Vapor Pressure and Enthalpy of Vaporization of Guanidinium Methanesulfonate as a Phase Change Material for Thermal Energy Storage.

This paper reports the vapor pressure and enthalpy of vaporization for a promising phase change material (PCM) guanidinium methanesulfonate ([Gdm][OMs]), which is a typical guanidinium organomonosulfonate that displays a lamellar crystalline architecture. [Gdm][OMs] was purified by recrystallization. The elemental analysis and infrared spectrum of [Gdm][OMs] confirmed the purity and composition. Differential scanning calorimetry (DSC) also confirmed its high purity and showed a sharp and symmetrical endothermic melting peak with a melting point (Tm) of 207.6 °C and a specific latent heat of fusion of 183.0 J g-1. Thermogravimetric analysis (TGA) reveals its thermal stability over a wide temperature range, and yet three thermal events at higher temperatures of 351 °C, 447 °C, and 649 °C were associated with vaporization or decomposition. The vapor pressure was measured using the isothermogravimetric method from 220 °C to 300 °C. The Antoine equation was used to describe the temperature dependence of its vapor pressure, and the substance-dependent Antoine constants were obtained by non-linear regression. The enthalpy of vaporization (ΔvapH) was derived from the linear regression of the slopes associated with the linear temperature dependence of the rate of weight loss per unit area of vaporization. Hence, the temperature dependence of vapor pressures ln Pvap (Pa) = 10.99 - 344.58/(T (K) - 493.64) over the temperature range from 493.15 K to 573.15 K and the enthalpy of vaporization ΔvapH = 157.10 ± 20.10 kJ mol-1 at the arithmetic mean temperature of 240 °C were obtained from isothermogravimetric measurements using the Antoine equation and the Clausius-Clapeyron equation, respectively. The flammability test indicates that [Gdm][OMs] is non-flammable. Hence, [Gdm][OMs] enjoys very low volatility, high enthalpy of vaporization, and non-flammability in addition to its known advantages. This work thus offers data support, methodologies, and insights for the application of [Gdm][OMs] and other organic salts as PCMs in thermal energy storage and beyond.

The cohesive properties and pyrolysis mechanism of an aprotic ionic liquid tetrabutylammonium bis(trifluoromethanesulfonyl)imide.

As the cohesive properties (such as the enthalpy of sublimation) of solid organic salts (or ionic liquids, ILs) are unmeasurable, a method of their indirect determination is proposed in this paper. For this purpose, the thermogravimetric analysis (TGA) and differential scanning calorimetric analysis (DSC) were carried out over a wide range of temperatures. In this study, the mathematical relationship of the thermodynamic properties between the liquid and solid phases of ILs is established using the Born-Fajans-Haber cycle, in which the sum of the vaporization enthalpy of ILs, melting enthalpy and the enthalpy of solid-solid phase transition is regarded as the sublimation enthalpy of solid organic salts. With this method, the cohesive properties of tetrabutylammonium bis(trifluoromethanesulfonyl)imide ([N4444][NTf2]), which is an aprotic IL, were successfully obtained. Additionally, the difference between the lattice energy and the cohesive energy was employed to quantitatively calculate the charge separation distance of single ion pair (r12) in the gas phase of ionic liquids for the first time, which can serve as a standard methodology to measure the closeness in distance between the anion and the cation in a gas phase ion pair. The pyrolysis mechanism of [N4444][NTf2] was also explored.

Rock-breaking performances of innovative triangular-shaped polycrystalline diamond compact cutter.

Due to high hardness and high abrasion, conventional planar polycrystalline diamond compact (PDC) cutters can easily get broken and dull when drilling in (ultra-)deep formations. To enhance the drilling performance, an innovative kind of non-planar PDC cutter, namely, a triangular-shaped PDC cutter, has been developed by altering the 2D planar cutting face into a 3D cutting structure of a triangular trustum of a pyramid. According to the numerical simulation results, the triangular-shaped PDC cutter can easily break hard rocks by a smaller cutting force than the conventional planar PDC cutter. Furthermore, it requires less mechanical specific energy for breaking the same volume of rock than the planar PDC cutter. The triangular-shaped PDC cutter shows great potential in improving the drilling performances of the PDC bit in hard and abrasive formations.

Emodin, a natural anthraquinone, suppresses liver cancer in vitro and in vivo by regulating VEGFR2 and miR-34a.

The pharmacokinetic (PK) and potential effects of Emodin on liver cancer were systematically evaluated in this study. Both the intragastric administration (i.g.) and hypodermic injection (i.h.) of Emodin exhibited a strong absorption (absorption rate < 1 h) and elimination capacity (t1/2 ≈ 2 h). The tissue distribution of Emodin after i.h. was rapid and wide. The stability of Emodin in three species of liver microsomes wasrat >human> beagle dog. These PK data provided the basis for the subsequent animal experiments. In liver cancer patient tissues, the expression of vascular endothelial growth factor (VEGF)-induced signaling pathways, including phosphorylated VEGF receptor 2 (VEGFR2), AKT, and ERK1/2,were simultaneously elevated, but miR-34a expression was reduced and negatively correlated with SMAD2 and SMAD4. Emodin inhibited the expression of SMAD2/4 in HepG2 cells by inducing the miR-34a level. Subsequently, BALB/c nude mice received a daily subcutaneous injection of HepG2 cells with or without Emodin treatment (1 mg/kg or 10 mg/kg), and Emodin inhibited tumorigenesis and reduced the mortality rate in a dose-dependent manner. In vivo experiments showed that cell proliferation, migration, and invasion were promoted by VEGF or miR-34a signal treatment but were inhibited when combined with Emodin treatment. All these results demonstrated that Emodin inhibited tumorigenesis in liver cancer by simultaneously inhibiting the VEGFR2-AKT-ERK1/2signaling pathway and promoting a miR-34a-mediated signaling pathway.

C/EBPα Regulates FOXC1 to Modulate Tumor Growth by Interacting with PPARγ in Hepatocellular Carcinoma.

BACKGROUND: Forkhead box C1 (FOXC1) is an important cancer-associated gene in tumor. PPAR-γ and C/EBPα are both transcriptional regulators involved in tumor development. OBJECTIVE: We aimed to clarify the function of PPAR-γ, C/EBPα in hepatocellular carcinoma (HCC) and the relationship of PPAR-γ, C/EBPα and FOXC1 in HCC. METHODS: Western blotting, immunofluorescent staining, and immunohistochemistry were used to evaluate protein expression. qRT-PCR was used to assess mRNA expression. Co-IP was performed to detect the protein interaction. And ChIP and fluorescent reporter detection were used to determine the binding between protein and FOXC1 promoter. RESULTS: C/EBPα could bind to FOXC1 promoter and PPAR-γ could strengthen C/EBPα's function. Expressions of C/EBPα and PPAR-γ were both negatively related to FOXC1 in human HCC tissue. Confocal displayed that C/EBPα was co-located with FOXC1 in HepG2 cells. C/EBPα could bind to FOXC1 promoter by ChIP. Luciferase activity detection exhibited that C/EBPα could inhibit FOXC1 promoter activity, especially FOXC1 promoter from -600 to -300 was the critical binding site. Only PPAR-γ could not influence luciferase activity but strengthen inhibited effect of C/EBPα. Further, the Co-IP displayed that PPAR-γ could bind to C/EBPα. When C/EBPα and PPAR-γ were both high expressed, cell proliferation, migration, invasion, and colony information were inhibited enormously. C/EBPα plasmid combined with or without PPAR-γ agonist MDG548 treatment exhibited a strong tumor inhibition and FOXC1 suppression in mice. CONCLUSION: Our data establish C/EBPα targeting FOXC1 as a potential determinant in the HCC, which supplies a new pathway to treat HCC. However, PPAR-γ has no effect on FOXC1 expression.

Leptin Receptor Mediates Bmal1 Regulation of Estrogen Synthesis in Granulosa Cells.

Chronobiology affects female fertility in mammals. Lepr is required for leptin regulation of female reproduction. The presence of E-box elements in the Lepr promoter that are recognized and bound by clock genes to initiate gene transcription suggested that circadian systems might regulate fertility through Lepr. However, it is unclear whether Bmal1, a key oscillator controlling other clock genes, is involved in leptin regulation in hormone synthesis through Lepr. In this study, serum estradiol (E2) concentration and the expressions of Bmal1, Lepr, Cyp19a1, and Cyp11a1 genes were found to display well-synchronized circadian rhythms. Knockdown of Bmal1 significantly reduced expression levels of Lepr, Fshr, and Cyp19a1 genes; protein production of Bmal1, Lepr, and Cyp19a1; and the E2 concentration in granulosa cells. Knockdown of Lepr reduced the expression levels of Cyp19a1 and Cyp11a1 genes and Cyp19a1 protein, and also reduced E2 concentration. Addition of leptin affected the expression of Cyp19a1, Cyp11a1, and Fshr genes. Bmal1 deficiency counteracted leptin-stimulated upregulation of the genes encoding E2 synthesis in granulosa cells. These results demonstrated that Bmal1 participates in the process by which leptin acts on Lepr to regulate E2 synthesis.

IGFBP5 suppresses oleate-induced intramyocellular lipids deposition and enhances insulin signaling.

Excess intramyocellular lipids are often accompanied by muscle insulin resistance (IR) and type 2 diabetes. The mechanism of the formation of intramyocellular lipids is unclear yet. In this study, we optimized the cellular model of intramyocellular lipids from differentiated C2C12 cells and identified that the expression of insulin-like growth factor-binding protein 5 (IGFBP5) is diminished in this process. Then, we added exogenous recombinant IGFBP5 during myocyte triglyceride (TAG) formation and found decreased lipids accumulation. In addition, IGFBP5 could promote lipolysis when added to the cellular model after the formation of intramyocellular lipids. Moreover, IGFBP5 could enhance myocyte insulin sensitivity by inhibiting the expression of the thioredoxin-interacting protein (TXNIP) and arrestin domain-containing 4 (ARRDC4), which are a negative regulator of insulin signaling in both cases. Meanwhile, IGFBP5 also inhibited the expression of glycerol-3-phosphate acyltransferase (GPAM) and diglyceride acyltransferase 2 (DGAT2), which were involved in TAG synthesis from a fatty acid. IGFBP5 also reduced TAG storage by promoting lipolysis. Therefore, IGFBP5 may play a role in the excess accumulation of lipid in muscle cells of diabetic patients and serve as a reference for further research and treatment of muscle IR and diabetes.

MicroRNA-106a-5p Inhibited C2C12 Myogenesis via Targeting PIK3R1 and Modulating the PI3K/AKT Signaling.

The microRNA (miR)-17 family is widely expressed in mammalian tissues and play important roles in various physiological and pathological processes. Here, the functions of miR-106a-5p, a member of miR-17 family, were explored during myogenic differentiation in C2C12 cell line. First, miR-106a-5p was found to be relatively lower expressed in two-month skeletal muscle tissues and gradually decreased upon myogenic stimuli. Forced expression of miR-106a-5p significantly reduced the differentiation index, fusion index as well as the expression of myogenic markers (MyoD, MyoG, MyHC, Myomixer, Myomarker). Meanwhile, the levels of phosphorylated AKT were reduced by overexpression of miR-106a-5p, and administration of insulin-like growth factor 1 (IGF1), a booster of myogenic differentiation, could recover all the inhibitory effects above of miR-106a-5p. Furthermore, miR-106a-5p was elevated in aged muscles and dexamethasone (DEX)-treated myotubes, and up-regulation of miR-106a-5p significantly reduced the diameters of myotubes accompanied with increased levels of muscular atrophy genes and decreased PI3K/AKT activities. Finally, miR-106a-5p was demonstrated to directly bind to the 3'-UTR of PIK3R1, thus, repress the PI3K/AKT signaling.

Bmal1 interference impairs hormone synthesis and promotes apoptosis in porcine granulosa cells.

In mammals, granulosa cell proliferation, differentiation, luteinization, apoptosis, and hormone synthesis are tightly related to oocyte maturation, follicular development and ovarian function. In current study, we investigated the role of the key circadian clock gene, brain and muscle arnt-like protein-1 (Bmal1), on porcine granulosa cell hormone secretion and apoptosis. The transcription levels of circadian clock genes, including Bmal1 and period circadian clock 2 (Per2), were detected by RT-qPCR. We found that the circadian clock genes exhibited rhythmic change and were further enhanced by dexamethasone synchronization in granulosa cells. Bmal1 knockdown reduced transcriptional levels of hormone receptor genes, including follicle stimulating hormone receptor (Fshr), luteinizing hormone/choriogonadotropin receptor (Lhcgr) and estrogen receptor 2 (Esr2), and decreased the mRNA and protein levels of cytochrome P450 family 11 subfamily A member 1 (Cyp11a1), cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) and steroidogenic acute regulatory protein (Star), which are the key enzymes involved in hormone synthesis. Synthesis of progesterone and estradiol were also inhibited by Bmal1 siRNA treatment in granulosa cells. Moreover, flow cytometry analysis demonstrated suppressing Bmal1 promoted granulosa cells apoptosis. Western blot analysis showed that Bmal1 interference inactivated the PI3K/Akt/mTOR signaling pathway. In conclusion, Bmal1 plays a critical role in secretion of hormone and apoptosis of porcine granulosa cells via the PI3K/Akt/mTOR signaling pathway.