scholarly journals Preserving Climacteric Fruits by Ripening Hormone Oxidation using nano-KMnO4 Confined within Nanoporous Carbon

2019 ◽  
Vol 19 (1) ◽  
pp. 54
Author(s):  
Addo Hernando ◽  
Teguh Ariyanto ◽  
Imam Prasetyo
Keyword(s):  
Oxidation Rate ◽  
Room Temperature ◽  
Reaction Model ◽  
Ethylene Oxidation ◽  
Gas Concentration ◽  
First Order ◽  
Oxidation Experiment ◽  
Gas Removal ◽  
Fruit Preservation ◽  
Gas Tight

Climacteric fruits naturally can be over-ripened because of ripening hormone composed of ethylene gas. Removal of ethylene gas by potassium permanganate (KMnO4) has successfully preserved the fruit, but there is still a room for improvement through nano-confinement process. This study was conducted to compare the ethylene oxidation rate and fruit preservation ability of KMnO4 and nano-KMnO4. Ethylene oxidation experiment was conducted in a gas-tight vial filled with ethylene gas (~20%v) and either KMnO4 or nano-KMnO4. Ethylene gas concentration inside the vial was periodically measured using gas chromatography (GC). The result revealed that ethylene oxidation rate by nano-KMnO4 is higher than KMnO4. The ethylene oxidation rate kinetic was modeled with a gas-solid reaction model, which is fundamentally more accurate than first-order reaction model. Fruit preservation experiment was conducted in sealed containers filled with banana (Musa acuminata) samples and either KMnO4 or nano- KMnO4, and stored at room temperature. The result revealed that banana preservation duration by nano-KMnO4 is remarkably longer than KMnO4, where unpreserved fruit was ripened after 7 days and fruit preserved by KMnO4 and nano-KMnO4 were ripened after 13 and 16 days respectively.

Electrochemical Oxidation of Perfluorooctanesulfonate by Magnéli Phase Ti4O7 Electrode in the Presence of Trichloroethylene

2020 ◽  
Vol 1 (4) ◽  
Author(s):  
Peizeng Yang ◽  
Yaye Wang ◽  
Junhe Lu ◽  
Viktor Tishchenko ◽  
Qingguo Huang ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
First Order ◽  
Degradation Rates ◽  
Oxidation Technology ◽  
Magnéli Phase ◽  
Polyfluoroalkyl Substances ◽  
Titanium Suboxide ◽  
Gas Tight ◽  
Magneli Phase

This study examined the degradation of perfluorooctanesulfonate (PFOS) in electrochemical oxidation (EO) processes in the presence of trichloroethylene (TCE). The EO experiment was performed in a gas-tight reactor using Magnéli phase titanium suboxide (Ti4O7) as the anode. The experimental data demonstrated that 75% of PFOS (2 μM) was degraded at 10 mA/cm2 current density in 30 min without TCE present in the solution, while the presence of 76 μM TCE apparently inhibited the degradation of PFOS, reducing its removal down to 53%. Defluorination ratio suggested that PFOS was significantly mineralized upon EO treatment, and it appeared to be not influenced by the presence of TCE. The respective pseudo-first order rate constants (kobs) of PFOS removal were 0.0471 and 0.0254 min-1 in the absence and presence of TCE. The degradation rates of both PFOS and TCE increased with current density rising from 2.5 to 20 mA/cm2. In the presence of TCE, chloride, chlorate, and perchlorate were formed that accounted for 79.7 %, 5.53%, and 1.51% of the total chlorine at 60 min. This work illustrates the promise of the Magnéli phase Ti4O7 electrode based electrochemical oxidation technology for degrading per- and polyfluoroalkyl substances (PFASs) and co-contaminants in groundwaters.

scholarly journals Engineering Increased Stability in the Antimicrobial Peptide Pediocin PA-1

2000 ◽  
Vol 66 (11) ◽  
pp. 4798-4802 ◽  
Author(s):  
Line Johnsen ◽  
Gunnar Fimland ◽  
Vincent Eijsink ◽  
Jon Nissen-Meyer
Keyword(s):  
Antimicrobial Peptide ◽  
Molecular Mass ◽  
Room Temperature ◽  
Bacteriocin Activity ◽  
Food Preservative ◽  
Food Grade ◽  
First Order ◽  
Methionine Residue ◽  
First Order Kinetics

ABSTRACT Pediocin PA-1 is a food grade antimicrobial peptide that has been used as a food preservative. Upon storage at 4°C or room temperature, pediocin PA-1 looses activity, and there is a concomitant 16-Da increase in the molecular mass. It is shown that the loss of activity follows first-order kinetics and that the instability can be prevented by replacing the single methionine residue (Met31) in pediocin PA-1. Replacing Met by Ala, Ile, or Leu protected the peptide from oxidation and had only minor effects on bacteriocin activity (for most indicator strains 100% activity was maintained). Replacement of Met by Asp was highly deleterious for bacteriocin activity.

Estimation of Effective Moisture Diffusivity in Starchy Materials Following Hydrothermal Treatments

2011 ◽  
Vol 312-315 ◽  
pp. 364-369 ◽  
Author(s):  
Seyed Amir Bahrani ◽  
Catherine Loisel ◽  
Jean Yves Monteau ◽  
Sid Ahmed Rezzoug ◽  
Zoulikha Maache-Rezzoug
Keyword(s):  
Reaction Rate ◽  
Effective Diffusivity ◽  
Moisture Diffusivity ◽  
Reaction Model ◽  
Reaction Rate Constant ◽  
Diffusivity Coefficient ◽  
Maize Starch ◽  
First Order ◽  
Melting Phenomenon ◽  
Treatment Processes

Two hydrothermal treatment processes (DV-HMT and DIC treatment) were investigated on standard maize starch for three processing temperatures; 100, 110 and 120°C. The gravimetric change of starch powder during the treatment was analyzed by a simultaneous water diffusion and starch reaction model. The effective diffusivity coefficient (Deff) and reaction rate constant (k) were estimated by minimizing the error between experimental and analytical results. The values of Deff and k clearly increased with temperature. The degree of starch melting was evaluated for the two treatments using the first-order reaction model as a function of processing time. The results suggest that the absorption process is controlled by water–starch reactivity that induces melting phenomenon of starch crystallites, which progresses when temperature increases. The two hydrothermal treatments considerably differ: DIC being more prone to water absorption as demonstrated by the values of Deff and k.

scholarly journals Effect of GNWs/NiO-WO3/GNWs Heterostructure for NO2 Gas Sensing at Room Temperature

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 626
Author(s):  
Seokhun Kwon ◽  
Seokwon Lee ◽  
Joouk Kim ◽  
Chulmin Park ◽  
Hosung Jung ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Room Temperature ◽  
Microwave Plasma ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Gas Concentration ◽  
Negative Change ◽  
Low Concentrations ◽  
Detection Characteristics ◽  
No2 Detection

Recently, as air pollution and particulate matter worsen, the importance of a platform that can monitor the air environment is emerging. Especially, among air pollutants, nitrogen dioxide (NO2) is a toxic gas that can not only generate secondary particulate matter, but can also derive numerous toxic gases. To detect such NO2 gas at low concentration, we fabricated a GNWs/NiO-WO3/GNWs heterostructure-based gas sensor using microwave plasma-enhanced chemical vapor deposition (MPECVD) and sputter, and we confirmed the NO2 detection characteristics between 10 and 50 ppm at room temperature. The morphology and carbon lattice characteristics of the sensing layer were investigated using field emission scanning electron microscopy (FESEM) and Raman spectroscopy. In the gas detection measurement, the resistance negative change according to the NO2 gas concentration was recorded. Moreover, it reacted even at low concentrations such as 5–7 ppm, and showed excellent recovery characteristics of more than 98%. Furthermore, it also showed a change in which the reactivity decreased with respect to humidity of 33% and 66%.

Influence of the Ge distribution on the first order magnetic transition of the MnFe(P,Ge) magnetocaloric material

2018 ◽  
Vol 20 (26) ◽  
pp. 18117-18126 ◽  
Author(s):  
Zhen-Lu Zhang ◽  
Dan-Min Liu ◽  
Wei-Qiang Xiao ◽  
Hui Li ◽  
Shao-Bo Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Transition ◽  
First Order

MnFe(P,Ge) is a promising magnetocaloric material for potential refrigeration applications near room temperature.

Ferroelectricity of trimethylammonium bromide below room temperature

2020 ◽  
Vol 8 (17) ◽  
pp. 5868-5872 ◽  
Author(s):  
Zhangran Gao ◽  
Yuying Wu ◽  
Zheng Tang ◽  
Xiaofan Sun ◽  
Zixin Yang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Curie Temperature ◽  
Ferroelectric Phase Transition ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
First Order

Ferroelectricity of trimethylammonium bromide was discovered near room temperature, which undergoes a first-order paraelectric–ferroelectric phase transition at the Curie temperature around 286 K.

scholarly journals Enhancement of zero-field skyrmion density in [Pt/Co/Fe/Ir]2 multilayers at room temperature by the first-order reversal curve

2020 ◽  
Vol 127 (22) ◽  
pp. 223901 ◽  
Author(s):  
Mangyuan Ma ◽  
Calvin Ching Ian Ang ◽  
Yong Li ◽  
Zizhao Pan ◽  
Weiliang Gan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Zero Field ◽  
First Order

scholarly journals Kinetic Profiling of the Hydrolytic Reaction of Benazepril: Metabolic Pathway Simulation

2018 ◽  
Vol 101 (4) ◽  
pp. 1009-1013
Author(s):  
A Hemdan ◽  
Adel M Michael
Keyword(s):  
Room Temperature ◽  
Enzyme Inhibitor ◽  
Internal Standard ◽  
Official Method ◽  
First Order ◽  
First Order Kinetics ◽  
Accuracy And Precision ◽  
Inhibitor Analysis ◽  
Hydrolytic Reaction ◽  
Significant Difference

Abstract A simple, specific, and rapid kinetic study of benazepril (BNZ) hydrolysis was developed and validated using HPLC. BNZ was degraded using 0.1 N sodium hydroxide at room temperature to produce benazeprilat, which is an active metabolite of BNZ and acts as an angiotensin-converting enzyme inhibitor. Analysis was carried out using an Athena C18 column (4.6 × 250 mm, 5 µm particle size). The mobile phase consists of a mixture of phosphate buffer (pH 4.5) and acetonitrile (53 + 47, v/v) at a flow rate of 1 mL/min. UV detection was accomplished at 242 nm using moexipril as the internal standard. The method was validated according to International Conference on Harmonization guidelines, and the calibration curve was linear over the range 10–100 µg/mL, with acceptable accuracy and precision. Kinetic profiling of the hydrolysis was shown to follow pseudo-first-order kinetics. The method was applied to the assay of BNZ in combined dosage form with no interference from other ingredients. The obtained results were statistically compared with those of the official method, showing no significant difference.

scholarly journals 127I NQR and Crystal Structure Studies of [N(CH3)4]2 CdI4

2000 ◽  
Vol 55 (1-2) ◽  
pp. 225-229 ◽  
Author(s):  
Hideta Ishihara ◽  
Keizo Horiuchi ◽  
Thorsten M. Gesing ◽  
Shi-qi Dou ◽  
J.-Christian Buhl ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Order Phase Transition ◽  
Intensity Ratio ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Temperature Phase ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

The temperature dependence of 127I NQR and DSC as well as the crystal structure at room temperature of the title compound were determined. This compound shows a first-order phase transition of an order-disorder type at 245 K. Eight 127I(v1:m = ±1/2 ↔ ±3/2) NQR lines of 79.57, 81.86, 82.56, 83.36, 84.68, 87.72, 88.34, and 88.86 MHz, and corresponding eight 127I(v2: m = ±3/2 ↔±5/2) NQR lines were observed at liquid nitrogen temperature. Three 127I(υi) NQR lines wfth an intensity ratio of 1:1:2 in the order of decreasing frequency were observed just above the transition point and two NQR lines except for the middle-frequency line disappeared around room temperature. This temperature behavior of NQR lines is very similar to that observed in [N(CH3)4]2Hgl4. Another first-order phase transition takes place at 527 K. The structure of the room-temperature phase was redetermined: orthorhombic, Pnma, Z = 4, a = 1342.8(3), b = 975.7(2), c = 1696.5(3) pm. The NQR result of three lines with an intensity ratio of 1:1:2 is in agreement with this structure. The thermal displacement parameters of atoms in both cations and anions are large.

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