scholarly journals On the optimal use of isotherm models for the characterization of biosorption of lead onto algae

2016 ◽  
Author(s):  
F. Brouers ◽  
Tariq Al-Musawi
Keyword(s):  
Removal Rate ◽  
Coefficient Of Determination ◽  
Isotherm Models ◽  
Good Representation ◽  
Nonlinear Fitting ◽  
Linearization Methods ◽  
Complete Set ◽  
The Hill ◽  
First Time

For the first time we apply a new method based on the mathematical derivation of some known isotherm from the Burr function which describes many birth-death (sorption-desorption) phenomena in ecology and economy. Therefore, in this study the experimental isotherm data of biosorption of Pb(II) onto algae was modeled to Langmuir, Hill-Sips, Brouers-Sotolongo, Brouers-Gaspard, and Redlich-Peterson isotherm models. The parameters of each model were determined by nonlinear fitting algorithms using Mathematica program. The maximum Pb(II) removal rate increased with the increase of temperature and reached the maximum value (98%) at the temperature of 40 C. The results showed that the Hill-Sips and the Brouers-Sotolongo isotherms were definitely the most suitable models to satisfactorily describe biosorption of Pb(II) on the algal biomass. In addition, as these two models gave very close results, the use of an intermediate one the Brouers-Gaspard isotherm model could also describe the sorption in most cases. High coefficient of determination values was obtained by using nonlinear methods and these findings are contrary to most works in this field that use linearization methods. Further, this study showed that a complete set of data is necessary to have a good representation of the isotherm and using only coefficient of determination is not always an adequate tool to compare the goodness of the nonlinear fit of an isotherm models.

scholarly journals On the Optimal Use of Isotherm Models for the Characterization of Biosorption of Lead Onto Algae

2015 ◽  
Author(s):  
F. Brouers ◽  
Tariq Al-Musawi
Keyword(s):  
Algal Biomass ◽  
Removal Rate ◽  
Isotherm Models ◽  
Good Representation ◽  
Experimental Isotherm ◽  
Nonlinear Fitting ◽  
Maximum Value ◽  
Complete Set ◽  
Best Fit

In this study the experimental isotherm data of biosorption of Pb(II) onto algae was modeled using several models. These models are: Langmuir, Hill-Sips, Brouers-Sotolongo, Brouers-Gaspard, and Redlich-Peterson models. The coefficients of each model were determined by non-linear fitting using Mathematica9 program. The maximum Pb(II) removal rate increased with the increase of temperature and reached the maximum value (98%) at the temperature of 40°C. Even if the R2 error quantity is not the unique and always the best measure for nonlinear fitting, the Brouers-Sotolongo model gives in all cases the best fit and is definitely the most suitable one to satisfactorily describe bioisorption of Pb(II) on the algal biomass. In addition, this study shows that a complete set of data is necessary to have a good representation of the isotherm.

scholarly journals Characterization of Each St and Y Genome Chromosome of Roegneria grandis Based on Newly Developed FISH Markers

2021 ◽  
pp. 213-222
Author(s):  
Dandan Wu ◽  
Xiaoxia Zhu ◽  
Lu Tan ◽  
Haiqin Zhang ◽  
Lina Sha ◽  
...  
Keyword(s):  
Structural Changes ◽  
Distribution Patterns ◽  
Proximal Region ◽  
Genome Chromosome ◽  
High Affinity ◽  
Complete Set ◽  
Genome Analyses ◽  
First Time ◽  
Homoeologous Chromosomes

The genera of the tribe Triticeae (family Poaceae), constituting many economically important plants with abundant genetic resources, carry genomes such as St, H, P, and Y. The genome symbol of <i>Roegneria</i> C. Koch (Triticeae) is StY. The St and Y genomes are crucial in Triticeae, and tetraploid StY species participate extensively in polyploid speciation. Characterization of St and Y nonhomologous chromosomes in StY-genome species could help understand variation in the chromosome structure and differentiation of StY-containing species. However, the high genetic affinity between St and Y genome and the deficiency of a complete set of StY nonhomologous probes limit the identification of St and Y genomes and variation of chromosome structures among <i>Roegneria</i> species. We aimed to identify St- and Y-enhanced repeat clusters and to study whether homoeologous chromosomes between St and Y genomes could be accurately identified due to high affinity. We employed comparative genome analyses to identify St- and Y-enhanced repeat clusters and generated a FISH-based karyotype of <i>R. grandis</i> (Keng), one of the taxonomically controversial StY species, for the first time. We explored 4 novel repeat clusters (StY_34, StY_107, StY_90, and StY_93), which could specifically identify individual St and Y nonhomologous chromosomes. The clusters StY_107 and StY_90 could identify St and Y addition/substitution chromosomes against common wheat genetic backgrounds. The chromosomes V_St, VII_St, I_Y, V_Y, and VII_Y displayed similar probe distribution patterns in the proximal region, indicating that the high affinity between St and Y genome might result from chromosome rearrangements or transposable element insertion among V_St/Y, VII_St/Y, and I_Y chromosomes during allopolyploidization. Our results can be used to employ FISH further to uncover the precise karyotype based on colinearity of Triticeae species by using the wheat karyotype as reference, to analyze diverse populations of the same species to understand the intraspecific structural changes, and to generate the karyotype of different StY-containing species to understand the interspecific chromosome variation.

scholarly journals Production and Characterization of Antibodies against Each of the Three Subunits of the Bacillus cereus Nonhemolytic Enterotoxin Complex

2005 ◽  
Vol 71 (12) ◽  
pp. 8214-8220 ◽  
Author(s):  
Richard Dietrich ◽  
Maximilian Moravek ◽  
Christine Bürk ◽  
Per Einar Granum ◽  
Erwin Märtlbauer
Keyword(s):  
Bacillus Cereus ◽  
Rabbit Antiserum ◽  
Food Poisoning ◽  
Cross Reactivity ◽  
Terminal Part ◽  
Complete Set ◽  
Different Strains ◽  
First Time ◽  
Three Components

ABSTRACT The nonhemolytic enterotoxin (Nhe) is one of the two three-component enterotoxins which are responsible for diarrheal food poisoning syndrome caused by Bacillus cereus. To facilitate the detection of this toxin, consisting of the subunits NheA, NheB, and NheC, a complete set of high-affinity antibodies against each of the three components was established and characterized. A rabbit antiserum specific for the C-terminal part (15 amino acids) of NheC was produced using a respective synthetic peptide coupled to a protein carrier for immunization. Using purified B. cereus exoprotein preparations as immunogens, one monoclonal antibody against NheA and several antibodies against NheB were obtained. No cross-reactivity with other proteins produced by different strains of B. cereus was observed. Antibodies against the NheB component were able to neutralize the cytotoxic activity (up to 98%) of Nhe. Based on indirect enzyme immunoassays, the antibodies developed in this study were successfully used in the characterization of the enterotoxic activity of several B. cereus strains. For the first time, it could be shown that strains carrying the nhe genes usually express the complete set of the three components, including NheC. However, the amount of toxin produced varies considerably between the different strains.

Characterization of Slurry System and Suppression of Oxide Erosion in Aluminum CMP (Chemical-Mechanical Planarization)

1999 ◽  
Vol 566 ◽  
Author(s):  
Lei Zhong ◽  
Jerry Yang ◽  
Karey Holland ◽  
Joost Grillaert ◽  
Katia Devriend ◽  
...  
Keyword(s):  
Titanium Nitride ◽  
Barrier Layer ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Experimental Result ◽  
Mixture Ratio ◽  
Slurry System ◽  
First Time

In this work, we investigated the dependence of the removal rate upon the oxidizer (peroxide) addition into commercially available slurries for a variety of films such as aluminum, titanium, titanium nitride and oxide. We found that the barrier layer materials were extremely sensitive to the peroxide addition while the removal rate varied only slightly for aluminum and oxide. The selectivity to titanium and titanium nitride drops from as high as 1000 to almost close to 1 as the mixture ratio (peroxide : slurry) increases. We proposed that the barrier layer be used to protect the oxide from being over-exposed and suppress the erosion eventually. This can be easily realized by dividing the process into two steps with each step being run at a specific peroxide mixture ratio. The experimental result unambiguously proved, for the first time, the effectiveness of this approach.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

Chemical Constituents and Antibacterial Activity of Cissus Aralioides.

2020 ◽  
Vol 17 ◽  
Author(s):  
Balogun Olaoye Solomon ◽  
Ajayi Olukayode Solomon ◽  
Owolabi Temitayo Abidemi ◽  
Oladimeji Abdulkarbir Oladele ◽  
Liu Zhiqiang
Keyword(s):  
Plant Extract ◽  
Chemical Constituents ◽  
Ethyl Acetate Fraction ◽  
Antibacterial Activities ◽  
Sub Saharan Africa ◽  
Chromatographic Purification ◽  
Whole Plant ◽  
Sub Saharan ◽  
First Time

: Cissus aralioides is a medicinal plant used in sub-Saharan Africa for treatment of infectious diseases; however the chemical constituents of the plant have not been investigated. Thus, in this study, attempt was made at identifying predominant phytochemical constituents of the plant through chromatographic purification and silylation of the plant extract, and subsequent characterization using spectroscopic and GC-MS techniques. The minimum inhibitory concentration (MICs) for the antibacterial activities of the plant extract, chromatographic fractions and isolated compounds were also examined. Chromatographic purification of the ethyl acetate fraction from the whole plant afforded three compounds: β-sitosterol (1), stigmasterol (2) and friedelin (3). The phytosterols (1 and 2) were obtained together as a mixture. The GC-MS analysis of silylated extract indicated alcohols, fatty acids and sugars as predominant classes, with composition of 24.62, 36.90 and 26.52% respectively. Results of MICs indicated that friedelin and other chromatographic fractions had values (0.0626-1.0 mg/mL) comparable with the standard antibiotics used. Characterization of natural products from C. aralioides is being reported for the first time in this study.

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

scholarly journals Waste-Based One-Part Alkali Activated Materials

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2911
Author(s):  
Margarida Gonçalves ◽  
Inês Silveirinha Vilarinho ◽  
Marinélia Capela ◽  
Ana Caetano ◽  
Rui Miguel Novais ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Microstructural Analysis ◽  
Construction Materials ◽  
Sodium Metasilicate ◽  
High Compressive Strength ◽  
Hardened State ◽  
First Time ◽  
Furnace Slag ◽  
Alkali Activated

Ordinary Portland Cement is the most widely used binder in the construction sector; however, a very high carbon footprint is associated with its production process. Consequently, more sustainable alternative construction materials are being investigated, namely, one-part alkali activated materials (AAMs). In this work, waste-based one-part AAMs binders were developed using only a blast furnace slag, as the solid precursor, and sodium metasilicate, as the solid activator. For the first time, mortars in which the commercial sand was replaced by two exhausted sands from biomass boilers (CA and CT) were developed. Firstly, the characterization of the slag and sands (aggregates) was performed. After, the AAMs fresh and hardened state properties were evaluated, being the characterization complemented by FTIR and microstructural analysis. The binder and the mortars prepared with commercial sand presented high compressive strength values after 28 days of curing-56 MPa and 79 MPa, respectively. The mortars developed with exhausted sands exhibit outstanding compressive strength values, 86 and 70 MPa for CT and CA, respectively, and the other material’s properties were not affected. Consequently, this work proved that high compressive strength waste-based one-part AAMs mortars can be produced and that it is feasible to use another waste as aggregate in the mortar’s formulations: the exhausted sands from biomass boilers.

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