Adsorption Characteristics of Combined Sulfhydryl Collector on Chalcopyrite and Arsenopyrite in Flotation of Complex Gold Ores

The paper presents the results of experimental study of the adsorption properties of the combined sulfhydril collecting reagent –a mixed solution of sodium diethyl-dithiocarbamate (DEDTC) and oxypropyl diethyl-dithiocarbamate ester (OPDTC) towardschalcopyrite and arsenopyrite with a view to its application as a selective collector of Au-containing sulfide minerals in flotationof complex refractory ores. Combined diethyl-dithiocarbamate solution (DEDTCc) incorporated a fixed content of anionic andnon-ionic components (DEDTC:OPDTC = 1:1) and occurred variable hydrophobic effect on the surface of the basic gold-bearingsulfide minerals – chalcopyrite and arsenopyrite.The mechanism of adsorption of the components of combined collector on the surface of chalcopyrite and arsenopyrite was identifiedto form characteristic molecular shape of adsorbed collector convex neoplasms and sinter chemically adsorbed film of thereactant, which is firmly anchored on the surface. The newly formed phase of the adsorbed reagent did not dissolve in water at asubsequent washing. In this case, the phase of nonionic ester OPDTC was partially removed by water and the residual adsorbeddroplets changed their shape and became flatter. By X-ray microanalysis C and O bands relating to the structure of the combinedDEDTCc were identified on the surface of arsenopyrite and chalcopyrite. The original technic for analyzing the liner dimension ofsurface images with an application of scanning laser microscopy and the software of the Analyzer was developed and the authorssucceeded to provide a quantitative evaluation of the adsorption of DEDTCc on the surface of chalcopyrite and arsenopyrite.

Confocal Scanning Laser Microscopy in Medicine

Confocal Scanning Laser Microscopy (CSLM) offers high resolution morphological details and generates en-face images with excellent depth discrimination for visualizing different structures of the living human body non-invasively. There have been significant advances in technology since the CSLM was first defined. It has been used commonly, especially in ophthalmological area, in order to diagnose and give direction for the treatment of corneal pathologies. Ocular surface, corneal subbasal nerve plexus, filtering blebs of glaucoma surgery were also investigated widely by CSLM. With the improvements in CSLM technology over time, it is widely used in other fields than ophthalmology. The combined use of CSLM with the slit lamp biomicroscopy and optical coherence tomography will also lead to significant advances in the diagnosis and treatment of more diseases in the future.

Bacterial aggregate size determines phagocytosis efficiency of polymorphonuclear leukocytes

The ability of bacteria to aggregate and form biofilms impairs phagocytosis by polymorphonuclear leukocytes (PMNs). The aim of this study was to examine if the size of aggregates is critical for successful phagocytosis and how bacterial biofilms evade phagocytosis. We investigated the live interaction between PMNs and Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Staphylococcus epidermidis using confocal scanning laser microscopy. Aggregate size significantly affected phagocytosis outcome and larger aggregates were less likely to be phagocytized. Aggregates of S. epidermidis were also less likely to be phagocytized than equally-sized aggregates of the other three species. We found that only aggregates of approx. 5 μm diameter or smaller were consistently phagocytosed. We demonstrate that planktonic and aggregated cells of all four species significantly reduced the viability of PMNs after 4 h of incubation. Our results indicate that larger bacterial aggregates are less likely to be phagocytosed by PMNs and we propose that, if the aggregates become too large, circulating PMNs may not be able to phagocytose them quickly enough, which may lead to chronic infection.

The origin of extracellular DNA in bacterial biofilm infections in vivo

ABSTRACT Extracellular DNA (eDNA) plays an important role in both the aggregation of bacteria and in the interaction of the resulting biofilms with polymorphonuclear leukocytes (PMNs) during an inflammatory response. Here, transmission electron and confocal scanning laser microscopy were used to examine the interaction between biofilms of Pseudomonas aeruginosa and PMNs in a murine implant model and in lung tissue from chronically infected cystic fibrosis patients. PNA FISH, DNA staining, labeling of PMN DNA with a thymidine analogue and immunohistochemistry were applied to localize bacteria, eDNA, PMN-derived eDNA, PMN-derived histone H3 (H3), neutrophil elastase (NE) and citrullinated H3 (citH3). Host-derived eDNA was observed surrounding bacterial biofilms but not within the biofilms. H3 localized to the lining of biofilms while NE was found throughout biofilms. CitH3, a marker for neutrophil extracellular traps (NETs) was detected only sporadically indicating that most host-derived eDNA in vivo was not a result of NETosis. Together these observations show that, in these in vivo biofilm infections with P. aeruginosa, the majority of eDNA is found external to the biofilm and derives from the host.

Micro-Embossing Process in Ultrafine-Grained Pure Aluminum Processed by Equal-Channel Angular Pressing with Elevated Temperature

Micro-embossing tests were performed on ultrafine-grained pure Al processed by equal-channel angular pressing (ECAP) with 100 μm width of female die at different deformation temperature ranging from 298 K to 523 K under a force of 5 kN. The filling height, surface topography and microstructure of the cross section were measured by confocal scanning laser microscopy (CSLM), scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD), respectively. The effects of deformation temperature on formability of ultrafine-grained (UFG) pure Al during micro-embossing were analyzed. The results show that increase in deformation temperature can improve the formability of UFG pure Al on micro-embossing. Micro hot embossing of UFG pure aluminum is characterized by the rib sidewall, surface quality, and fully transferred patterns, which shows ultrafine-grained pure Al has potential application in micro-forming.