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Owning to complex properties of ergodicity, non-periodic ability and sensitivity to initial states, chaotic systems are widely used in cryptography. In this paper, we propose a sinusoidal--polynomial composite chaotic system (SPCCS), and prove that it satisfies Devaney's definition of chaos: the sensitivity to initial conditions, topological transitivity and density of periodic points. The experimental results show that the SPCCS has better unpredictability and more complex chaotic behavior than the classical chaotic maps. Furthermore, we provide a new image encryption algorithm combining pixel segmentation operation, block chaotic matrix confusing operation, and pixel diffusion operation with the SPCCS. Detailed simulation results verify effectiveness of the proposed image encryption algorithm.

The association between benign paroxysmal positional vertigo (BPPV) and impaired calcium metabolism has attracted widespread interest. Several studies have suggested that decreased bone mineral density (BMD) and serum 25-hydroxyvitamin D (25(OH)D) level are related to the occurrence and/or recurrence of BPPV; however, the characteristics of bone metabolism in patients with BPPV subtypes have not been fully investigated, and conclusions have been controversial. This study aimed to evaluate BMD and serum levels of 25(OH)D and bone turnover markers to clarify the characteristics of bone metabolism in patients with different types of BPPV.We retrospectively analysed the data of new-onset idiopathic postmenopausal female patients with BPPV at our institution from January 2016 to January 2020. The patients' demographic data including age, medication history, concomitant diseases, onset time, clinical form, laboratory indicators, such as serum levels of 25(OH)D, bone formation markers, namely, amino-terminal propeptide of type I procollagen (PINP) and osteocalcin (OC), bone resorption marker, namely, β-isomerized carboxy-terminal telopeptide of type I collagen (β-CTX), and BMD were collected and analysed.This study included 201 consecutive postmenopausal female patients with BPPV. Among them, 138 were diagnosed with posterior semicircular canal BPPV, 42 were diagnosed with lateral semicircular canal canalolithiasis, and 21 were diagnosed with lateral semicircular canal cupulolithiasis. There were no significant differences in age distribution, body mass index, clinical history, levels of albumin, globulin, uric acid, creatinine, or blood urea nitrogen, lipid profiles (except high-density lipoprotein cholesterol) and routine blood parameters among these groups (P 0.05). There were no significant differences in the mean T-score and BMD values of different sites or in the serum levels of 25(OH)D and bone turnover markers (PINP, OC and β-CTX) among the subgroups (P 0.05). The proportion of reduction in BMD (T-score -1 SD) and decreased serum vitamin D level (20 ng/ml) were not significantly different between the subgroups (P 0.05).There were no significant differences in bone metabolism in postmenopausal female patients with different types of idiopathic BPPV.

Objective: Otolin-1, a main specific otoconia matrix protein, passes through the labyrinth-blood barrier and is detectable in peripheral blood. Serum otolin-1 levels differ between patients with benign paroxysmal positional vertigo (BPPV) and healthy controls and are significantly age-related, increasing in healthy controls with age, suggesting that serum otolin-1 levels reflect otolith status. The aim of this study was to determine whether otolin-1 levels change during vertigo episodes in patients with BPPV and whether any change is specific and sensitive enough for BPPV episodes.Method: Patients diagnosed with de novo idiopathic BPPV during an acute episode were included in the study from May 2017 to May 2018. Blood samples were drawn before patients were treated with canalith-repositioning maneuvers. Serum otolin-1 levels were compared between 78 patients and 121 age- and sex-matched healthy individuals.Results: There were no significant differences between the groups in the age distribution, sex ratio, body mass index, clinical history, routine blood parameters, or total protein, albumin, uric acid, creatinine, blood urea nitrogen and lipid profiles (P > 0.05). Serum levels of otolin-1 were significantly higher in BPPV patients than in healthy controls (P < 0.001). Receiver operating characteristic analysis revealed that a serum otolin-1 value of 299.45 pg/ml was the optimal cut-off value to discriminate patients with BPPV from healthy controls (area under the curve 0.757, 95% CI 0.687~0.826) with a sensitivity of 67.9% and a specificity of 72.7%.Conclusion: Serum levels of otolin-1 may be a potential biomarker for BPPV episodes.

Objective This study aimed to investigate the clinical association between idiopathic benign paroxysmal positional vertigo (BPPV) and reduction of bone mineral density (BMD). Methods BMD was measured in 78 native Chinese female de novo idiopathic BPPV patients and 126 healthy controls using dual-energy X-ray absorptiometry. We compared the mean T-scores and abnormal BMD prevalence between the two groups. Results The mean T-scores were significantly lower in idiopathic BPPV patients than in healthy controls. The prevalence of osteopenia and osteoporosis were significantly higher in idiopathic BPPV patients than in healthy controls (65.4% vs 48.4%, p = 0.013). Conclusion BMD reduction may be associated with idiopathic BPPV occurrence.

Objective: Vestibular neuritis (VN) is characterized by acute onset of vertigo, nausea, and vomiting, without auditory or other neurological symptoms. Although the pathogenesis of VN is not yet clear, many studies have shown that a pro-inflammatory environment can lead to the induction and progression of the disease. Considering the importance of vitamin D in modulating the activation, proliferation, and differentiation of inflammatory physiological processes, we hypothesized that decreased serum vitamin D may be associated with the development of VN. In this study, we evaluated serum levels of 25-hydroxyvitamin D [25(OH)D] in patients presenting acutely with VN and healthy controls and investigated the possible correlation of serum 25(OH)D levels with VN.Methods: A total of 59 consecutive patients diagnosed with VN within 7 days of symptom onset and 112 age- and sex-matched healthy controls referred to Hwa Mei Hospital, University of Chinese Academy of Science, between March 2017 and March 2019 were recruited. Demographic and clinical data, such as age, sex, height, weight, living habits, ongoing health problems, and medication history, for all subjects were recorded, and levels of 25(OH)D were measured and compared.Results: Serum levels of 25(OH)D were lower in patients with VN than in controls (19.01 ± 6.53 vs. 22.94 ± 6.74 ng/ml, p < 0.001). Patients with VN had a higher frequency of vitamin D deficiency (61.0 vs. 34.8%, P = 0.001) than did controls. Regression analyses demonstrated that vitamin D deficiency was associated with VN, with an odds ratio of 4.53 (95% CI = 1.342–15.279, P = 0.015).Conclusion: This prospective study is the first to evaluate serum 25(OH)D levels in patients with VN and found that decreased serum 25(OH)D may be associated with VN occurrence.

Objective: Several studies have suggested a probable association between benign paroxysmal positional vertigo (BPPV) and both reduction of bone mineral density (BMD) and serum vitamin D levels, but none of these studies have explored their findings by examining bone turnover markers (BTM) in male idiopathic BPPV patients. This study aimed to evaluate the relationship between BMD and serum 25-hydroxyvitamin D (25(OH) D), with the occurrence of BPPV along with the characteristics of bone metabolism in male idiopathic BPPV patients. Methods: This retrospective study comprised 60 male idiopathic BPPV patients and 92 age-matched healthy controls referred to Ningbo No.2 Hospital during the period of February 2016 to February 2018. All subjects' serum levels of 25(OH) D, bone formation marker amino-terminal propeptide of type I procollagen (PINP), and bone resorption marker β-isomerized carboxy-terminal telopeptide of type I collagen (β-CTX) were measured. BMD was determined by dual energy X-ray absorption at the lumbar spine and hip. Results: Among male patients with BPPV, the prevalence of BMD reduction was 35.0%, which was similar to that of 27.2% in healthy controls. There were significant differences in the mean serum 25(OH) D level and prevalence of vitamin D deficiency between the two groups, with p-values of 0.049 and 0.009, respectively. The bone turnover markers of PINP and β-CTX in BPPV patients were lower than those in healthy controls. Logistic regression showed that vitamin D deficiency were associated with BPPV with an odds ratio of 3.8 (95% confidence interval = 1.25-11.73). Conclusion: Our study found that decreased serum vitamin D may be a risk factor for BPPV in male patients. The level of bone turnover among male patients with BPPV was lower than that among healthy controls.