Pathogen Control in Complex Fluids with Water-coupled Excimer Lamps at 282 and 308 nm

Kosakonia cowanii (syn. Enterobacter cowanii) is a highly competitive bacterium that lives with plant, insect, fish, bird, and human organisms. It is pathogenic on some plants and an opportunistic pathogen of human. Nine novel viruses that lyse plant pathogenic strains and/or human strains of K. cowanii were isolated, sequenced, and characterized. Kc166A is a novel kayfunavirus, Kc261 is a novel bonnellvirus, and Kc318 is a new cronosvirus (all Autographiviridae). Kc237 is a new sortsnevirus, but Kc166B and Kc283 are members of new genera within Podoviridae. Kc304 is a new winklervirus, and Kc263 and Kc305 are new myoviruses. The viruses differ in host specificity, plaque phenotype, and lysis kinetics. Some of them should be suitable also as pathogen control agents.

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A review of the second normal-stress difference; its importance in various flows, measurement techniques, results for various complex fluids and theoretical predictions

Journal of Non-Newtonian Fluid Mechanics ◽

10.1016/j.jnnfm.2021.104522 ◽

2021 ◽

Vol 292 ◽

pp. 104522

Author(s):

O. Maklad ◽

R.J. Poole

Keyword(s):

Normal Stress ◽

Complex Fluids ◽

Measurement Techniques ◽

Normal Stress Difference ◽

Stress Difference ◽

Second Normal Stress Difference ◽

Theoretical Predictions

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Interactions between Rainbow Trout Eyed Eggs and Flavobacterium spp. Using a Bath Challenge Model: Preliminary Evaluation of Bacteriophages as Pathogen Control Agents

Microorganisms ◽

10.3390/microorganisms9050971 ◽

2021 ◽

Vol 9 (5) ◽

pp. 971

Author(s):

Valentina L. Donati ◽

Inger Dalsgaard ◽

Anniina Runtuvuori-Salmela ◽

Heidi Kunttu ◽

Johanna Jørgensen ◽

...

Keyword(s):

Rainbow Trout ◽

Pathogenic Bacteria ◽

Infection Model ◽

Preliminary Evaluation ◽

Fish Eggs ◽

Short Term ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Pathogen Control ◽

Number Of Bacteria ◽

Bath Challenge

The microbial community surrounding fish eyed eggs can harbor pathogenic bacteria. In this study we focused on rainbow trout (Oncorhynchus mykiss) eyed eggs and the potential of bacteriophages against the pathogenic bacteria Flavobacterium psychrophilum and F. columnare. An infection bath method was first established, and the effects of singular phages on fish eggs was assessed (survival of eyed eggs, interaction of phages with eyed eggs). Subsequently, bacteria-challenged eyed eggs were exposed to phages to evaluate their effects in controlling the bacterial population. Culture-based methods were used to enumerate the number of bacteria and/or phages associated with eyed eggs and in the surrounding environment. The results of the study showed that, with our infection model, it was possible to re-isolate F. psychrophilum associated with eyed eggs after the infection procedure, without affecting the survival of the eggs in the short term. However, this was not possible for F. columnare, as this bacterium grows at higher temperatures than the ones recommended for incubation of rainbow trout eyed eggs. Bacteriophages do not appear to negatively affect the survival of rainbow trout eyed eggs and they do not seem to strongly adhere to the surface of eyed eggs either. Finally, the results demonstrated a strong potential for short term (24 h) phage control of F. psychrophilum. However, further studies are needed to explore if phage control can be maintained for a longer period and to further elucidate the mechanisms of interactions between Flavobacteria and their phages in association with fish eggs.

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Vane Rheometry with a Large, Finite Gap

Applied Rheology ◽

10.1515/arh-2002-0005 ◽

2002 ◽

Vol 12 (2) ◽

pp. 81-87 ◽

Cited By ~ 33

Author(s):

Christophe Baravian ◽

Audrey Lalante ◽

Alan Parker

Keyword(s):

Viscoelastic Properties ◽

Complex Fluids ◽

Standard Procedure ◽

Effective Radius ◽

Stress Factors ◽

Work Flow ◽

Flow Curves ◽

Alternative Procedures ◽

Newtonian Liquids ◽

Stream Lines

Abstract The vane geometry with a large gap is used to determine the Newtonian, non-Newtonian and viscoelastic properties of complex fluids. We show that when this geometry is carefully characterized, it can be used for precise rheometry. A novel effective cylinder approximation is used to obtain the shear rate and shear stress factors. The effective radius is found to be close to the height of the triangle formed by joining the tips of adjacent blades. This result differs significantly from that of previous work. Flow visualization has been used to confirm that the stream lines bend towards the centre between the blades. These factors can be used to determine the flow curves of non-Newtonian liquids, using Krieger’s power law expansion. The standard procedure for using the vane to determine the yield stress is also carefully investigated and alternative procedures are suggested.

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