Corrosion resistance of bioinspired DNA-induced Ca-P coating on biodegradable magnesium alloy

Bioinspired coatings with decreased corrosion rate and enhanced bond strength are at the core of future clinic applications on degradable magnesium(Mg)-based implants.The hybrid of organic and inorganic compounds offers a strategy to fabricate biodegradable,biocompatible and compact coatings on biomedical Mg alloys.Hereby,a comparison with and without DNA addition was made on the corrosion resistance and adhesion strength of Ca-P coatings fabricated on AZ31 alloy via hydrothermal deposition.The morphology,chemical composition,and crystallographic structure of the coatings were investigated by means of SEM,EDS and FTIR as well as XRD before and after corrosion tests.Corrosion resistance was evaluated via potentiodynamic polarization curves,electrochemical impedance spectroscopy(EIS)and hydrogen evolution tests in Hank’s solution.Results show that the coatings are mainly characterized by tricalcium phosphate(TCP),dicalcium phosphate anhydrous(DCPA)and calcium-deficient hydroxyapatite(CDHA).The presence of DNA leads to the formation of Ca-P coating with improved corrosion resistance and adhesion strength.Additionally,the formation mechanism for DNA-induced Ca-P coating is proposed.The DNA-induced Ca-P coating exhibits a promising future for controlling the corrosion rate of biodegradable Mg alloys.©2019 Published by Elsevier B.V.on behalf of Chongqing University.

The influence of the eruption of mandibular third molars on the craniofacial morphology in Han youth of North China

Teeth affect not only oral problems but also facial morphology.In China,there are few reports about the influence of the third molars on the craniofacial morphology of Han youths.Using in vivo imaging software,3D reconstruction of craniofacial CTs were performed on 32 Chinese Han youths without mandibular third molars and 25 Chinese Han youth with full mandibular third molars.The morphology of their mandible and mandibular tissue was measured to identify differences.Among the morphological characteristics of hard tissues,except for∠ANB,people with a full eruption of the mandibular third molars had statistically significantly larger angle indicators than people without the eruption of the third molars.The soft tissue indicators also showed statistically significant discrepancies in terms of morphological facial height,mouth to gnathion distance,lip height,and mouth breadth.The most influential index for mandibular third molars was length of symphysis,followed by the four indicators of soft tissue and mandible length and height.Morphology facial height,mouth to gnathion distance,lip height,and height of symphysis were moderately correlated.The experimental results show that among Han youth in North China,the third molar eruption has a widespread influence on mandibular morphology,especially in angle,length,and height indicators.It also has a certain influence on maxillofacial soft tissue morphology.These results can be applied to future clinical risk assessment of the wisdom teeth and forensic personal identification of the cranial and maxillofacial region.

Comprehensive Metabolic Profiling of Modified Gegen Qinlian Decoction by Ultra-high-Performance Liquid Chromatography-Diode Array Detection-Q-Exactive-Orbitrap-Electrospray Ionization-Mass Spectrometry/Mass Spectrometry and Application of High-Performance

Objective:Gegen Qinlian decoction(GQD)is a classical traditional Chinese medicine formulation which has been used for almost 2000 years.At Guang'anmen Hospital,Beijing,a modified GQD version(m GQD)with seven instead of four herbal ingredients has been applied to treat Type 2 diabetes.Quality control is a crucial prerequisite for the therapeutic application of herbal medicines.For the identification of products derived from classical GQD,the Chinese Pharmacopeia requires the analysis of only three marker compounds.Because m GQD is a more complex mixture containing seven herbs and hundreds of constituents,the pharmacopoeia method for GQD is inadequate.Materials and Methods:A more comprehensive characterization of the formula's constituents has been developed using ultra-high-performance liquid chromatography-diode array detection(UHPLC-DAD)-Q-Exactive-mass spectrometry(MS)in electrospray ionization positive and negative mode.Moreover,a new method for the fingerprint analysis of m GQD via high-performance thin-layer chromatography(HPTLC)has been established.Results:Altogether,91 compounds have been assigned to their originating plants and 84 substances were identified either by comparison with authentic references or with data from the literature.The HPTLC method is based on the application of two different mobile phases and is able to detect both lipophilic and hydrophilic constituents of m GQD.Conclusions:The modified GQD was extensively characterized by UHPLC combined with DAD and Q-Exactive Orbitrap high-resolution MS detection,leading to the assignment and identification of compounds present in the decoction.In addition,a new method for the fingerprint analysis of the m GQD using HPTLC was established,which allows fast and simple identification of the herbal ingredients in the mixture.