Search

Surgery combined with orthodontic uprighting of impacted mandibular second molars requires sequential treatment procedures. This article presents a rare case of horizontally impacted bilateral mandibular second molars accompanied by dental crowding. The patient’s mandibular second molars were fully embedded in bone with overlying mesially-impacted mandibular third molars and the mandibular first molars were inclined distally. The treatment involved staged bilateral extraction of the second premolars and mandibular third molars, followed by the surgical implantation of micro-implants for anchorage in the mandibular ramus. At a subsequent stage, the mandibular second molars were successfully orthodontically uprighted, leading to a favourable treatment outcome.

Parkinson's disease (PD) is commonly characterized by asymmetrical motor impairment. This study aimed to clarify the iron distributions in PD patients with significant motor asymmetry and their longitudinal alterations. This study included 123 PD patients and 121 normal controls. Thirty-eight PD patients were revisited. PD patients with significant motor asymmetry were identified by using an objective criterion. Inter-group, inter-hemisphere and inter-visit differences of regional tissue susceptibility were analyzed. Iron accumulation in dominantly and non-dominantly affected substantia nigra (SN) were observed in PD patients with motor asymmetry compared with normal controls (p < 0.005, Bonferroni corrected). Iron accumulation in the dominantly affected SN was significantly higher than that in the non-dominantly affected SN (p < 0.01, Bonferroni corrected). After follow-up, time effect on the iron content in SN was observed, directing to decrease in PD patients with motor asymmetry without hemispherical difference (p < 0.05). In conclusion, asymmetrical iron accumulation in SN was associated with the motor asymmetry in PD at baseline, while along the disease evolution iron content in SN became longitudinally decreased. All these findings provide new evidence for PD pathogenesis that the abnormal iron metabolism in SN is complicated and not always unidirectional.

Bonding of brackets to dental fluorosis has always been a difficult problem for clinicians. At present, clinical research has adopted several methods to facilitate bracket bonding, including prolonging etching time, enamel microabrasion, enamel ground, using adhesion promoter and laser etching. Prolonging etching time is suitable for mild-to-moderate dental fluorosis with easy chair-side operation; however, over-etching may cause severe tooth damage. Microabrasion can be applied to mild dental fluorosis while removing pigment deposition simultaneously; however, rubber dam protection is needed. Enamel ground can improve the bond strength to all kinds of dental fluorosis at the price of removing a relatively large amount of superficial enamel. Adhesion promoters might improve the bond strength of moderate to severe dental fluorosis; however, the current results conflict with one another. This needs further verification using larger-sample clinical trials. Laser etching has no effect on improving bond strength; however, it can remove pigment without destroying tooth enamel, which is worth further modification and enhancement.

Remote sensing extraction of glacial lakes is an effective way of monitoring water body distribution and outburst events. At present, the lack of glacial lake datasets and the edge recognition problem of semantic segmentation networks lead to poor accuracy and inaccurate outlines of glacial lakes. Therefore, this study constructed a high-resolution dataset containing seven types of glacial lakes and proposed a refined glacial lake extraction method, which combines the LinkNet50 network for rough extraction and simple linear iterative clustering (SLIC) dense conditional random field (DenseCRF) for optimization. The results show that (1) with Google Earth images of 0.52 m resolution in the study area, the recall, precision, F1 score, and intersection over union (IoU) of glacial lake extraction based on the proposed method are 96.52 %, 92.49 %, 94.46 %, and 90.69 %, respectively, and (2) with the Google Earth images of 2.11 m resolution in the Qomolangma National Nature Reserve, 2300 glacial lakes with a total area of 65.17 km 2 were detected by the proposed method. The area of the minimum glacial lake that can be extracted is 160 m 2 (less than 6×6 pixels). This method has advantages in small glacial lake extraction and refined outline detection, which can be applied to extracting glacial lakes in the high-Asia region with high-resolution images. [ABSTRACT FROM AUTHOR]

Aims: To detect functional connectomes of akinetic‐rigid (AR) and tremor and compare their connection pattern. Methods: Resting‐state functional MRI data of 78 drug‐naïve PD patients were enrolled to construct connectomes of AR and tremor via connectome‐based predictive modeling (CPM). The connectomes were further validated with 17 drug‐naïve patients to verify their replication. Results: The connectomes related to AR and tremor were identified via CPM method and successfully validated in the independent set. Additional regional‐based CPM demonstrated neither AR nor tremor could be simplified to functional changes within a single brain region. Computational lesion version of CPM revealed that parietal lobe and limbic system were the most important regions among AR‐related connectome, and motor strip and cerebellum were the most important regions among tremor‐related connectome. Comparing two connectomes found that the patterns of connection between them were largely distinct, with only four overlapped connections identified. Conclusion: AR and tremor were found to be associated with functional changes in multiple brain regions. Distinct connection patterns of AR‐related and tremor‐related connectomes suggest different neural mechanisms underlying the two symptoms. [ABSTRACT FROM AUTHOR]

Objective: To determine whether white matter hyperintensity (WMH) volumes in specific regions are associated with Parkinson's disease (PD) compared to non‐PD controls, and to assess their impact on motor signs through cross‐sectional and longitudinal analyses. Methods: A total of 50 PD participants and 47 age‐ and gender‐matched controls were enrolled. All PD participants were followed up for at least 2 years. To detect regions of greater WMH in the PD, the WMH volume of each region was compared with the corresponding region in the control group. Linear regression and linear mixed effects models were respectively used for cross‐sectional and longitudinal analyses of the impact of increases in WMH volume on motor signs. Results: The PD group had greater WMH volume in the occipital region compared with the control group. Cross‐sectional analyses only detected a significant correlation between occipital WMH volume and motor function in PD. Occipital WMH volume positively correlated with the severity of tremor, and gait and posture impairments, in the PD group. During the follow‐up period, the participants' motor signs progressed and the WMH volumes remained stable, no longitudinal association was detected between them. The baseline occipital WMH volume cannot predict the progression of signs after adjustment for baseline disease duration and the presence of vascular risk factors. Interpretation: PD participants in this study were characterized by greater WMH at the occipital region, and greater occipital WMH volume had cross‐sectional associations with worse motor signs, while its longitudinal impact on motor signs progression was limited. [ABSTRACT FROM AUTHOR]