scholarly journals Influence of Salts on Virus Adsorption to Microporous Filters

2000 ◽  
Vol 66 (7) ◽  
pp. 2914-2920 ◽  
Author(s):  
Jerzy Lukasik ◽  
Troy M. Scott ◽  
Diane Andryshak ◽  
Samuel R. Farrah
Keyword(s):  
Aluminum Chloride ◽  
Indirect Effects ◽  
Hydrophobic Interactions ◽  
Tween 80 ◽  
Direct Effects ◽  
Virus Removal ◽  
Ph Values ◽  
Virus Adsorption ◽  
Enhanced Adsorption ◽  
Viral Adsorption

ABSTRACT We investigated the direct and indirect effects of mono-, di-, and trivalent salts (NaCl, MgCl2, and AlCl3) on the adsorption of several viruses (MS2, PRD-1, φX174, and poliovirus 1) to microporous filters at different pH values. The filters studied included Millipore HA (nitrocellulose), Filterite (fiberglass), Whatman (cellulose), and 1MDS (charged-modified fiber) filters. Each of these filters except the Whatman cellulose filters has been used in virus removal and recovery procedures. The direct effects of added salts were considered to be the effects associated with the presence of the soluble salts. The indirect effects of the added salts were considered to be (i) changes in the pH values of solutions and (ii) the formation of insoluble precipitates that could adsorb viruses and be removed by filtration. When direct effects alone were considered, the salts used in this study promoted virus adsorption, interfered with virus adsorption, or had little or no effect on virus adsorption, depending on the filter, the virus, and the salt. Although we were able to confirm previous reports that the addition of aluminum chloride to water enhances virus adsorption to microporous filters, we found that the enhanced adsorption was associated with indirect effects rather than direct effects. The increase in viral adsorption observed when aluminum chloride was added to water was related to the decrease in the pH of the water. Similar results could be obtained by adding HCl. The increased adsorption of viruses in water at pH 7 following addition of aluminum chloride was probably due to flocculation of aluminum, since removal of flocs by filtration greatly reduced the enhancement observed. The only direct effect of aluminum chloride on virus adsorption that we observed was interference with adsorption to microporous filters. Under conditions under which hydrophobic interactions were minimal, aluminum chloride interfered with virus adsorption to Millipore, Filterite, and 1MDS filters. In most cases, less than 10% of the viruses adsorbed to filters in the presence of a multivalent salt and a compound that interfered with hydrophobic interactions (0.1% Tween 80 or 4 M urea).

Adsorption of Poliovirus 1 and F+ Bacteriophages onto Sand

1993 ◽  
Vol 27 (7-8) ◽  
pp. 331-338 ◽  
Author(s):  
A. M. Nasser ◽  
A. Adin ◽  
B. Fattal
Keyword(s):  
Alkaline Ph ◽  
Virus Removal ◽  
Ph Values ◽  
Water Composition ◽  
Virus Adsorption ◽  
Influence Of Water ◽  
Adsorption Processes ◽  
Pathogenic Viruses ◽  
Trivalent Cations ◽  
Study Support

This study was performed to determine the influence of water composition, virus type, pH and various salts and their concentration on the adsorption of F+bacteriophages and poliovirus to sand. Virus adsorption to sand was greater at acidic than alkaline pH values. At alkaline values (8.0, 9.0) virus adsorption was poor particularly in distilled water. The presence of divalent and trivalent cations in the medium enhanced the virus adsorption appreciably. On the other hand, the presence of humic acid at 10 and 100 mg/l reduced virus adsorption onto sand. The rate of F+bacteriophage adsorption to sand was similar or lower than that of poliovirus 1. Therefore, F+bacteriophages removal by adsorption processes is expected to be at similar or lower rates than that of pathogenic viruses. The results of this study support the initiative of proposing F+bacteriophages as anindex for virus removal through sand filtration.

The Effect of pH on the Performance of High-Rate Oxidation Ponds

1987 ◽  
Vol 19 (12) ◽  
pp. 381-383 ◽  
Author(s):  
Y. Azov ◽  
G. Shelef
Keyword(s):  
Indirect Effects ◽  
High Rate ◽  
Carbon Limitation ◽  
Direct Effects ◽  
Carbonate System ◽  
Algal Production ◽  
Ph Values ◽  
Common Observation ◽  
Algal Photosynthesis ◽  
Oxidation Ponds

A common observation in high-rate oxidation ponds (HROP) is that pH riseswill usually be followed by decreases in algal production and in overall pond performance. It was found that pH has minor direct effects on algal production but has major indirect effects as it determines the ratios of the carbonate system species and the dissociation of ammonia in the pond. Thus, increased pH values may cause carbon limitation of algal production or free ammonia inhibition of algal photosynthesis in HROP.

Trophic Cascades in Grasslands

2018 ◽  
Author(s):  
Brian J. Wilsey
Keyword(s):  
Indirect Effects ◽  
Prey Species ◽  
Trophic Levels ◽  
Herbaceous Plant ◽  
Direct Effects ◽  
Temperate Grasslands ◽  
Cascading Effect ◽  
Top Predators ◽  
Invertebrate Predators ◽  
Ecology Of Fear

Top predators have effects that can ‘cascade down’ on lower trophic levels. Because of this cascading effect, it matters how many trophic levels are present. Predators are either ‘sit and wait’ or ‘active’. Wolves are top predators in temperate grasslands and can alter species composition of smaller-sized predators, prey, and woody and herbaceous plant species, either through direct effects or indirect effects (‘Ecology of Fear’). In human derived grasslands, invertebrate predators fill a similar ecological role as wolves. Migrating populations of herbivores tend to be more limited by food than non-migratory populations. The phenology and synchrony of births vary among prey species in a way that is consistent with an adaptation to predation. Precocious species have highly synchronous birth dates to satiate predators. Non-precocious species (‘hiders’) have asynchronous births. Results from studies that manipulate both predators and food support the hypothesis that bottom-up and top-down effects interact.

scholarly journals Characterization of Virus Adsorption by Using DEAE-Sepharose and Octyl-Sepharose

2002 ◽  
Vol 68 (8) ◽  
pp. 3965-3968 ◽  
Author(s):  
Patricia A. Shields ◽  
Samuel R. Farrah
Keyword(s):  
Sodium Chloride ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Chloride Concentration ◽  
Sodium Chloride Concentration ◽  
Virus Adsorption ◽  
Nacl Concentration

ABSTRACT Viruses were characterized by their adsorption to DEAE-Sepharose or by their elution from octyl-Sepharose by using buffered solutions of sodium chloride with different ionic strengths. Viruses whose adsorption to DEAE-Sepharose was reduced most rapidly by an increase in the sodium chloride concentration were considered to have the weakest electrostatic interactions with the solids; these viruses included MS2, E1, and φX174. Viruses whose adsorption to DEAE-Sepharose was reduced least rapidly were considered to have the strongest electrostatic interactions with the column; these viruses included P1, T4, T2, and E5. All of the viruses studied adsorbed to octyl-Sepharose in the presence of 4 M NaCl. Viruses that were eluted most rapidly following a decrease in the concentration of NaCl were considered to have the weakest hydrophobic interactions with the column; these viruses included φX174, CB4, and E1. Viruses that were eluted least rapidly from the columns after the NaCl concentration was decreased were considered to have the strongest hydrophobic interactions with the column; these viruses included f2, MS2, and E5.

scholarly journals Possible Traffic Safety Effects of the Implementation of Section Control in Hungary

2020 ◽  
Vol 13 (4) ◽  
pp. 309-323
Author(s):  
Zsolt Sándor
Keyword(s):  
Traffic Safety ◽  
Indirect Effects ◽  
Social Cost ◽  
Cost Savings ◽  
International Studies ◽  
Direct Effects ◽  
Implementation Cost ◽  
Short Term ◽  
Environmental Loads

This article presents the anticipated safety effects of the implantation of section control in Hungary. The proposed results were originated from international studies and the local circumstances. Effects are depending on the control coverage and the magnitude of the sanctions. Direct (short term benefits) and indirect effects (long term benefits) can be identified. Direct effects are the decreasing of accident numbers, while indirect effects are the decrease of other externalities of transport like environmental loads. Based on the results the implementation cost of the enforcement system is measureable with the proposed social cost savings come from the decreasing number of accidents.

The Interaction of Reactions and Transport Part II: Combined Reactors and Exchangers

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Stuart W. Churchill
Keyword(s):  
Indirect Effects ◽  
Molecular Level ◽  
Chemical Reactor ◽  
Complex Behavior ◽  
Geometrical Configuration ◽  
Direct Effects ◽  
Optimal Conditions ◽  
Chemical Reactors ◽  
And Performance ◽  
Transport Part

The interactions between chemical reactions and transport may be divided into direct effects, for example on the molecular level, and indirect effects, for example those arising from the geometrical configuration of the integrated reactor/exchanger. Attention herein is focused on the latter, although in many instances the direct effects must be accounted for as well. Particular attention is given to the identification of behavior that does not arise in chemical reactors not connected to an exchanger or in exchangers not connected to a chemical reactor, as well as to optimal conditions and configurations of combined reactors and exchangers. Generalizations are difficult to formulate for such complex behavior and equipment, necessitating a primary reliance on illustrative examples. However, some general conclusions are drawn concerning the occurrence, identification, and performance of interactive designs.

A generalist nematode destabilizes plant competition: no evidence for direct effects, but strong evidence for indirect effects on rhizobia abundance

2021 ◽  
Author(s):  
Samantha A. Catella ◽  
Castilleja Fallon Olmsted ◽  
Shaniya H. Markalanda ◽  
Connor J. McFadden ◽  
Corlett W. Wood ◽  
...  
Keyword(s):  
Strong Evidence ◽  
Indirect Effects ◽  
Plant Competition ◽  
Direct Effects

6. Remedies in EU Law: Direct Effects, Indirect Effects, State Liability, and Art 267 TFEU

2021 ◽  
pp. 166-207
Author(s):  
Nigel Foster
Keyword(s):  
Indirect Effects ◽  
Preliminary Ruling ◽  
Direct Effects ◽  
Eu Law ◽  
Procedural Law ◽  
National Courts ◽  
State Liability ◽  
Cover Art ◽  
Direct Applicability ◽  
The Eu

This chapter brings together a number of related issues that are indirectly linked to the preliminary ruling procedure under Art 267 of the Treaty on the Functioning of the EU (TFEU)—the vehicle by which the leading principles and remedies in EU law were developed by the Court of Justice; in particular, the means by which EU law could be enforced by individuals via the national courts, rather than by the Commission, or other institutions, or member states in direct actions before the CJEU. The discussions cover Art 267 TFEU; direct applicability and direct effects; state liability; and national procedural law and the system of remedies.

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