Effective Separation of Enantiomers Based on Novel Chiral Hierarchical Porous Metal-Organic Gels.

Metal-organic gel (MOG) matrices with tunable pore sizes ranging from micropore to macropore, derived from microporous metal-organic coordination polymers (PCPs), has attracted great attention for their enhanced pore accessibility compared with the multifunctional PCP materials themselves. The enhanced pore accessibility of chiral MOGs is especially imperative for mass transfer applications, including enantioseparations and purifications. Here, for the first time, a novel hierarchical porous MOG-coated SiO2 , derived from a chiral metal-organic coordination polymer, is employed as chiral stationary phase for effective high-performance liquid chromatography (HPLC) separation of enantiomers. The selected enantiomers with diverse functional groups are all efficiently separated in a few minutes with significantly higher resolution.

[Measuring three-dimensional displacement of tooth-supported rigid fixed bridge under oblique concentrated loading using digital laser speckle photography].

OBJECTIVE: To measure three-dimensional displacements of rigid fixed bridge under oblique concentrated loading and to analyze the effect of displacement on the stability of abutment teeth. METHODS: Right mandible of Beagle dog was used to establish the tooth-supported rigid fixed bridge. Digital laser speckle photography was employed to measure the three-dimensional displacements of the prosthesis under oblique concentrated loading ranging from 200 g to 3000 g. RESULTS: The displacements of prosthesis increased as the load increased. When the load was on the abutment, the buccolingual displacement of the abutment under loading was the biggest but no more than 100 microm. This was followed by mesiodistal and occlusallingual displacements. With slighter loadings, the buccolingual displacements of non-loaded abutment were greater than the mesiodistal displacements. However, as the loading increased greater mesiodistal displacements on non-loaded abutment were found compared to buccolingual displacements. When the bridge was loaded, the biggest displacements of the prosthesis were always shown on the buccolingual direction, followed by the mesiodistal direction and the occlusallingual direction. The displacements with loaded bridge were smaller than those when the load was applied on abutment. CONCLUSION: The displacements of rigid fixed bridge change with different loading positions. This has implications on the design of prosthesis. Lateral force should be minimized and early occlusion contact should be avoided, especially on the feeble abutment. This study has developed a new method for measuring bit shift of teeth.

[Three-dimensional displacement of implant-supported cantilever fixed partial denture under oblique loading].

The purpose of this study was to research the three-dimensional displacements of implant-supported cantilever fixed partial denture (CFPD) under oblique loading. One Beagle dog was used in this experiment. Two immediate implants of ITI were inserted in the mandible of the dog, and the implant-supported CFPD which used the implants as abutments was made in vitro fresh mandible. Then the digital laser speckle technique was employed to measure the three-dimensional displacements of CFPD under different oblique loading. We found that when an oblique loading was exerted on the pontic, the displacement increased with increasing of load. Under equal loading, the displacement of the abutment near to the pontic was smaller than that of the pontic but greater than that of the abut-ment far from the pontic. When oblique loading was exerted on the abutment, the displacement of the direct loaded abutment was greater than that of the other abutment and the pontic. Under the.eeual loading, the displacement of implant-supported CFPD of loading on pontic was greater than that of loading on abutments. The experiments demonstrated that implant-supported cantilever fixed partial denture (CFPD) is an effective and advisable therapy for totally? or partially edentulous patients. However, it is also suggested that the clinicians should avoid exerting oblique loading, especially the obliqe loading of the pontic when th e CPDF is used.

[Study on the digital laser speckle technique of three-dimensional displacement of cantilever fixed partial denture under oblique loading].

The purpose of this study was to investigate the three-dimensional displacement of the cantilever fixed partial denture (CFPD) under an oblique loading. One Beagle dog was used in this experiment. The CFPD, which used the second premolar and the first molar as abutments and the second molar as pontic, was made in vitro fresh mandible of the Beagle dog, and the digital laser speckle (DLS) technique was employed to measure the three-dimensional displacement of the CFPD under the oblique loading for the first time. We found that when an oblique loading was exerted on the pontic, the displacement of CFPD was the greatest, and the displacement of the abutment near the pontic was smaller than that of the pontic but greater than that of the abutment far from the pontic. We also found that when an oblique loading was exerted on the abutment, the displacement of the directly loaded abutment was greater than that of the other abutment and the pontic. Under the oblique loading, the displacement increased with increasing of load. The experiment demonstrated that it would be advisable for the clinicians to avoid oblique loading, especially the oblique loading of the pontic when using the CPDF. The DLS technique may be one kind of methods for measuring the three-dimensional displacements of the small and irregular objects.

[Analysis of the effect of contact strength on three-dimensional displacement of an implant-supported fixed bridge under axial-concentrated load using digital laser speckle photography].

The purpose of this study was to investigate the effect of four kinds of different contact strength on the three-dimensional displacement of an implant-supported fixed bridge using digital laser speckle photography method. An in vitro model of beagle mandible with an implant-supported fixed bridge in its right premolar region was developed. The bridge was Au-Pt metal-ceramic. The contact was recovered to four different tightnesses, named 0, 1, 2, and 3. Different axial concentrated static load was applied to abutments and bridge respectively. The three-dimensional displacement of the implant-supported fixed bridge was measured using digital laser speckle photographic method. The results demonstrated that the influence of contact tightness was mainly on the mesio-distal and buccal lingual parts. When the contact tightness reached number 3, the regularity of displacement distribution was changed. The present study proved that digital laser speckle photography was an effective method of measuring the micro-displacement. One of the criterions of contact recovering decreased the implant displacement effectively without changing the regularity of displacement distribution.

Effect of proximal contact strength on the three-dimensional displacements of implant-supported cantilever fixed partial dentures under axial loading.

OBJECTIVE: This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture (CFPD) under vertically concentrated loading with digital laser speckle (DLS) technique. METHODS: Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen. DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3000 g. The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness. RESULTS: When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD, the displacement of the CFPD was the greatest. The displacement of the prosthesis decreased with the increase of contact strength. When the contact strength was 0, 0.95, and 3.25 N, the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction. When the force on the contact area was 6.50 N, the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest. CONCLUSIONS: The implant-supported CFPD is an effective therapy for fully or partially edentulous patients. The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD, and get a better stress distribution. The most appropriate force value is 3.25 N in this study.