Hydrogenation of Alkali Lignin Catalyzed by Pd/C

AbstractHydrogenation of alkali lignin was carried out in the presence of Pd/C catalyst at hydrogen pressure 1∼5 MPa. Catalytic activity of Pd/C catalyst was investigated according to the structure changes of alkali lignin, which were characterized by UV and 1H-NMR spectroscopy. The measurement of average molecular weight undertook by gel permeation chromatography (GPC). Changes on function groups of alkali lignin were analyzed through chemical methods. Results show that total hydroxyl, phenolic hydroxyl and alcoholic hydroxyl increase 64.23%, 37.10% and 89.67%, respectively, while carbonyl and carboxyl decrease separately 43.50% and 53.41%. No significant differences of the total acidic groups and the phenyl structure were found after reaction. GPC analysis shows the weight average molecular weight (Mw) and number average molecular weight (Mn) are both decreased, and the polydispersity of alkali lignin is increased The active function groups of alkali lignin are increased obviously, and reactive activity of alkali lignin is enhanced as a result. The present results demonstrate Pd/C catalyst shows an excellent catalytic activity on reductive reaction of alkali lignin and hydrogen

Grain refinement of commercial pure al treated by Pulsed Magneto-Oscillation on the top surface of melt

Commercial pure Al can be refined by Pulsed Magneto-Oscillation (PMO) treatment applied via a plate induction coil above the top surface of the melt. The proportion of the equiaxed zone area increases with decreasing Height to Diameter (H/D) ratios from 3.5 to1.8 and further to 1.0. Meanwhile, it increases and then decreases with increasing peak current for the three kinds of ingots with H/D ratios of 3.5, 1.8 and 1.0, respectively. However, when the H/D ratio decreases to 0.44, the area proportion of equiaxed zone can reach the maximum value with a lower peak current. FEA software simulation indicates that smaller H/D ratio results in larger current density, electromagnetic force and convection on the top surface of the melt, favoring nucleation and subsequent grain formation. Through evaluating Joule heating effect by PMO, it was found that the proper amount of Joule heating benefits grain refinement. Excessive Joule heating can reduce the size of the equiaxed zone and change the growth morphology of the grains

5-Arc transitive cubic Cayley graphs on finite simple groups

AbstractIn this paper, we determine all connected 5-arc transitive cubic Cayley graphs on the alternating group A47; there are only two such graphs (up to isomorphism). By earlier work of the authors, these are the only two non-normal connected cubic arc-transitive Cayley graphs for finite nonabelian simple groups, and so this paper completes the classification of such non-normal Cayley graphs

HIF-1α Contributes to Hypoxia-induced Invasion and Metastasis of Esophageal Carcinoma via Inhibiting E-cadherin and Promoting MMP-2 Expression

Hypoxia-inducible factor-1α (HIF-1α) has been found to enhance tumor invasion and metastasis, but no study has reported its action in esophageal carcinoma. The goal of this study was to explore the probable mechanism of HIF-1α in the invasion and metastasis of esophageal carcinoma Eca109 cells in vitro and in vivo. mRNA and protein expression of HIF-1α, E-cadherin and matrix metalloproteinase-2 (MMP-2) under hypoxia were detected by RT-PCR and Western blotting. The effects of silencing HIF-1α on E-cadherin, MMP-2 mRNA and protein expression under hypoxia or normoxia were detected by RT-PCR and Western blotting, respectively. The invasive ability of Eca109 cells was tested using a transwell chambers. We established an Eca109-implanted tumor model and observed tumor growth and lymph node metastasis. The expression of HIF-1α, E-cadherin and MMP-2 in xenograft tumors was detected by Western blotting. After exposure to hypoxia, HIF-1α protein was up-regulated, both mRNA and protein levels of E-cadherin were down-regulated and MMP-2 was up-regulated, while HIF-1α mRNA showed no significant change. SiRNA could block HIF-1α effectively, increase E-cadherin expression and inhibit MMP-2 expression. The number of invading cells decreased after HIF-1α was silenced. Meanwhile, the tumor volume was much smaller, and the metastatic rate of lymph nodes and the positive rate were lower in vivo. Our observations suggest that HIF-1α inhibition might be an effective strategy to weaken invasion and metastasis in the esophageal carcinoma Eca109 cell line

Overexpression of the Tomato Pollen Receptor Kinase LePRK1 Rewires Pollen Tube Growth to a Blebbing Mode

The tubular growth of a pollen tube cell is crucial for the sexual reproduction of flowering plants. LePRK1 is a pollen-specific and plasma membrane–localized receptor-like kinase from tomato (Solanum lycopersicum). LePRK1 interacts with another receptor, LePRK2, and with KINASE PARTNER PROTEIN (KPP), a Rop guanine nucleotide exchange factor. Here, we show that pollen tubes overexpressing LePRK1 or a truncated LePRK1 lacking its extracellular domain (LePRK1ΔECD) have enlarged tips but also extend their leading edges by producing “blebs.” Coexpression of LePRK1 and tomato PLIM2a, an actin bundling protein that interacts with KPP in a Ca2+-responsive manner, suppressed these LePRK1 overexpression phenotypes, whereas pollen tubes coexpressing KPP, LePRK1, and PLIM2a resumed the blebbing growth mode. We conclude that overexpression of LePRK1 or LePRK1ΔECD rewires pollen tube growth to a blebbing mode, through KPP- and PLIM2a-mediated bundling of actin filaments from tip plasma membranes. Arabidopsis thaliana pollen tubes expressing LePRK1ΔECD also grew by blebbing. Our results exposed a hidden capability of the pollen tube cell: upon overexpression of a single membrane-localized molecule, LePRK1 or LePRK1ΔECD, it can switch to an alternative mechanism for extension of the leading edge that is analogous to the blebbing growth mode reported for Dictyostelium and for Drosophila melanogaster stem cells.Fil: Gui, Cai Ping. Chinese Academy of Sciences; República de ChinaFil: Dong, Xin. Chinese Academy of Sciences; República de ChinaFil: Liu, Hai Kuan. Chinese Academy of Sciences; República de ChinaFil: Huang, Wei Jie. Chinese Academy of Sciences; República de ChinaFil: Zhang, Dong. Chinese Academy of Sciences; República de ChinaFil: Wang, Shu Jie. Chinese Academy of Sciences; República de ChinaFil: Barberini, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Gao, Xiao Yan. Chinese Academy of Sciences; República de ChinaFil: Muschietti, Jorge Prometeo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: McCormick, Sheila. University of California at Berkeley; Estados UnidosFil: Tang, Wei Hua. Chinese Academy of Sciences; República de China. University of California at Berkeley; Estados Unido

Comparative morphology and plant volatile responses of antennal sensilla in Cinara cedri (Hemiptera: Lachninae), Eriosoma lanigerum (Hemiptera: Eriosomatinae), and Therioaphis trifolii (Hemiptera: Calaphidinae)

Olfaction is important for mediating aphid behaviors and is involved in host location and mating. Antennal primary rhinaria play a key role in the chemoreception of aphids. The function of the peripheral olfactory system in the subfamily Aphidinae has been intensively studied, but little is known about other subfamilies of Aphididae. Therefore, three aphid species were selected to study the olfactory reception of plant volatiles: Cinara cedri (Lachninae), Eriosoma lanigerum (Eriosomatinae), and Therioaphis trifolii (Calaphidinae). In this study, the morphology and distribution of the antennal sensilla of apterous adults were observed by scanning electron microscopy. Three morphological types were identified (placoid sensilla, coeloconic sensilla, and trichoid sensilla); the first two were distributed on the antennal primary rhinaria. A pattern of primary rhinaria in C. cedri was found that differed from that of E. lanigerum and T. trifolii and consists of 1 large placoid sensillum (LP) on the 4th segment, 2 LPs on the 5th segment, and a group of sensilla on the 6th antennal segments. Later, we recorded and compared neuronal responses of the distinct placoid sensilla in the primary rhinaria of the three aphid species to 18 plant volatiles using a single sensillum recording (SSR) technique. The results indicated that the functional profiles based on the tested odorants of the primary rhinaria of the three investigated aphid species were clustered into three classes, and exhibited excitatory responses to certain types of odorants, especially terpenes. In C. cedri, the ORNs in LP6 exhibited the highest responses to (±)-citronellal across all tested chemicals, and showed greater sensitivity to (±)-citronellal than to (+)-limonene. ORNs in LP5 were partially responsive to α-pinene and (–)-β-pinene in a dose-dependent manner. Across different species, E. lanigerum showed significantly stronger neuronal responses of LP5 to several terpenes, such as (–)-linalool and α-terpineol, compared to other species. In T. trifolii, the neuronal activities in LP6 showed a greater response to methyl salicylate as compared to LP5. Overall, our results preliminarily illustrate the functional divergence of ORNs in the primary rhinaria of aphids from three subfamilies of Aphididae and provide a basis for better understanding the mechanism of olfactory recognition in aphids

N,N′-Bis(2-methoxy­phen­yl)biphenyl-2,2′-dicarboxamide

In the title compound, C28H24N2O4, the dihedral angle between the two rings of the biphenyl unit is 75.34 (9)°. The outer aromatic rings form dihedral angles of 66.96 (1) and 85.69 (8)° with the rings to which they are attached . The mol­ecular structure is stabilized by intra­molecular C—H⋯O and N—H⋯O hydrogen bonds. In the crystal structure, inter­molecular N—H⋯O inter­actions are observed

Enhancement of polar phases in PVDF by forming PVDF/SiC nanowire composite

Different contents of silicon carbide (SiC) nanowires were mixed with Poly(vinylidene fluoride) (PVDF) to facilitate the polar phase crystallization. It was shown that the annealing temperature and SiC content affected on the phase and crystalline structures of PVDF/SiC samples. Furthermore, the addition of SiC nanowire enhanced the transformation of non-polar α phase to polar phases and increased the relative fraction of β phase in PVDF. Due to the nucleating agent mechanism of SiC nanowires, the ion-dipole interaction between the negatively charged surface of SiC nanowires and the positive CH2 groups in PVDF facilitated the formation of polar phases in PVDF