The synthesis of organosulfur compounds via the construction of C−S bonds using CO2 as a C1 resource is very interesting. Herein, a novel method of synthesizing benzothiazolones via the cyclocarbonylation of 2-aminothiophenols with CO2 was developed. A series of organic bases was investigated for the catalysis of cyclocarbonylation, and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) displayed the best catalytic activity. Then, various reaction parameters such as CO2 pressure, temperature, amount of catalyst, and reaction time for the catalytic performance were studied. Finally, a series of benzothiazolones was synthesized under the optimal reaction conditions, and a possible catalytic mechanism was also proposed.
The heat dissipation problem of high-power LEDs (Light-Emitting Diodes) limits their applications in automobile headlights. The heat demand for cooling LED headlights is analyzed based on heat transfer theory. This study proposes an initiative heat dissipation technology of temperature feedback control combined heat pipe and heat sink. The corresponding hardware and software control processes are designed. The temperature feedback control is realized with an MCU (Micro Control Unit) that judges and controls the synthetic jet device working process. A 3D model for the heat pipe radiator is constructed using CATIA. The model is optimized with the fluid thermodynamic simulation software FLOEFD. Finally, a sample lamp is prepared and tested with an infrared thermometer. The temperature distribution on each LED light source and radiator fin is quantitatively measured and analyzed. These results confirm that the designs of the thermal management system and the proposed technique solve the heat dissipation problem of high-power LED automotive headlights under the ambient temperature 50 °C indeed.
Structuring scaffold with both osteogenic and angiogenesis capabilities is a challenge for bone tissue engineering. Powder structured Si-CaP materials have shown excellent osteogenic properties and induction of stem cell differentiation. Our research group have successful produced 3D printed Si-CaP scaffolds by DLP technology. This study aims to explore the angiogenic effects of SiO
Abstract Transient global cerebral ischemia (tGCI) is a cerebrovascular disorder that can cause apoptotic neuronal damage and functional deficits. Basic fibroblast growth factor (bFGF) was reported to be highly expressed in the central nervous system (CNS) and to exert neuroprotective effects against different CNS diseases. However, the effects of bFGF on tGCI have not been studied intensively. This study was conducted to investigate the effect of bFGF and its underlying mechanism in an animal model of tGCI. After intracerebroventricular (i.c.v.) injection of bFGF, functional improvement was observed, and the number of viable neurons increased in the ischemia-vulnerable hippocampal CA1 region. Apoptosis was induced after tGCI and could be attenuated by bFGF treatment via inhibition of p53 mitochondrial translocation. In addition, autophagy was activated during this process, and bFGF could inhibit activation of autophagy through the mTOR pathway. Rapamycin, an activator of autophagy, was utilized to explore the relationship among bFGF, apoptosis, and autophagy. Apoptosis deteriorated after rapamycin treatment, which indicated that excessive autophagy could contribute to the apoptosis process. In conclusion, these results demonstrate that bFGF could exert neuroprotective effects in the hippocampal CA1 region by suppressing excessive autophagy via the mTOR pathway and inhibiting apoptosis by preventing p53 mitochondrial translocation. Furthermore, our results suggest that bFGF may be a promising therapeutic agent to for treating tGCI in response to major adverse events, including cardiac arrest, shock, extracorporeal circulation, traumatic hemorrhage, and asphyxiation.
The pressure drop and particular geometric structure of the nozzle exit region of an effervescent atomizer cause complex changes in the flow pattern, which could affect the spray performance. In this study, the gas–liquid two-phase flow behavior in the nozzle exit region of the effervescent atomizer was investigated numerically. The results show that the flow behaviors in the nozzle exit region have disparate characteristics with different upstream flow regimes. For upstream churn flow, the liquid film morphology is closely related to fluctuation in the gas–liquid velocity, and the flow parameters (fluids’ velocities and gas void fraction) at the exit section vary regularly with time. For upstream bubbly flow, the instantaneous gas void fraction is determined by the bubble distribution inside the mixing chamber. The bubble will form a tadpole-like shape as a result of the complex flow field and the surface tension. The flow parameters at the exit section are in an oscillatory decay, and the fluctuation amplitude is larger than for churn flow. For upstream slug flow, the gas void fraction varies significantly with time. The discrete characteristic of the gas–liquid flow parameters at exit section is very obvious.
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