scholarly journals Tunneling in the Hydrogen-Transfer Reaction from a Vitamin E Analog to an Inclusion Complex of 2,2-Diphenyl-1-picrylhydrazyl Radical with β-Cyclodextrin in an Aqueous Buffer Solution at Ambient Temperature

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1966
Author(s):  
Ikuo Nakanishi ◽  
Yoshimi Shoji ◽  
Kei Ohkubo ◽  
Shunichi Fukuzumi
Keyword(s):  
Vitamin E ◽  
Phosphate Buffer ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Phosphate Buffer Solution ◽  
Water Soluble ◽  
Quantum Mechanical ◽  
Buffer Solution ◽  
Quantum Mechanical Tunneling ◽  
Hydrogen Transfer Reaction

Recently, increasing attention has been paid to quantum mechanical behavior in biology. In this study, we investigated the involvement of quantum mechanical tunneling in the hydrogen-transfer reaction from Trolox, a water-soluble analog of vitamin E (α-tocopherol), to 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) in a phosphate buffer solution (0.05 M, pH 7.0). DPPH• was used as a reactivity model of reactive oxygen species and solubilized in water using β-cyclodextrin (β-CD). The second-order rate constants, kH and kD, in 0.05 M phosphate buffer solutions prepared with H2O (pH 7.0) and D2O (pD 7.0), respectively, were determined for the reaction between Trolox and DPPH•, using a stopped-flow technique at various temperatures (283–303 K). Large kinetic isotope effects (KIE, kH/kD) were observed for the hydrogen-transfer reaction from Trolox to the β-CD-solubilized DPPH• in the whole temperature range. The isotopic ratio of the Arrhenius prefactor (AH/AD = 0.003), as well as the isotopic difference in the activation energies (19 kJ mol−1), indicated that quantum mechanical tunneling plays a role in the reaction.

Highly efficient electrocatalytic hydrogen evolution from neutral aqueous solution by a water-soluble anionic cobalt(ii) porphyrin

2015 ◽  
Vol 51 (81) ◽  
pp. 15067-15070 ◽  
Author(s):  
Belete B. Beyene ◽  
Sandeep B. Mane ◽  
Chen-Hsiung Hung
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Evolution ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Water Soluble ◽  
Applied Potential ◽  
Buffer Solution ◽  
Faradaic Efficiency ◽  
Highly Efficient ◽  
Neutral Aqueous Solution

CoTPPS is an efficient electrocatalyst for H2 generation from neutral phosphate buffer solution. It features quantitative Faradaic efficiency with a TOF of ∼1.83 s−1 and a TON of 1.9 × 104 mol of H2 per mole of catalyst at an applied potential of −1.29 V (vs. SHE).

Preparation of Vitamin E Liposomes by the Thin Film Method and Study on its Leakage Rate

2011 ◽  
Vol 236-238 ◽  
pp. 2207-2210 ◽  
Author(s):  
Wei Guang Zhang ◽  
Ji Hong Liang ◽  
You Jie Cai
Keyword(s):  
Thin Film ◽  
Vitamin E ◽  
Optimum Condition ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Entrapment Efficiency ◽  
Leakage Rate ◽  
Buffer Solution ◽  
Film Method

This text adopted the thin film method to prepare the vitamin E liposomes, the influence of proportion of components in vitamin E liposomes, and experiment condition on the envelopment rate were studied. The results showed that the optimum condition of the making technology of the vitamin E liposomes was:temperature42°C,m(vitamin E):m(lecithin)=1:25,m(vitamin E) :m(the cholesterol )=1:3, m(vitamin E) :m(the octadecylamine )=5:1, the phosphate buffer solution was 20 ml. In this case, the entrapment efficiency of the vitamin E liposomes was 76% .This method was accurate, and applicable for the preparation of vitamin E liposomes, and the property of it was very stable.

scholarly journals Platinum(ii)–porphyrin as a sensitizer for visible-light driven water oxidation in neutral phosphate buffer

2015 ◽  
Vol 8 (3) ◽  
pp. 975-982 ◽  
Author(s):  
Hung-Cheng Chen ◽  
Dennis G. H. Hetterscheid ◽  
René M. Williams ◽  
Jarl Ivar van der Vlugt ◽  
Joost N. H. Reek ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Oxidation ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
High Potential ◽  
Water Soluble ◽  
Buffer Solution ◽  
Visible Light Driven

A water-soluble Pt(ii)–porphyrin with a high potential for one-electron oxidation (∼1.42 V vs. NHE) proves very suitable for visible-light driven water oxidation in neutral phosphate buffer solution in combination with a variety of WOCs.

Bioceramic Hydroxyapatite Granules for Purification of Biotechnological Products

2011 ◽  
Vol 284-286 ◽  
pp. 1764-1769 ◽  
Author(s):  
Vitalijs Lakevics ◽  
Janis Locs ◽  
Dagnija Loca ◽  
Valentina Stepanova ◽  
Liga Berzina-Cimdina ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Phosphate Buffer ◽  
Bovine Serum ◽  
Phosphate Buffer Solution ◽  
Sorption Process ◽  
Buffer Solution ◽  
Ph Values ◽  
Bovine Serum Albumin Adsorption ◽  
Albumin Adsorption

Sorption experiments of bovine serum albumin (BSA) on hydroxyapatite (HAp) ceramic granules, prepared at three temperatures 900°C, 1000°C and 1150°C were performed at room temperature 18,6 °C and phosphate buffer, pH 5,83; 6.38 and 7,39. Thermal treatment contributed to the decrease of bovine serum albumin immobilization indicating that sorption process depended on HAp ceramics specific surface area and pH values of phosphate buffer solution. However, it was confirmed that granule size was also an important parameter for bovine serum albumin adsorption. As a result of these experiments, the most appropriate adsorption conditions and phosphate buffer pH values influence on to BSA sorption were analyzed.

Reduction of Escherichia coli O157:H7 Counts on Whole Fresh Apples by Treatment with Sanitizers

2000 ◽  
Vol 63 (6) ◽  
pp. 703-708 ◽  
Author(s):  
MARCY A. WISNIEWSKY ◽  
BONITA A. GLATZ ◽  
MARK L. GLEASON ◽  
CHERYLL A. REITMEIER
Keyword(s):  
Escherichia Coli ◽  
Chlorine Dioxide ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
Water Control ◽  
Buffer Solution ◽  
E Coli ◽  
Log Reduction

The objectives of this study were to determine if washing of whole apples with solutions of three different sanitizers (peroxyacetic acid, chlorine dioxide, or a chlorine-phosphate buffer solution) could reduce a contaminating nonpathogenic Escherichia coli O157:H7 population by 5 logs and at what sanitizer concentration and wash time such a reduction could be achieved. Sanitizers were tested at 1, 2, 4, 8, and 16 times the manufacturer's recommended concentration at wash times of 5, 10, and 15 min. Whole, sound Braeburn apples were inoculated with approximately 1 × 108 or 7 × 106 CFU per apple, stored for 24 h, then washed with sterile water (control) or with sanitizers for the prescribed time. Recovered bacteria were enumerated on trypticase soy agar. Washing with water alone reduced the recoverable population by almost 2 logs from the starting population; this can be attributed to physical removal of organisms from the apple surface. No sanitizer, when used at the recommended concentration, reduced the recovered E. coli population by 5 logs under the test conditions. The most effective sanitizer, peroxyacetic acid, achieved a 5-log reduction when used at 2.1 to 14 times its recommended concentration, depending on the length of the wash time. The chlorine-phosphate buffer solution reduced the population by 5 logs when used at 3 to 15 times its recommended concentration, depending on wash time. At no concentration or wash time tested did chlorine dioxide achieve the 5-log reduction.

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