Design and preparation of Ti-xFe antibacterial titanium alloys based on micro-area potential difference.

Fe was selected as an alloying element for the first time to prepare a new antibacterial titanium alloy based on micro-area potential difference (MAPD) antibacterial mechanism. The microstructure, the corrosion resistance, the mechanical properties, the antibacterial properties and the cell biocompatibility have been investigated in detail by optical microscopy, scanning electron microscopy, electrochemical testing, mechanical property test, plate count method and cell toxicity measurement. It was demonstrated that heat treatment had a significant on the compressive mechanical properties and the antibacterial properties. Ti-xFe (x = 3,5 and 9) alloys after 850 °C/3 h + 550 °C/62 h heat treatment exhibited strong antimicrobial properties with an antibacterial rate of more than 90% due to the MAPD caused by the redistribution of Fe element during the aging process. In addition, the Fe content and the heat treatment process had a significant influence on the mechanical properties of Ti-xFe alloy but had nearly no effect on the corrosion resistance. All Ti-xFe alloys showed non-toxicity to the MC3T3 cell line in comparison with cp-Ti, indicating that the microzone potential difference had no adverse effect on the corrosion resistance, cell proliferation, adhesion, and spreading. Strong antibacterial properties, good cell compatibility and good corrosion resistance demonstrated that Ti-xFe alloy might be a candidate titanium alloy for medical applications.

Highly Sensitive Temperature-Pressure Bimodal Aerogel with Stimulus Discriminability for Human Physiological Monitoring.

Multimodal sensor with high sensitivity, accurate sensing resolution, and stimuli discriminability is very desirable for human physiological state monitoring. A dual-sensing aerogel is fabricated with independent pyro-piezoresistive behavior by leveraging MXene and semicrystalline polymer to assemble shrinkable nanochannel structures inside multilevel cellular walls of aerogel for discriminable temperature and pressure sensing. The shrinkable nanochannels, controlled by the melt flow-triggered volume change of semicrystalline polymer, act as thermoresponsive conductive channels to endow the pyroresistive aerogel with negative temperature coefficient of resistance of -10.0% °C-1 and high accuracy within 0.2 °C in human physiological temperature range of 30-40 °C. The flexible cellular walls, working as pressure-responsive conductive channels, enable the piezoresistive aerogel to exhibit a pressure sensitivity up to 777 kPa-1 with a detectable pressure limit of 0.05 Pa. The pyro-piezoresistive aerogel can detect the temperature-dependent characteristics of pulse pressure waveforms from artery vessels under different human body temperature states.

Carboxylate-functionalized sugarcane bagasse as an effective and renewable adsorbent to remove methylene blue.

This study prepared a carboxylate-functionalized sugarcane bagasse (CF-SCB) from sugarcane bagasse (SCB) via a simple and low-toxicity chemical modification to enhance its capacity for adsorbing methylene blue (MB) from aqueous solutions. The success of chemical modification was confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), the pore area and porosity, and zeta potential measurement analysis. The adsorption capacity of CF-SCB was investigated at different pHs, ionic strengths, temperatures, contact times and initial dye concentrations. Equilibrium data were best described by the Langmuir isotherm model, and the maximum monolayer adsorption capacity of CF-SCB (296.74 mg g-1) was greatly improved compared with SCB (77.16 mg g-1) at 30 °C. The thermodynamic study indicated that MB adsorption onto CF-SCB was a spontaneous, endothermic and entropy increased process. Adsorption kinetics followed a pseudo-second-order mode, and the adsorption mechanism was based on electrostatic interactions. The reusability study showed that CF-SCB had reasonably good reuse potential. All the results suggested that CF-SCB has high potential to be used as an effective and renewable adsorbent for MB removal from wastewater.

Selective separation and enrichment of glibenclamide in health foods using surface molecularly imprinted polymers prepared via dendritic grafting of magnetic nanoparticles.

In this paper, the novel surface molecularly imprinted polymers based on dendritic-grafting magnetic nanoparticles were developed to enrich and separate glibenclamide in health foods. The density functional theory method was used to give theoretical directions to the synthesis of molecularly imprinted polymers. The polymers were prepared by using magnetic nanoparticles as supporting materials, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The characteristics of magnetic nanoparticles and polymers were measured by transmission electron microscope and SEM, respectively. The enriching ability of molecularly imprinted polymers was measured by Freundlich Isotherm. The molecularly imprinted polymers were used as dispersive SPE materials to enrich, separate, and detect glibenclamide in health foods by HPLC. The average recoveries of glibenclamide in spiked health foods were 81.46-93.53% with the RSD < 4.07%.

An in situ and rapid self-healing strategy enabling a stretchable nanocomposite with extremely durable and highly sensitive sensing features.

Progress toward the development of wearable electromechanical sensors with durable and reliable sensing performance is critical for emerging wearable integrated electronic applications. However, it remains a long-standing challenge to realize mechanically stretchable sensing materials with extremely durable and high-performing sensing ability due to the fundamental dilemma lying in the sensing mechanism. In this work, we proposed an in situ and rapid self-healing strategy through nano-confining a dynamic host-guest supramolecular polymer network in a graphene-based multilevel nanocomposite matrix to fabricate a mechanically stretchable and structurally healable sensing nanocomposite which is provided with intriguing sensing durability and sensitivity simultaneously. When repeatedly stretching and releasing the nanocomposite sensing film, the fast association kinetics of cyclodextrin and adamantane host-guest inclusion complexes and good polymer chain dynamics in the supramolecular polymer network endowed by the nanoconfinement effect enable autonomous and rapid repair of the micro-cracks in situ generated in the sensing material. As a result, our strain sensing devices can achieve an extremely high durability and retain stable sensing performance even after over 100 000 stretching-releasing cycles at large strain of 50%. Moreover, the brittle nature originated from the inorganically dominated structure in conjunction with the thermodynamically stable host-guest interactions and dynamic hydrogen bonds inside the multilevel nanocomposite allow the sensing material to exhibit an ultrahigh gauge factor over 1500 with a large working strain of 58%. This work presents a reliable approach for the construction of ultradurable and high-performing wearable electronics.

Confounding factors affecting the marginal quality of an intra-oral scan.

OBJECTIVES: To assess the effect of clinical factors on the quality of intra-oral scans of crown margins. These factors are; presence of adjacent teeth, proximity to gingivae, encumbrance of wand positioning within oral cavity. METHODS: A typodont lower molar (Frasaco, Germany) was prepared for an all-ceramic crown with 1.5mm supragingival (lingual) and equigingival (buccal) margins. The tooth was scanned in a model scanner, creating a master scan. An intra-oral scanner (IOS) (Omnicam, Sirona Dental) was used to acquire sets of 5 scans each, under varying conditions; (1) the presence/absence of adjacent teeth, (2) model mounted in manikin head/hand-held, (3) with/without a 1mm shim to elevate the margin. Every combination was investigated, yielding 40 scans (8 groups of 5). The master scan margin was identified by selecting the highest curvature region (>1.8). The master was aligned to each IOS scan, and 4 regions of each IOS scan margin were extracted, lying within 100µm of predefined mesial, distal, buccal and lingual sections of the master margin. The mean curvature of each margin section was calculated using Meshlab. The effect of each confounding factor on margin curvature was analysed using ANOVA. RESULTS: Lingual margin curvature remained consistent regardless of scanning conditions. Buccal margin curvature was significantly affected when located equigingivally. Mesial margin curvature was significantly affected in the presence of adjacent teeth and proximity to the gingivae. Distal margin curvature was significantly affected by all three confounding factors. CONCLUSIONS: The curvature (sharpness) of the margin recorded by a commercial IOS is significantly affected by clinical factors obscuring visibility.

FGFR2 mutation in a Chinese family with unusual Crouzon syndrome.

AIM: To describe the clinical characteristics with genetic lesions in a Chinese family with Crouzon syndrome. METHODS: All five patients from this family were included and received comprehensive ophthalmic and systemic examinations. Direct sequencing of the FGFR2 gene was employed for mutation identification. Crystal structure analysis was applied to analyze the structural changes associated with the substitution. RESULTS: All patients presented typical Crouzon features, including short stature, craniosynostosis, mandibular prognathism, shallow orbits with proptosis, and exotropia. Intrafamilial phenotypic diversities were observed. Atrophic optic nerves were exclusively detected in the proband and her son. Cranial magnetic resonance imaging (MRI) implied a cystic lesion in her sellar and third ventricular regions. A missense mutation, FGFR2 p.Cys342Trp, was found as disease causative. This substitution would generate conformational changes in the extracellular Ig-III domain of the FGFR-2 protein, thus altering its physical and biological properties. CONCLUSION: We describe the clinical presentations and genotypic lesions in a Chinese family with Crouzon syndrome. The intrafamilial phenotypic varieties in this family suggest that other genetic modifiers may also play a role in the pathogenesis of Crouzon syndrome.

Amperometric detection of dopamine in human serum by electrochemical sensor based on gold nanoparticles doped molecularly imprinted polymers.

In this work, a highly sensitive and selective biomimetic electrochemical sensor for the amperometric detection of trace dopamine (DA) in human serums was achieved by gold nanoparticles (AuNPs) doped molecularly imprinted polymers (MIPs). Functionalized AuNPs (F-AuNPs), a novel functional monomer bearing aniline moieties on the surface of the AuNPs, were prepared via a direct synthesis method and then used to fabricate the conductive MIPs film on the modified electrode by electropolymerization method in the presence of DA and p-aminobenzenethiol (p-ATP). The obtained electrochemical sensor based on the conductive film of AuNPs doped MIPs (AuNPs@MIPs) could effectively minimize the interferences caused by ascorbic acid (AA) and uric acid (UA). The linear range for amperometric detection of DA was from 0.02 µmol L(-1) to 0.54 µmol L(-1) with the detection limit of 7.8 nmol L(-1) (S/N=3). Furthermore, the AuNPs@MIPs modified electrode (AuNPs@MIES) was successfully employed to detect trace DA in different human serums.