Purification of real car wash wastewater with complex coagulation/flocculation methods using polyaluminum chloride, polyelectrolyte, clay mineral and cationic surfactant.

In the present study, real car wash wastewater was purified by different coagulation/flocculation methods. As coagulant, polyaluminum chloride ('BOPAC'), conventional iron(III) chloride, iron(III) sulfate, and aluminum(III) chloride were used, while as flocculant non-ionic and anionic polyelectrolytes were investigated. The effects of added clay mineral (Na-bentonite) and cationic surfactant (hexadecyltrimethyl ammonium bromide - 'HTABr') were also investigated. The use of BOPAC was significantly more effective than conventional coagulants. Extra addition of clay mineral was also beneficial in relation to both the sediment volume and sedimentation speed, while polyelectrolyte addition enhanced further the sedimentation. Moreover, the simultaneous addition of HTABr significantly enhanced the color removal efficiency due to the successful in-situ generation of organophilic bentonite. In summary, the application of 100 mg L-1 Na-bentonite with 20 mg L-1 Al3+ (from BOPAC) and 0.5 mg L-1 anionic polyelectrolyte resulted in the efficient reduction of the turbidity (4-6 NTU), the COD (158 mg L-1) and the extractable oil content (4 mg L-1) with efficiencies of 98%, 59%, and 85%, respectively. By applying organophilic bentonite in high concentration (500 mg L-1) with identical concentrations of BOPAC and anionic polyelectrolyte, significant color removal (5 times lower absorbance at λ = 400 nm) and 27% lower sediment volume were achieved.

Investigation of surface and filtration properties of TiO2 coated ultrafiltration polyacrylonitrile membranes.

In the present work, the surface and filtration properties of TiO2 coated polyacrylonitrile ultrafiltration membranes were investigated. The membranes were coated using the physical deposition method. The appropriate TiO2 coverage proved to be 0.3 mg/cm2, which formed a hydrophilic cake layer on the membrane surface. The cleanability without chemicals and the retention of the coated membranes was compared to the neat membrane after model oily wastewater filtration. The cleaning sustained of rinsing with distilled water and ultraviolet (UV) irradiation of the fouled membranes. The coated membranes have better antifouling properties; higher flux values during oily water filtration and by the mentioned cleaning process a significantly better flux recovery can be achieved. The amount of the catalyst and the irradiation time are limiting factors to the effectiveness of the cleaning process. The UV irradiation increases the wettability of the fouled membrane surface by degrading the oil layer. The coating, the continuous use, and the cleaning process do not significantly affect the membrane retention expressed in chemical oxygen demand.

Changes of trends in the size of the dental implants in recent years Part 1. The role of short implants in dental implantology The literature review.

The requirements for osseointegration have been determined decades ago, among which was the appropriate size of the dental implants. In the last few years, in both - domestic and foreign literature- we can find more and more articles suggesting short and narrow dental implants as a treatment possibility. They may serve as an alternative to various bone grafting techniques and may replace the time demanding, more invasive and expensive horizontal and vertical bone augmentation procedures. Using short and narrow implants we can avoid interventions often accompanied by serious complications, such as bone distraction and inferior alveolar nerve transposition which pose greater risk for the patient. Our objective is a two-part review of the periodic literature in order to establish whether short and narrow dental implants can serve as a real alternative treatment modality.

Repeated inseminations required for natural fertility in a wild bird population.

In most bird species, pairs copulate many times before egg laying. The exact function of repeated inseminations (i.e. successful copulations) is unknown, but several suggestions have been made. We tested the hypothesis that repeated inseminations are required to ensure fertilization of eggs, by using an experimental method where free-ranging male collared flycatchers (Ficedula albicollis) were prevented from inseminating their mates. We show that egg fertility was lower when females had not copulated during the studied part of their fertile period. By counting sperm on the inner perivitelline layer of eggs, we estimated that a minimum of 86 sperm must reach the site of fertilization to ensure average fertility. Using the timing of inseminations and the numbers of sperm on successive eggs, we show that repeated copulations are necessary to achieve an average rate of fertilization of a single clutch. Our results thus provide evidence that repeated inseminations function to ensure fertilization success. We discuss possible constraints on sperm production and utilization that may have contributed to this pattern.

Oxidation of [Fe(CN)6]4- and reduction of [Fe(CN)6]3- in VUV-irradiated aqueous solutions.

Vacuum ultraviolet (VUV) photolysis is one of the straightforward alternatives method among the advanced oxidation processes (AOPs) for the elimination of pollutants from water and air. The VUV photolysis of water produces hydroxyl radicals and hydrogen atoms, which have widely different oxidation and reduction abilities. In this work the oxidation and reduction properties of VUV-irradiated solutions were compared by investigating the reduction of [Fe(CN)6]3- and the oxidation of [Fe(CN)6]4-. The rate of oxidation of [Fe(CN)6]3- was found to be practically the same as the reduction rate of [Fe(CN)6]4- in the irradiated oxygen-free solutions under identical conditions. Dissolved oxygen strongly influences the redox properties of this system.

Adhesion molecules in human pancreatic cancer.

BACKGROUND AND OBJECTIVES: Adhesion molecules are cell surface glycoproteins that are important in cell-to-cell and cell-to-extracellular matrix interactions. In the present study, we analyzed the adhesion molecules ICAM-1 (intercellular adhesion molecule-1), VCAM-1 (vascular cell adhesion molecule-1), and ELAM-1 (endothelial leukocyte adhesion molecule-1) in human pancreatic cancer. METHODS: ICAM-1, VCAM-1, and ELAM-1 were analyzed in 20 pancreatic cancer specimens and 20 normal pancreatic tissues. mRNA expression encoding ICAM-, VCAM-1, and ELAM-1 was assessed with Northern blot analysis. The distribution and localization of ICAM-1, VCAM-1, and ELAM-1 was determined in the pancreatic specimens by immunohistochemistry. RESULTS: Northern blot analysis revealed a 5.4-fold increase of ICAM-1 (P<0.01) and a 3.7-fold increase in VCAM-1 (P<0.01) mRNA expression in cancer samples in comparison with normal controls. In contrast, ELAM-1 mRNA levels did not show significant differences between the cancer and the normal tissues. Immunohistochemical analysis of cancer tissues showed strong immunostaining for ICAM-1 and VCAM-1, and faint immunostaining for ELAM-1 in the pancreatic cancer cells. Fibrotic or noncancerous pancreatic tissue adjacent to the cancer mass was devoid of any immunoreactivity for ICAM-1, ELAM-1, and VCAM-1. In contrast, the normal pancreas exhibited no immunoreactivity of ICAM-1, ELAM-1, and VCAM-1. CONCLUSIONS: Enhanced expression of ICAM-1 and VCAM-1 in human pancreatic cancers suggests a role in tumor pathogenesis. The increase of these adhesion molecules might influence the detachment of cancer cells in the primary tumor, might contribute to cancer cell migration and the spread of cancer cells to distant organs, or both.