Simultaneous recrystallization, phosphorous diffusion and antireflection coating of silicon films using laser treatment

Laser technique application to polycrystalline silicon thin-film solar cell fabrication on glass substrates has received appreciable attention. In this paper, a laser-doping technique is developed for plasma-deposited amorphous silicon film. A process involving recrystallization, phosphorous diffusion and antireflection coating can be achieved simultaneously using the laser annealing process. The doping precursor, a phosphorous-doped titanium dioxide (TiO₂) solution, is synthesized using a sol-gel method and spin-coated onto the sample. After laser irradiation, the polycrystalline silicon grain size was about 0.5∼1.0 μm with a carrier concentration of 2 × 10¹⁹ cm^− 3 and electron mobility of 92.6 cm²/V s. The average polycrystalline silicon reflectance can be reduced to a value of 4.65% at wavelengths between 400 and 700 nm, indicating the upper TiO₂ film of antireflection coating.     

Carotene Degradation and Isomerization during Thermal Processing: A Review on the Kinetic Aspects

Kinetic models are important tools for process design and optimization to balance desired and undesired reactions taking place in complex food systems during food processing and preservation. This review covers the state of the art on kinetic models available to describe heat-induced conversion of carotenoids, in particular lycopene and β-carotene. First, relevant properties of these carotenoids are discussed. Second, some general aspects of kinetic modeling are introduced, including both empirical single-response modeling and mechanism-based multi-response modeling. The merits of multi-response modeling to simultaneously describe carotene degradation and isomerization are demonstrated. The future challenge in this research field lies in the extension of the current multi-response models to better approach the real reaction pathway and in the integration of kinetic models with mass transfer models in case of reaction in multi-phase food systems.     

Antiviral Activity of a Novel Compound CW-33 against Japanese Encephalitis Virus through Inhibiting Intracellular Calcium Overload

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, has five genotypes (I, II, III, IV, and V). JEV genotype I circulates widely in some Asian countries. However, current JEV vaccines based on genotype III strains show low neutralizing capacities against genotype I variants. In addition, JE has no specific treatment, except a few supportive treatments. Compound CW-33, an intermediate synthesized derivative of furoquinolines, was investigated for its antiviral activities against JEV in this study. CW-33 exhibited the less cytotoxicity to Syrian baby hamster kidney (BHK-21) and human medulloblastoma (TE761) cells. CW-33 dose-dependently reduced the cytopathic effect and apoptosis of JEV-infected cells. Supernatant virus yield assay pinpointed CW-33 as having potential anti-JEV activity with IC₅₀ values ranging from 12.7 to 38.5 μM. Time-of-addition assay with CW-33 indicated that simultaneous and post-treatment had no plaque reduction activity, but continuous and simultaneous treatments proved to have highly effective antiviral activity, with IC₅₀ values of 32.7 and 48.5 μM, respectively. CW-33 significantly moderated JEV-triggered Ca²⁺ overload, which correlated with the recovery of mitochondria membrane potential as well as the activation of Akt/mTOR and Jak/STAT1 signals in treated infected cells. Phosphopeptide profiling by LC-MS/MS revealed that CW-33 upregulated proteins from the enzyme modulator category, such as protein phosphatase inhibitor 2 (I-2), Rho GTPase-activating protein 35, ARF GTPase-activating protein GIT2, and putative 3-phosphoinositide-dependent protein kinase 2. These enzyme modulators identified were associated with the activation of Akt/mTOR and Jak/STAT1 signals. Meanwhile, I-2 treatment substantially inhibited the apoptosis of JEV-infected cells. The results demonstrated that CW-33 exhibited a significant potential in the development of anti-JEV agents.     

Disinfection Capacity of High-Power Ultrasound Against E. coli O157:H7 in Process Water of the Fresh-Cut Industry

The fresh-cut industry must treat process water to guarantee its microbial quality before reuse or recirculation back into the processing line. In the present study, the suitability of high-power ultrasound (HPU) for disinfecting and recycling process water was evaluated. An ultrasonic horn (20 kHz) was used to inactivate Escherichia coli O157:H7 inoculated in five types of process water which showed different physical and chemical characteristics. Differences in the inactivation level of E. coli O157:H7 at different HPU densities (0.14, 0.28, 0.56, and 1.12 kW/L) with controlled (20–25 °C) and uncontrolled (15–72 °C, 3.6 °C/min) temperature increase were studied. Results showed that the higher the power density and temperature, the higher the efficiency, reaching up to 6 log reductions of E. coli O157:H7. Alkalinity (between 0 and 253 mg HCO₃ ^?/L) and organic matter concentration (between 9 and 3,525 mg O₂/L) in water did not reduce ultrasonic efficacy against E. coli O157:H7. Agglomerates >90 μm, which represented 34 % of those present in the process water, were reduced to only 11 % by HPU. Results indicate that HPU can be successfully applied to treat process water of the fresh produce industry because the antimicrobial efficacy was not affected by the continuous variation of the process water quality. HPU can be a suitable technology for the fresh produce industry to be able to reduce consumption of water and decrease wastewater and the generation of disinfection by-products.     

Mimic Drug Dosage Modulation for Neuroplasticity Based on Charge-Trap Layered Electronics

The human brain is often likened to an incredibly complex and intricate computer, rather than electrical devices, consisting of billions of neuronal cells connected by synapses. Different brain circuits are responsible for coordinating and performing specific functions. The reward pathway of the synaptic plasticity in the brain is strongly related to the features of both drug addiction and relief. In the current study, a synaptic device based on layered hafnium disulfide (HfS₂) is developed for the first time, to emulate the behavioral mechanisms of drug dosage modulation for neuroplasticity. A strong gate-dependent persistent photocurrent is observed, arising from the modulation of substrate-trapping events. By controlling the polarity of gate voltage, the basic functions of biological synapses are realized under a range of light spiking conditions. Furthermore, under the control of detrapping/trapping events at the HfS₂/SiO₂ interface, positive/negative correlations of the A_n/A₁ index, which significantly reflected the weight change of synaptic plasticity, are realized under the same stimulation conditions for the emulation of the drug-related addition/relief behaviors in the brain. The findings provide a new advance for mimicking human brain plasticity.     

High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s⁻¹ with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation.     

Defect Engineering in Ambipolar Layered Materials for Mode-Regulable Nociceptor

Defect engineering represents a significant approach for atomically thick 2D semiconductor material development to explore the unique material properties and functions. Doping-induced conversion of conductive polarity is particularly beneficial for optimizing the integration of layered electronics. Here, controllable doping behavior in palladium diselenide (PdSe₂) transistor is demonstrated by manipulating its adatom-vacancy groups. The underlying mechanisms, which originate from reversible adsorption/desorption of oxygen clusters near selenide vacancy defects, are investigated systematically via their dynamic charge transfer characteristics and scanning tunneling microscope analysis. The modulated doping effect allows the PdSe₂ transistor to emulate the essential characteristics of photo nociceptor on a device level, including firing signal threshold and sensitization. Interestingly, electrostatic gating, acting as a neuromodulator, can regulate the adaptive modes in nociceptor to improve its adaptability and perceptibility to handle different danger levels. An integrated artificial nociceptor array is also designed to execute unique image processing functions, which suggests a new perspective for extension of the promise of defect engineered 2D electronics in simplified sensory systems toward use in advanced humanoid robots and artificial visual sensors.     

Spontaneous cervical epidural hematoma in a patient with end-stage renal disease

Spontaneous spinal epidural hematoma (SEH) is extremely rare in patients with end-stage renal disease (ESRD). We report a case of a 71-year-old man with ESRD presented with progressive left limb weakness. Magnetic resonance imaging (MRI) revealed spinal cervical SEH involving C3-5 level. The patient received emergent decompression laminectomy with the evacuation of the epidural hematoma.     

Mathematical modeling and numerical simulation of flow characteristics in an upflow reactor

Abstract

Determining and modeling of the extent of a treatment process in a reactor require knowledge of the flow characteristics. Residence time distribution (RTD), hydrodynamic dispersion coefficients, and velocity distribution are three important terms. Velocity distribution can be measured by a laser doppler anemometer (LDA) accurately, but RTD and hydrodynamic dispersion coefficients must be analyzed by mathematical modeling and dye testing. In this paper, the mathematical modeling and numerical simulation of a upflow reactor are developed. Rhodamine B and a fluorometer are used in laboratory testing. By applying the Euler FTCS (forward‐time‐center‐space) finite‐difference method, the results of dye tests and convection‐dispersion models are compared. The relationship between hydro‐dynamic dispersion coefficients and flow rates is discussed.