Longitudinal Invariance and Construct Validity of the Chinese Version of the Mini-Mental State Examination Across 10 Years in the Elderly Population.

Background and Purpose: In this study, we investigate the longitudinal measurement invariance of the Chinese version of the mini-mental state examination (CMMSE). Methods: The factor structure and longitudinal equivalence of the CMMSE were examined by confirmatory factor analysis. Four CMMSE measurements of 13,132 participants from the China Longitudinal Health and Longevity Study between 2008 and 2018 were included. The nested model of longitudinal invariance proves the existence of strict longitudinal invariance. Results: It showed that the factor structure, factor loadings, intercept error variance, and latent factor means of the CMMSE were invariant across four measurements. Conclusion: These findings indicate that the changes in CMMSE scores can be attributed to real structural change, indicating that the CMMSE is a reliable measurement tool for the study of cognitive aging.

QTAIM and Stress Tensor Characterization of Intramolecular Interactions Along Dynamics Trajectories of a Light-Driven Rotary Molecular Motor.

A quantum theory of atoms in molecules (QTAIM) and stress tensor analysis was applied to analyze intramolecular interactions influencing the photoisomerization dynamics of a light-driven rotary molecular motor. For selected nonadiabatic molecular dynamics trajectories characterized by markedly different S1 state lifetimes, the electron densities were obtained using the ensemble density functional theory method. The analysis revealed that torsional motion of the molecular motor blades from the Franck-Condon point to the S1 energy minimum and the S1/S0 conical intersection is controlled by two factors: greater numbers of intramolecular bonds before the hop-time and unusually strongly coupled bonds between the atoms of the rotor and the stator blades. This results in the effective stalling of the progress along the torsional path for an extended period of time. This finding suggests a possibility of chemical tuning of the speed of photoisomerization of molecular motors and related molecular switches by reshaping their molecular backbones to decrease or increase the degree of coupling and numbers of intramolecular bond critical points as revealed by the QTAIM/stress tensor analysis of the electron density. Additionally, the stress tensor scalar and vector analysis was found to provide new methods to follow the trajectories, and from this, new insight was gained into the behavior of the S1 state in the vicinity of the conical intersection.

A QTAIM and stress tensor investigation of the torsion path of a light-driven fluorene molecular rotary motor.

The utility of the QTAIM/stress tensor analysis method for characterizing the photoisomerization of light driven molecular rotary machines is investigated on the example of the torsion path in fluorene molecular motor. The scalar and vector descriptors of QTAIM/stress tensor reveal additional information on the bonding interactions between the rotating units of the motor, which cannot be obtained from the analysis of the ground and excited state potential energy surfaces. The topological features of the fluorene motor molecular graph display that, upon the photoexcitation a certain increase in the torsional stiffness of the rotating bond can be attributed to the increasing topological stability of the rotor carbon atom attached to the rotation axle. The established variations in the torsional stiffness of the rotating bond may cause transfer of certain fraction of the torsional energy to other internal degrees of freedom, such as the pyramidalization distortion. © 2016 Wiley Periodicals, Inc.

[Application of gastric tube interposition by touching laryngeal prominence in postoperative oral cancer patients].

OBJECTIVE: This study explores the application of gastric tube interposition by touching laryngeal prominence in postoperative oral cancer patients. METHODS: This trial includes 66 patients treated in the West China Hospital of Stomatology from August 2014 to December 2014. These patients were randomly divided into two groups: the test group included 33 patients who underwent gastric tube interposition by touching laryngeal prominence; the 33 other patients, who served as control group, underwent regular gastric tube interposition. The two groups were compared in terms of the occurrence rate of bucking, success rate of one-time gastric tube placement, and interposition time. RESULTS: Compared with those in the control group, the occurrence rate of bucking and the interposition time in the test group decreased while the success rate of one-time gastric tube placement increased (P<0.05). CONCLUSIONS: Gastric tube interposition by touching laryngeal prominence can improve the success rate of one-time gastric tube interposition; moreover, it can reduce the average interposition time and the pain experienced by patients.

[Three dimensional finite element stress analysis in the vertical fractured first premolar after bonding and replantation].

PURPOSE: To evaluate the change of stress distribution after bonding and replantation of vertical fractured first maxillary premolar. METHODS: The stress distribution in two types of loading and different treatments on the vertical fractured first maxillary premolar were analyzed by three dimensional finite element. The gap was respectively filled with Clearfil SE Bond and Super Bond C & B; and vertical and lateral stress force was calculated. RESULTS: The result of the FEM study of adhesive fracture tooth indicated that the stress distribution was similar to the normal tooth, Clearfil SE Bond was better than Super Bond C & B. CONCLUSION: The treatment of bonding and replantation for vertical fractured tooth is effective.

[Analysis the effect on the stress of root canal wall of pulpless teeth by different degree of root canal preparation].

OBJECTIVE: To analyze the stress variations of wall of root canal of pulpless teeth that resulted from different diameters of root canal. METHODS: On the basis of the finite-element model of the mandibular first molar that modified by routine, diameter of root canal was modified and enlarged so as to the diameter of root canal was 1/3 and 1/2 of root diameter, then modified models were loaded and the maximal stress of each part of teeth and wall of root canal was calculated. RESULTS: The results revealed that enlargement of root canal diameter will bring on increase of stress of root canal wall at the orifice and coronal 1/3. The stress difference of lateral loading was greater than that of vertical loading. CONCLUSION: The principle of root canal preparation should be infected material removed and good shape of root canal gained. Over-preparation is unnecessary and harmful.

[Analysis of the effect on the stress of root canal wall by vertical and lateral condensation procedures].

OBJECTIVE: To analyse the stress variations of root canal wall that resulted from vertical and lateral condensation. METHODS: On the basis of the finite-element model of the mandibular first molar that modified by step-back technique, mesial-buccal root canal was chosen as tested root canal and simulated the procedure of vertical and lateral condensation. The maximal stress of root canal wall and its position were calculated by special software upon different loading condition. RESULTS: Stress of root canal wall caused by vertical condensation was higher than that by lateral condensation on the same loading condition. Maximal stress of vertical condensation was located on loading section and one of lateral condensation was located on coronal and middle 1/3 of root. The lower the position that was loaded, the higher the stress of wall of root canal. CONCLUSION: Lateral condensation will not bring on vertical root fracture directly,but over-force and improper operation are both dangerous that gives rise to vertical root fracture with whichever method.

[Analysis the effect on the stress of wall of root canal by different proportion between crown and root].

OBJECTIVE: Use FEM to observe the relationship between the change of alveolar ridge's height and the stress change of wall of root canal. METHODS: Modify the model on the basis of the set up model of the mandibular first molar, simulating the height of alveolar ridge and reducing 1/4, 1/3, 1/2 of the height to set up modified model, and load on the modified model by vertical and lateral forces. Then calculate the maximum mises stress of each part of teeth and wall of root canal. RESULTS: The stress-changing tendency of each part of wall was similar to the changing tendency of each part of teeth, but the stress of wall was fewer than the stress of teeth. The stress value of original model was close to the modified model at the orifice. Then the stress of original model obviously reduced, and the stress of the modified model reached maximum in the coronal thirds, and when the fixed height was lower, the stress was larger, the stress reduced more slowly. The lateral stress was larger than the vertical stress, and when the fixed height was lower, the difference was more obvious. CONCLUSION: The change of alveolar ridge's height will affect the stress change of wall of root canal, and which is in an inverse proportion.

[Analysis the stress variations of the root canal wall of pulpless tooth by different root canal preparation with finite-element method].

OBJECTIVE: To analyze the stress variations of the root canal wall of pulpless tooth by different root canal preparations. METHODS: On the basis of the set up model of the mandibular first molar, modified model was established by simulation of the routine or step-back root canal preparation and filling in. Then the maximum mises stress of each part of teeth and wall of root canal were calculated by special finite-element software. RESULTS: The stress-changing tendency is similar between two modified models but the maximum mises stress of the model by step-back technique is a little greater than one by routine. The stress of wall of mesial-buccal root canal was the greatest and one of mesial-lingual root canal was the least at three root canals. The stress-changing tendency of modified models was similar to original model. The maximum mises stress of modified models was near or less than one of original model except that of amalgam layer because of material property alteration. CONCLUSION: Not only routine but step-back technique is an effective and safe method. Dentist can choose them in practice.

[Three dimensional finite element stress analysis in various class II cavity design on first maxillary premolar].

OBJECTIVE: To evaluate the stress influence in different contour of class II cavity with different filling materials on first maxillary premolar. METHODS: The stress distribution in two types and all three contours of class II cavity in maxillary premolar were analyzed by three dimensional finite element. The cavity was respectively filled with amalgam and composite resin; and the vertical and lateral stress force was calculated. RESULTS: In the different contours, the stress of composite restoration by slot design was close to that by dovetail design, and the stress of amalgam restoration by slot design, especially in vertical force, descended respectively at 41%,29% and 27%. CONCLUSION: When class II lesions is only limited in proximal region of the premolar, the filling of composite resin with slot design is recommended.