Statistical Analysis of Gait Maturation in Children Using Nonparametric Probability Density Function Modeling

Analysis of gait dynamics in children may help understand the development of neuromuscular control and maturation of locomotor function. This paper applied the nonparametric Parzen-window estimation method to establish the probability density function (PDF) models for the stride interval time series of 50 children (25 boys and 25 girls). Four statistical parameters, in terms of averaged stride interval (ASI), variation of stride interval (VSI), PDF skewness (SK), and PDF kurtosis (KU), were computed with the Parzen-window PDFs to study the maturation of stride interval in children. By analyzing the results of the children in three age groups (aged 3–5 years, 6–8 years, and 10–14 years), we summarize the key findings of the present study as follows. (1) The gait cycle duration, in terms of ASI, increases until 14 years of age. On the other hand, the gait variability, in terms of VSI, decreases rapidly until 8 years of age, and then continues to decrease at a slower rate. (2) The SK values of both the histograms and Parzen-window PDFs for all of the three age groups are positive, which indicates an imbalance in the stride interval distribution within an age group. However, such an imbalance would be meliorated when the children grow up. (3) The KU values of both the histograms and Parzen-window PDFs decrease with the body growth in children, which suggests that the musculoskeletal growth enables the children to modulate a gait cadence with ease. (4) The SK and KU results also demonstrate the superiority of the Parzen-window PDF estimation method to the Gaussian distribution modeling, for the study of gait maturation in children.This work was supported by the Fundamental Research Funds for the Central Universities of China (grant no. 2010121061), the Natural Science Foundation of Fujian (grant no. 2011J01371), and the National Natural Science Foundation of China (grant no. 81101115). N. Xiang was supported by Xiamen University Undergraduate Innovation Training Project (grant no. XDDC201210384072). Z. T. Zhong was supported by the Fundamental Research Funds for the Central Universities (grant no. CXB2011023). J. He was supported by the Xiamen University undergraduate student innovative experiment project (grant no. XDDC2011007). The authors acknowledge Hausdorff et al. for providing the data of gait experiments with public access via PhysioNet

Clinical efficacy of periodontal endoscopy-assisted subgingival scaling and root planning and its effect on psychology and quality of life in patients with periodontitis

Objective To investigate the clinical efficacy and effects of periodontal endoscope (PE)-assisted subgingival scaling and root planning (SRP) and traditional SRP on the psychological and quality of life of patients with periodontitis. Methods This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Patients with periodontitis who were treated in the Department of Periodontology, Nanjing Stomatological Hospital, Medical School of Nanjing University from April 2018 to December 2022 with residual periodontal pockets (PD ≥ 5 mm) 6 weeks after traditional SRP treatment were enrolled, and the residual periodontal pockets were further treated with PE-assisted SRP (PE+SRP). After 6 weeks of traditional SRP treatment and 3 months of PE+SRP treatment, clinical indicators, including plaque index (PLI), probing depth (PD), clinical attachment loss (CAL) and bleeding on probing (BOP), were measured, and periodontal tissue self-awareness scale scores, oral health impact profile-14 (OHIP-14) score and dental fear scale (DFS) score were collected. Moreover, visual analog scale (VAS) scores were collected after traditional SRP and PE-assisted SRP treatments. Results Twenty-three patients with periodontitis, including 832 sites of 486 affected teeth, were included in the clinical study. Three months after PE+SRP treatment, all clinical periodontal indicators, PLI (t = 9.254, P<0.001), PD (t = 50.724, P<0.001), CAL (t = 22.407, P<0.001) and BOP (t = 9.217, P<0.001), were significantly improved. Compared with traditional SRP (VAS: 2.48 ± 1.70), the pain caused by PE+SRP (VAS: 2.57±1.80) was not significantly different (t = 0,192, P = 0.850). There was no significant difference in the scores of the periodontal tissue self-awareness scale between the two groups (t = 1.485, P = 0.152). The OHIP-14 (SRP: 12.13±7.63; PE+SRP: 10.26 ± 5.25, t = -1.589, P = 0.126) and DFS (SRP: 40.70 ± 12.63; SRP+PE: 41.57 ± 12.61, t = 0.404, P = 0.690) scores were not significantly different. Conclusion All clinical periodontal indicators were significantly improved after PE-assisted SRP treatment of residual periodontal pockets, and compared with traditional SRP, PE-assisted SRP had no negative impact on the quality of life or psychological status of patients with periodontitis. Therefore, PE+SRP can be promoted in clinical practice

Study on the microwave absorbing properties of SiC@Ni powders with core@shell structure

Hybridization of dielectric and magnetic materials is considered a promising option for the preparation of electromagnetic wave absorbing materials with excellent properties. In this paper, SiC@Ni powders were prepared by a surface heat-assisted process, in which SiC was first cleaned sequentially with anhydrous ethanol and NaOH solutions, and the samples were etched into a mixed solution of HF and HCl, the SiC@Ni powders were then mixed at high speed at 120 °C under argon atmosphere. The sample were characterized by Scanning electron microscopy (SEM) and vector network analyzer (VNA). It is found that the absorption characteristics of SiC@Ni in the 2–18 GHz band are significantly enhanced due to the introduction of the ni layer which enhances the loss of the sample to solve the problem of a single absorption mechanism and high impedance of SiC. The reflection loss value of SiC@Ni in the 8.7 GHz band decreases to − 22.45 dB when the material thickness is 2.5 mm, the effective absorption frequency width is 2.5 GHz, which is a significant advantage over the initial SiC. The experimental methodology of this work is simple and easy to follow, and provides some guidance for the large-scale production of SiC-based microwave absorbing materials

PROBABILISTIC FATIGUE LIFE PREDICTION APPROACH FOR MULTI-SITE DAMAGE COMPONENTS

Fatigue is a phenomenon of high uncertainty,especially for components with multiple damage sites.The fatigue life（ either mean value or probability distribution of the random variable） of a complex component with multiple damage sites is not equal to that of a simple component with only one damage site.A multi-site damage component is a series system with many weak links（ damage sites） in probability sense.A probabilistic fatigue life prediction model for multi-site damage component is presented based on a systematic thought,as well as the order statistics and extreme statistics concept.Such developed model can naturally reflect the effect of the dependence among different damage sites.Experimental result and the example on multi-site damage component fatigue life prediction shows that the fatigue life of a multi-site damage component is much lower than that of a single site damage component

Simulation Analysis and Experimental Study of the Strength of Aluminum Alloy Suspension Structure

High-speed trains have a large amount of ancillary equipment, which is suspended from the underside of the train by means of a suspension structure. Due to the large mass of the ancillary equipment, the suspension structure is subjected to various loads during train operation and there is a risk of fatigue failure. In this paper, the stress distribution at the suspension point and the lo-cation of the maximum stress point under load are investigated in detail based on actual test loads at the suspension point and finite element simulation analysis. In order to further investigate the fracture failure of the suspension points, experimental studies were carried out. Firstly, static strength tests were carried out to obtain the load–displacement curves of the structural members and to determine the fracture strength of the structure based on the displacement sensors, and secondly, fatigue tests at different stress levels were carried out to obtain the load–life curves of the structural members and to investigate the probabilistic load–life curves at different reliability levels. The test results show that the structural component has a high fracture strength of 65kN, while the conditional fatigue strength is relatively low, corresponding to a load level of 12.5kN at a median life of 106 cycles. The above research work provides the necessary basis for the design, optimization and reliability assessment of the suspension structures of high-speed trains

High incidence of HPV infection in minors with oral squamous cell carcinoma

Abstract Background Oral squamous cell carcinoma in minors is considered to be a distinct entity from OSCC in older patients, with an uncertain etiology. Human papillomavirus (HPV) infection may trigger the initiation and promote the progression of OSCC, but these roles have not been firmly established.We aimed to explore the correlation between HPV infection and the development of oral squamous cell carcinoma in minors and know the characteristics of OSCC in young patients more thoroughly. Method From January 2013 to December 2022,6 cases of OSCC aged < 15 years were selected from the Department of Oral Pathology, Peking University School of Stomatology, Beijing, China. All cases underwent testing for high-risk HPV mRNA infection using the RNA scope technique, and immunohistochemical staining was performed to investigate the expression of p16, pan-cytokeratin (CK), CK5/6, CK7, CK8/18, epidermal growth factor receptor (EGFR), p53, and Ki-67. Furthermore, we reviewed the literature on OSCC in patients aged < 21 years. Conclusions Minors OSCC is associated with HPV infection, and that p16 can serve as an immunohistochemical marker of HPV positivity

Cerebral malaria presenting as nonconvulsive status epilepticus: a case report

Abstract Background Malaria is an infectious malady caused by Plasmodium parasites, cerebral malaria standing out as one of its most severe complications. Clinical manifestation include elevated body temperature, loss of consciousness, and seizures. However, reports of cerebral malaria presenting as nonconvulsive status epilepticus are extremely rare. The case presented involves psychiatric symptoms, with the electroencephalogram indicated nonconvulsive status epilepticus associated with cerebral malaria. Case presentation A 53-year-old male, was urgently admitted, due to confusion and abnormal behaviour for 10 h. The patient returned to China after developing a fever while working in Tanzania two months ago. The blood smear revealed Plasmodium vivax and Plasmodium falciparum, and he was diagnosed with malaria. He recovered following anti-malarial treatment. After admission, the patient was confused, unable to communicate normally, and unwilling to cooperate with the physical examination. Plasmodium was not found in the blood smear, but the DNA sequence of P. falciparum was discovered using metagenomic next-generation sequencing of cerebrospinal fluid. Brain MRI revealed no significant abnormalities. Continuous electroencephalogram monitoring revealed that the patient had non-convulsive status epilepticus, which was treated with diazepam and levetiracetam. The patient had normal consciousness and behaviour. He received anti-malarial treatment for two weeks and fully recovered. Conclusions This case demonstrates that nonconvulsive status epilepticus can be a manifestation of cerebral malaria. It is imperative for attending physicians to heighten vigilance when encountering patients with a history of travel to malaria-endemic regions or a prior malaria infection, especially in the presence of unusual clinical presentations