scholarly journals Natural Flavonoids as Superior Reagents for Separation of Clinically Important Zr Radionuclides

2019 ◽  
Author(s):  
Kalpita Ghosh ◽  
Nabanita Naskar ◽  
Dibyasree Choudhury ◽  
Susanta Lahiri
Keyword(s):  
Radical Scavenging ◽  
High Energy ◽  
Energy Proton ◽  
Wide Ph Range ◽  
The Stability ◽  
Ph Range ◽  
Solid Liquid ◽  
Strong Radiation ◽  
Separating Agent

This paper exploits the affinity of bio-flavonoid hesperidin, isolated from orangepeel, towards the separation of clinically important 88Zr radionuclide from high energy proton bombarded yttrium target. The extraction of Zr with hesperidin was studied by solid-liquid extraction (SLX) technique over a wide pH range. The advantage of hesperidin is that it acts as separating agent as well as free-radical scavenging agent upon injection of the radionuclidehesperidin complex in-vivo. The stability of isolated hesperidin under strong radiation field was also studied. The selectivity of the bio-flavonoid towards 88Zr was maximum at pH=4 where in >78% Zr was extracted with <1% contamination from bulk yttrium target.

scholarly journals Natural Flavonoids as Superior Reagents for Separation of Clinically Important Zr Radionuclides

2019 ◽  
Author(s):  
Kalpita Ghosh ◽  
Nabanita Naskar ◽  
Dibyasree Choudhury ◽  
Susanta Lahiri
Keyword(s):  
Radical Scavenging ◽  
High Energy ◽  
Energy Proton ◽  
Wide Ph Range ◽  
The Stability ◽  
Ph Range ◽  
Solid Liquid ◽  
Strong Radiation ◽  
Separating Agent

This paper exploits the affinity of bio-flavonoid hesperidin, isolated from orangepeel, towards the separation of clinically important 88Zr radionuclide from high energy proton bombarded yttrium target. The extraction of Zr with hesperidin was studied by solid-liquid extraction (SLX) technique over a wide pH range. The advantage of hesperidin is that it acts as separating agent as well as free-radical scavenging agent upon injection of the radionuclidehesperidin complex in-vivo. The stability of isolated hesperidin under strong radiation field was also studied. The selectivity of the bio-flavonoid towards 88Zr was maximum at pH=4 where in >78% Zr was extracted with <1% contamination from bulk yttrium target.

scholarly journals THE EPIDEMIOLOGY OF PNEUMOCOCCUS INFECTION

1931 ◽  
Vol 53 (4) ◽  
pp. 535-552 ◽  
Author(s):  
Leslie T. Webster ◽  
Thomas P. Hughes
Keyword(s):  
Seasonal Variation ◽  
Host Resistance ◽  
The Other ◽  
Colony Morphology ◽  
Type Transformation ◽  
Wide Ph Range ◽  
Adults And Children ◽  
Nasal Passages ◽  
Ph Range

1. Pneumococci were obtained at one time or another from the nasal passages or throats of 80 per cent of 105 adults and children studied. In adults, they were obtained more frequently from the throat; in children, as often from the nasal passages as from the throat. 2. Of 500 pneumococcus strains studied, 97 per cent proved to be serologically specific. They formed smooth colonies and were for the most part avirulent for mice. Types I and II were obtained from one and two individuals respectively on one occasion only. Type III was obtained from nine individuals; Type XIII from nine individuals; Type XVI and Type XVIII from three individuals, for varying periods in each case. Atypical pneumococci were secured from 13 persons on single and scattered occasions. They varied in colony morphology, did not kill mice, or agglutinate in saline, but flocculated in all types of antipneumococcus sera employed and over a wide pH range in acid buffers. Their occurrence was apparently not associated with any type-transformation or virulence-enhancement process in vivo. 3. Strains of pneumococcus obtained on successive cultures from a given carrier were, with rare exceptions, of the same serological type and were similar in colony morphology, virulence for mice, and other tested biological characteristics. 4. Pneumococci of Types I and II were obtained under conditions suggestive that they lacked a capacity to spread readily; pneumococci of Types III and XIII, on the other hand, were obtained under conditions suggestive that they were spreading from person to person. 5. The persons studied differed consistently with respect to the occurrence of pneumococci. Some were pneumococcus-free, some were transient carriers, some periodic, and some chronic carriers. Data are given which suggest that the differences were due to variations in host resistance. 6. The incidence of pneumococci in all individuals studied underwent a seasonal variation paralleling that of coryza and sore throats in the same persons.

Biochemical and Biophysical characterization of the main protease, 3-chymotrypsin-like protease (3CLpro), from the novel coronavirus disease 19 (COVID-19)

2020 ◽  
Author(s):  
Juliana C. Ferreira ◽  
Wael M. Rabeh
Keyword(s):  
Antiviral Drug ◽  
Analytical Techniques ◽  
The Novel ◽  
Buffer Solution ◽  
Biophysical Characterization ◽  
Main Protease ◽  
Wide Ph Range ◽  
The Stability ◽  
Ph Range ◽  
Novel Coronavirus

Abstract Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is responsible for the novel coronavirus disease 2019 (COVID-19). An appealing antiviral drug target is the coronavirus 3C-like protease (3CLpro) that is responsible for the processing of the viral polyproteins and liberation of functional proteins essential for the maturation and infectivity of the virus. In this study, multiple thermal analytical techniques have been implemented to acquire the thermodynamic parameters of 3CLpro at different buffer conditions. 3CLpro exhibited relatively high thermodynamic stabilities over a wide pH range; however, the protease was found to be less stable in the presence of salts. Divalent metal cations reduced the thermodynamic stability of 3CLpro more than monovalent cations; however, altering the ionic strength of the buffer solution did not alter the stability of 3CLpro. Furthermore, the most stable thermal kinetic stability of 3CLpro was recorded at pH 7.5, with the highest enthalpy of activation calculated from the slope of Eyring plot. The biochemical and biophysical properties of 3CLpro explored here will improve the solubility and stability of 3CLpro for optimum conditions for the setup of an enzymatic assay for the screening of inhibitors to be used as lead candidates in the drug discovery and antiviral design for therapeutics against COVID-19.

scholarly journals pH effect on stability and kinetics degradation of nitazoxanide in solution

2020 ◽  
Vol 4 (1) ◽  
pp. 12-17
Author(s):  
Fábio Barbosa ◽  
Leonardo Pezzi ◽  
Julia Sorrentino ◽  
Martin Steppe ◽  
Nadia Volpato ◽  
...  
Keyword(s):  
Rate Constant ◽  
Degradation Product ◽  
Degradation Rate ◽  
Degradation Kinetics ◽  
Ph Effect ◽  
Degradation Rate Constant ◽  
Main Degradation Product ◽  
Wide Ph Range ◽  
The Stability ◽  
Ph Range

Stability studies correspond to a set of tests designed to assess changes in the quality of a given drug over time and under the influence of a number of factors. Among these factors, pH plays an important role, due to the catalytic effect that hydronium and hydroxide ions can play in several reactions. In the present study, the degradation kinetics of nitazoxanide was evaluated over a wide pH range, and the main degradation product generated was identified by LC-MS/MS. Nitazoxanide showed first-order degradation kinetics in the pH range of 0.01 to 10.0 showing greater stability between pH 1.0 and 4.0. The degradation rate constant calculated for these pH was 0.0885 x 10-2 min-1 and 0.0689 x 10-2 min-1, respectively. The highest degradation rate constant value was observed at pH 10.0 (0.7418 x 10-2 min-1) followed by pH 0.01 (0.5882 x 10-2 min-1). A major degradation product (DP-1) was observed in all conditions tested. Through LC-MS/MS analysis, DP-1 was identified as a product of nitazoxanide deacetylation. The effect of pH on the stability of nitazoxanide and the kinetic data obtained contribute to a better understanding of the intrinsic stability characteristics of nitazoxanide.

Monomeric and Polymeric Tetra-aminophthalocyanatocobalt(II) Modified Electrodes: Electrocatalytic Reduction of Oxygen

1997 ◽  
Vol 01 (01) ◽  
pp. 3-16 ◽  
Author(s):  
YU-HONG TSE ◽  
PAVEL JANDA ◽  
HERMAN LAM ◽  
JIUJUN ZHANG ◽  
WILLIAM J. PIETRO ◽  
...  
Keyword(s):  
Modified Electrodes ◽  
Rotating Disc ◽  
Graphite Electrodes ◽  
Monomeric Species ◽  
Electrocatalytic Oxygen Reduction ◽  
Wide Ph Range ◽  
Electron Reduction ◽  
The Stability ◽  
Ph Range ◽  
Stable Reduction

The monomeric and polymeric tetra-aminophthalocyane to, cobalt(II) species adsorbed onto graphite electrodes are active in electrocatalytic oxygen reduction. While the monomeric species is unstable, the polymerized species is an effective and stable reduction catalyst over a wide pH range. Both the two-electron reduction of oxygen to hydrogen peroxide and the four-electron reduction of oxygen to water are characterized by cyclic voltammetry, rotating disc and rotating ring-disc studies with appropriate theoretical analysis. Some mechanistic information is obtained. This is the first cobalt phthalocyanine species to provide a four-electron reduction pathway which exists over a wide pH range and is stable. The stability is associated with the polymerization since the monomeric species is not stable.

scholarly journals Biochemical and biophysical characterization of the main protease, 3-chymotrypsin-like protease (3CLpro) from the novel coronavirus SARS-CoV 2

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Juliana C. Ferreira ◽  
Wael M. Rabeh
Keyword(s):  
Antiviral Drug ◽  
Analytical Techniques ◽  
The Novel ◽  
Buffer Solution ◽  
Biophysical Characterization ◽  
Main Protease ◽  
Wide Ph Range ◽  
The Stability ◽  
Ph Range ◽  
Novel Coronavirus

AbstractSevere acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is responsible for the novel coronavirus disease 2019 (COVID-19). An appealing antiviral drug target is the coronavirus 3C-like protease (3CLpro) that is responsible for the processing of the viral polyproteins and liberation of functional proteins essential for the maturation and infectivity of the virus. In this study, multiple thermal analytical techniques have been implemented to acquire the thermodynamic parameters of 3CLpro at different buffer conditions. 3CLpro exhibited relatively high thermodynamic stabilities over a wide pH range; however, the protease was found to be less stable in the presence of salts. Divalent metal cations reduced the thermodynamic stability of 3CLpro more than monovalent cations; however, altering the ionic strength of the buffer solution did not alter the stability of 3CLpro. Furthermore, the most stable thermal kinetic stability of 3CLpro was recorded at pH 7.5, with the highest enthalpy of activation calculated from the slope of Eyring plot. The biochemical and biophysical properties of 3CLpro explored here may improve the solubility and stability of 3CLpro for optimum conditions for the setup of an enzymatic assay for the screening of inhibitors to be used as lead candidates in the discovery of drugs and design of antiviral therapeutics against COVID-19.

scholarly journals Drosophila paramyosin/miniparamyosin gene products show a large diversity in quantity, localization, and isoform pattern: a possible role in muscle maturation and function.

1996 ◽  
Vol 134 (1) ◽  
pp. 81-92 ◽  
Author(s):  
M Maroto ◽  
J Arredondo ◽  
D Goulding ◽  
R Marco ◽  
B Bullard ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Thick Filament ◽  
One Dimensional ◽  
Thick Filaments ◽  
Wide Ph Range ◽  
Muscle Types ◽  
Flight Muscles ◽  
Ph Range ◽  
And Function

The Drosophila paramyosin/miniparamyosin gene expresses two products of different molecular weight transcriptionally regulated from two different promoters. Distinct muscle types also have different relative amounts of myosin, paramyosin, and miniparamyosin, reflecting differences in the organization of their thick filaments. Immunofluorescence and EM data indicate that miniparamyosin is mainly located in the M line and at both ends of the thick filaments in Drosophila indirect flight muscles, while paramyosin is present all along the thick filaments. In the tergal depressor of the trochanter muscle, both proteins are distributed all along the A band. In contrast, in the waterbug, Lethocerus, both paramyosin and miniparamyosin are distributed along the length of the indirect flight and leg muscle thick filaments. Two-dimensional and one-dimensional Western blot analyses have revealed that miniparamyosin has several isoforms, focusing over a very wide pH range, all of which are phosphorylated in vivo. The changes in isoform patterns of miniparamyosin and paramyosin indicate a direct or indirect involvement of these proteins in muscle function and flight. This wide spectrum of potential regulatory characteristics underlines the key importance of paramyosin/miniparamyosin and its complex isoform pattern in the organization of the invertebrate thick filament.

scholarly journals Stability of Gamma-valerolactone Under Pulping Conditions as a Basis for Process Optimization and Chemical Recovery

2021 ◽  
Author(s):  
Marianna Granatier ◽  
Inge Schlapp-Hackl ◽  
Huy Quang Lê ◽  
Kaarlo Nieminen ◽  
Herbert Sixta
Keyword(s):  
Elevated Temperatures ◽  
Reaction Times ◽  
Chemical Recovery ◽  
Wide Ph Range ◽  
Alkaline Conditions ◽  
Naoh Solution ◽  
Hydroxyvaleric Acid ◽  
The Stability ◽  
Ph Range ◽  
Spent Liquor

Abstract This study investigates the extent of the g-valerolactone (GVL) hydrolysis forming an equilibrium with 4-hydroxyvaleric acid (4-HVA) in aqueous solutions over a wide pH range. The hydrolysis of pure 50 wt% GVL to 4-HVA (3.5 mol%) was observed only at elevated temperatures. The addition of sulfuric acid (0.2×10-5 wt% to 6 wt%) at elevated temperatures (150 – 180°C) and reaction times between 30-180 min caused the formation of 4 mol% 4-HVA but with decreasing acidity, the 4-HVA remained constant at about 3 mol%. The hydrolysis reactions in alkaline conditions were conducted at constant time (30 min) and temperature (180 °C) with variation of the NaOH concentration (0.2×10-6 wt% to 7 wt%). The addition of less than 0.2 wt % of NaOH resulted in the formation of less than 4 mol% of sodium 4-hydroxyvalerate. A maximum amount of 21 mol% of 4-HVA was observed in a 7 wt% NaOH solution. The stability after synthesis was determined by NMR analysis. To verify the GVL stability results obtained under practical conditions, Betula pendula sawdust was fractionated in 50% GVL with and without addition of H2SO4 or NaOH at 180°C and 120 min, and spent liquor was analyzed. The spent liquor contained 5.6 mol% and 6.0 mol% of 4-HVA in a highly acidic (20 kg H2SO4/t wood) and alkaline (192 kg NaOH/ t wood) environment, respectively.

Biochemical and functional characterization of OsCSD3, a novel CuZn superoxide dismutase from rice

2018 ◽  
Vol 475 (19) ◽  
pp. 3105-3121 ◽  
Author(s):  
Ravi Prakash Sanyal ◽  
Amol Samant ◽  
Vishal Prashar ◽  
Hari Sharan Misra ◽  
Ajay Saini
Keyword(s):  
Oxidative Stress ◽  
Thermal Inactivation ◽  
Biochemical Characterization ◽  
Spectral Characteristics ◽  
Functional Characterization ◽  
Double Knockout ◽  
Wide Ph Range ◽  
Ph Range

Superoxide dismutases (SODs, EC 1.15.1.1) belong to an important group of antioxidant metalloenzymes. Multiple SODs exist for scavenging of reactive oxygen species (ROS) in different cellular compartments to maintain an intricate ROS balance. The present study deals with molecular and biochemical characterization of CuZn SOD encoded by LOC_Os03g11960 (referred to as OsCSD3), which is the least studied among the four rice isozymes. The OsCSD3 showed higher similarity to peroxisomal SODs in plants. The OsCSD3 transcript was up-regulated in response to salinity, drought, and oxidative stress. Full-length cDNA encoding OsCSD3 was cloned and expressed in Escherichia coli and analyzed for spectral characteristics. UV (ultraviolet)–visible spectroscopic analysis showed evidences of d–d transitions, while circular dichroism analysis indicated high β-sheet content in the protein. The OsCSD3 existed as homodimer (∼36 kDa) with both Cu2+ and Zn2+ metal cofactors and was substantially active over a wide pH range (7.0–10.8), with optimum pH of 9.0. The enzyme was sensitive to diethyldithiocarbamate but insensitive to sodium azide, which are the characteristics features of CuZn SODs. The enzyme also exhibited bicarbonate-dependent peroxidase activity. Unlike several other known CuZn SODs, OsCSD3 showed higher tolerance to hydrogen peroxide and thermal inactivation. Heterologous overexpression of OsCSD3 enhanced tolerance of E. coli sod double-knockout (ΔsodA ΔsodB) mutant and wild-type strain against methyl viologen-induced oxidative stress, indicating the in vivo function of this enzyme. The results show that the locus LOC_Os03g11960 of rice encodes a functional CuZn SOD with biochemical characteristics similar to the peroxisomal isozymes.

The Determination of the Solubility of Amorphous UO2 (Sn and the Mononuclear Hydrolysis Constants of Uranium(IV) at 25° C.

1986 ◽  
Vol 84 ◽  
Author(s):  
Jordi Bruno ◽  
Ignasi Casas ◽  
Bo Lagerman ◽  
Maria Munoz
Keyword(s):  
Stability Constants ◽  
Solubility Data ◽  
Hydrolysis Constants ◽  
Reducing Conditions ◽  
Wide Ph Range ◽  
The Stability ◽  
Ph Range ◽  
Good Agreement

AbstractWe have measured the solubility 8f amorphous UO2in a wide pH range (2 to 10.5), in 0.5 M NaClO, at T=25 C. The species responsible for the solubility are U(OH) + and U'0H)h, with the stability constants lo:1,3=-1.1± 0.1 and log, 4 =- 5.4_.O. 2, respectively. No evidence for U(OH) is f6und up to pH=10.5. The same model explains satisfactorily the solubility data obtained by Parks and Pohl(5) at T=1000 C., in the pH range 1 to 10. The measured solubility of amorphous UO2 (s) in the pH_ýange 6 to 10.5, under reducing conditions, is rather high,. U(IV) =5 10 mols/l. This is in good agreement with previous data of Gayer and Leider(6) and Galkin and Stepanov(9).

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