Structure and laminar flame speed of an ammonia/methane/air premixed flame under varying pressure and equivalence ratio

This paper presents a joint experimental and numerical study on premixed laminar ammonia/methane/air flames, aiming to characterize the flame structures and NO formation and determine the laminar flame speed under different pressure, equivalence ratio, and ammonia fraction in the fuel. The experiments were carried out in a lab-scale pressurized vessel with a Bunsen burner installed with a concentric co-flow of air. Measurements of NH and NO distributions in the flames were made using planar laser-induced fluorescence. A novel method was presented for determination of the laminar flame speed from Bunsen-burner flame measurements, which takes into account the non-uniform flow in the unburned mixture and local flame stretch. NH profiles were chosen as flame front markers. Direct numerical simulation of the flames and one-dimensional chemical kinetic modeling were performed to enhance the understanding of flame structures and evaluate three chemical kinetic mechanisms recently reported in the literature. The stoichiometric and fuel-rich flames exhibit a dual-flame structure, with an inner premixed flame and an outer diffusion flame. The two flames interact, which affects the NO emissions. The impact of the diffusion flame on the laminar flame speed of the inner premixed flame is however minor. At elevated pressures or higher ammonia/methane ratios, the emission of NO is suppressed as a result of the reduced radical mass fraction and promoted NO reduction reactions. It is found that the laminar flame speed measured in the present experiments can be captured by the investigated mechanisms, but quantitative predictions of the NO distribution require further model development

A novel small molecule ZYZ384 targeting SMYD3 for hepatocellular carcinoma via reducing H3K4 trimethylation of the Rac1 promoter

SMYD3 (SET and MYND domain-containing 3) is a histone lysine methyltransferase highly expressed in different types of cancer(s) and is a promising epigenetic target for developing novel antitumor therapeutics. No selective inhibitors for this protein have been developed for cancer treatment. Therefore, the current study describes developing and characterizing a novel small molecule ZYZ384 screened and synthesized based on SMYD3 structure. Virtual screening was initially used to identify a lead compound and followed up by modification to get the novel molecules. Several technologies were used to facilitate compound screening about these novel molecules' binding affinities and inhibition activities with SMYD3 protein; the antitumor activity has been assessed in vitro using various cancer cell lines. In addition, a tumor-bearing nude mice model was established, and the activity of the selected molecule was determined in vivo. Both RNA-seq and chip-seq were performed to explore the antitumor mechanism. This work identified a novel small molecule ZYZ384 targeting SMYD3 with antitumor activity and impaired hepatocellular carcinoma tumor growth by reducing H3K4 trimethylation of the Rac1 promoter triggering the tumor cell cycle arrest through the AKT pathway

Chemically-Induced Cancers Do Not Originate from Bone Marrow-Derived Cells

BACKGROUND: The identification and characterization of cancer stem cells (CSCs) is imperative to understanding the mechanism of cancer pathogenesis. Growing evidence suggests that CSCs play critical roles in the development and progression of cancer. However, controversy exists as to whether CSCs arise from bone marrow-derived cells (BMDCs). METHODOLOGY AND PRINCIPAL FINDINGS: In the present study, n-nitrosodiethylamine (DEN) was used to induce tumor formation in female mice that received bone marrow from male mice. Tumor formation was induced in 20/26 mice, including 12 liver tumors, 6 lung tumors, 1 bladder tumor and 1 nasopharyngeal tumor. Through comparison of fluorescence in situ hybridization (FISH) results in corresponding areas from serial tumor sections stained with HandE, we determined that BMDCs were recruited to both tumor tissue and normal surrounding tissue at a very low frequency (0.2-1% in tumors and 0-0.3% in normal tissues). However, approximately 3-70% of cells in the tissues surrounding the tumor were BMDCs, and the percentage of BMDCs was highly associated with the inflammatory status of the tissue. In the present study, no evidence was found to support the existence of fusion cells formed form BMDCs and tissue-specific stem cells. CONCLUSIONS: In summary, our data suggest that although BMDCs may contribute to tumor progression, they are unlike to contribute to tumor initiation.published_or_final_versio

Natural carriers in bioremediation: a review

Bioremediation of contaminated groundwater or soil is currently the cheapest and the least harmful method of removing xenobiotics from the environment. Immobilization of microorganisms capable of degrading specific contaminants significantly promotes bioremediation processes, reduces their costs, and also allows for the multiple use of biocatalysts. Among the developed methods of immobilization, adsorption on the surface is the most common method in bioremediation, due to the simplicity of the procedure and its non-toxicity. The choice of carrier is an essential element for successful bioremediation. It is also important to consider the type of process (in situ or ex situ), type of pollution, and properties of immobilized microorganisms. For these reasons, the article summarizes recent scientific reports about the use of natural carriers in bioremediation, including efficiency, the impact of the carrier on microorganisms and contamination, and the nature of the conducted research

A compendium of genetic regulatory effects across pig tissues

The Farm Animal Genotype-Tissue Expression (FarmGTEx) project has been established to develop a public resource of genetic regulatory variants in livestock, which is essential for linking genetic polymorphisms to variation in phenotypes, helping fundamental biological discovery and exploitation in animal breeding and human biomedicine. Here we show results from the pilot phase of PigGTEx by processing 5,457 RNA-sequencing and 1,602 whole-genome sequencing samples passing quality control from pigs. We build a pig genotype imputation panel and associate millions of genetic variants with five types of transcriptomic phenotypes in 34 tissues. We evaluate tissue specificity of regulatory effects and elucidate molecular mechanisms of their action using multi-omics data. Leveraging this resource, we decipher regulatory mechanisms underlying 207 pig complex phenotypes and demonstrate the similarity of pigs to humans in gene expression and the genetic regulation behind complex phenotypes, supporting the importance of pigs as a human biomedical model.</p

DGAT1 Expression Promotes Ovarian Cancer Progression and Is Associated with Poor Prognosis

Background. Ovarian cancer is the most fatal gynecological malignancy. Owing to its insidious onset, rapid development, and poor prognosis, ovarian cancer is the fifth most common cause of death in women. Although immunotherapy-related drugs, such as Olaparib, can alleviate ovarian cancer progression, there are no remarkable breakthroughs for its effective treatment. It is considered that the transformation of normal cells to cancerous ones involves “recoding” of certain metabolic pathways. Diacylglycerol O-acyltransferase 1 (DGAT1) can synthesize triglycerides by transferring acyl-CoA to diacylglycerol, which plays a key role in lipid synthesis. However, the role of DGAT1 in ovarian cancer is not yet elucidated. Materials and Methods. We analyzed the correlation between DGAT1 and ovarian cancer staging, grading, vascular invasion, and prognosis by collating the information of ovarian cancer specimens from The Cancer Genome Atlas (TCGA) database. Furthermore, the effects of DGAT1 expression on proliferation, migration, invasion, and tumor growth were studied using ovarian cancer cell lines. GSEA was used to analyze the KEGG pathways and biological function enriched because of DGAT1 expression in ovarian cancer. Results. The expression of DGAT1 was elevated in advanced (p=0.0432), poorly differentiated (p=0.0148), and vascular invaded (p=0.0002) ovarian cancer specimens. Prognosis among patients with high expression of DGAT1 was poor. After DGAT1 expression was interfered, proliferation, migration, invasion, colony forming, and tumor growth of ovarian cancer cells were inhibited. In addition, GSEA showed that DGAT1 may be involved in the immune process. Conclusion. DGAT1 expression is associated with the clinical phenotype of ovarian cancer. We suggest that DGAT1 has potential implications in the treatment of ovarian cancer

Experimental study of an anti-icing method over an airfoil based on pulsed dielectric barrier discharge plasma

Aircraft icing has long been a plague to aviation for its serious threat to flight safety. Even though lots of methods for anti-icing have been in use or studied for quite a long time, new methods are still in great demand for both civil and military aircraft. The current study in this paper uses widely used Dielectric Barrier Discharge (DBD) plasma actuation to anti-ice on a NACA0012 airfoil model with a chord length of 53.5 cm in a closed-circuit icing wind tunnel. An actuator was installed at the leading edge of the airfoil model, and actuated by a pulsed low-temperature plasma power source. The actuator has two types of layout, a striped electrode layout and a meshy electrode layout. The ice accretion process or anti-icing process was recorded by a CCD camera and an infrared camera. Instantaneous pictures and infrared contours show that both types of DBD plasma actuators have the ability for anti-ice under a freestream velocity of 90 m/s, a static temperature of −7 °C, an Median Volume droplet Diameter (MVD) of 20 μm, and an Liquid Water Content (LWC) of 0.5 g/m3. The detected variations of temperatures with time at specific locations reveal that the temperatures oscillate for some time after spraying at first, and then tend to be nearly constant values. This shows that the key point of the anti-icing mechanism with DBD plasma actuation is to achieve a thermal equilibrium on the model surface. Besides, the power consumption in the anti-icing process was estimated in this paper by Lissajous figures measured by an oscilloscope, and it is lower than those of existing anti-icing methods. The experimental results presented in this paper indicate that the DBD plasma anti-icing method is a promising technique in the future. Keywords: Anti-icing, Icing wind tunnel, Lissajous figures, Plasma actuator, Pulsed dielectric barrier discharg

Combined gas well hydrate prevention and control technology and its application.

The high pressure in some gas wells, such as those in the Xushen gas field in Daqing, China, makes them susceptible to freezing and hydrate blockages. Downhole throttling technology is widely used to reduce costs during well construction, however, due to the limitations of temperature, pressure and depth structure, this technology is sometime applied independently in some gas wells in which freezing and blockages are a frequent problem that can seriously affect production capacity. Moreover, artificial alcohol injection of 'passive plugging' to prevent hydrate formation not only consumes significant amounts of methanol but its efficiency is also dependent on factors such as weather, personnel and equipment, so it is not a continuous solution. In order to solve the above problems, the mechanism of hydrate formation was analyzed in this study, from which a combined mechanical and chemical hydrate control process was developed. OLGA software was used to design the process parameters of the novel mechanical and chemical inhibition technology for hydrate prevention and control, and also to simulate and analyze the wellhead temperature, pressure and hydrate generation once the process was implemented. Based on the results of the parameters calculation, the downhole throttle and hydrate inhibitor automatic filling device are used to realize the functions of downhole throttle depressurization and hydrate inhibitor continuous filling, reduce the wellhead pressure and hydrate generation temperature, and ensure the continuous production of gas well. This novel combination process was subsequently tested in three wells in the Daqing gas oilfield. Measurements showed that the average daily gas increase from a single well was 0.5×104m3, methanol consumption was reduced from the original maximum daily amount of 1750 kg to just 60 kg, the manual maintenance workload was reduced by 80%, and the rate of the well openings was increased from 45% to 100%. These results proved that this technology is feasible and efficient for applications in gas wells with high downhole pressure and low wellhead temperature, and, thus, provides important technical support for the prevention of gas hydrate and improvement of gas well production