Till now, the novel Mg alloys acting as the medical materials have drawn much attention, due to their spontaneous degradability, favorable mechanical properties and the excellent biocompatibilities. ...Unfortunately, they were inevitably affected by flow erosion, corrosion fatigue, stress-interaction and dynamic wear under the human body conditions, leading to significant mechanical-performance attenuation and premature fracture failure. Thus, how to explore and obtain the biomedical Mg-based alloys with controllable degradation rate and suitable biocompatibility was the key issue. Surface modification is a typical method to improve the corrosion resistance. It can isolate the Mg-matrix from the electrolyte by establishing the corrosion barrier without changing the microstructure characteristics. Also, it can change the layer structure and further enhance the degradation behaviors and biological activities of biomedical Mg alloys. In this text, the latest research progresses of surface modification for Mg alloys were reviewed, and the formation mechanism, film layer features as well as the rupture mechanism of conversion coatings were revealed. Besides, the interaction roles of Mg-matrix/modified-layer and modified-layer/electrolyte were analyzed through the comparison of film-layer structure, morphology and the establishment of degradation rates for various modified Mg alloys. Moreover, the internal relationships between the biological biocompatibilities and degradation rates in different corrosive conditions were deeply explored. Finally, the problems of surface modification on biomedical Mg alloys were proposed and the future development directions were prospected.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Due to excellent biological-functionality, unique/suitable elastic-modulus as well as spontaneous degradation behaviors, Mg alloys acted as medical implants have shown enormous potential in surgical ...operation and bone-fixation fields. Unfortunately, the extreme mass loss and unmarked-fracture could easily induce the implant failure. In the present study, the microstructure characteristics and degradation behaviors of the Mg-10.6Gd-0.3Ag-x(Y/Zn) alloys were investigated through the XRD, TEM, EPMA, XPS, 3D/CLSM and SECM. Results revealed that with the increment of Y/Zn contents, the amount of Mg24(Gd/Y)5 precipitates increased, which were mainly distributed in grains and on grain boundaries. The addition of Zn and Y increased the undercooling and Y had a large mismatch degree with Mg atoms, which could promote the precipitation of second phases. Additionally, the corrosion rates of Mg-10.6Gd-0.3Ag-x(Y/Zn) increased firstly and then reduced. Also, the best corrosion resistance was achieved in the Mg-10.6Gd-0.3Ag-Y-Zn, with the current intensities of 58.49 μA/cm2, attributed to the formation of continuous reticular structure oxide film, which can act as physical barriers and impede the corrosion process.
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•Corrosion rate of studied alloys were increased firstly and then reduced.•Y and Zn addition provide nucleation cites to form compact surface protective layer.•The evolution of corrosion current densities was analyzed by SECM.•Y and Zn addition promote the precipitation of Mg24(Gd, Y, Zn)5 phase.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Using density functional theory calculations, we investigate the electronic properties of arsenene/graphene van der Waals (vdW) heterostructures by applying external electric field perpendicular to ...the layers. It is demonstrated that weak vdW interactions dominate between arsenene and graphene with their intrinsic electronic properties preserved. We find that an n-type Schottky contact is formed at the arsenene/graphene interface with a Schottky barrier of 0.54eV. Moreover, the vertical electric field can not only control the Schottky barrier height but also the Schottky contacts (n-type and p-type) and Ohmic contacts (n-type) at the interface. Tunable p-type doping in graphene is achieved under the negative electric field because electrons can transfer from the Dirac point of graphene to the conduction band of arsenene. The present study would open a new avenue for application of ultrathin arsenene/graphene heterostructures in future nano- and optoelectronics.
•It is demonstrated that weak vdW interactions dominate between arsenene and graphene with their intrinsic electronic properties preserved.•the vertical electric field can not only control the Schottky barrier height but also the Schottky contacts (n-type and p-type) and Ohmic contacts (n-type) at the interface.•Tunable p-type doping in graphene is achieved under the negative electric field.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In the new stage of trans-omics and trans-subjects for medicinal plants, it is an urgent need to integrate big data, provide interactive applications, and form a unified and multi-level research ...system and big data platform. Dao-di medicinal material, as an important source of medicinal plants, is a unique quality concept and comprehensive standard of tranditional Chinese medicine(TCM). Several databases have been developed in China and abroad, such as the Encyclopedia of Traditional Chinese Medicine(ETCM) and the Global Pharmacopoeia Genome Database(GPGD). Yet, most databases do not provide multi-dimensional data, including geographic data, phenotype data, compound data, and genetic data. Sichuan, known as the hometown of TCM therapies and the treasure trove of TCM, is the most representative region of medicinal plant diversity in China. According to the latest data of the fourth national survey of TCM resources, there are more than 8 000 TCM and 86 Dao-di medicinal materials in Sichuan province. Based on re
To increase spatial resolution and signal-to-noise ratio in PET imaging, we present in this paper the design and performance evaluation of a PET detector module combining both depth-of-interaction ...(DOI) and time-of-flight (TOF) capabilities. The detector module consists of a staggered dual-layer LYSO block with 2 mm × 2 mm × 7 mm crystals. MR-compatible SiPM sensors (MicroFJ-30035-TSV, SensL) are assembled into an 8 × 8 array. SiPM signals from both fast and slow outputs are read out by a 128-channel ASIC chip. To test its performance, a flood histogram is acquired with a
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Na point source on top of the detector, and the energy resolution and the coincidence resolving time (CRT) value for each individual crystal are measured. The flood histogram shows excellent crystal separation in both layers. The average energy resolution at 511 keV is 14.0 and 12.7% at the bottom and top layers, respectively. The average CRT of a single crystal is 635 and 565 ps at the bottom and top layers, respectively. In conclusion, the compact DOI–TOF PET detector module is of excellent crystal identification capability, good energy resolution and reasonable time resolution and has promising application prospective in clinical TOF PET, PET/MRI, and brain PET systems.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
As a new generation of medical degradable biomaterials, magnesium alloys were known as "revolutionary medical metal materials" due to their good biocompatibility, unique degradability and excellent ...mechanical transmission. However, the corrosion resistance of magnesium alloys is poor and there are phenomena such as rapid and uneven degradation.The research progress in improving the degradation properties of magnesium alloys was introduced from four aspects: microalloying, heat treatment process, plastic deformation and surface modification. The degradation rate and degradation modes of medical magnesium alloys in vivo and in vitro under different processing methods were compared. The influence of microstructure evolution and film characteristics of magnesium alloys under different processing conditions on the destruction mechanism of the Cl- for the film layer and the three-dimensional degradation morphology were revealed.The correlation data analysis model between different process conditions and corrosion d
Aim
To investigate the potential effects of berberine on renal interstitial fibrosis (RIF) of obstructed kidneys in a unilateral ureteral obstruction (UUO) rat model.
Methods
Forty‐eight rats were ...randomly divided into three groups: sham‐operated, vehicle‐treated UUO, and berberine‐treated UUO. Rats were gavaged with berberine (200 mg/kg per day) or vehicle. Eight randomly chosen rats in each group were kiled and specimens were collected at day 14 after UUO. Physiological parameters and histological changes were assessed, RIF was evaluated using Masson's trichrome and Sirius red staining, oxidative stress and inflammation markers were determined, transforming growth factor β1 (TGF‐β1), phosphorylated Smad3 (pSmad3) and α‐smooth muscle actin (α‐SMA) were measured using immunohistochemistry or western blotting analysis. The obstruction was relieved at day 14 by percutaneous nephrostomy in the remaining UUO rats. The resistive index of left kidneys was undertaken by coloured Doppler flow imaging at day 14 before nephrostomy and day 7 after the relief.
Results
Berberine treatment significantly attenuated RIF induced by UUO. The UUO‐induced reduction in kidney superoxide dismutase and catalase activities increased, whereas elevated kidney malondialdehyde level markedly decreased. Berberine treatment significantly ameliorated UUO‐induced inflammation, and decreased TGF‐β1, pSmad3 and α‐SMA expression of UUO kidneys. Moreover, berberine treatment significantly suppressed the increase of resistive index compared with UUO group at day 14 after UUO as well as day 7 after the relief of obstruction.
Conclusion
Berberine treatment ameliorates RIF in a UUO rat model by inhibition of oxidative stress, inflammatory responses, and TGF‐β1/pSmad3 signalling.
Summary at a Glance
Berberine is an isoquinoline quaternary alkaloid isolated from a variety of medicinal plants, which is used as a therapeutic agent for microbial infection in East Asian countries. In the current study, Berberine exhibits an anti‐fibrotic activity in the UUO model of renal fibrosis via inhibition of oxidative stress, inflammation and TGF‐β1/Smad3 signalling.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
The ultra-fine-grained ferrite (UFGF) with the size of less than 1 μm is often difficult to be obtained for low-alloyed steel in practical production processing. In this study, considering the rod ...and wire production process, a new method for preparing the UFGF with submicron scale is proposed by warm deformation of six passes with total strain of 2.6, followed by the cooling process in Gleeble-3500 thermo-mechanical simulator. The results show that the UFGF with an average size of 0.64 μm could be obtained via the phase transformation from austenite grains with an average size of 3.4 μm, which are achieved by the deformation-induced reversal austenization during the high strain rate warm deformation. The main driving force for the reversal transformation is the stress. And the interval between the passes also plays an important role in the reversal austenization.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The microstructure, retained austenite and mechanical property of low-carbon steels with different precursor microstructures were studied by means of intercritical reheating-quenching and ...partitioning (IQ&P) processes. The results show that the structure of IQ&P-I multiphase steel with precursor ferrite + pearlite (F+P) is blocky ferrite, martensite (M). The blocky retained austenite(RA) of IQ&P-I multiphase steel exists in the boundary of ferrite and martensite and film-like retained austenite distributes around the lath martensite as the shape of thin slice. The transformation induced plastic effect of IQ&P-I multiphase steel with less content of retained austenite is unapparent. The tensile strength of IQ&P-I multiphase steel reaches 957 MPa, but the tensile elongation is only 20%, and the production of strength and elongation is 19905.6 MPamiddot%. The structure of IQ&P-II multiphase steel with precursor martensite is needle or lath grey-black ferrite and martensite. The fine needle like martensite is d
Background: Phloroglucinol plays an important role in oxidative stress and inflammatory responses. The effects of phloroglucinol have been proven in various disease models. The aim of the present ...study was to investigate the efficacy and possible mechanisms of phloroglucinol in the treatment of interstitial cystitis (IC).
Methods: Thirty-two female Sprague-Dawley (SD) rats were used in this study. IC was induced by intraperitoneal injection of cyclophosphamide (CYP). Rats were randomly allocated to one of four groups (n = 8 per group): A control group, which was injected with saline (75 mg/kg; i.p.) instead of CYP on days 1, 4, and 7; a chronic IC group, which was injected with CYP (75 mg/kg; i.p.) on days 1, 4, and 7; a high-dose (30 mg/kg) phloroglucinol-treated group; and a low-dose (15 mg/kg) phloroglucinol-treated group. On day 8, the rats in each group underwent cystometrography (CMG), and the bladders were examined for evidence of oxidative stress and inflammation. Statistical analysis was performed by analysis of variance (ANOVA) followed by least square difference multiple comparison post-hoc test.
Results: Histological evaluation showed that bladder inflammation in CYP-treated rats was suppressed by phloroglucinol. CMG revealed that the CYP treatment induced overactive bladder in rats that was reversed by phloroglucinol. Up-regulated tumor necrosis factor-α and interleukin-6 expression in the CYP-treated rats were also suppressed in the phloroglucinol treated rats. CYP treatment significantly increased myeloperoxidase activity as well as the decreased activities of catalase of the bladder, which was reversed by treatment with phloroglucinol.
Conclusions: The application of phloroglucinol suppressed oxidative stress, inflammation, and overactivity in the bladder. This may provide a new treatment strategy for IC.
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