Objective To determine the prevalence of symmetry of C shaped root canal system in mandibular second molars.MethodsA total of 70 madibular second molars with C shaped root canal system to be considered as needing root canal therapy were included in this study,of which 68 contralateral X ray apical films were obtained.The symmetry of the root and the root canal system was analyzed using magnifying glass.ResultsOf the 68 mandibular second molars with C shaped root canal system diagnosed clinically,62 cases with C shaped root canal system bilaterally,with the prevalence 91.18%.ConclusionThe anatomic feature of mandibular molars with C shaped root canal system is complicated,and the prevalence of symmetry is very high,which is in favor of estimating the anatomic feature from contralateral tooth.

Pollution and control of microcystins released during the toxic bloom was reviewed in the present paper. As a risk factor in safety assessment, microcystins aroused broad attention. It was a topic of general interest that how to control microcystins reproduction and how to enhance the degradation of microcystins in the water treatment procedure. Based on the state of China, it was considered that a combined method of biological, physical and chemical treatment should be the best way to control microcystins pollution in drinking water.

Objective:To explore the feasibility of ultrasound screening and diagnosis of fetal cleft palate in early pregnancy, analyze and summarize the imaging technology and image characteristics of two-dimensional and three-dimensional ultrasound in normal fetus and cleft palate fetus.Methods:A total of 10 519 pregnant women participated in the early pregnancy were included from January 2016 to June 2020 in Shenzhen Hospital, University of Chinese Academy of Sciences. The palatal line on the standard section of fetal nuchal translucency (NT) measurement was used as a screening marker for routine observation. For fetuses with abnormal palatine line, posterior nasal triangle of coronal plane and axial plane of maxillary alveolar arch of two-dimensional ultrasound were added as the diagnostic sections, and three-dimensional volume data of fetal face were collected, and three dimensional multimodal imaging technology was used to analyze the volume data off-line to determine or exclude fetal severe cleft palate. All fetuses were followed up during the second trimester for deformity scanning and post natal (or induced labor) assessment.Results:Of the 10 519 fetuses, the standard NT plane was obtained and the palatal line was observed in 10 204 cases(97.01%), with normal palatal line in 10 169 cases.In 35 suspected cases, 13 cases were confirmed cleft lip and palate by two and three dimensions ultrasound, and were confirmed by induced labor. There were 7 cases in unilateral side, 3 cases in bilateral, 2 cases in median cleft lip and palate, 1 cases in irregular cleft lip and palate, and no false positive results were reported. Twenty-two suspicious cases were excluded by increasing the two-dimensional sectional and three-dimensional volumetric off-line analysis, and screening after the second trimester and after birth. There was 1 case of missed diagnosis of simple cleft palate.Conclusions:Palatal line is a good screening marker for fetal cleft palate in early pregnancy. For fetuses with abnormal palatine line, the adding of posterior nasal triangle and the axial plane of maxillary alveolar arch, and combining three-dimensional volume data for off-line analysis can determine or exclude severe cleft palate. This study is of great significance for early screening and diagnosis of severe fetal cleft palate, prenatal genetic counseling and prevention birth defect.

The kinematic model parameter deviation is the main factor affecting the positioning accuracy of neurosurgical robots. To obtain more realistic kinematic model parameters, this paper proposes an automatic parameters identification and accuracy evaluation method. First, an identification equation contains all robot kinematics parameter was established. Second, a multiple-pivot strategy was proposed to find the relationship between end-effector and tracking marker. Then, the relative distance error and the inverse kinematic coincidence error were designed to evaluate the identification accuracy. Finally, an automatic robot parameter identification and accuracy evaluation system were developed. We tested our method on both laboratory prototypes and real neurosurgical robots. The results show that this method can realize the neurosurgical robot kinematics model parameters identification and evaluation stably and quickly. Using the identified parameters to control the robot can reduce the robot relative distance error by 33.96% and the inverse kinematics consistency error by 67.30%.
Biomechanical Phenomena ; Robotic Surgical Procedures

Objective To investigate the effect of melatonin on mice with ischemia-reperfusion via a silent information regulator 1 (SIRT1) reducing mitochondrial oxidative stress mechanism. Methods A transient middle cerebral artery occlusion ( MCAO) cerebral ischemia-reperfusion ( IR) model in mice was established by the suture-occluded method. One hundred and ninety mice were injected with melatonin intraperitoneally or the SIRT1 inhibitor (EX527) intracerebroventricularly,30 dead and model failure mice were excluded. They were divided into IR,melatonin,melatonin +EX527,and EX527 groups (n =40 in each group ) according to the random number table. The cerebral infarct volume was detected by the triphenyltetrazolium chloride (TTC) method,the brain edema was measured by the wet and dry weight method and the neurological deficit scores were measured. Western blot was used to detect SIRT1,Ac-P53, acetylated-nuclear factorκB (Ac-NF-κB),BCl2,Bax proteins in the mitochondria and cytoplasm,as well as the cytochrome C protein expression. A single factor analysis of variance was used for comparison among the groups. Results ( 1 ) There were significant differences in cerebral infarction volume, neurological dysfunction scores and cerebral edema among the four groups ( F values,16. 452,23. 622,and 18. 786, respectively (all P<0. 05). There were significant differences in the expression levels of SIRT1,Ac-P53, Ac-NF-κB,BCl2, and Bax among the four groups ( F values, 2348. 158, 1434. 841, 7042. 563, 14627. 128,and 691. 475,respectively,all P<0. 05). There were significant differences in mitochondrial membrane potential,mitochondrial reactive oxygen species,and complex I activity in mice among the four groups (F value,28. 454,33. 728 and 29. 716,respectively,all P <0. 05). (2) Compared with the IR group,the infarct volume was reduced (32 ± 5 mm3 vs. 57 ± 5 mm3,P<0. 05),neurological deficit scores were decreased (2. 4 ± 0. 3 vs. 3. 5 ± 0. 3,P<0. 05);brain edema was reduced (80. 2 ± 0. 9% vs. 83. 9 ± 1. 2%,P<0. 05);the expression levels of SIRT1 and anti-apoptosis protein BCL2 were increased in the melatonin group (P<0. 05);the expression levels of pro-apoptotic protein BAX and Ac-P53,Ac-NF-κB were reduced ( P <0. 05 );the mitochondrial membrane potential, mitochondrial complex I activity and cytochrome C level were increased (P<0. 05);and the cytoplasmic reactive oxygen species and cytochrome C level were decreased (P < 0. 05). (3) Compared with the melatonin group,cerebral infarction volume were increased (42 ± 5 mm3 vs. 32 ± 5 mm3,P < 0. 05);nerve dysfunction scores were increased(3. 2 ± 0. 3 vs. 2. 4 ± 0. 3,P<0. 05);cerebral edema was aggravated (83. 4 ± 0. 8% vs. 80. 2 ± 0. 9%, P < 0. 05 );the expression levels of SIRT1 and anti-apoptotic protein BCL2 were reduced (P <0. 05);the pro-apoptotic protein BAX,Ac-P53,and Ac-NF-κB expression levels were increased (P<0. 05);the mitochondrial membrane potential and mitochondrial complex I activity and cytochrome C level were decreased (P<0. 05);and the cytoplasmic reactive oxygen species and cytoplasmic cytochrome C level were increased in the melatonin+EX527 group (P<0. 05). Conclusion In ischemic stroke model mice, melatonin plays a neuroprotective role by activating the SIRT1 signaling pathway and reducing oxidative stress injury and cell death in mitochondria,thus plays a role in cerebral protection.

Objective:To study the role of DDX3X/NF-κB pathway in early neuronal apoptosis in subarachnoid hemorrhage(SAH)mice.Methods:The mouse model of SAH was established by internal carotid artery puncture,and the neurological function score of the mice was evaluated.The DDX3X expression was knocked down using recombinant lentivirus expressing DDX3X targeted shRNA(Lv-shDDX3X),or the NF-κB pathway was inhibited by NF-κB-IN-1(IN-1).Western Blot was used to detect the expression of DDX3X and NF-κB(p65)in mouse cortex.TUNEL/NeuN staining was used to detect the apoptosis of cerebral cortex neurons.Results:Twenty-four hours after SAH operation,the neurological function of mice was significantly impaired(P＜0.05).While the expression of DDX3X was signifi-cantly increased and the expression of NF-κB(p65)was significantly decreased in the cortex(P＜0.05).When the DDX3X expression is knocked down firstly,then SAH surgery is performed.The neurological function of mice was sig-nificantly recovered,and the expression of NF-κB(p65)protein was significantly higher than that in SAH group(P＜0.05);If the NF-κB activity was inhibited by IN-1 while DDX3X knockdown,there is no significant recovery of neuro-logical function in SAH mice.TUNEL/NeuN staining showed that the number of TUNEL-positive neurons in the brain tissue after DDX3X knockdown was less than that in the SAH group(P＜0.05),while the number of TUNEL-positive neurons was not significantly reduced when IN-1 was used to inhibit NF-κB activity at the same time of DDX3X knock-down.Conclusion:DDX3X/NF-κB mediated cell death in mice with early brain injury after SAH.

Objective The purpose of this study was to investigate the differences in the anti cyclic fatigue performance of Woride KS (WKS), Proteper Gold (PTG), and Hyflex CM (HCM) nickel titanium instruments with different tip diameters in curved root canal models, and to provide reference for the targeted selection of suitable nickel titanium instruments in clinical preparation of curved root canals.

Traumatic cerebrospinal fluid leakage commonly presents in traumatic brain injury patients, and it may lead to complications such as meningitis, ventriculitis, brain abscess, subdural hematoma or tension pneumocephalus. When misdiagnosed or inappropriately treated, traumatic cerebrospinal fluid leakage may result in severe complications and may be life-threatening. Some traumatic cerebrospinal fluid leakage has concealed manifestations and is prone to misdiagnosis. Due to different sites and mechanisms of trauma and degree of cerebrospinal fluid leak, treatments for traumatic cerebrospinal fluid leakage varies greatly. Hence, the Craniocerebral Trauma Professional Group of Neurosurgery Branch of Chinese Medical Association and the Neurological Injury Professional Group of Trauma Branch of Chinese Medical Association organized relevant experts to formulate the " Chinese expert consensus on the diagnosis and treatment of traumatic cerebrospinal fluid leakage in adults ( version 2023)" based on existing clinical evidence and experience. The consensus consisted of 16 recommendations, covering the leakage diagnosis, localization, treatments, and intracranial infection prevention, so as to standardize the diagnosis and treatment of traumatic cerebrospinal fluid leakage and improve the overall prognosis of the patients.