The Generation And Experimental Study Of Microscale Droplets In Drop-On-Demand Inkjet Printing

Ph.DDOCTOR OF PHILOSOPH

Stemness Analysis Uncovers That The Peroxisome Proliferator-Activated Receptor Signaling Pathway Can Mediate Fatty Acid Homeostasis In Sorafenib-Resistant Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) stem cells are regarded as an important part of individualized HCC treatment and sorafenib resistance. However, there is lacking systematic assessment of stem-like indices and associations with a response of sorafenib in HCC. Our study thus aimed to evaluate the status of tumor dedifferentiation for HCC and further identify the regulatory mechanisms under the condition of resistance to sorafenib. Datasets of HCC, including messenger RNAs (mRNAs) expression, somatic mutation, and clinical information were collected. The mRNA expression-based stemness index (mRNAsi), which can represent degrees of dedifferentiation of HCC samples, was calculated to predict drug response of sorafenib therapy and prognosis. Next, unsupervised cluster analysis was conducted to distinguish mRNAsi-based subgroups, and gene/geneset functional enrichment analysis was employed to identify key sorafenib resistance-related pathways. In addition, we analyzed and confirmed the regulation of key genes discovered in this study by combining other omics data. Finally, Luciferase reporter assays were performed to validate their regulation. Our study demonstrated that the stemness index obtained from transcriptomic is a promising biomarker to predict the response of sorafenib therapy and the prognosis in HCC. We revealed the peroxisome proliferator-activated receptor signaling pathway (the PPAR signaling pathway), related to fatty acid biosynthesis, that was a potential sorafenib resistance pathway that had not been reported before. By analyzing the core regulatory genes of the PPAR signaling pathway, we identified four candidate target genes, retinoid X receptor beta (RXRB), nuclear receptor subfamily 1 group H member 3 (NR1H3), cytochrome P450 family 8 subfamily B member 1 (CYP8B1) and stearoyl-CoA desaturase (SCD), as a signature to distinguish the response of sorafenib. We proposed and validated that the RXRB and NR1H3 could directly regulate NR1H3 and SCD, respectively. Our results suggest that the combined use of SCD inhibitors and sorafenib may be a promising therapeutic approach

Experimental and Numerical Investigations of Fracture Behavior for Transversely Isotropic Slate Using Semi-Circular Bend Method

Slate with inherently transverse isotropy is abundant in metamorphic rock, in buildings, and in geotechnical engineering worldwide; the tensile and shear fracture behavior of layered slate is vital to know for engineering applications. In this paper, the Brazilian and semi-circular bend (SCB) tests of layered slate were performed. The fracture characteristics of the slate were investigated by numerical simulations developed by the hybrid finite and cohesive element method (FCEM). Results showed that the measured experimental tensile strength, and mode I fracture toughness of layered slate all showed a typical V-type trend as the bedding angle increased from 0° to 90°, and with divider type. The developed empirical relationship between tensile fracture toughness and tensile strength KIC = 0.094σt + 0.036 fitted experimentally and strongly correlated. The mechanical response and fracture patterns predicted by FCEM agreed well with those of the laboratory experiments. Moreover, the shear fracture behavior and mode II fracture toughness of the layered slate were explored by systematic numerical simulations. Research results provide potential insights for further prediction and improvement of the complex fracture behavior of anisotropic rock masses for rock engineering

The effect of ligand and acid promoter on hydroesterification of ethylene to methyl propionate and kinetic studies

A new palladium/tris(4-fluomphenyephosphine/p-toluenesulfonic acid catalytic system was developed to synthesize methyl propionate from ethylene hydroesterification. The influence of phosphine ligands and acid promoters on catalytic activity was systematically studied. A volcano relationship between the catalytic activity and the electric effect of phosphine ligand was achieved through the characterization of P-31 NMR of selenium phosphine compounds. An acid strength range favorable to the hydroesterification of ethylene was found by characterizing the pKa value of Brunsted acid. Then, the effect of phosphine ligand/Pd(OAc)(2) ratio, p-toluene-sulfonic/Pd(OAc)(2) ratio, temperature, time, and pressure on this reaction were investigated. Finally, the elementary reaction-based kinetic model was developed, which indicated that nucleophilic attack of methanol on the Pd-acyl intermediate to give methyl propionate is the rate-determining step. The activation barrier of rate-determining step is 83.1 kJ.mol(-1)

The effect of ligand and acid promoter on hydroesterification of ethylene to methyl propionate and kinetic studies

A new palladium/tris(4-fluomphenyephosphine/p-toluenesulfonic acid catalytic system was developed to synthesize methyl propionate from ethylene hydroesterification. The influence of phosphine ligands and acid promoters on catalytic activity was systematically studied. A volcano relationship between the catalytic activity and the electric effect of phosphine ligand was achieved through the characterization of P-31 NMR of selenium phosphine compounds. An acid strength range favorable to the hydroesterification of ethylene was found by characterizing the pKa value of Brunsted acid. Then, the effect of phosphine ligand/Pd(OAc)(2) ratio, p-toluene-sulfonic/Pd(OAc)(2) ratio, temperature, time, and pressure on this reaction were investigated. Finally, the elementary reaction-based kinetic model was developed, which indicated that nucleophilic attack of methanol on the Pd-acyl intermediate to give methyl propionate is the rate-determining step. The activation barrier of rate-determining step is 83.1 kJ.mol(-1)

On the classical risk model with credit and debit interests under absolute ruin

In this paper, we consider the dividend payments in a compound Poisson risk model with credit and debit interests under absolute ruin. We first obtain the integro-differential equations satisfied by the moment generating function and moments of the discounted aggregate dividend payments. Secondly, applying these results, we get the explicit expressions of them for exponential claims. Then, we give the numerical analysis of the optimal dividend barrier and the expected discounted aggregate dividend payments which are influenced by the debit and credit interests. Finally, we find the integro-differential equations satisfied by the Laplace transform of absolute ruin time and give its explicit expressions when the claim sizes are exponentially distributed.

Organic Petrological Characteristics of Graptolite and Its Contribution to Buried Organic Carbon of Longmaxi Formation Shales, Middle Yangtze Region

The shale gas exploration of the Longmaxi Formation in the Yangtze Region of China has made a significant breakthrough. As an important hydrocarbon generation organism, graptolite is widely distributed in the Longmaxi Formation shales, but its hydrocarbon potential is still unclear. Taking the Longmaxi Formation shales in the Middle Yangtze Region as an example, this paper discusses the organic petrological characteristics of graptolite and its contribution to buried organic carbon. The Longmaxi shales in the study area can be divided into organic-rich shales (TOC > 2.0%) and organic-bearing shales (TOC < 2.0%). The organic-rich shales have high quartz content and low clay mineral content, which is opposite in the organic-bearing shales. Organic maceral results show that graptolite is widely distributed in nearly all the samples, while solid bitumen is relatively developed in organic-rich shale. The equivalent vitrinite reflectance obtained from the conversion of graptolite reflectance ranges from 2.46% to 2.76%, indicating that the organic matter maturity of the Longmaxi Formation shale is overmature. Combining an optical microscope and a field emission scanning electron microscope, the proportion of graptolite area to organic matter area can be obtained, the average of which is 32.71%. Solid bitumen mainly contributes to buried organic carbon of the organic-rich shales in the Longmaxi Formation, while graptolites contribute little to organic carbon burial. However, solid bitumen in the organic-bearing shales is relatively undeveloped, and graptolite is an important hydrocarbon generation organism, which is the main contributor to buried organic carbon

Intensification of water on the extraction of pyridine from n-hexane using ionic liquid

One novel extraction process for denitrification of fuel based on ionic liquid was developed. Influence of water on this process was systematically investigated. The mechanism of this process was illustrated by density functional theory (DFT) calculations. The optimized extraction parameters were obtained by a series of experiments, such as mass ratio of ionic liquid and the initial N content. Meanwhile, [Bmim]BF4 was recycled through rotary evaporation, and exhibited good recycling properties and extraction efficiency. Finally, a specific separation process and technology was proposed based on the experimental data.</p

Experimental Study on Tensile Characteristics of Layered Carbonaceous Slate Subject to Water–Rock Interaction and Weathering

The transverse isotropy of rock masses formed by sedimentation is a common stratum environment in engineering, and the physical–mechanical properties can degrade due to water–rock interaction (WRI) and natural weathering, which potentially lead to the instability or collapse of tunneling, slopes and mining. Taking the carbonaceous slate of the Muzhailing tunnel as the research object, two types of specimens, which include oven-drying (instant drying in oven after fabrication) and natural air-drying (static weathering for 60 days after fabrication) were prepared, respectively, after which Brazilian tests were carried out and the tensile properties were analyzed under the two conditions. The experimental results showed that the two kinds of carbonaceous slate all show brittle failure, but the mechanical response such as failure displacement and peak load is obviously different. The tensile strength of the specimens is significantly all affected by the bedding, while the cleavage failure patterns of the two kinds are affected to different degrees. The softening coefficient of the natural air-drying specimen is 0.11–0.13, which implies that WRI and natural weathering play a vital role in the course of rock failure but have little influence on the transverse isotropy tensile property of bedding. Moreover, the mechanisms of specimen failure subject to WRI and 60 days’ weathering were explained by the SEM technique, which analyzed the micro-components and observes the process of specimen deterioration due to physicochemical reaction, the gradual development of cracks and erosion by weathering

Alkali and Alkaline Earth Metals (K, Ca, Sr) Promoted Cu/SiO₂ Catalyst for Hydrogenation of Methyl Acetate to Ethanol

The advancing effects of various alkali and alkaline earth metals (inclusive of K, Ca, and Sr) modified Cu/SiO2 catalysts, prepared with a modified precipitation-gel method, were investigated for the production of ethanol via hydrogenation of methyl acetate. Our results showed that Sr-doped catalysts exhibited the best and most consistent results during catalytic tests. A series of techniques, including X-ray diffraction technique, Raman spectroscopy, N2 adsorption/desorption, N2O titration method, FTIR spectroscopy, and H2 temperature, programmed desorption and reduction (TPD and TPR), and X-ray Photoelectron Spectroscopy, which was used to check the detailed characterization of Sr modification in the catalyst and its structural impacts on the properties of the catalyst. These results demonstrated that the addition of 5%Sr could strengthen the intrinsic stability of the catalyst by formulating the appropriate ratio of Cu+/(Cu0 + Cu+) to facilitate catalytic outcome improvement. The addition of 5%Sr-30%Cu/SiO2 under the most favorable conditions, resulting in the peak conversion of MA (95%) and ethanol selectivity (96%), indicates its magnificent catalytic stabilizing effects. Furthermore, the best performing catalyst was compared and tested under various conditions (LHSV and temperatures) and a 300 h long life run