scholarly journals Effect of gamma-irradiation on the properties of aluminum dihydrogen triphosphate

2017 ◽  
Vol 82 (10) ◽  
pp. 1111-1121 ◽  
Author(s):  
Weiqiang Song ◽  
Qinghuan Song ◽  
Longchao Wu ◽  
Lantao Yang
Keyword(s):  
Thermal Analysis ◽  
Corrosion Resistance ◽  
Gamma Irradiation ◽  
Electrochemical Impedance ◽  
Dose Range ◽  
Xrd Analysis ◽  
High Dose ◽  
Crystal Transition ◽  
Steel Panels ◽  
High Doses

The effect of gamma irradiation on the properties of aluminum dihydrogen triphosphate (ADTP) in the dose range of 0 to 150 kGy was studied by X-ray diffraction (XRD) analysis, thermal analysis, acid?base titration, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Although the XRD and SEM results indicated that there were no significant effects on the crystal structure and the surface morphology of ADTP, thermal analysis revealed that the crystal transition of Al(PO3)3 from Type-B to Type-A did not occur at a high temperature in irradiated ADTP. EIS results showed that high-dose gamma irradiation (100 kGy and 150 kGy, 60Co) improved the corrosion inhibition ability of ADTP on tinplate steel. SEM was used to investigate the surface of tinplate steel panels after immersion in ADTP extracts for 69 h, and revealed that many slices were formed on the surface. The slices were attributed to the formation of Fe2P3O10. Inter-slice gaps may be the reason for the lower corrosion resistance of ADTP compared with the resistance of some toxic pigments containing lead and chromium. Overall, high doses of gamma irradiation improved the corrosion resistance of ADTP.

scholarly journals Effect of Molybdenum Content on the Corrosion and Microstructure of Low-Ni, Co-Free Maraging Steels

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 852
Author(s):  
Asiful H. Seikh ◽  
Hossam Halfa ◽  
Mahmoud S. Soliman
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
X Ray ◽  
Maraging Steels ◽  
Eds Analysis ◽  
Electroslag Refining

Molybdenum (Mo) is an important alloying element in maraging steels. In this study, we altered the Mo concentration during the production of four cobalt-free maraging steels using an electroslag refining process. The microstructure of the four forged maraging steels was evaluated to examine phase contents by optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. Additionally, we assessed the corrosion resistance of the newly developed alloys in 3.5% NaCl solution and 1 M H2SO4 solution through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Furthermore, we performed SEM and energy-dispersive spectroscopy (EDS) analysis after corrosion to assess changes in microstructure and Raman spectroscopy to identify the presence of phases on the electrode surface. The microstructural analysis shows that the formation of retained austenite increases with increasing Mo concentrations. It is found from corrosion study that increasing Mo concentration up to 4.6% increased the corrosion resistance of the steel. However, further increase in Mo concentration reduces the corrosion resistance.

scholarly journals Tg.rasH2 Mice and not CByB6F1 Mice Should Be Used for 28-Day Dose Range Finding Studies Prior to 26-Week Tg.rasH2 Carcinogenicity Studies

2017 ◽  
Vol 36 (4) ◽  
pp. 287-292 ◽  
Author(s):  
Madhav G. Paranjpe ◽  
Jessica Belich ◽  
Tom J. Vidmar ◽  
Reem H. Elbekai ◽  
Marie McKeon ◽  
...  
Keyword(s):  
Selection Process ◽  
Dose Range ◽  
Maximum Tolerated Dose ◽  
High Dose ◽  
Dose Selection ◽  
Range Finding ◽  
Body Weights ◽  
Vehicle Test ◽  
High Doses ◽  
Dose Levels

Our recent retrospective analysis of data, collected from 29 Tg.rasH2 mouse carcinogenicity studies, determined how successful the strategy of choosing the high dose for the 26-week studies was based on the estimated maximum tolerated dose (EMTD) derived from earlier 28-day dose range finding (DRF) studies conducted in CByB6F1 mice. Our analysis demonstrated that the high doses applied at EMTD in the 26-week Tg.rasH2 studies failed to detect carcinogenic effects. To investigate why the dose selection process failed in the 26-week carcinogenicity studies, the initial body weights, terminal body weights, body weight gains, food consumption, and mortality from the first 4 weeks of 26-week studies with Tg.rasH2 mice were compared with 28-day DRF studies conducted with CByB6F1 mice. Both the 26-week and the earlier respective 28-day studies were conducted with the exact same vehicle, test article, and similar dose levels. The analysis of our results further emphasizes that the EMTD and subsequent lower doses, determined on the basis of the 28-day studies in CByB6F1 mice, may not be an accurate strategy for selecting appropriate dose levels for the 26-week carcinogenicity studies in Tg.rasH2 mice. Based on the analysis presented in this article, we propose that the Tg.rasH2 mice and not the CByB6F1 mice should be used in future DRF studies. The Tg.rasH2 mice demonstrate more toxicity than the CByB6F1 mice, possibly because of their smaller size compared to CByB6F1 mice. Also, the Tg.rasH2 males appear to be more sensitive than the female Tg.rasH2 mice.

scholarly journals Gamma-Tocotrienol, A Radiation Countermeasure, Reverses Proteomic Changes In Serum Following Total-Body Gamma Irradiation In Mice

2021 ◽  
Author(s):  
Elliot Rosen ◽  
Oluseyi Fatanmi ◽  
Stephen Y. Wise ◽  
V. Ashutosh Rao ◽  
Vijay K. Singh
Keyword(s):  
Gamma Irradiation ◽  
Immune Cell ◽  
Serum Proteins ◽  
Complement C3 ◽  
High Dose ◽  
Cell Trafficking ◽  
Associated Proteins ◽  
High Doses ◽  
Significant Expression ◽  
Total Body

Abstract Radiological incidents or terrorist attacks would likely expose civilians and military personnel to high doses of ionizing radiation, leading to the development of acute radiation syndrome (ARS). While the effects and symptoms of high dose radiation exposure have been established, prophylactic treatments and methods for determining the extent of exposure remain limited. We examined the effectiveness of prophylactic administration of a developmental radiation countermeasure, g-tocotrienol (GT3), in a total-body irradiation (TBI) mouse model. CD2F1 mice received GT3 24 h prior to 11 Gy cobalt-60 gamma-irradiation, a supralethal dose for this strain. Two-dimensional differential in-gel electrophoresis was followed by mass spectrometry and Ingenuity Pathway Analysis (IPA). Analysis revealed a change in expression of 18 proteins in response to TBI, and these changes were reversed with prophylactic treatment of GT3. IPA revealed a network of associated proteins involved in cellular movement, immune cell trafficking, and inflammatory response. Of particular interest, significant expression changes in beta-2-glycoprotein 1, alpha-1-acid glycoprotein 1, alpha-2-macroglobulin, complement C3, mannose-binding protein C, and major urinary protein 6 were noted after TBI and reversed with GT3 treatment. This study reports the network and specific serum proteins which could be translated as biomarkers of both radiation injury and protection by radiation countermeasures.

A Proposal for New Strategies in Dose Selection for 26-Week Tg.Rash2 Carcinogenicity Studies

2021 ◽  
pp. 109158182110033
Author(s):  
Madhav G. Paranjpe ◽  
Tom J. Vidmar ◽  
Melissa D. Denton ◽  
Reem H. Elbekai ◽  
Peter C. Mann ◽  
...  
Keyword(s):  
Dose Group ◽  
Body Weight Gain ◽  
Dose Range ◽  
High Dose ◽  
Dose Selection ◽  
Test Article ◽  
Range Finding ◽  
Body Weights ◽  
High Doses ◽  
New Strategies

Our experience indicates that extrapolation of doses from the maximum tolerated doses (MTD) derived from 4-week dose range finding (DRF) studies conducted in CByB6F1 may overpredict tolerability and undermine utility of the high-dose groups in 26-week carcinogenicity studies conducted in Tg.rasH2. In the 26-week carcinogenicity studies conducted in Tg.rasH2 mice, we analyzed the initial body weights, food consumption (FC), terminal body weights, body weight gain (BWG), mortality, and tumor incidence for vehicle and test article–treated dose groups for 26 studies conducted from 2014 to 2018. Although not statistically significant compared to the control dose group, the % BWG decreased in male mice of mid- and high-dose groups by >10%, whereas in females there were no differences. The mortality increased in a statistically significant manner for medium and high doses of males. In female mice, the mortality increased in the high-dose group but not in a statistically significant manner. When the cause of death (COD) was analyzed in all dose groups of both sexes, the COD due to tumors was highest in the control groups, whereas it was lowest in high-dose groups of both sexes. At the same time, the COD due to undetermined causes, which is possible indication of test article–induced toxicity, was highest in high-dose groups of both sexes. These findings together indicate that MTD derived from earlier DRF studies was exceeded when applied to 26-week carcinogenicity studies and did not serve any purpose in the outcome of these studies.

scholarly journals Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Shiv Govind Prasad ◽  
Abhijit De ◽  
Udayan De
Keyword(s):  
Free Radicals ◽  
Gamma Irradiation ◽  
Polymer Films ◽  
Wavelength Region ◽  
Xrd Analysis ◽  
High Dose ◽  
Plane Vibration ◽  
Bending Mode ◽  
Vis Spectroscopy ◽  
Gamma Irradiated

Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET) polymer films have been investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-VIS) spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1 (depicting C–H bending mode of out-of-plane vibration) and another at 1303 cm−1 (representing C–H bending mode of in-plane vibration) disappear for gamma-irradiated PET. In this study, it has also been found that γ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by the γ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasing γ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations on γ-damage have been correlated.

scholarly journals Thermoluminescence Properties of Bioglass for Radiation Dosimetry

2021 ◽  
Author(s):  
Huda A. Alazab ◽  
N.Y. Abdou ◽  
H. A. Saudi ◽  
wesam Abd-Allah
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Radiation Dosimetry ◽  
Dose Range ◽  
Glow Peak ◽  
Gamma Dose ◽  
High Dose ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Gamma

Abstract The thermoluminescence technique was employed to study bioglass matrices prepared using the traditional technique of glass making. The synthesized bioglass matrices were investigated using X-ray diffraction (XRD), and differential thermal analysis (DTA) has been studied. The highest thermoluminescent intensity was found for the bioglass matric of 26.91% CaO, 46.134% SiO2, 2.60% P2O5, 24.34%Na2O (mol%), with only one glow peak at 460 k. The TL response illustrations linearity in high gamma dose range from 25 to 1000 Gy. This new bioglass matric might become useful in high-dose fields for dosimetry.

The Influence of Serotonin on Clot Retraction and the Thrombelastogram

1958 ◽  
Vol 02 (01/02) ◽  
pp. 111-124 ◽  
Author(s):  
E Deutsch ◽  
K Martiny
Keyword(s):  
Human Plasma ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Specific Effect ◽  
High Dose ◽  
Clot Retraction ◽  
Platelet Counts ◽  
Essential Value ◽  
High Doses ◽  
Free Plasma

Summary1. Normal platelets are necessary for induction of normal clot retraction.2. Serotonin does not induce retraction in human platelet-free plasma-clots or enhance clot firmness as measured in the coagulogram.3. Serotonin does not improve clot retraction or firmness in plasma clots with sub-optimal platelet counts.4. Methylserotonin inhibits clot retraction of platelet-rich plasma to a certain extent in moderate doses, whereas, high doses are ineffective. BOL 148 has a similar, but less significant action. There is a possibility that these effects are specific antiserotonin-effects.5. LSD 25 was ineffective in all concentrations used.6. Largactil and reserpin inhibit retraction in high doses. There seems to be a non specific effect caused by the high dose.7. Reserpine does not release a retraction-inducing agent from the platelets, which could be detected in the centrifuged platelet-free plasma used for the incubation.8. Serotonin does not replace the retraction-cofactor of Hartert, or the dialyzable factor of Lüscher in synthetic clotting substrates.9. Serotonin is of no essential value in inducing normal retraction of human plasma clots.

Influence of β-D-mannuronic acid, as a new member of non-steroidal anti-inflammatory drugs family, on expression pattern of chemokines and their receptors in rheumatoid arthritis

2019 ◽  
Vol 16 ◽  
Author(s):  
Mona Aslani ◽  
Arman Ahmadzadeh ◽  
Zahra Aghazadeh ◽  
Majid Zaki-Dizaji ◽  
Laleh Sharifi ◽  
...  
Keyword(s):  
Cell Surface ◽  
Mrna Expression ◽  
Surface Expression ◽  
Phase Iii ◽  
Cell Surface Expression ◽  
Optimum Dose ◽  
High Dose ◽  
Mannuronic Acid ◽  
Anti Inflammatory ◽  
High Doses

Background: : Based on the encouraging results of phase III clinical trial of β-D-mannuronic acid (M2000) (as a new anti-inflammatory drug) in patients with RA, in this study, we aimed to evaluate the effects of this drug on the expression of chemokines and their receptors in PBMCs of RA patients. Methods:: PBMCs of RA patients and healthy controls were separated and the patients' cells were treated with low, moderate and high doses (5, 25 and 50 μg/mL) of M2000 and optimum dose (1 μg/mL) of diclofenac, as a control in RPMI-1640 medium. Real-time PCR was used for evaluating the mRNA expression of CXCR3, CXCR4, CCR2, CCR5 and CCL2/MCP-1. Cell surface expression of CCR2 was investigated using flow cytometry. Results:: CCR5 mRNA expression reduced significantly, after treatment of the patients' cells with all three doses of M2000 and optimum dose of diclofenac. CXCR3 mRNA expression down-regulated significantly followed by treatment of these cells with moderate and high doses of M2000 and optimum dose of diclofenac. CXCR4 mRNA expression declined significantly after treatment of these cells with moderate and high doses of M2000. CCL2 mRNA expression significantly reduced only followed by treatment of these cells with high dose of M2000, whereas, mRNA and cell surface expressions of CCR2 diminished significantly followed by treatment of these cells with high dose of M2000 and optimum dose of diclofenac. Conclusion:: According to our results, M2000 through the down-regulation of chemokines and their receptors may restrict the infiltration of immune cells into the synovium.

scholarly journals Hydrophobic Modification of Graphene Oxide and Its Effect on the Corrosion Resistance of Silicone-Modified Epoxy Resin

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 89
Author(s):  
Wei Yuan ◽  
Qian Hu ◽  
Jiao Zhang ◽  
Feng Huang ◽  
Jing Liu
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Graphene Oxide ◽  
Physical Properties ◽  
Epoxy Resin ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
X Ray ◽  
Modified Graphene Oxide ◽  
Modified Epoxy

This study modified graphene oxide (GO) with hydrophilic octadecylamine (ODA) via covalent bonding to improve its dispersion in silicone-modified epoxy resin (SMER) coatings. The structural and physical properties of ODA-GO were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle tests. The ODA-GO composite materials were added to SMER coatings by physical mixing. FE-SEM, water absorption, and contact angle tests were used to evaluate the physical properties of the ODA-GO/SMER coatings, while salt spray, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP) methods were used to test the anticorrosive performance of ODA-GO/SMER composite coatings on Q235 steel substrates. It was found that ODA was successfully grafted onto the surfaces of GO. The resulting ODA-GO material exhibited good hydrophobicity and dispersion in SMER coatings. The anticorrosive properties of the ODA-GO/SMER coatings were significantly improved due to the increased interfacial adhesion between the nanosheets and SMER, lengthening of the corrosive solution diffusion path, and increased cathodic peeling resistance. The 1 wt.% ODA-GO/SMER coating provided the best corrosion resistance than SMER coatings with other amounts of ODA-GO (including no addition). After immersion in 3.5 wt.% NaCl solution for 28 days, the low-frequency end impedance value of the 1 wt.% ODA-GO/SMER coating remained high, at 6.2 × 108 Ω·cm2.

scholarly journals Design and Multidimensional Screening of Flash-PEO Coatings for Mg in Comparison to Commercial Chromium(VI) Conversion Coating

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 337
Author(s):  
Ewa Wierzbicka ◽  
Marta Mohedano ◽  
Endzhe Matykina ◽  
Raul Arrabal
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Chromium Vi ◽  
Alkaline Electrolytes ◽  
Az31b Alloy ◽  
Plasma Electrolytic

REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations demand for an expedient discovery of a Cr(VI)-free alternative corrosion protection for light alloys even though the green alternatives might never be as cheap as current harmful technologies. In the present work, flash- plasma electrolytic oxidation coatings (FPEO) with the process duration < 90 s are developed on AZ31B alloy in varied mixtures of silicate-, phosphate-, aluminate-, and fluoride-based alkaline electrolytes implementing current density and voltage limits. The overall evaluation of the coatings’ anticorrosion performance (electrochemical impedance spectroscopy (EIS), neutral salt spray test (NSST), paintability) shows that from nine optimized FPEO recipes, two (based on phosphate, fluoride, and aluminate or silicate mixtures) are found to be an adequate substitute for commercially used Cr(VI)-based conversion coating (CCC). The FPEO coatings with the best corrosion resistance consume a very low amount of energy (~1 kW h m−2 µm−1). It is also found that the lower the energy consumption of the FPEO process, the better the corrosion resistance of the resultant coating. The superb corrosion protection and a solid environmentally friendly outlook of PEO-based corrosion protection technology may facilitate the economic justification for industrial end-users of the current-consuming process as a replacement of the electroless CCC process.

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