Influence of Temperature and Oxygen Concentration on the Radiation Induced Oxidation of Phenylalanine

1995 ◽  
Vol 50 (9) ◽  
pp. 864-870 ◽  
Author(s):  
P. Krajnik ◽  
R. M. Quint ◽  
S. Solar ◽  
N. Getoff ◽  
G. Sontag
Keyword(s):  
Oxygen Concentration ◽  
Room Temperature ◽  
Degradation Process ◽  
Storage Conditions ◽  
Food Storage ◽  
Reaction Conditions ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Radiation Induced ◽  
Induced Changes

AbstractThe formation of tyrosine isomers by γ-radiolysis of neutral aqueous phenylalanine solutions was found to be strongly dependent on oxygen concentration and temperature. Changing the dose rate did not influence the degradation process. In the presence of 0.25 x 10-3 mol dm-3 oxygen at room temperature the yields of o-tyrosine as well as of m- and p-tyrosine drop from G(o-Tyr) = 0.5 and G(m-Tyr) = G(p-Tyr) = 0.4 at a dose of 0.3 kGy to 0.18 and 0.16 at 2.5 kGy, respectively. In solutions containing 1.25 x 10-3 mol dm-3 oxygen the initial yields remain unchanged but decrease at 2.5 kGy only to G(o-Tyr) = 0.3 and G(m-Tyr) = G(p-Tyr) = 0.20. Under the latter reaction conditions also 3,4-dihydroxyphenylalanine was found.Samples irradiated in frozen state did not show remarkable radiolysis of phenylalanine and tyrosine formation. In the range between 5 and 20°C no essential influence of temperature on the phenylalanine radiolysis and tyrosine yields was observable. The obtained results are important for methods using the tyrosine yields as markers for the detection of irradiated food. Storage conditions and irradiation temperature play an essential role on radiation induced changes of food.

Temperature induced phase transition in fluorescence active zein nanoparticles

2021 ◽  
Vol 99 (1) ◽  
pp. 18-23
Author(s):  
Charlie Joe Croxford ◽  
Rajpreet Kaur ◽  
Kultar Singh ◽  
Mandeep Singh Bakshi
Keyword(s):  
Phase Transition ◽  
Temperature Variation ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Precipitation Method ◽  
Effect Of Temperature ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Potential Use ◽  
Controlled Precipitation

Stable colloidal zein nanoparticles (NPs) were synthesized by using controlled precipitation method. They were made fluorescence active by incorporating a small amount of fluorescence quinolinium surfactant. The incorporation of fluorescence surfactant provided both the colloidal stability and the fluorescence ability to determine the phase transition in zein NPs under the effect of temperature variation. Maintaining colloidal stability under the effect of temperature variation is an essential aspect of zein NPs applicability as a source of vegetarian protein supplement in different food suspensions. Different techniques such as fluorescence, DLS size, zeta potential, and FTIR measurements were applied to determine the influence of temperature on the colloidal stability of zein NPs. Zein NPs undergo phase transition well above room temperature while maintaining their size in nanometer range, and the phase transition temperature decreased with the amount of zein used in the synthesis of zein NPs. The results highlighted the potential use of zein NPs as a vegetarian supplement protein in different food products.

Effect of Temperature on Crater Formation and Ejecta Composition in Aluminum Alloy Targets

2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Crater Formation ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Influence Of Temperature On ◽  
Increasing Temperature

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.

scholarly journals THE INFLUENCE OF TEMPERATURE ON THE ACTION OF STRYCHNIN IN FROGS

1913 ◽  
Vol 18 (3) ◽  
pp. 300-309 ◽  
Author(s):  
Thomas Stotesbury Githens
Keyword(s):  
Low Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Room Temperature ◽  
Drug Action ◽  
The State ◽  
Great Caution ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

In order to establish the influence of temperature upon the effect of varying doses of strychnin injected into frogs, the animals must be kept under observation for several days and at various definite degrees of temperature. Statements that the animal was kept "cold," "at room temperature," or "warm" are insufficient. With a certain dose tetanus may result constantly at 30° C. yet never appear at 21° C., and either of these temperatures might be described as warm, when compared to a room temperature of 15° C. Furthermore an animal may apparently fail to respond in the cold to an injection of certain doses of strychnin and yet be found in tetanic convulsions the next day. That an animal may have late, long lasting, or strong tetanus while kept at such a low temperature as 5° C. after an injection of a dose of strychnin smaller than 0.01 of a milligram per frog emphasizes the fact that great caution must be exercised in formulating laws as to the influence of temperature on drug action. The main results of this investigation may be summarized as follows: Doses of strychnin amounting to 0.0006 of a milligram per gram of frog will cause tetanus at all temperatures between 5° C. and 30° C., although at low temperatures the tetanus may appear late. A dose of 0.0003 of a milligram per gram of frog will frequently produce tetanus at 5° C. as well as at 30° or 27° C., but may nevertheless fail to produce any reaction at such an intermediary temperature as 21° C. Smaller doses, 0.0002 of a milligram per gram, will cause tetanus in the cold but not at high temperatures. It may be stated in general that in frogs kept at low temperatures the tetanic state sets in later, continues longer, and each tetanic attack is of longer duration, while in the interval between the attacks the state of tonus is higher and the animals are more irritable than when they are kept at higher temperatures.

scholarly journals Pengaruh pH Ekstraksi pada Pewarnaan Batik Sutera Menggunakan Pewarna Alami Kulit Kayu Mahoni (Switenia Mahagoni)

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Dwi Wiji Lestari ◽  
Vivian Atika ◽  
Isnaini Isnaini ◽  
Agus Haerudin ◽  
Tin Kusuma Arta
Keyword(s):  
Room Temperature ◽  
Natural Dye ◽  
Alkaline Ph ◽  
Influence Of Temperature ◽  
Ph Values ◽  
Influence Of Temperature On ◽  
Good Scale ◽  
Swietenia Mahagoni

The natural dye extracted from Swietenia mahagoni was applied to silk batik. Mahagoni bark is known to contain dyestuff components such as flavonoids and tannins. The dye compound was extracted using water at pH values of 6 (original pH extract), pH 2 (acid), and pH 12 (base) at 100 °C for 1 hour. Variation of extraction pH values was carried out to determine the influence of temperature on the results of the extract. Batik dyeing was carried out at room temperature using dye products. The pre-mordanting and post-mordanting used were alum (Al2(SO4)3.K2SO4.24H2O). The results showed that the dye product extracted in alkaline pH shows a high amount of tannins and flavonoids and the ability to color the silk batik better. The color direction is reddish-brown. The pH values of extraction do not affect the results of the colorfastness to washing test, which is on 4-5 (good) scale. A B S T R A KPewarna alami yang diekstrak dari mahoni (Swietenia mahagoni) diaplikasikan pada kain batik sutra. Kulit kayu mahoni diketahui mengandung komponen zat warna berupa flavonoid dan tanin. Komponen zat warna diekstraksi menggunakan air pada pH 6, pH 2 (asam) dan pH 12 (basa) pada suhu 100 °C selama 1 jam. Variasi pH ekstraksi dilakukan untuk mengetahui pengaruhnya terhadap hasil ekstrak. Pewarnaan dilakukan pada suhu ruang menggunakan pewarna hasil ekstraksi. Mordan awal dan mordan akhir yang digunakan adalah tawas (Al2(SO4)3.K2SO4.24H2O). Ekstraksi pada pH basa terbukti meningkatkan jumlah zat tanin dan flavonoid yang terekstrak dan mampu mewarnai kain batik sutra dengan lebih baik. Arah warna yang dihasilkan adalah cokelat kemerahan. Derajat keasaman (pH) ekstraksi tidak berpengaruh pada hasil uji ketahanan luntur warna terhadap pencucian, yaitu skala 4-5 (baik).

scholarly journals Temperatura y concentración de fluoruro de sodio en geles fluorados

2019 ◽  
Vol 7 (01) ◽  
pp. 294-301
Author(s):  
Vianne Diana Huamán Baca ◽  
Alejandro pablo Pletickosich ◽  
Teófila Baca Carbajal
Keyword(s):  
Sodium Fluoride ◽  
Room Temperature ◽  
Acidic Ph ◽  
Influence Of Temperature ◽  
Neutral Ph ◽  
Influence Of Temperature On ◽  
Para Determinar

ResumenEl objetivo de esta investigación fue determinar la influencia de la temperatura en la concentración de fluoruro de sodio; la muestra estuvo conformada por 60 geles fluorados de un mismo lote y la validez de dos marcas: ‘Fluofar®’ en sus dos presentaciones (pH neutro y acidulado) y el ‘Fluorgel Maquira®’ en sus dos presentaciones (pH neutro y acidulado). De cada gel fluorado se obtuvieron cuatro muestras: para comprobar el pH, para determinar la concentración de fluoruro de sodio a temperatura ambiente, para fijar la concentración de fluoruro de sodio después de haber sido sometido a una temperatura de 8 °C durante tres meses, y para, determinar la concentración de fluoruro de sodio después de haber sido sometido a una temperatura de 20 °C durante tres meses.La determinación de concentración de fluoruro de sodio, se realizó mediante la técnica de destilación y titulación. Por los resultados obtenidos se concluyó: que el incremento de la temperatura influye en la disminución de la concentración de fluoruro de sodio —siendo estadísticamente significativa en los geles fluorados con pH ácido (geles acidulados) y, en los geles fluorados con pH neutro mantiene su concentración—, aún se incrementó la temperatura. La concentración de fluoruro de sodio, indicado por el fabricante, disminuyó significativamente al comparar con la concentración de fluoruro de sodio encontrado en el laboratorio.Palabras claves; Geles fluorados, concentración de fluoruro de sodio, temperatura, pHAbstractThe objective of this investigation was to determine the influence of temperature on the concentration of sodium fluoride; the sample consisted of 60 fluorinated gels from the same batch and validity of two brands: Fluofar ® in its two presentations (neutral and acidulated pH) and Fluorgel Maquira ® and its two presentations (neutral pH and acidulated). From each fluorinated gel four samples were obtained: to determine the pH, to determine the concentration of sodium fluoride at room temperature, to determine the concentration of sodium fluoride after having been subjected to temperature of 8 °C for three months, and to determine the concentration of sodium fluoride after having been subjected to temperature of 20 °C for three months.The determination of concentration of Sodium Fluoride was carried out by means of the distillation and titration. From the results obtained, it was concluded that the increase in temperature influences the decrease in the concentration of sodium fluoride -being statistically significant in fluorinated gels with acidic pH (acidified gels) and, in fluorinated gels with neutral pH, it maintains its concentration-, the temperature was still increased. The concentration of sodium fluoride, indicated by the manufacturer, decreased significantly when compared to the concentration of sodium fluoride found in the laboratory.

scholarly journals Influence of temperature on the respiratory rate of Nile Tilapia, Oreochromis niloticus (Pisces: Cichlidae) in the laboratory

2016 ◽  
Vol 8 (1) ◽  
pp. 27-30
Author(s):  
Ahmed S. Dan-kishiya ◽  
John R. Solomon ◽  
Umar A. Alhaji ◽  
Hadi S. Dan kishiya
Keyword(s):  
Water Temperature ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Room Temperature ◽  
Average Frequency ◽  
Influence Of Temperature ◽  
Nile Tilapia Oreochromis Niloticus ◽  
The World ◽  
Influence Of Temperature On ◽  
Weight Groups

Tilapia, Oreochromis niloticus, (Linneaus, 1758) is an important aquaculture species in Nigeria and other parts of the world. We obtained specimens (3,5-13,00 cm total length; 1,7 to 49 g) from Jabi Reservoir, Nigeria, and exposed them to 18-38o C. The frequency of opercular beats (i.e.respiratory rate) was determined from videos. At room temperature (28o C), the average frequency of opercular beats per minute for the weight groups of 1, 7 – 3,3; 4,0 – 7,0; 11,0 – 20 and 40 – 49g were 218, 190, 167 and 119 respectively. It decreased to 153, 137, 94 and 77 beats respectively when the water temperature was lowered to 18o C. It subsequently increased to 283, 267, 209 and 136 beats respectively when water temperature was raised to 38o C (p<0, 05).

Influence of temperature on low cycle properties of martensitic cast steel

2012 ◽  
Vol 59 (3) ◽  
pp. 329-342 ◽  
Author(s):  
Grzegorz Golanski ◽  
Stanisław Mrozinski ◽  
Krzysztof Werner
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Room Temperature ◽  
Cast Steel ◽  
Cyclic Softening ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Two Temperatures ◽  
Stabilization Period

The paper presents the results of research on low cycle properties of highchromium martensitic GX12CrMoVNbN9-1 (GP91) cast steel. The tests of fatigue strength were carried out at two temperatures: room temperature and at 600°C. At both temperatures the occurrence of cyclic softening of the cast steel was observed, revealing no clear stabilization period. Moreover, it has been proved that the fatigue life is influenced by the temperature which depends on the level of strain. The greatest influence was observed for the smallest strain levels applied in the research.

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