An Optimum Concentration for the Suspension of Solids in Stirred Vessels

2000 ◽  
pp. 83-94 ◽  
Author(s):  
G. R. Drewer ◽  
N. Ahmed ◽  
G. J. Jameson
Keyword(s):  
Optimum Concentration ◽  
Stirred Vessels

Specific Targeting of HER2-Positive Head and Neck Squamous Cell Carcinoma Line HN5 by Idarubicin-ZHER2 Affibody Conjugate

2018 ◽  
Vol 19 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Marzieh Ghanemi ◽  
Aminollah Pourshohod ◽  
Mohammad Ali Ghaffari ◽  
Alireza kheirollah ◽  
Mansour Amin ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Head And Neck ◽  
Cell Line ◽  
Squamous Cell ◽  
Optimum Concentration ◽  
Her2 Positive ◽  
Affibody Molecules ◽  
Specific Targeting ◽  
Mcf 7

Background:Expression of human epidermal growth factor receptor type 2 (HER2) in head and neck squamous cell carcinoma (HNSCC) cell line HN5 can be employed with great opportunities of success for specific targeting of anti-cancer chemotherapeutic agents.Objective:In the current study, HER2-specific affibody molecule, ZHER2:342 (an engineered protein with great affinity for HER2 receptors) was selected for conjugation to idarubicin (an anti-neoplastic antibiotic).Method:ZHER2:342 affibody gene with one added cysteine code at the its 5′ end was synthesized de novo and then inserted into pET302 plasmid and transferred to E. Coli BL21 hosting system. After induction of protein expression, the recombinant ZHER2 affibody molecules were purified using Ni- NTA resin and purity was analyzed through SDS-PAGE. Affinity-purified affibody molecules were conjugated to idarubicin through a heterobifunctional crosslinker, sulfosuccinimidyl 4-(Nmaleimidomethyl) cyclohexane-1-carboxylate (Sulfo-SMCC). Specific toxicity of idarubicin-ZHER2 affibody conjugate against two HER2-positive cells, HN5 and MCF-7 was assessed through MTT assay after an exposure time of 48 hours with different concentrations of conjugate.Results:Idarubicin in the non-conjugated form showed potent toxic effects against both cell lines, while HN5 cells were significantly more sensitive compared to MCF-7 cells. Dimeric ZHER2 affibody showed a mild decreasing effect on growth of both HN5 and MCF-7 cells at optimum concentration. Idarubicin-ZHER2 affibody conjugate at an optimum concentration reduced viability of HN5 cell line more efficiently compared to MCF-7 cell line.In conclusion, idarubicin-ZHER2 affibody conjugate in optimum concentrations can be used for specific targeting and killing of HN5 cells.

A Study on UV Filter Chemicals from Annex VII of European Union Directive 76/768/EEC, in the In Vitro 3T3 NRU Phototoxicity Test

1998 ◽  
Vol 26 (5) ◽  
pp. 679-708 ◽  
Author(s):  
Horst Spielmann ◽  
Michael Balls ◽  
Jack Dupuis ◽  
Wolfgang J. W. Pape ◽  
Odile de Silva ◽  
...  
Keyword(s):  
Neutral Red ◽  
Optimum Concentration ◽  
Alternative Methods ◽  
Uv Filter ◽  
Eu Directive ◽  
Optimum Concentration Range ◽  
The Impact ◽  
Positive Results

In 1996, the Scientific Committee on Cosmetology of DGXXIV of the European Commission asked the European Centre for the Validation of Alternative Methods to test eight UV filter chemicals from the 1995 edition of Annex VII of Directive 76/768/EEC in a blind trial in the in vitro 3T3 cell neutral red uptake phototoxicity (3T3 NRU PT) test, which had been scientifically validated between 1992 and 1996. Since all the UV filter chemicals on the positive list of EU Directive 76/768/EEC have been shown not to be phototoxic in vivo in humans under use conditions, only negative effects would be expected in the 3T3 NRU PT test. To balance the number of positive and negative chemicals, ten phototoxic and ten non-phototoxic chemicals were tested under blind conditions in four laboratories. Moreover, to assess the optimum concentration range for testing, information was provided on appropriate solvents and on the solubility of the coded chemicals. In this study, the phototoxic potential of test chemicals was evaluated in a prediction model in which either the Photoirritation Factor (PIF) or the Mean Photo Effect (MPE) were determined. The results obtained with both PIF and MPE were highly reproducible in the four laboratories, and the correlation between in vitro and in vivo data was almost perfect. All the phototoxic test chemicals provided a positive result at concentrations of 1μg/ml, while nine of the ten non-phototoxic chemicals gave clear negative results, even at the highest test concentrations. One of the UV filter chemicals gave positive results in three of the four laboratories only at concentrations greater than 100μg/ml; the other laboratory correctly identified all 20 of the test chemicals. An analysis of the impact that exposure concentrations had on the performance of the test revealed that the optimum concentration range in the 3T3 NRU PT test for determining the phototoxic potential of chemicals is between 0.1μg/ml and 10μg/ml, and that false positive results can be obtained at concentrations greater than 100μg/ml. Therefore, the positive results obtained with some of the UV filter chemicals only at concentrations greater than 100μg/ml do not indicate a phototoxic potential in vivo. When this information was taken into account during calculation of the overall predictivity of the 3T3 NRU PT test in the present study, an almost perfect correlation of in vitro versus in vivo results was obtained (between 95% and 100%), when either PIF or MPE were used to predict the phototoxic potential. The management team and participants therefore conclude that the 3T3 NRU PT test is a valid test for correctly assessing the phototoxic potential of UV filter chemicals, if the defined concentration limits are taken into account.

Numerical simulations of jacket side thermal-hydraulic performance for large stirred vessels

2021 ◽  
Vol 79 (7) ◽  
pp. 513-536
Author(s):  
Ankur Kumar ◽  
Jyeshtharaj B. Joshi ◽  
Vivek Vitankar
Keyword(s):  
Numerical Simulations ◽  
Hydraulic Performance ◽  
Stirred Vessels

Peptide synthesis in bone marrow: insulin and thyroxin effects

1962 ◽  
Vol 203 (4) ◽  
pp. 693-696 ◽  
Author(s):  
Thomas F. Necheles
Keyword(s):  
Bone Marrow ◽  
Nucleic Acid ◽  
Peptide Synthesis ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Optimum Concentration ◽  
The Other ◽  
Anabolic Effect ◽  
Oxygen Buffer

Myeloid marrow was rapidly removed from femurs of fasting young rabbits, sectioned, and incubated in Krebs-bicarbonate-CO2-oxygen buffer with appropriate C14-labeled precursors. All manipulations were designed to preserve the architecture of the tissue. After 1 hr the protein or nucleic acid-adenine was isolated and purified. Insulin, 0.01 U/ml added in vitro, stimulated histidine-2(ring)-C14 incorporation into protein by 26 ± 1.4%; alkali-treated insulin was inactive. Thyroxin elicited a 49.4 ± 2.1% stimulation at an optimum concentration of 10–7 m. Triiodothyronine, but not diiodothyronine, also had a significant effect. Insulin increased incorporation of carbon from adenosine-8-C14 into adenine of ribonucleic acid and deoxyribonucleic acid. Thyroxin, on the other hand, was without consistent effect on this process. Thyroxin stimulated significantly the incorporation of C14 of glycine-2-C14 into adenine. The possibility that part of the anabolic effect of thyroxin on bone marrow may arise from a stimulus to incorporation of precursors into purines is suggested.

Electrochemical Characteristics of Aptasensor Based on MEMS Thin-Film Gold Electrode

2013 ◽  
Vol 562-565 ◽  
pp. 441-445
Author(s):  
Yan Xia Yan ◽  
Li Ying Jiang ◽  
Fen Fen Wang ◽  
Yan Zhang ◽  
Jie Hu
Keyword(s):  
Thin Film ◽  
Self Assembly ◽  
Gold Electrode ◽  
Ac Impedance ◽  
Optimum Concentration ◽  
Electrochemical Characteristics ◽  
Universal Method

A new fabrication methods of thin-film gold electrode is reported. Electrochemical characteristics of self-assembly aptasensor based on MEMS thin-film gold electrode has been studied by lots of experiments, characteristics include immobilizing time, AC impedance, CV curves. Experiments indicate immobilizing time of DNA-SH on gold electrode is more than 15 hours. CV curves and AC impedance of MEMS thin-film gold electrode show the same conclusion that 20μm/L DNA is optimum concentration when DNA is immobilized on gold electrode. Those results present a potential universal method for other aptasensors.

scholarly journals A DNA Ligase from a Hyperthermophilic Archaeon with Unique Cofactor Specificity

2000 ◽  
Vol 182 (22) ◽  
pp. 6424-6433 ◽  
Author(s):  
Masaru Nakatani ◽  
Satoshi Ezaki ◽  
Haruyuki Atomi ◽  
Tadayuki Imanaka
Keyword(s):  
Biochemical Study ◽  
Protein Product ◽  
Optimum Concentration ◽  
Dna Ligase ◽  
Gene Encoding ◽  
Hyperthermophilic Archaeon ◽  
Dna Ligases ◽  
Cofactor Specificity ◽  
Thermophilic Archaeon ◽  
Optimum Ph

ABSTRACT A gene encoding DNA ligase (ligTk ) from a hyperthermophilic archaeon, Thermococcus kodakaraensisKOD1, has been cloned and sequenced, and its protein product has been characterized. ligTk consists of 1,686 bp, corresponding to a polypeptide of 562 amino acids with a predicted molecular mass of 64,079 Da. Sequence comparison with previously reported DNA ligases and the presence of conserved motifs suggested that Lig Tk was an ATP-dependent DNA ligase. Phylogenetic analysis indicated that Lig Tk was closely related to the ATP-dependent DNA ligase fromMethanobacterium thermoautotrophicum ΔH, a moderate thermophilic archaeon, along with putative DNA ligases fromEuryarchaeota and Crenarchaeota. We expressedligTk in Escherichia coli and purified the recombinant protein. Recombinant Lig Tk was monomeric, as is the case for other DNA ligases. The protein displayed DNA ligase activity in the presence of ATP and Mg2+. The optimum pH of Lig Tk was 8.0, the optimum concentration of Mg2+, which was indispensable for the enzyme activity, was 14 to 18 mM, and the optimum concentration of K+ was 10 to 30 mM. Lig Tk did not display single-stranded DNA ligase activity. At enzyme concentrations of 200 nM, we observed significant DNA ligase activity even at 100°C. Unexpectedly, Lig Tk displayed a relatively small, but significant, DNA ligase activity when NAD+ was added as the cofactor. Treatment of NAD+ with hexokinase did not affect this activity, excluding the possibility of contaminant ATP in the NAD+ solution. This unique cofactor specificity was also supported by the observation of adenylation of Lig Tk with NAD+. This is the first biochemical study of a DNA ligase from a hyperthermophilic archaeon.

CFD Simulation of Particle Suspension Height in Stirred Vessels

2004 ◽  
Vol 82 (9) ◽  
pp. 1204-1213 ◽  
Author(s):  
G. Micale ◽  
F. Grisafi ◽  
L. Rizzuti ◽  
A. Brucato
Keyword(s):  
Cfd Simulation ◽  
Particle Suspension ◽  
Stirred Vessels
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