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degradable magnesium

Arivalagan Pugazhendhi, Raju Prabhu, Kavitha Muruganantham, Rajasree Shanmuganathan, Suganthy Natarajan
A rapid and ecofriendly fabrication of metal oxide nanoparticles using biogenic sources is the current trend being used to replace the toxic chemical method. The present study was carried out to synthesize magnesium oxide nanoparticles (MgONPs) using the marine brown algae Sargassum wighitii as the reducing and capping agent. The as-prepared MgONPs were characterized by spectroscopic and microscopic analyses. UV-visible spectrum of the MgONPs showed a sharp absorption peak at 322 nm. X- ray diffraction analysis illustrated that the MgONPs were crystalline in nature with a face-centered cubic structure...
November 23, 2018: Journal of Photochemistry and Photobiology. B, Biology
Anna Gumieniczek, Anna Berecka, Tomasz Mroczek, Krzysztof Wojtanowski, Kinga Dąbrowska, Katarzyna Stępień
Sitagliptin was stored at high temperature/high humidity, dry hot air, UV/VIS light and different pH. Then, a selective LC-UV method was developed for determination of sitagliptin in the presence of degradation products and for estimation of degradation kinetics. Because parent drugs can react with excipients in final pharmaceutical formulations, stability of sitagliptin was also examined in the presence of excipients of different reactivity, using FT-IR and LC-UV methods. Finally, LC-MS method was used for identification of degradation products of sitagliptin...
November 15, 2018: Journal of Pharmaceutical and Biomedical Analysis
Amirhesam Amerinatanzi, Reza Mehrabi, Hamdy Ibrahim, Amir Dehghan, Narges Shayesteh Moghaddam, Mohammad Elahinia
Magnesium (Mg) and its alloys can degrade gradually up to complete dissolution in the physiological environment. This property makes these biomaterials appealing for different biomedical applications, such as bone implants. In order to qualify Mg and its alloys for bone implant applications, there is a need to precisely model their degradation (corrosion) behavior in the physiological environment. Therefore, the primary objective develop a model that can be used to predict the corrosion behavior of Mg-based alloys in vitro, while capturing the effect of pitting corrosion...
November 29, 2018: Bioengineering
Fatemeh Gholami, Hamid Mosmeri, Mahmoud Shavandi, Seyed Mohammad Mehdi Dastgheib, Mohammad Ali Amoozegar
One of the challenges in the petroleum hydrocarbon contaminated groundwater remediation by oxygen releasing compounds (ORCs) is to identify the remediation mechanism and determine the impact of ORCs on the environment and the intrinsic groundwater microorganisms. In this research, the application of encapsulated magnesium peroxide (MgO2 ) nanoparticles in the permeable reactive barrier (PRB) for bioremediation of the groundwater contaminated by toluene and naphthalene was studied in the continuous flow sand-packed plexiglass columns within 50 d experiments...
November 20, 2018: Science of the Total Environment
Jinhe Dou, Yupeng Zhao, Lu Lu, Guochao Gu, Huijun Yu, Chuanzhong Chen
The applications of magnesium (Mg) alloys as biodegradable orthopedic implants are mainly restricted due to their rapid degradation rate in the physiological environment. In this study, Si-CaP micro-arc oxidation (MAO) coatings were prepared on a Mg-Zn-Ca alloy by a second-step MAO process at different voltages in order to decrease the degradation rate and increase the bioactivity of the alloy. The microstructure and morphology of the samples were characterized using XRD, FT-IR SEM and EDS. The degradation behaviours of samples were evaluated using electrochemical techniques, and immersion tests in simulated body fluid (SBF)...
October 2018: Royal Society Open Science
Yishu Lin, Shu Cai, Song Jiang, Dongli Xie, Rui Ling, Jiayue Sun, Jieling Wei, Kaier Shen, Guohua Xu
To overcome the defect of high degradation rate of magnesium (Mg), bioactive coatings with compact structure, sufficient bonding strength and enhanced corrosion resistance are essential for Mg-based biodegradable implants. In this study, a dense Mg-substituted β-tricalcium phosphate and magnesium hydroxide (β-TCMP/Mg(OH)2 ) composite coating was prepared on AZ31 alloy via one-step hydrothermal method. The influences of hydrothermal temperature on its composition, microstructure of the surface and interface, bonding strength and corrosion behavior were evaluated...
November 12, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Yongqing Wang, Fengyue Zhao, Yumin Qian, Hongbing Ji
Room-temperature sodium-ion batteries (NIBs) using manganese-based layered cathode has been considered promising candidates for grid-scale energy storage applications. However, manganese-based materials suffer from seriously Jahn-Teller distortion, phase transition and unstable interface, resulting in severe structure degradation, sluggish sodium diffusion kinetics, and poor cycle, respectively. Herein, we demonstrate a Zr-doped Na0.70Mn0.80Co0.15Zr0.05O2 material with much improved specific capacity and rate capability compared with Zr-free Na0...
November 21, 2018: ACS Applied Materials & Interfaces
Md Nayeem Hossain, Benoît Igne, Carl A Anderson, James K Drennen
To develop a robust quantitative calibration model for spectroscopy, different sources of variability that are not directly related to the components of interest should be included in the calibration samples; this variability should be similar to that which is anticipated during validation and routine operation. Moisture content of pharmaceutical samples can vary as a function of supplier, storage conditions, geographic origin or seasonal variation. Additionally, some pharmaceutical operations (e. g., wet granulation) cause exposure of excipients and API to water...
October 15, 2018: Journal of Pharmaceutical and Biomedical Analysis
Izabela Przetaczek-Rożnowska, Teresa Fortuna, Monika Wodniak, Maria Łabanowska, Paulina Pająk, Karolina Królikowska
The paper discusses how microwave radiation and mineral additives affect selected physical and chemical properties of potato starch. Potato starch was irradiated with microwaves of 440 W or 800 W and then enriched with ions of potassium, magnesium, copper, or iron. Atomic absorption spectroscopy showed an effective incorporation of ions, while mineral saturation depended on both the microwave radiation density and the element being introduced. The data obtained prove that the microwave radiation and saturation with minerals affect the rheology and thermal characteristics of the samples under examination...
November 16, 2018: International Journal of Biological Macromolecules
Nathalia Mutis González, Posidia Pineda Gómez, Mario Enrique Rodríguez García
Starch is a biopolymer widely used in the industry; however, rarely used in its native form, making necessary its modification. This work studied the effect of the inclusion of potassium and magnesium ions on the physicochemical properties of plantain starch. Ionic solutions were prepared at five concentrations between 0.0 and 0.3 M. The gelatinization, thermal degradation, viscosity, swelling power, morphological and structural changes were studied. Results showed that ion addition increased the swelling and solubility index...
November 14, 2018: International Journal of Biological Macromolecules
Monica Echeverry-Rendon, Valentina Duque, David Quintero, Sara M Robledo, Martin C Harmsen, Felix Echeverria
The optimal mechanical properties render magnesium widely used in industrial and biomedical applications. However, magnesium is highly reactive and unstable in aqueous solutions, which can be modulated to increase stability of reactive metals that include the use of alloys or by altering the surface with coatings. Plasma electrolytic oxidation is an efficient and tuneable method to apply a surface coating. By varying the plasma electrolytic oxidation parameters voltage, current density, time and (additives in the) electrolytic solution, the morphology, composition and surface energy of surface coatings are set...
November 2018: Journal of Biomaterials Applications
Ruiqing Hou, Regine Willumeit-Römer, Vasil M Garamus, Marion Frant, Joachim Koll, Frank Feyerabend
Although the adsorption of proteins on Mg surface was ascribed to be the main reason for the effect of proteins on magnesium (Mg) degradation, few studies about the adsorption of proteins on Mg surface were performed due to the labile circumstance during immersion. In the present study, the adsorption of bovine serum albumin (BSA) and fibrinogen (Fib) on Mg surface during and after immersion was extensively investigated in different media for the first time. The results revealed that BSA and Fib showed a similar adsorption trend on Mg surface during and after immersion, and they adsorbed more on Mg surface in HBSS than in DMEM...
November 15, 2018: ACS Applied Materials & Interfaces
Iman Roohaniesfahani, Jie Wang, Young Jung No, Christian de Candia, Xinchao Miao, Zufu Lu, Jeffrey Shi, David L Kaplan, Xinquan Jiang, Hala Zreiqat
Injectable silk hydrogels are ideal carriers of therapeutic agents due to their biocompatibility and low immunogenicity. Injectable silk hydrogels for bone regeneration have been previously developed but often utilize expensive biologics. In this study, we have developed an injectable silk composite incorporated with a triphasic ceramic called MSM-10 (54 Mg2 SiO4 , 36 Si3 Sr5 and 10 MgO (wt%)) capable of simultaneously releasing magnesium, silicon, and strontium ions into its environment. These ions have been previously reported to possess therapeutic effects for bone regeneration...
January 1, 2019: Materials Science & Engineering. C, Materials for Biological Applications
Seul Ki Lee, Cheol-Min Han, Wooram Park, Ik Hwan Kim, Yoon Ki Joung, Dong Keun Han
Synthetic biodegradable polymers including poly(lactide-co-glycolide) (PLGA) have been widely used as alternatives to metallic implantable materials in the orthopedic field due to their superior biocompatibility and biodegradability. However, weak mechanical properties of the biodegradable polymers and inflammatory reaction caused by the acidic degradation products have limited their biomedical applications. In this study, we have developed a PLGA composite containing beta-tricalcium phosphate (β-TCP) and magnesium hydroxide (Mg(OH)2 ) as additives to improve mechanical, osteoconductivity, and anti-inflammation property of the biopolymer composite simultaneously...
January 1, 2019: Materials Science & Engineering. C, Materials for Biological Applications
Laura C Córdoba, Christophe Hélary, Fátima Montemor, Thibaud Coradin
Magnesium alloys have shown high potential as biodegradable implants for bone repair applications. However, their fast degradation in physiological media demands tuning their corrosion rate to accompany the natural tissue healing processes. Here, a new bi-layered silane-TiO2 /collagen coating efficient in stabilizing and biofunctionalizing the surface of AZ31 and ZE41 Mg alloys is presented. Corrosion tests performed in cell culture medium over 7 weeks showed that the bi-layered coating promotes the formation of a stable layer of Mg(OH)2 /MgCO3 /CaCO3 that provides effective protection to the alloys at advanced immersion stages...
January 1, 2019: Materials Science & Engineering. C, Materials for Biological Applications
Yushi Kashihara, Yui Terao, Kensaku Yoda, Takeshi Hirota, Toshio Kubota, Miyuki Kimura, Shunji Matsuki, Masaaki Hirakawa, Shin Irie, Ichiro Ieiri
BACKGROUND: Magnesium oxide (MgO) is often co-prescribed with L-dopa/carbidopa (LDCD) to improve constipation in Parkinson's disease patients. The mixing of L-dopa and MgO has been shown to degrade L-dopa; however, there is no interaction study on humans. We proposed mechanisms for the interaction between LDCD and MgO and conducted pharmacokinetic studies on rats and humans. To assess pharmacodynamic changes with the MgO treatment, we applied a model-based meta-analysis (MBMA). METHODS: The effects of MgO on the stabilities of L-dopa and carbidopa were evaluated in in vitro studies...
October 31, 2018: European Journal of Clinical Pharmacology
Danilo Spasiano, Vincenzo Luongo, Marco Race, Andrea Petrella, Saverio Fiore, Ciro Apollonio, Francesco Pirozzi, Umberto Fratino, Alberto F Piccinni
In this paper, the treatment of asbestos-cement waste (ACW) has been attempted by a dark fermentation (DF) pre-treatment followed by hydrothermal and anaerobic digestion (AD) treatments. During DF, glucose, employed as a biodegradable substrate, was mainly converted to H2 -rich biogas and organic acids (OAs). The latter caused the dissolution of the cement matrix and the partial structural collapse of chrysotile (white asbestos). To complete the chrysotile degradation, hydrothermal treatment of the DF effluents was performed under varying operating conditions (temperature, acid type, and load)...
October 15, 2018: Journal of Hazardous Materials
Tyler Scott, Huilei Zhao, Wei Deng, Xuhui Feng, Ying Li
Phenol is one of the most widespread, toxic and recalcitrant compounds in water sources. Due to its persistent nature, conventional wastewater treatment methods are not effective to remove or degrade phenol from water. In this work, novel photocatalysts were developed to effectively degrade phenol under simulated sunlight. The catalysts were composed of one-dimensional titanium dioxide (TiO2 ) nanorods decorated with silver (Ag) nanoparticles, coated by an ultrathin magnesium oxide (MgO) overlayer through atomic layer deposition (ALD)...
February 2019: Chemosphere
Wonseok Hwang, Jungmin Yoo, Yuno Lee, Suyeon Park, Phuong Lien Hoang, HyeokJin Cho, Jeongmin Yu, Thi Minh Hoa Vo, Minsang Shin, Mi Sun Jin, Daeho Park, Changbong Hyeon, Gwangrog Lee
Metal ions at the active site of an enzyme act as cofactors, and their dynamic fluctuations can potentially influence enzyme activity. Here, we use λ-exonuclease as a model enzyme with two Mg2+ binding sites and probe activity at various concentrations of magnesium by single-molecule-FRET. We find that while MgA 2+ and MgB 2+ have similar binding constants, the dissociation rate of MgA 2+ is two order of magnitude lower than that of MgB 2+ due to a kinetic-barrier-difference. At physiological Mg2+ concentration, the MgB 2+ ion near the 5'-terminal side of the scissile phosphate dissociates each-round of degradation, facilitating a series of DNA cleavages via fast product-release concomitant with enzyme-translocation...
October 23, 2018: Nature Communications
Mehdi Razavi, Mohammadhossein Fathi, Omid Savabi, Lobat Tayebi, Daryoosh Vashaee
Magnesium (Mg) alloys as a new group of biodegradable metal implants are being extensively investigated as a promising selection for biomaterials applications due to their apt mechanical and biological performance. However, as a foremost drawback of Mg alloys, the high degradation in body fluid prevents its clinical applications. In this work, a bioceramic composite coating is developed composed of diopside, bredigite, and fluoridated hydroxyapatite on the AZ91 Mg alloy in order to moderate the degradation rate, while improving its bioactivity, cell compatibility, and mechanical integrity...
October 22, 2018: Journal of Materials Science. Materials in Medicine
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