The Mg doping ZIF-8 loaded with Icariin and its antibacterial and osteogenic performances.

In this study, ICA@Mg-ZIF-8 was synthesized by Mg doping in ZIF-8 and loaded with icariin (ICA). The morphologies and phases were observed and analyzed by SEM, XRD, and the release behaviors of Mg, Zn ions and ICA were tested. Its antibacterial and mineralization performances were evaluated. The results showed that ICA@Mg-ZIF-8 has the same morphology and crystal structure as ZIF-8. ICA@Mg-ZIF-8 showed enhanced antibacterial activity against Escherichia coli and Staphylococcus aureus, and the antibacterial rate was increased to 87.7 % and 64.0 %, respectively. The results of in vitro mineralization showed that ICA@Mg-ZIF-8 presented better osteogenic performance promoting the uniform deposition of more calcium and phosphorus in simulated body fluids compared to ZIF-8.

Development and internal validation of a Wasp Sting Severity Score to assess severity and indicate blood purification in persons with Asian wasp stings.

BACKGROUND: In recent years, the incidence of wasp sting has increased annually in China. Organ damage and high mortality due to mass wasp envenomation remain major challenges. Timely and appropriate medical intervention can improve survival. However, there are currently no normalized tools for early assessment of severity. METHODS: The clinical data of wasp sting patients hospitalized from 2011 to 2019 were used as a training set. Logistic regression was used to explore major risk factors for the development of a severe case of wasp sting (SC). The Wasp Sting Severity Score (WSS) was determined considering these risk factors to identify SCs and was tested in a validation dataset that was prospectively collected in 2020. RESULTS: The data of 1131 wasp sting patients from 2011 to 2019 were included in the training set. Logistic regression analysis showed that tea-colored urine, number of stings, and lactate dehydrogenase and total bilirubin levels were risk factors for developing an SC. The WSS was developed considering these four risk factors, and the total possible WSS was 20 points. The WSS was tested using the validation dataset, comprising the data of 153 patients, in 2020, and we found that a WSS ≥3 points was an important indication for blood purification, with a sensitivity of 71.9%, specificity of 92.6% and an area under the curve of 0.918 (95% confidence interval 0.873-0.962). Among patients with more than 30 stings, mortality in those who underwent plasma exchange (PE) within 24 h after admission was significantly lower than that in those who did not receive PE treatment (14.3% versus 46.9%, P = 0.003). However, continuous venovenous hemofiltration (CVVH) (P = 0.317) and hemoperfusion (HP) (P = 0.869) did not significantly reduce mortality. CONCLUSIONS: Patients with WSS scores ≥3 should be considered for blood purification as early as possible in addition to routine treatment. In addition, PE is better than CVVH and HP at reducing mortality in patients suffering from severe wasp stings.

Anodic Voltage Dependence of Ti-6Al-4V Substrates and Hydroxyapatite Coating.

Ti-6Al-4V alloys were anodized in a solution containing 0.15 M HF and 2 M H3PO4 for 30 min under different voltages and then coated with hydroxyapatite (HA) by hydrothermal-electrochemical deposition. The effects of anodizing voltage on the morphology and bioactivity of the HA coating and on the bonding strength between the HA coating and the anodized substrates were investigated. Results indicated that highly ordered amorphous TiO2 nanotube arrays formed on the Ti-6Al-4V surface after anodic oxidation. The pore size of the nanotube increased up to approximately 100 nm with increasing anodic voltage until 25 V. The nanotube was damaged at anodic voltages above 25 V. The crystal structure of TiO2 changed from amorphous to anatase when the anodized substrates were heated at 450 °C for 3 h. The contact angle between the Ti-6Al-4V surfaces and the simulated body fluid evidently decreased after anodic oxidation. The roughness increased with increasing anodic voltage, and Ra reached about 0.56 µm under 25 V. The HA coating exhibited layered growth. The deposition of rod-like HA crystals as well as the crystallinity of the HA coating initially increased and then decreased with the further increase of the anodic volatage. The degree of crystallinity reached the maximum of approximately 73% at 25 V. The bonding strength between the coating and the anodized substrates increased and then slightly decreased with increasing voltage. The bonding strength was about 20.0 MPa when titanium substrate was anodized under 25 V. The results of simulated body fluid immersing experiments suggest that the HA coating exhibits promising bioactivity.

Improvement of ß-TCP/PLLA biodegradable material by surface modification with stearic acid.

Poly-L-lactide (PLLA) is a biodegradable polymer and used widely. Incorporation of beta tricalcium phosphate (ß-TCP) into PLLA can enhance its osteoinductive properties. But the interfacial layer between ß-TCP particles with PLLA matrix is easy to be destroyed due to inferior interfacial compatibility of the organic/inorganic material. In this work, a method of ß-TCP surface modification with stearic acid was investigated to improve the ß-TCP/PLLA biomaterial. The effects of surface modification on the ß-TCP were investigated by FTIR, XPS, TGA and CA. It was found that the stearic acid reacted with ß-TCP and oxhydryl was formed during the surface modification. Hydrophilicity of untreated or modified ß-TCP/PLLA composite was increased by the addition of 10 wt.% ß-TCP, but it decreased as the addition amount increased from 10 wt.% to 20 wt.%. Two models were suggested to describe the effect of ß-TCP concentration on CA of the composites. Mechanical properties of ß-TCP/PLLA composites were tested by bending and tensile tests. Fractures of the composites after mechanical test were observed by SEM. It was found that surface modification with stearic acid improved bending and tensile strengths of the ß-TCP/PLLA composites obviously. The SEM results indicated that surface modification decreased the probability of interface debonding between fillers and matrix under load.

Martensitic transformation of FeNi nanofilm induced by interfacial stress generated in FeNi/V nanomultilayered structure.

FeNi/V nanomultilayered films with different V layer thicknesses were synthesized by magnetron sputtering. By adjusting the thickness of the V layer, different interfacial compressive stress were imposed on FeNi layers and the effect of interfacial stress on martensitic transformation of the FeNi film was investigated. Without insertion of V layers, the FeNi film exhibits a face-centered cubic (fcc) structure. With the thickness of V inserted layers up to 1.5 nm, under the coherent growth structure in FeNi/V nanomultilayered films, FeNi layers bear interfacial compressive stress due to the larger lattice parameter relative to V, which induces the martensitic transformation of the FeNi film. As the V layer thickness increases to 2.0 nm, V layers cannot keep the coherent growth structure with FeNi layers, leading to the disappearance of interfacial compressive stress and termination of the martensitic transformation in the FeNi film. The interfacial compressive stress-induced martensitic transformation of the FeNi nanofilm is verified through experiment. The method of imposing and modulating the interfacial stress through the epitaxial growth structure in the nanomultilayered films should be noticed and utilized.

New understanding of hardening mechanism of TiN/SiNx-based nanocomposite films.

In order to clarify the controversies of hardening mechanism for TiN/SiNx-based nanocomposite films, the microstructure and hardness for TiN/SiNx and TiAlN/SiNx nanocomposite films with different Si content were studied. With the increase of Si content, the crystallization degree for two series of films firstly increases and then decreases. The microstructural observations suggest that when SiNx interfacial phase reaches to a proper thickness, it can be crystallized between adjacent TiN or TiAlN nanocrystallites, which can coordinate misorientations between nanocrystallites and grow coherently with them, resulting in blocking of the dislocation motions and hardening of the film. The microstructure of TiN/SiNx-based nanocomposite film can be characterized as the nanocomposite structure with TiN-based nanocrystallites surrounded by crystallized SiNx interfacial phase, which can be denoted by nc-TiN/c-SiNx model ('c' before SiNx means crystallized) and well explain the coexistence between nanocomposite structure and columnar growth structure within the TiN/SiNx-based film.