Combination of electrochemically activated persulfate process and electro-coagulation for the treatment of municipal landfill leachate with low biodegradability.

To handle complex wastewater with limited biodegradability, hybrid treatment systems are necessary. The current study represents the combined effectiveness of sulfate-radical associated electro-chemical advanced oxidation process (SR-EAOP) and electro-coagulation (EC) for the treatment of stabilized landfill leachate. For SR-EAOP, Pt/Ti was employed as the anode and an iron plate as the cathode; while EC treatment was performed by switching the polarity. Hence, both electrochemical treatment was carried out in single reactor. Initially, the effects of pH, applied voltage, persulfate and Fe2+ dosage, on the performance of SR-EAOP was examined. Sulfate radical was generated in the electrolytic system via cathodic reduction of persulfate (PS) and ferrous (Fe2+) ion activation. Auxiliary processes such as anodic oxidation via Pt/Ti anode and indirect electro-chemical oxidation were also contributed for pollutant degradation. Combined process SR-EAOP followed by EC (SR-EAOP + EC) has better leachate treatment efficacy in comparison with EC + SR-EAOPs. The SR-EAOP + EC based combined treatment mechanism achieved an efficient COD reduction of 88.67% than that of EC + SR - EAOP process (74.51% COD reduction). Characterization studies have been carried out for post-treated dried-sludge using Field Emission scanning electron microscope (FE-SEM) and X-ray powder diffraction (XRD) techniques. The combined process treatment (SR-EAOP + EC) can be applied as pre-treatment for leachate decontamination.

Targeting the hsp70 gene delays mammary tumor initiation and inhibits tumor cell metastasis.

Elevated levels of the inducible heat-shock protein 70 (Hsp72) have been implicated in mammary tumorigenesis in histological investigations of human breast cancer. We therefore examined the role of Hsp72 in mice, using animals in which the hsp70 gene was inactivated. We used a spontaneous tumor system with mice expressing the polyomavirus middle T (PyMT) oncogene under control of the mouse mammary tumor virus (MMTV) long-terminal repeat (MMT mice). These mice developed spontaneous, metastatic mammary cancer. We then showed Hsp72 to be upregulated in a fraction of mammary cancer initiating cells (CIC) within the MMT tumor cell population. These cells were characterized by elevated surface levels of stem cell markers CD44 and Sca1 and by rapid metastasis. Inactivation of the hsp70 gene delayed the initiation of mammary tumors. This delay in tumor initiation imposed by loss of hsp70 was correlated with a decreased pool of CIC. Interestingly, hsp70 knockout significantly reduced invasion and metastasis by mammary tumor cells and implicated its product Hsp72 in cell migration and formation of secondary neoplasms. Impaired tumorigenesis and metastasis in hsp70-knockout MMT mice was associated with downregulation of the met gene and reduced activition of the oncogenic c-Met protein. These experiments therefore showed Hsp72 to be involved in the growth and progression of mammary carcinoma and highlighted this protein as a potential target for anticancer drug development.

Signal Transduction Pathways Leading to Heat Shock Transcription.

Heat shock proteins (HSP) are essential for intracellular protein folding during stress and protect cells from denaturation and aggregation cascades that can lead to cell death. HSP genes are regulated at the transcriptional level by heat shock transcription factor 1 (HSF1) that is activated by stress and binds to heat shock elements in HSP genes. The activation of HSF1 during heat shock involves conversion from an inert monomer to a DNA binding trimer through a series of intramolecular folding rearrangements. However, the trigger for HSF1 at the molecular level is unclear and hypotheses for this process include reversal of feedback inhibition of HSF1 by molecular chaperones and heat-induced binding to large non-coding RNAs. Heat shock also causes a profound modulation in cell signaling pathways that lead to protein kinase activation and phosphorylation of HSF1 at a number of regulatory serine residues. HSP genes themselves exist in an accessible chromatin conformation already bound to RNA polymerase II. The RNA polymerase II is paused on HSP promoters after transcribing a short RNA sequence proximal to the promoter. Activation by heat shock involves HSF1 binding to the promoter and release of the paused RNA polymerase II followed by further rounds of transcriptional initiation and elongation. HSF1 is thus involved in both initiation and elongation of HSP RNA transcripts. Recent studies indicate important roles for histone modifications on HSP genes during heat shock. Histone modification occurs rapidly after stress and may be involved in promoting nucleosome remodeling on HSP promoters and in the open reading frames of HSP genes. Understanding these processes may be key to evaluating mechanisms of deregulated HSP expression that plays a key role in neurodegeneration and cancer.

ER-to-Golgi transport and cytoskeletal interactions in animal cells.

The endoplasmic reticulum (ER)-Golgi system has been studied using biochemical, genetic, electron and light microscopic techniques. We now understand many aspects of trafficking from the ER to the Golgi apparatus, including some of the signals and mechanisms for selective retention and retrieval of ER resident proteins and export of cargo proteins. Proteins that leave the ER emerge in 'export complexes' or ER 'exit sites' and accumulate in pleiomorphic transport carriers referred to sometimes as VTCs or intermediate compartments. These structures then transit from the ER to the Golgi apparatus along microtubules using the dynein/dynactin motor and fuse with the cis cisterna of the Golgi apparatus. Many proteins (including vSNAREs, ERGIC53/p58 and the KDEL receptor) must cycle back to the ER from pre-Golgi intermediates or the Golgi. We will discuss both the currently favored model that this cycling occurs via 50-nm COPI-coated vesicles and in vivo evidence that suggests retrograde trafficking may occur via tubular structures.

Pentastarch versus albumin in cardiopulmonary bypass prime: impact on blood loss.

BACKGROUND: Albumin is commonly used as a volume expander in cardiopulmonary bypass (CPB) prime. Pentastarch, a low molecular weight hetastarch, may provide similar efficacy at decreased cost but is known to alter coagulation profiles. Infectious concerns forced the temporary withdrawal of albumin in our institution. Therefore we evaluated pentastarch as an alternative with regards to perioperative hemostasis and blood loss. METHODS: One hundred consecutive adult patients undergoing first-time aorto-coronary bypass were given 750 mL of 10% pentastarch (represented as P in calculations) diluted in 1000 mL of Ringer's solution added in their CPB prime. A similar control group of 100 consecutive patients had received 200 mL of 25% albumin (represented as A in calculations) diluted in 1500 mL of Ringer's solution. RESULTS: Postoperative prothrombin time (PT) was slightly higher with pentastarch (P: 14.9 +/- 1.5 seconds, A: 14.2 +/- 1.3 seconds, p = 0.003). Postoperative bleeding was also increased (P: 2337 +/- 1242 mL, A: 1981 +/- 1121 mL, p = 0.034), mostly because of recirculated shed mediastinal blood (P: 834 +/- 499 mL, A: 640 +/- 388, p = 0.002) rather than lost pleural tube blood (P: 1503 +/- 821 mL, A: 1341 +/- 824 mL, p = 0.16). Overall net blood loss (P: 2014 +/- 914 mL, A: 2061 +/- 1015, p = 0.73) was similar. Blood-product transfusion requirements and postoperative daily hematocrits did not differ. CONCLUSION: The diminished coagulability associated with this dose of pentastarch resulted in increased postoperative bleeding. However, with recirculation of shed mediastinal blood, there was no net increase in blood loss. In this setting, pentastarch may serve as a suitable alternative to albumin.