Influence Of Physicochemical Parameters Research Articles

Biosorption Potential of the Macrofungus Ganoderma carnosum for Removal of Lead(II) Ions from Aqueous Solutions

This paper reports the utilization of a macro-fungus Ganoderma carnosum as a biosorbent material for the removal of lead(II) ions from aqueous solutions. The biosorption potential of G. carnosum was investigated by batch experiments. The influences of physico-chemical parameters like pH, biosorbent dosage, contact time and initial metal ion concentration were evaluated. The biosorption equilibrium was attained in 10 minutes. Equilibrium biosorption data were analyzed by the Freundlich, Langmuir and Dubinin–Radushkevich (D–R) isotherm models. Maximum biosorption capacity of biosorbent was found to be 22.79 mg g− 1 (1.10 × 10− 4 mol g− 1) at the pH value of 5.0. The biosorbent was regenerated using 10 mM HCl solution, with up to 96% recovery, and reused four times in biosorption-desorption cycles successively. Biosorption efficiency of G. carnosum was also examined in a real effluent. The mechanism of the biosorption was investigated with FTIR, SEM and EDAX analysis and the findings suggested that the biosorption process involved in ion exchange as dominant mechanism as well as complexation. The ion exchange mechanism was also confirmed by the mean free energy value obtained from D–R isotherm model.

The Influence of Physicochemical Parameters on the Efficacy of Non-Viral DNA Transfection Complexes: A Comparative Study

Various polycationic vehicles have been developed to facilitate the transfer of foreign DNA into mammalian cells. Structure-activity studies suggested that biophysical properties, such as size, charge, and morphology of the resulting DNA complexes determine transfection efficiency within one class of vector. To investigate the general validity of these criteria, we studied the efficacy of a variety of DNA delivery vehicles including liposomes (DOTAP, SAINT2) with and without helper lipid (DOPE), the polymer polyethyleneimine (PEI), and cationic nanoparticles (Si26H, PLGA/chitosan) in a comparative manner. Sizes of the DNA complexes varied between 100 and 500 nm for PEI polyplexes and DOTAP/DOPE lipoplexes, respectively. The zeta potential was positive for PEI, Si26H, and DOTAP based complexes, while it was neutral for SAINT2-DNA complexes and negative for PLGA/chitosan-DNA complexes. The latter finding was elucidated by AFM, showing a layer of DNA adsorbed onto the nanoparticles. Transfection activity was negligible for PLGA/chitosan nanospheres, moderate for Si26H nanospheres and high for all other complexes, PEI being the most active carrier. The liposomal preparations were of low (DOTAP) or moderate (SAINT2) stability in serum, resulting in a pronounced reduction of gene expression, which was partially restored by the addition of chloroquine. In conclusion, transfection efficiency (i) seems to require a positive or neutral zeta potential, (ii) is depending on size, e.g., is higher for smaller particles, and (iii) requires a vector that is stable in serum.

Influence of Physicochemical Parameters on Internal Stress in Electroformed Nickel Produced with Sulfamate Plating Baths

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Influence of some physico-chemical parameters on the composition and distribution of benthic fauna in Woji Creek, Niger Delta, Nigeria

Investigation into the influence of certain physico-chemical parameters on the distribution of macrobenthic invertebrates in Woji creek was done between April, 2001 and March, 2002. Temperature of the sub-surface water ranged from 25.5°C to 30.9°C. The degree of hydrogen ion concentration, pH varied between 5.5-7.8. Salinity showed spatial variation ranging from 012.7%0 while Dissolved Oxygen Concentration (DO) had values between 1.6mg/l and 10.1mg/l. A total of thirty taxa of benthic macroinvertebrates were encountered. These belong to 20 families within 5 classes. Regression analyses revealed that pH significantly (P

Influence of Some Physicochemical Parameters on Artemia Biomass and Cyst Production in Some Thalassohaline Aquatic Environments in the Colombian Caribbean

Abstract.–From July 1998 to June 2000 four thalassohaline aquatic environments along the Colombian Caribbean coast (Manaure, Galerazamba, Salina Cero, and Tayrona) were surveyed monthly to determine the influence of salinity, percent 02 saturation, pH, temperature, and nutrients (NO2‐, NO3‐ and PO4‐3) on Artemia (Crustacean, Anostracan) biomass production and cyst production potential. The effects of the regularly measured physicochemical parameters on biomass and cyst production potential were analyzed using univariate analysis of variance (SPSS VI 0.0). The influence of physicochemical parameters on biomass production was not significant (P > 0.05). In contrast, there was a significant interaction (P<0.05) of salinity, percent 02 saturation, and nitrate (used as a proxy for chlorophyll a) on cyst production potential. In addition, for all four locations nitrate levels were directly proportional to salinity. This might be explained by the fact that in saltworks numerous organisms are trapped and slowly die as salinity increases progressively in the evaporating basins; thus, organic matter accumulates and decomposes. Consequently, the concentration of the nitrogenous compounds, first nitrite and later nitrate, increases through time as salinity increases. Moreover, decreasing nitrate levels seem to increase cyst production potential; thus supporting the notion that when insufficient food is available cyst production increases.

Devenir des virus entériques en mer et influence des facteurs environnementaux

To improve the knowledge of the survival of enteric viruses in a marine environment, the influence of physico-chemical parameters (temperature, UV, salinity) on the survival of infectious poliovirus 1 and hepatitis A virus (HAV) in seawater was first studied, the influence of suspended solids (SS) on poliovirus adsorption and survival in seawater was then evaluated and the detection of rotavirus genome in environmental samples (shellfish, river water, treated wastewater) was finally investigated. The results show that temperature has a major impact on virus survival in seawater as the time necessary to inactivate 90 % of the virus (T 90) is 671 days at 4 °C and only 25 days at 25 °C. Ultraviolet light (42 mW s cm −2) rapidly inactivates viruses but HAV is more resistant (T 90 = 2.6 min) than the poliovirus 1 (T 90 = 1.3 min). By contrast, seawater salinity has no effect on virus survival. In presence of SS, 90 % to 99.9 % of the viruses were adsorbed. This adsorption does not provide any protection for viruses with low SS concentrations (3 and 15 mg L −1) but a slight increase in virus survival was observed with a high SS concentration (500 mg L −1). Finally environmental sample analysis indicated that 20 % shellfish, about 40 % river water and 40 % treated wastewater tested positive for the rotavirus genome.

Dynamic Sorptive Behavior of Tributyltin on Quartz Sand at Low Concentration Levels: Effect of pH, Flow Rate, and Monovalent Cations

The highly toxic organotin compounds which have been used as biocides in ship antifouling paints have been introduced into aquatic ecosystems. Among them, tributyltin (TBT) is the most important organotin compound which has been produced on the largest scale. Understanding its fate in the environment is therefore of primary importance to prevent its migration. TBT sorption from aqueous solutions was studied at much lower concentrations (10 nM to 2 μM) than those used in previous studies. Experiments were performed using column reactors filled with a quartz sand. The influence of physicochemical parameters on TBT partitioning, i.e. ionic strength, pH, and nature of electrolyte cation was investigated. Equilibrium times were short as TBT retention appeared to be independent of the mean pore velocity. TBT sorption was affected strongly by the pH and slightly by the ionic strength of the solution. Competitions with monovalent alkaline cations showed a small influence of Li+, Na+, K+, Rb+, with respect to Cs+ ...

Lethal effects of Mexel® 432 to common carp embryolarval stages in river water: Influence of physicochemical parameters in synthetic ISO water

The lethal effects of Mexel® 432, an antifouling agent for industrial water circuits, on common carp embryolarval stages in Moselle and Seine River waters and synthetic water were tested in the laboratory. Diluting Mexel 432 in river water resulted in the disappearance of its lethal effects within a few days. In freshly prepared 3-mg/L solutions, 100% mortality occurred within 1 d in synthetic International Standards Organization (ISO) water, compared to 96 h in Seine River water (10-mg/L solutions). No lethal effect was observed after 7 d of exposure in an 8- to 15-d-old 50-mg/L solution in Moselle River water or in a 2-d-old 10-mg/L solution in Seine River water. Inhibition of Mexel 432 toxicity by river waters was not due to calcium concentration, temperature, or pH, because these factors had a negligible influence on the lethal effects of Mexel 432 in synthetic ISO water (ranges, 0.8–800 mg/L, 15–24°C, and 6.9–9.0, respectively). Aldrich Chemical humic acids immediately suppressed the lethal effects of Mexel 432 with an apparent ratio of 1 to 2 mg Mexel 432/mg humic acids. Also, clays and humic acids immediately reduced the concentration of Mexel 432 in semiquantitative colorimetric dosages.

Influence of physicochemical parameters and perfusate flow rate on the distribution of solutes in the isolated perfused rat hindlimb determined by the impulse-response technique

The relationship between solute distribution, physicochemical properties, and tissue physiology was determined by the impulse-response (IR) technique and statistical moment analysis in the isolated perfused rat hindlimb. The concentration of bovine serum albumin (BSA; 2, 4.7, and 7%, w/v), perfusate flow rate (4 and 8 mL/min), and solute physicochemical properties (lipophilicity,P; fraction unbound to protein,fu; fraction ionized,fi;and molecular weight MW) were varied to better understand the underlying determinants of solute distribution. An apparent low availability was found for a number of the solutes as a consequence of tissue sequestration. This low availability precludes the estimation of an apparent volume of distribution (V) for these solutes. TheVof solute and tissue (skin, fat, and muscle) blood flow increased with perfusion flow rate (p< 0.01). The unbound distribution volume (Vu) of basic solutes was significantly linear with respect toP. Multiple linear regression analysis showed that the distribution volume of solute in tissue was significantly related tofu(p< 0.01), but not improved by including relationships toP, MW, andfi. Data obtained with this IR technique yield results consistent within vivostudies in terms of the importance offuas a determinant ofV. This work has shown that the estimations of soluteVby the IR technique in a single-pass preparation are unreliable for solutes with a low availability due to apparent solute sequestration into tissue. The parameterVmay also be affected by changes in the perfused limb physiology associated with the perfusion conditions used. TheVs for lidocaine and diazepam vary withfuin accordance with deductions based on the results of steady-state studies.

Preconcentration of strontium by micelle modified solid phase extraction

The preconcentration of strontium using a solid phase separation technique with selective micelle forming complexant has been studied. Di-2-ethylhexylphosphoric acid and its thio- and dithio derivatives were used as modifiers. The goal of this work was to study the influence of physico-chemical parameters on recovery of strontium after its preconcentration on reverse phase (Si−C-18) using micelle modifiers.

Characteristics of inert beads provoking humoral immune responses in Galleria mellonella larvae

Injection of ion exchange beads or sterile latex beads into the haemocoel of wax moth ( Galleria mellonella) larvae provokes an humoral immune response measurable as antibacterial activity in cell-free haemolymph. The influence of provocator surface properties on the intensity of response was investigated. Comparing the antibacterial activities provoked by injection of anion and cation exchangers it can be concluded, that anion exchangers are better provocators than cation exchangers. The influence of physicochemical parameters was confirmed by the fact, that injection of latex beads pretreated with sulphuric acid lead to enhanced antibacterial activities in larvae as compared to the activities provoked by injection of untreated beads. In order to prove if it is possible to enhance the provocation capacity of beads by binding molecules to their surfaces, the following substances were covalently coupled onto the beads prior to injection: fibronectin, peptides with a cell adhesive signal of fibronectin (GLY-ARG-GLY-ASP-SER-PRO-LYS, GLY-ARG-GLY-ASP-SER, ARG-GLY-ASP-SER), poly-lysine, adjuvant peptide, lysozyme, bovine serum albumin, bovine plasma, cell-free haemolymph and haemolymph lysate supernatant (haemolymph preparations from G. mellonella) Coupling of adjuvant peptide, fibronectin or haemolymph preparations enhanced the provocation capacity of beads very clearly. Likewise, but to a lower extent, an enhancement was noticed for nearly all the other substances tested in comparison to results obtained by injection of unloaded beads. The results will be discussed in relation to the known facts about the influence of provocator characteristics onto the onset of a cellular reaction by arthropod and vertebrate cells.

Influence of Physicochemical Parameters of Some Ring-Substituted Phenol Derivatives on Their Retention on a Porous Graphitized Carbon Column

Abstract The retention characteristics of 29 phenol derivatives were determined on a porous graphitized carbon column in unbuffered acetonitrile—water and methanol—water eluent mixtures at various organic phase concentrations. Each phenol derivative showed symmetric peaks in each eluent without buffers. Good linear correlations were found between the log k' value and the organic mobile phase concentration in the eluent. Principal component analysis indicated that methanol and acetonitrile expose different selectivities. Stepwise regression analysis proved that the retention of ring—substituted phenol derivatives is mainly governed by the sterical parameters, electron-withdrawing power and hydrogen donor capacity of substituents. According to the results of Free-Wilson analysis, the substituents with large steric parameters, strong electron-withdrawing power and hydrogen donor capacity have the highest impact on the retention. The lipophilicity of phenol derivatives did not affect significantly the retenti...

Modelling of the behaviour of microporous membrane sensors used in the detection of volatile organic solutes in aqueous media

The behaviour of microporous hydrophobic membrane sensors for volatile solutes was studied experimentally and theoretically in different conditions. Attention was focused on the influence of physico-chemical parameters on mass transfer in the sensors, and consequently, on the response of the sensors. The effects of the gas flow rate, membrane surface area, temperature, stirring speeds, chemical additives in solution, nature of the solute and the polymer material were analysed. The sensors were successfully used in alcoholic fermentations for on-line monitoring.

The impact of heavy metals on lowland rivers and the implications for man and the environment

Increased public awareness of river water quality problems has led to concern over the continued discharge of low-level contaminants in sewage treatment work (STW) final effluents. This paper discusses the source and nature of heavy metals during sewage treatment processes and examines their behaviour and fate in the aquatic environment. The influences of physico-chemical parameters and chemical speciation on metal mobility during sewage treatment and in receiving waters have been assessed. The importance of metal speciation with regard to aquatic toxicology is discussed and the effectiveness of current legislation in controlling the release of heavy metals to lowland river systems has been reviewed.

Retard-insulins formed by complexing with polyamino acids

Polyglycine, polyalanine, polyleucine, poly-α-glutamic acid, poly-γ-glutamic acid and poly-α-lysine were complexed with insulin under non-denaturating conditions. The liberation behaviour of the hormone was investigated in vivo and in vitro in dependence on the insulin content, molecular weight, ionic interactions and hydrophobicity of the polyamino acid. The in vitro results were confirmed by the in vivo experiments with animals. They clearly pointed out the influence of physicochemical parameters on the bioavailability of insulin. Complexes of poly-α-lysine and polyglycine were shown to be the most suitable retard forms, producing significant blood glucose lowering effects over 12 hours.