heating temperature. The catalytic oxidation rate of the V(2)O(5)/TiO(2) catalyst formed by thermal decomposition process at a catalytic reaction temperature of 150 and 200 degrees C was 46% and 95%, respectively. As a result, it was concluded that the V(2)O(5)/TiO(2) catalysts synthesized by a thermal decomposition process showed good performance for 1,2-DCB decomposition at a lower temperature.