A practicable strategy for enrichment and separation of four minor flavonoids including two isomers from barley seedlings by macroporous resin column chromatography, medium-pressure LC, and high-speed countercurrent chromatography.

Separation of minor compounds especially with similar polarities and structures from complex samples is a challenging work. In the present study, an efficient method was successfully established by macroporous resin column chromatography, medium-pressure liquid chromatography, and high-speed countercurrent chromatography for separation of four minor flavonoids from barley seedlings. Macroporous resin column chromatography and medium-pressure liquid chromatography were used for enrichment of these four flavonoids. High-pressure liquid chromatography analysis showed the total content of these four flavonoids increased from 2.2% in the crude extract to 95.3% in the medium-pressure liquid chromatography fraction. It was indicated that the combination of macroporous resin column chromatography and medium-pressure liquid chromatography could be a practicable strategy for enrichment of minor compounds from complex sample. Then, high-speed countercurrent chromatography was employed for separation of these four flavonoids using ethyl acetate/n-butanol/water (0.1% glacial acetic acid) (4:1:5, v/v/v) as solvent system. As a result, four flavonoids including two isomers with purities higher than 98% were obtained. Interestingly, two flavonoids existing in one high-pressure liquid chromatography peak were also successfully separated. All these indicated high-speed countercurrent chromatography had great potential for separation of compounds with similar structures and polarities. This study provides a reference for efficient enrichment and separation of minor compounds from complex sample.

Enhanced proton conductivity of Nafion membrane induced by incorporation of MOF-anchored 3D microspheres: a superior and promising membrane for fuel cell applications.

A novel 3D core-shell material composed of polyacrylate carboxyl microspheres (PCMs) and ZIF-8 nanoparticles was used to promote proton conduction in the Nafion matrix. The Nafion/ZIF-8@PCM membranes displayed excellent proton conductivity (0.24 S cm-1) and physicochemical properties due to special structural characteristics. More importantly, this new concept has a strong practical guiding significance for the fabrication of novel PEMs.

Targeted Delivery of Dual Anticancer Drugs Based on Self-Assembled iRGD-Modified Soluble Drug-Polymer Pattern Conjugate Nanoparticles.

A tumor-penetrating peptide, iRGD (a tumor-homing peptide, CRGDKGPDC), could enhance the penetration of drugs via the specific receptor-binding affinity to αvß3 and NRP-1 that overexpressed on tumor vasculature and tumor cells. Considering the side effects of traditional chemotherapy, here, poly(ethylene glycol) (PEG, Mw = 7500)-based and iRGD-modified poly(ethylene glycol)-based nanoparticles were successfully prepared. iRGD, as a tumor-targeting and tumor-penetrating agent, was combined with PEG after the esterification reaction between PEG and diosgenin (DGN). After the efficient loading of 10-hydroxycamptothecin (HCPT), the iRGD-PEG-DGN/HCPT NPs of chemotherapy were established. The characteristics of iRGD-PEG-DGN/HCPT NPs were evaluated. This nano-delivery system possessed high drug loading efficiency (∼17.34 wt % HCPT), controlled release rate, good pH response, and iRGD active targeting and passive targeting with an appropriate size (∼140 nm). All these features forcefully indicated that the iRGD-modified drug delivery system could markedly ameliorate the tumor therapy efficacy compared to the nontargeted nanoparticles through enhancing the tumor accumulation and penetration.

An efficient prodrug-based nanoscale delivery platform constructed by water soluble eight-arm-polyethylene glycol-diosgenin conjugate.

Drug resistance in tumors is one of the reasons result in the low anticancer efficiency of numerous drugs. Combination therapy has been proven to be a valid way against drug-resistant cancers. However, simply mix the drugs will not only cause many side efforts but also decrease anticancer effect. Herein, a self-assembled nanoparticle platform based on eight-arm-polyethylene glycol-diosgenin (8armPEG-DGN) conjugate was produced for encapsulating another hydrophobic anticancer drug. The 8armPEG-DGN/HCPT NPs were prepared through a simple nanoprecipitation method. The 8armPEG-DGN/HCPT NPs possess suitable size (~107 nm) and high binary drug loading capacity (15.67 wt% of DGN and 14.72 wt% of HCPT). Laser confocal scanning microscopy revealed that 8armPEG-DGN/HCPT NPs significantly increased intracellular uptake toward B16 cells compared with free drugs. Cytotoxicity assay showed the IC50 of 8armPEG-DGN/HCPT NPs were lower than simply mixing DGN and HCPT. In vivo tumor transplantation assay indicated that 8armPEG-DGN/HCPT NPs exhibited superior tumor grown inhibition compared with free drugs and HCPT/DGN Mix. These studies showed that the prepared 8armPEG-DGN/HCPT NPs drug delivery system could serve as a promising candidate for cancer therapy.

Accuracy evaluation of computer-designed surgical guide template in oral implantology.

OBJECTIVE: The purpose of this study was to assess the accuracy of implant placement using surgical guide templates, and to compare the results with implant placement based on computer-aided design (CAD) planning merely. MATERIAL AND METHODS: A total of 60 patients with dentition defects were included in our study, who were equally divided into group I and group II. Preoperative cone beam computed tomography (CBCT) was performed and preoperative planning was designed with Simplant software for all 60 patients. A total of 52 implants were placed in group I patients based on the preoperative planning without surgical guide templates. Implant surgical guide templates for group II patients were designed and produced by a rapid prototyping (RP) technique. A total of 57 implants were inserted in group II patients with the assistance of surgical templates. Postoperative CBCT was performed for all 60 patients. Image registration was carried out between postoperative CBCT data and that of preoperative planning data. Deviations of the implant between the actual and planned positions were measured and compared. RESULTS: There was no significant structure damage during the surgery. Osseointegration was achieved in all implants, and both soft and hard tissues around implants were stable. Variation at the implant shoulder in group II was 1.18 ± 0.72 mm, apex 1.43 ± 0.74 mm, angulation 4.21 ± 1.91 mm, and depth 0.54 ± 0.29 mm, whereas the variation in group I was 2.07 ± 0.51 mm (P < 0.01), 2.89 ± 1.02 mm (P < 0.01), 8.84 ± 4.64 mm (P < 0.05), and 0.78 ± 0.33 mm (P > 0.05). CONCLUSION: The use of surgical guide templates can achieve higher precision and accuracy in implant shoulder, apex, and angulation, which is much more suitable for complicated procedures and conditions such as the flapless method, immediate loading, aesthetic restoration, and insufficient bone height.

Endoscopic lift of the maxillary sinus floor in Beagles.

The aim of this study was to introduce a modified endoscopic lift of the floor of the maxillary sinus in Beagles. Twelve operations (bilateral and randomly chosen) were done in 6 Beagles each in the test group (modified endoscopic operation), and the control group, in which the operation was done with an osteotome. All operations were evaluated by two indices of safety (perforation of the sinus membrane and nasal bleeding) and 3 effective indices (the intraoperative height after lifting, volume of bone grafts, and dislocation of the sinus grafts). The sinus membrane was not perforated and there were no nasal bleeds in either group. The intraoperative height after lifting was 13.7 (0.8) mm in the test group and 9.1 (0.5) mm in the control group, so it was significantly higher in the test group than the control group (p=0.0001). Similarly, the volume of bone graft was 0.9 (0.04) ml in the test group and 0.5 (0.02) ml in the control group (p=0.0001). The volume of the anterior and posterior bone grafts in the implant cavity in the test group did not differ significantly (p=0.102), while there were significant differences in the control group (p=0.002). Endoscopic lifting of the floor of the maxillary sinus is a safe and effective approach based on direct observation in Beagles.

Systematic modification and evaluation of a canine model for elevation of the floor of the maxillary sinus.

We have modified a canine model for raising the floor of the maxillary sinus by selecting a new surgical approach, and have evaluated the model with computed tomographic (CT) scans and endoscopy. Preoperative CT scans were taken of two beagle cadavers and four healthy, live beagles. The CT data were entered into Simplant software to select a candidate site for a surgical incision located between the first molar and the greater palatine foramen. All animals had the floor of the maxillary sinus raised from the candidate site. During the operation an endoscope was put outside the candidate site and into the maxillary sinus through a lateral puncture to record the condition of the Schneiderian membrane and the position of the candidate site. Postoperative CT scans were used to measure the position of the site, and the positions were compared. Eleven variables were measured on the coronal and sagittal sections. The two most important variables were the mean (SD) horizontal distance from the candidate site to the palatal alveolar ridge (8.1 (0.9)mm) and the residual bone height (2.0 (0.4)mm). There were no significant differences in the anteroposterior or internal-external position of the candidate site. Intraoperative endoscopic views showed the intact, white, and opaque membrane from the candidate site, and the movement of the membrane in the middle of the sinus floor from the lateral puncture. The candidate site is therefore an ideal surgical approach for raising the floor of the maxillary sinus, and the canine model is suitable for research in this area.