En masse pyrolysis of flexible printed circuit board wastes quantitatively yielding environmental resources.

This paper reports the recycling of flexible printed circuit board (FPCB) waste through carbonization of polyimide by dual pyrolysis processes. The organic matter was recovered as pyrolyzed oil at low temperatures, while valuable metals and polyimide-derived carbon were effectively recovered through secondary high temperature pyrolysis. The major component of organics extracted from FPCB waste comprised of epoxy resins were identified as pyrolysis oils containing bisphenol-A. The valuable metals (Cu, Ni, Ag, Sn, Au, Pd) in waste FPCB were recovered as granular shape and quantitatively analyzed via ICP-OES. In attempt to produce carbonaceous material with increased degree of graphitization at low heat-treatment conditions, the catalytic effect of transition metals within FPCB waste was investigated for the efficient carbonization of polyimide films. The morphology of the carbon powder was observed by scanning electron microscopy and graphitic carbonization was investigated with X-ray analysis. The protocols outlined in this study may allow for propitious opportunities to salvage both organic and inorganic materials from FPCB waste products for a sustainable future.

Norepinephrine induces VEGF expression and angiogenesis by a hypoxia-inducible factor-1α protein-dependent mechanism.

A growing number of studies have demonstrated that physiological factors can influence the progression of several cancers via cellular immune function, angiogenesis and metastasis. Recently, stress-induced catecholamines have been shown to increase the expression of various cancer progressive factors, including vascular endothelial growth factor (VEGF), matrix metalloproteinases and interleukins. However, a detailed mechanism remains to be identified. In this study, we investigated the role of adrenergic receptors and hypoxia-inducible factor (HIF)-1α protein in catecholamine-induced VEGF expression and angiogenesis. Treatment of the cells with norepinephrine (NE) or isoproterenol induced VEGF expression and HIF-1α protein amount in a dose-dependent manner. Induction of VEGF expression by NE was abrogated when the cells were transfected with HIF-1α-specific siRNA. Similarly, adenylate cyclase activator forskolin and cyclic AMP-dependent protein kinase A inhibitor H-89 enhanced and decreased HIF-1α protein amount, respectively. More importantly, conditioned medium of NE-stimulated cancer cells induced angiogenesis in a HIF-1α protein-dependent manner. In addition, pretreatment of cells with propranolol, a ß-adrenergic receptor (AR) blocker, completely abolished induction of VEGF expression and HIF-1α protein amount by NE in all of the tested cancer cells. However, treatment with the α1-AR blocker prazosin inhibited NE-induced HIF-1α protein amount and angiogenesis in SK-Hep1 and PC-3 but not MDA-MB-231 cells. Collectively, our results suggest that ARs and HIF-1α protein have critical roles in NE-induced VEGF expression in cancer cells, leading to stimulation of angiogenesis. These findings will help to understand the mechanism of cancer progression by stress-induced catecholamines and design therapeutic strategies for cancer angiogenesis.

Phase transition and physical features of nano-grained BaTiO3 ceramics Prepared by two-step sintering.

Nano-grained BaTiO3 ceramics were prepared by two-step sintering; nanoscale BaTiO3 powders of 100 and 500 nm in size were used as starting materials. The phase transition and physical features of the BaTiO3 ceramics were investigated as a function of the grain size and the boundary decoration. With increasing the grain size, the relative volume fraction of a tetragonal phase was increased; this seems to be due to the variation in boundary tension with grain size. The relation of the physical features of the nano-grained BaTiO3 ceramics with the structural variation is discussed in terms of process parameters.

Different roles of histone H3 lysine 4 methylation in chromatin maintenance.

Histone H3 methyltransferases are involved in the epigenetic control of transcription and heterochromatin maintenance. In Saccharomyces cerevisiae, deletion of a histone H3 methyltransferase SET1 leads to the induction of a subset of stress responsive genes in a Rad53 dependent manner. This type of induction was observed only in the absence of SET1 and not in the absence of other histone methyltransferases, SET2 or DOT1. We show that the increased expression of the stress responsive genes results from a lack of histone H3 lysine (K) 4 methylation. The loss of mono-methylation on H3 K4 is necessary to increase the expression of the stress responsive genes, while the loss of di- or tri-methylation induced by deletion of either RRM domain of Set1 or the upstream effector molecules hardly affected their expression. These results suggest that mono- and multiple methylation of H3 K4 have different roles. The mono-methylation of H3 K4 might be required for the global integrity of chromatin structure, which is normally monitored by the Rad53 dependent chromatin surveillance system.

Role of RNA polymerase II carboxy terminal domain phosphorylation in DNA damage response.

The phosphorylation of C-terminal domain (CTD) of Rpb1p, the largest subunit of RNA polymerase II plays an important role in transcription and the coupling of various cellular events to transcription. In this study, its role in DNA damage response is closely examined in Saccharomyces cerevisiae, focusing specifically on several transcription factors that mediate or respond to the phosphorylation of the CTD. CTDK-1, the pol II CTD kinase, FCP1, the CTD phosphatase, ESS1, the CTD phosphorylation dependent cis-trans isomerase, and RSP5, the phosphorylation dependent pol II ubiquitinating enzyme, were chosen for the study. We determined that the CTD phosphorylation of CTD, which occurred predominantly at serine 2 within a heptapeptide repeat, was enhanced in response to a variety of sources of DNA damage. This modification was shown to be mediated by CTDK-1. Although mutations in ESS1 or FCP1 caused cells to become quite sensitive to DNA damage, the characteristic pattern of CTD phosphorylation remained unaltered, thereby implying that ESS1 and FCP1 play roles downstream of CTD phosphorylation in response to DNA damage. Our data suggest that the location or extent of CTD phosphorylation might be altered in response to DNA damage, and that the modified CTD, ESS1, and FCP1 all contribute to cellular survival in such conditions.

Differential regulation of gene expression by RNA polymerase II in response to DNA damage.

Cells change their gene expression profile dynamically in various conditions. By taking the advantage of ChIP, we examined the transcription profile of Saccharomyces cerevisiae genes in response to DNA damaging agents such as MMS or 4NQO. Gene expression profiles of different groups of genes roughly correlated with that revealed by Northern blot assay or microarray method. Damage-inducible genes showed increased cross-linking signals of RNA polymerase II, TFIIH, and TFIIF, meanwhile damage repressible genes decreased them, which means that gene expression is mainly regulated at the level of transcription. Interestingly, the characteristic occupancy pattern of TFIIH and polymerase with phosphorylated carboxy-terminal domain (CTD) in promoter or in coding regions was not changed by the presence of DNA damaging agents in both non-inducible and inducible genes. ChIP data showed that the extent of phosphorylation of CTD per elongating polymerase complex was still maintained. These findings suggest that overall increase in CTD phosphorylation in response to DNA damage is attributed to the global shift of gene expression profile rather than modification of specific polymerase function.

mRNA capping enzyme activity is coupled to an early transcription elongation.

One of the temperature-sensitive alleles of CEG1, a guanylyltransferase subunit of the Saccharomyces cerevisiae capping enzyme, showed 6-azauracil (6AU) sensitivity at the permissive growth temperature, which is a phenotype that is correlated with a transcription elongation defect. This temperature-sensitive allele, ceg1-63, has an impaired ability to induce PUR5 in response to 6AU treatment and diminished enzyme-GMP formation activity. However, this cellular and molecular defect is not primarily due to the preferential degradation of the transcript attributed to a lack of cap structure. Our data suggest that the guanylyltransferase subunit of the capping enzyme plays a role in transcription elongation as well as cap formation. First, in addition to the 6AU sensitivity, ceg1-63 is synthetically lethal with elongation-defective mutations in RNA polymerase II. Secondly, it produces a prolonged steady-state level of GAL1 mRNA after glucose shutoff. Third, it decreases the transcription read through a tandem array of promoter-proximal pause sites in an orientation-dependent manner. Taken together, we present direct evidence that suggests a role of capping enzyme in an early transcription. Capping enzyme ensures the early transcription checkpoint by capping of the nascent transcript in time and allowing it to extend further.