Experimental Study on NOx Reduction of Diesel Engine by EGR Coupled with SCR.

Exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) are crucial technologies for mitigating nitrogen oxide (NOx) emissions in diesel engines. Although EGR reduces engine outlet NOx emissions, it simultaneously increases diesel consumption, leading to a poor economic performance. SCR requires AdBlue consumption; thus, striking the right balance for overall engine economy is of utmost importance. This study aims to evaluate NOx emission control and fluid cost in diesel engines. The total fluid cost of the diesel engine includes diesel and AdBlue. The engine is equipped with an aftertreatment system comprising a diesel oxidation catalyst (DOC), diesel particulate filter (DPF), selective catalytic reduction (SCR), and ammonia slip catalyst (ASC). The study was carried out at 1600 and 2100 rpm (25, 50, 75, and 100% load). The results show that with the increase of EGR valve opening, the exhaust temperature increased, the brake-specific fuel consumption (BSFC) increased, and the NOx emission decreased. With the increased AdBlue dosage, the NOx conversion efficiency gradually improved, ultimately approaching near-zero NOx emissions. However, as NOx emissions decreased, the equivalent diesel fluid cost rose. At 1600 r/min (100% load), when the NOx emissions were reduced by zero, the maximum fluid costs were 235, 223, and 218g/(kW·h) under the AdBlue/diesel price ratios of 1/1, 1/2, and 1/3, respectively. As the AdBlue/diesel price ratio decreases, the influence of EGR on the fluid cost diminishes. Coordinated control of EGR and AdBlue allows for reduced NOx emissions while mitigating the overall cost of diesel engines and aftertreatment systems. This research provides valuable guidance for EGR and urea control in diesel engines and contributes to the field of diesel engine emission control.

Monitoring and evaluation of anesthesia depth status data based on neuroscience.

Monitoring and analysis of anesthesia depth status data refers to evaluating the anesthesia depth status of patients during the surgical process by monitoring their physiological index data, and conducting analysis and judgment. The depth of anesthesia is crucial for the safety and success of the surgical process. By monitoring the state of anesthesia depth, abnormal conditions of patients can be detected in a timely manner and corresponding measures can be taken to prevent accidents from occurring. Traditional anesthesia monitoring methods currently include computer tomography, electrocardiogram, respiratory monitoring, etc. In this regard, traditional physiological indicator monitoring methods have certain limitations and cannot directly reflect the patient's neural activity status. The monitoring and analysis methods based on neuroscience can obtain more information from the level of brain neural activity. PURPOSE: In this article, the monitoring and analysis of anesthesia depth status data would be studied through neuroscience. METHODS: Through a controlled experiment, the monitoring accuracy of traditional anesthesia status monitoring algorithm and neuroscience-based anesthesia status monitoring algorithm was studied, and the information entropy and oxygen saturation of electroencephalogram signals in patients with different anesthesia depth were explored. RESULTS: The experiment proved that the average monitoring accuracy of the traditional anesthesia state monitoring algorithm in patients' blood drug concentration and oxygen saturation reached 95.55 and 95.00%, respectively. In contrast, the anesthesia state monitoring algorithm based on neuroscience performs better, with the average monitoring accuracy of drug concentration and oxygen saturation reaching 98.00 and 97.09%, respectively. This experimental result fully proved that the monitoring performance of anesthesia state monitoring algorithms based on neuroscience is better. CONCLUSION: The experiment proved the powerful monitoring ability of the anesthesia state monitoring algorithm based on neuroscience used in this article, and explained the changing trend of brain nerve signals and oxygen saturation of patients with different anesthesia depth states, which provided a new research method for the monitoring and analysis technology of anesthesia depth state data.

Study on Diesel Engine Selective Catalytic Reduction Performance at Different Atmospheric Pressures Using the Response Surface Method.

Nitrogen oxides (NO x ) are the main emissions of diesel engines. Selective catalytic reduction (SCR) is the main technology used to reduce NO x emissions from diesel engines. NO x conversion efficiency and ammonia (NH3) escape are the main indicators to evaluate SCR performance. In this work, the effects of diesel engine exhaust temperature and exhaust mass flow rate on the SCR performance under different atmospheric pressures were studied by the combination method of experiment and one-dimensional numerical simulation. At the same time, the response surface method (RSM) was used to analyze the interaction of atmospheric pressure, exhaust temperature, and exhaust mass flow rate on the SCR performance. The results show that the lower the atmospheric pressure, the lower the NO x conversion efficiency and ammonia escape. Under the same exhaust temperature, the lower the atmospheric pressure, the smaller the impact of exhaust mass flow rate on NO x conversion efficiency. According to the RSM results, the optimal NO x conversion efficiency is 78.6% under the combination working conditions of an atmospheric pressure of 100 kPa, exhaust temperature of 395 °C, and exhaust mass flow rate of 250 kg/h, and the NH3 escape is also at a low level of 1.7 g/cycle.

Association between multiple gene promoter hypermethylation and the risk of gastric cancer: A systematic review and meta-analysis.

BACKGROUND: Several studies have demonstrated an association between multiple gene hypermethylation and gastric cancer. However, the intrinsic mechanisms remain elusive and highly debatable. To this end, our study aims to investigate the correlation between the methylation status of multiple gene promoters and gastric cancer. METHODS: PubMed, EMBASE, CNKI, WanFang, Cqvip, and Cochrane Library were queried from inception to May 2021, and the relationship between the methylation status of the CpG islands and gastric cancer risk was systematically assessed under the inclusion and exclusion criteria. The incidence of DNA methylation between tumor and non-tumor tissues was compared, and the clinicopathological significance of DNA methylation in gastric carcinoma was further evaluated. The odds ratio (OR) was estimated with a 95% confidence interval (CI), and forest plots were generated using the fixed-effects or random-effects model. RESULTS: In total, 201 studies were enrolled, and a higher frequency of CpG islands methylation was identified in gastric cancer tissues than in non-neoplastic tissues. This suggests that aberrant polygene methylation might be associated with the initial onset and progression of gastric cancer. CONCLUSION: This study sheds light on the significance of polygene methylation status in gastric cancer. The DNA methylation of these genes may serve as underlying epigenetic biomarkers, providing a promising molecular diagnostic approach for human gastric cancer clinical diagnosis. More large randomized trials are needed to confirm the findings.

Overexpression of RAD51B predicts a preferable prognosis for non-small cell lung cancer patients.

Lung cancer is the leading cause of cancer-related death. The majority of patients are diagnosed at an incurable advanced stage with poor prognosis. A recent study associated the methylation of homologous recombination genes with expression of immune checkpoints in lung squamous cell carcinoma. However, the correlation between them remains unclear. In our study, we propose that RAD51B, a repair gene in the homologous recombination process, which is noticed to be a key player in the maintenance of chromosome integrity and in sensing DNA damage, can act as an independent factor affecting the prognosis of non-small-cell lung cancer (NSCLC). Univariate analysis showed that overexpression of RAD51B is statistically significant correlated with better prognosis (P=0.013). Further, the multivariate Cox regression analysis showed that the morbidity of patients with high expression of RAD51B was decreased by 26% compared to those with low expression (HR=0.74, 95%CI: 0.59-0.93), especially for the patients with squamous cell carcinoma (HR=0.68, 95%CI: 0.51-0.90). In conclusion, RAD51B in mRNA level can be an important indicator to decide the prognosis of NSCLC and its overexpression predicts a preferable prognosis for NSCLC. Our results serve as a foundation for the investigation of the role of RAD51B in NSCLC, which may lead to potential therapeutic innovations.

Performance and emission characteristics of diesel engine fueled with ethanol-diesel blends in different altitude regions.

In order to investigate the effects ethanol-diesel blends and altitude on the performance and emissions of diesel engine, the comparative experiments were carried out on the bench of turbo-charged diesel engine fueled with pure diesel (as prototype) and ethanol-diesel blends (E10, E15, E20 and E30) under different atmospheric pressures (81 kPa, 90 kPa and 100 kPa). The experimental results indicate that the equivalent brake-specific fuel consumption (BSFC) of ethanol-diesel blends are better than that of diesel under different atmospheric pressures and that the equivalent BSFC gets great improvement with the rise of atmospheric pressure when the atmospheric pressure is lower than 90 kPa. At 81 kPa, both HC and CO emissions rise greatly with the increasing engine speeds and loads and addition of ethanol, while at 90 kPa and 100 kPa their effects on HC and CO emissions are slightest. The changes of atmospheric pressure and mix proportion of ethanol have no obvious effect on NO(x) emissions. Smoke emissions decrease obviously with the increasing percentage of ethanol in blends, especially atmospheric pressure below 90 kPa.

Production of reactive oxygen species, impairment of photosynthetic function and dynamic changes in mitochondria are early events in cadmium-induced cell death in Arabidopsis thaliana.

BACKGROUND INFORMATION: Cadmium (Cd) is a highly toxic heavy metal that causes changes in plant metabolism through inhibiting photosynthesis and respiration. The effects of Cd on the morphology and function of the chloroplast and mitochondria, as well as on the production and localization of ROS (reactive oxygen species), were studied at the single-cell level in Arabidopsis. RESULTS: The present study showed that the morphology of chloroplasts changed after Cd treatment, and the photochemical efficiency dramatically declined prior to obvious morphological distortion in the chloroplasts. A quick burst of ROS was detected after Cd treatment. The ROS appeared first in the mitochondria and subsequently in the chloroplast. Simultaneously, the mitochondria clumped irregularly around the chloroplasts or aggregated in the cytoplasm, and the movement of mitochondria was concomitantly blocked. Furthermore, the production of ROS was decreased after pre-treatment with ascorbic acid or catalase, which prevented inhibition of photosynthesis, organelle changes and subsequent protoplast death. Our results suggest that the distribution and mobility of mitochondria, the morphology of chloroplasts and the accumulation of ROS play important roles in Cd-induced cell death. The results are in good agreement with previous reports of many types of apoptotic-like cell death. CONCLUSION: The changes in the distribution and mobility of mitochondria, and morphology of chloroplasts, as well as the accumulation of ROS, play important roles in Cd-induced cell death.