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Based on the physical optics method, the scattering characteristics of fractal rough surface coated objects are studied in the terahertz (THz) range herein. A blunt model based on fractal rough surfaces is built. The surface current is calculated according to the Fresnel reflection coefficient, and the Radar Cross Section (RCS) of the rough coated target is obtained. The RCS of rough and smooth surface targets are compared. Numerical results for a rough coated blunt cone model are provided, and discussed from the perspective of different frequencies and coating thickness values. The results show that the surface roughness of the target has a significant effect on scattering in the terahertz range.

Objective To analyze the use of medical insurance expenses of diabetic patients with osteoarthritis (OA) in Beijing, and to explore the impact of OA on the economic burden of diabetes patients. Methods Diabetic patients aged>16 years with complete outpatient medical records from 2016 to 2018 in Beijing medical insurance were included, excluding those with less than 2 months of follow-up and no prescription records. Information was collected from the Beijing medical insurance database, including the international disease classification of diabetes and its complications and comorbidities, age, sex, disease course, drug (hypoglycemic and non-hypoglycemic drugs) treatment plan, and medical insurance costs. Multivariate regression model was used to control confounding factors, and Wilcoxon rank sum test, χ² test or Fisher exact test were used to compare the differences in various indicators between the patients with diabetes without OA and those with diabetes with OA. Results A total of 2 853 036 diabetic patients were included, of whom 673 251 patients (23.60%) had OA. Stratified by age, the proportion of diabetics with OA was higher in the 45-84 age group, 92.73%, 92.43% and 92.29% in 2016, 2017 and 2018, respectively. According to gender distribution, there were more females in diabetics with OA, 55.17%, 54.41% and 53.37% in 2016, 2017 and 2018, respectively. Compared with diabetics without OA, diabetics with OA had significantly more related to complications and comorbidities (P< 0.001). Compared with diabetics without OA, the total annual drug cost/drug number of diabetics with OA in 2018 was higher at (2 511±2 526) and (2 608±2 155) yuan/drug, respectively, of which the cost/drug number of hypoglycemic drugs and non-hypoglycemic drugs was higher. From 2016 to 2018, the types of drugs for diabetics with OA (especially the types of hypoglycemic drugs) showed an increasing trend year by year, while the total annual drug cost (including hypoglycemic drugs and non-hypoglycemic drugs) showed a decreasing trend, and the total annual drug cost/drug number of medications also showed a decreasing trend. Conclusions Diabetics with osteoarthritis have more diabetes complications and related comorbidities, and require more hypoglycemic drugs and medical expenses. Osteoarthritis significantly increases the medical expenses of diabetics. [ABSTRACT FROM AUTHOR]

The gear transmission system is the most widely used motion or power transmission device,such as vehicles,machinery,aviation,aerospace,metallurgy,electric power,coal,petrochemical,nuclear energy and many other key mechanical equipment in the industry. The fault of gear transmission system will cause mechanical equipment failure. If the diagnosis can be carried out in advance,it is effective to avoid the occurrence of accidents,eliminate the continued damage,save a lot of maintenance costs. In view of the research results in the field of fault diagnosis technology of the gear transmission system,focusing on the research status of the fault feature extraction and mode recognition method,and the problems to be further study is given.

In the melting process, the fundamental slag system of PbO-CaO-SiO2-FeO-ZnO was chosen based on the composition and phase of the jarosite residue and melt agent. The phase diagram of the slag system was drawn by FactSage thermodynamic software, combined with relevant slag performance measurement tests to explore the effect of changing the FeO/SiO2 ratio and CaO/SiO2 ratio on the physical and chemical properties of the slag. The results showed that if there are no more additional components in this system, the melting point gets higher with the FeO/SiO2 ratio increasing, and the melting point became lowest (1 338 °C) when the FeO/SiO2 ratio was 0.92. When the CaO/SiO2 ratio increased from 0.3 to 0.8, the melting point shows a decreasing trend, while the CaO/SiO2 ratio is 0.78, the lowest melting point appeared, and the value is 1 385 °C. The viscosity of slags with a low melting point was measured, and the results showed that when the temperature was 1 500 °C, the viscosities of all slags were less than 0.5 Pa ⋅ s. It means that the smelting requirements for fluidity could be achieved. Finally, the optimized slag adjustment scheme was proposed which is adding CaO and reducing SiO2 to a CaO/SiO2 ratio of 0.78. It is beneficial to the subsequent iron extraction after slag adjustment because the phases of slag are mainly magnetite and silicate. [ABSTRACT FROM AUTHOR]

Objective To investigate the relationship between diabetic peripheral neuropathy (DPN) and cognitive impairment in elderly patients with Type 2 diabetes mellitus (T2DM). Methods The elderly T2DM patients (aged 60 to 75 years) hospitalized in the Department of Endocrinology, Beijing Hospital from December 2020 to November 2021 were enrolled in the group sequentially. The patients' medical history, general data and laboratory results were collected, the cognitive function was assessed by mini-mental state examination (MMSE) and Montreal Cognitive Assessment (MOCA) scale, and the body function was evaluated by 4-meter walking speed and standing test on one foot with eyes closed. According to the presence or absence of DPN, patients were divided into DPN group and non-DPN group. Chi-square test, t test or Mann-Whitney U test were used to compare the differences of clinical features between the two groups, and logistic regression analysis was used to analyze the risk factors of cognitive impairment. Results Two hundred and six patients with T2DM were enrolled in the study, including 87 patients in the DPN group (42.2%) and 119 patients in the non-DPN group (57.8%). There were statistically significant differences in gender distribution, smoking history, the level of glycosylated hemoglobin A1c(HbA1c), 2 h postprandial C-peptide, 1, 25 (OH)2-vitamin D3, and standing time on one foot with eyes closed between non-DPN group and DPN group (P<0.05). There were statistically significant differences in MMSE score, MOCA score, memory score and attention score between non-DPN group and DPN group (P<0.05). According to MOCA score, patients were divided into normal cognitive function group (59 cases, 28.6%) and cognitive impairment group (147 cases, 71.4%). The education level, 2 h postprandial C-peptide level, standing time on one foot with eyes closed and 4-meter walking speed in the cognitive impairment group were lower than those in the normal cognitive function group, while the proportion of clinical DPN patients in the cognitive impairment group was higher than that in the normal cognitive function group [50.3% (74/147) and 22.0% (13/59), respectively], and the differences were statistically significant (P<0.05). Logistic regression analysis showed that in elderly patients with T2DM, DPN was a risk factor for cognitive impairment [OR (95%CI) was 3.622 (1.722 to 7.619)]. Educational background [OR (95%CI) was 0.458 (0.247 to 0.849)], 4-meter walking speed [OR (95%CI) was 0.339 (0.151 to 0.762)] and standing time on one foot with eyes closed [(OR (95%CI) was 0.830 (0.698 to 0.987)] were protective factors for cognitive impairment. Conclusions Peripheral neuropathy was associated with cognitive impairment in elderly patients with T2DM, and DPN was a risk factor for cognitive dysfunction. [ABSTRACT FROM AUTHOR]

Objective To compare the effects of exenatide and insulin aspart 30 injection on carotid intima-media thickness (cIMT) in patients with type 2 diabetes mellitus (T2DM) with different baseline characteristics, and to explore the influencing factors of exenatide in improving atherosclerosis (AS). Methods A total of 59 patients with T2DM who were admitted to the Department of Endocrinology of Beijing Hospital from March 10, 2015 to June 20, 2017 were enrolled. The study was designed as a randomized, prospective, parallel positive drug control study. According to the baseline cIMT <1 mm and ≥1 mm, the patients were divided into the following groups: baseline non-atherosclerotic group and baseline atherosclerotic group; according to body mass index (BMI) <24 kg/m2 and ≥24 kg/m2, they were divided into normal weight group, overweight and obesity group; according to the baseline glycosylated hemoglobin A1c (HbA1c)<8.5% and HbA1c≥8.5%, they were divided into general hyperglycemia group and significant hyperglycemia group; according to the decrease of HbA1c<1.5% and HbA1c ≥1.5% at 52th week, the patients were assigned to the general hypoglycemic effect group and the good hypoglycemic effect group. The cIMT was measured. The results of each group were compared by group t test, nonparametric test and χ2 test. Results The prevalence rate of carotid atherosclerosis in patients with T2DM was 64.41% (38/59). After 52 weeks of treatment with exenatide, the cIMT of patients with baseline AS was significantly lower than that of patients without baseline AS (P=0.02). After 52 weeks of treatment with exenatide, the cIMT decreased in overweight and obese subjects, but slightly increased in normal weight subjects, and the difference was not statistically significant (P=0.21). After 52 weeks of treatment, the cIMT decreased in both the general hypoglycemic effect group and the good hypoglycemic effect group, but the difference was not statistically significant (P=0.17). After treatment with exenatide, there was no correlation between cIMT changes and blood glucose, low density lipoprotein cholesterol and BMI changes within 52 weeks (P=0.576, 0.188 and 0.352, respectively). Conclusions In patients with atherosclerosis at baseline, the improvement of cIMT was more significant and the benefit was greater after the administration of exenatide. cIMT levels were not affected by baseline body weight and hypoglycemic efficacy, and had no correlation with BMI and blood glucose changes after exenatide treatment. [ABSTRACT FROM AUTHOR]

Objective To investigate the prevalence of sarcopenia in middle aged and elderly patients with type 2 diabetes (T2DM) and clarify the associated risk factors. Methods From January 2016 to March 2018, 1 125 T2DM patients over 50 years old in endocrinology departments of nine hospitals in Beijing were enrolled in this study with system random sampling method. All patients, including 586 males and 539 females, were grouped into middle aged group (50-59 years), young elderly group (60-74 years) and elderly group (over 75 years) by age. Body composition was measured with bioimpedance analysis. Low muscle mass was defined as the appendicular skeletal muscle mass index below 7.18 kg/m² in men and 5.73 kg/m² in women. Low muscle strength was defined as grip strength below 29.5 kg in men and 21.2 kg in women. Sarcopenia was defined with low muscle mass coexisted with low grip strength. Chi-square test was used to compare the prevalence difference between groups. Multivariate Logistic regression was used for correlation analysis. Results (1) The detection rate of low muscle mass in all participants was 14.0% (157/1 125), which was significantly higher in male than that in female (18.3% vs 9.3%, χ²=18.867, P<0.05). (2) The detection rate of low grip strength in all participants was 36% (405/1 125), which was significantly higher in male than that in female (50.3% vs 20.4%, χ²=109.183, P<0.05). (3) The prevalence of sarcopenia in all participants was 8.5% (96/1 125), which was significantly higher in male than that in female (12.8% vs 3.9%, χ²=28.509, P<0.05). The prevalence of sarcopenia were 4.4%(21/475), 8.9%(49/548), 25.5%(26/102) in middle aged group, young elderly group and elderly group, respectively (χ²=47.984, P<0.05). The sarcopenic prevalence in male was obviously higher than that in female in young elderly and elderly group (χ² = 9.872-16.325, all P<0.05). (4) Logistic regression analysis showed that men, aging, low body mass index (BMI) and high glycated hemoglobin A1c (HbA1c) were risk factors associated with sarcopenia. The risk of sarcopenia increased obviously in patients older than 75 years (OR=4.992, 95%CI: 2.448-10.179) or whose HbA1c was over 10%(OR=3.563, 95%CI:1.526-8.322). Conclusions The risk of low muscle mass and low muscle strength increases in aged and elderly patients with T2DM. Low BMI, aging, high HbA1c were risk factors associated with sarcopenia in elderly patients with T2DM. [ABSTRACT FROM AUTHOR]

The dynamics characteristics of piston ring are analyzed by using proprietary software AVL_EX-CITE Piston & Rings. A dynamics model for piston ring is set up with consideration of fluid dynamic lubrication between piston ring and cylinder liner. The contact forces between piston ring and cylinder liner are then calculated, based on which the wear of cylinder liner is predicted with its results basically agree with that of tests presented in some literatures. [ABSTRACT FROM AUTHOR]

The human spine injury and various lumbar spine diseases caused by vibration have attracted extensive attention at home and abroad. To explore the biomechanical characteristics of different approaches for lumbar interbody fusion surgery combined with an interspinous internal fixator, device for intervertebral assisted motion (DIAM), finite element models of anterior lumbar interbody fusion (ALIF), transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) are created by simulating clinical operation based on a three-dimensional finite element model of normal human whole lumbar spine. The fusion level is at L4-L5, and the DIAM is implanted between spinous process of L4 and L5. Transient dynamic analysis is conducted on the ALIF, TLIF and LLIF models, respectively, to compute and compare their stress responses to an axial cyclic load. The results show that compared with those in ALIF and TILF models, contact forces between endplate and cage are higher in LLIF model, where the von-Mises stress in endplate and DIAM is lower. This implies that the LLIF have a better biomechanical performance under vibration. After bony fusion between vertebrae, the endplate and DIAM stresses for all the three surgical models are decreased. It is expected that this study can provide references for selection of surgical approaches in the fusion surgery and vibration protection for the postsurgical lumbar spine.

Objective: To investigate clinicopathologic features of succinate dehydrogenase-deficient gastrointestinal stromal tumors (SDH-deficient GIST)., Methods: Immunohistochemical EnVision technique was used to assess the expression of succinate dehydrogenase subunit B (SDHB) in 192 cases of GIST. Cases of SDH-deficient GIST were further evaluated for the presence of CKIT exons 9, 11, 13 and 17 mutations and PDGFRA exons 12 and 18 mutations with clinical followed-up data., Results: Seven of the 192 cases showed SDHB-deficiency (3.6%, 7/192). The patients ranged in age from 35 to 84 years (median=56 years; mean=60 years). Four were male and three were female. Six tumors involved stomach and one involved mesentery. Histopathologic features of SDHB-deficient GIST included four cases of mixed-cell type and three of epithelioid cell type. The tumors commonly involved muscularis propria of the stomach as multiple nodules, creating a plexiform pattern. The tumors had high cellularity with cytoplasmic vacuolization. Five cases developed lymph node metastases including one also metastasizing to liver and pancreas. Two cases showed no evidence of metastasis. None of the 7 cases of the SDHB-deficient GIST had CKIT exons 9, 11, 13 and 17 mutations and PDGFRA exons 12 and 18 mutations. Three of the seven SDHB-deficient GIST cases had followed-up data: two did not recur and one died after 24 months of surgery of unknown cause., Conclusion: SDHB-deficient GIST has characteristic clinicopathologic features with wide-type CKIT gene and a favorable prognosis.

Objective: To explore the relationship between the sleep quality and diabetic autonomic neuropathy of elder patients with type 2 diabetes mellitus., Methods: A total of 90 elder patients with diabetes in Beijing Hospital was enrolled in this study. Questionnaires of Pittsburgh Sleep Quality Index(PSQI) were completed to evaluate the quality of sleep and Holter was applied to evaluate heart rate variability (HRV). Other related clinical data such as, catecholamine[epinephrine(E); norepinephrine(NE); dopamine(DA)]and diabetes complications were also collected after admission to the hospital. Patients were divided into three groups: the poor-sleeper group, the common-sleeper group and the good-sleeper group according to PSQI score. HRV and the level of catecholamine were compared among three groups., Results: The level of HRV including meanNN [(743 ± 58) ms vs(824 ± 99)ms and (837 ± 104)ms], ASDNN [(30 ± 10)ms vs (39 ± 14)ms and (41 ± 14)ms], very low frequency(VLF)[(15.33 ± 6.10)ms(2) vs(22.11 ± 7.94)ms(2) and (22.66 ± 7.87)ms(2)], low frequency (LF)[(8.30 ± 3.95) ms(2) vs(12.58 ± 6.11)ms(2) and(12.81 ± 6.96)ms(2)] and LF/high frequency(HF)[(1.23 ± 0.32) vs (1.56 ± 0.46) and (1.47 ± 0.42)] in the poor-sleeper group were lower than in both the common-sleeper group and good-sleeper group (all P<0.05). The level of catecholamine in poor-sleeper group [E: (108.91 ± 4.19)ng/L; NE: (1458.0 ± 50.35)ng/L] were lower than both the common-sleeper group [E: (120.23 ± 4.37) ng/L; NE: (1901.09 ± 131.36)ng/L] and the good-sleeper group [E: (118.23 ± 19.9)ng/L; NE: (1771.87 ± 116.73)ng/L] (all P<0.05), suggesting a dysfunction in autonomic nervous system in subject in the poor-sleeper group., Conclusion: Sleep quality is associated with the severity of diabetic autonomic neuropathy and might be one of clinical features for diabetic autonomic neuropathy.

To study the effect of preservation temperature on the characteristics of anaerobic ammonium oxidation (Anammox) granules and optimize the preservation temperature of Anammox granules, the Anammox granules were cultivated in an upflow anaerobic sludge bed reactor through adjusting the hydraulic retention times, and the inorganic carbon with KHCO3/NaHCO3 was alternately supplied. Subsequently, the enriched Anammox granules were preserved at -40, 4 and 35 °C, and ambient temperature of (27 ± 4) °C. NaHCO3 can be used as the inorganic carbon for the growth of anaerobic ammonium oxidizing bacterium (AnAOB). The best preservation temperature was 4 °C for maintaining Anammox biomass, Anammox activity, settleability, and the integrity of the Anammox granule and AnAOB cell structure. During the preservation period, the first-order exponential decay model can simulate the decay of Anammox biomass and activity, and the decay coefficients (bAN) of Anammox biomass and activity had positive correlation with the degree of AnAOB cell lysis. Meanwhile, the rate of Anammox biomass decay was larger than that of Anammox activity. The ratio of protein to polysaccharide in extracellular polymeric substances and heme c cannot effectively indicate the changes of Anammox granules settleability and activity, respectively, and the bioactivity has a negative association with the degree of AnAOB cell lysis.

Objective: To analyze the impact of atorvastatin on blood lipids and arterial media thickness (IMT) in new-onset type 2 diabetes patients., Methods: 333 patients, 30-70 years old and diagnosed within one year as type 2 diabetes, were selected from the Chinese Diabetes Complication Prevention Study (CDCPS) to take part in this study. Changes of blood lipids and IMT of carotid, femoral and iliac artery pre and post the administration of atorvastatin were tested and followed for 24 months., Results: Total cholesterol, triglycerides and low-density lipoprotein decreased significantly (P = 0.000) and maintained at a low level. The carotid artery IMT decreased significantly (P = 0.022) at the end of this study, but the femoral and iliac artery IMT did not show any obvious change. There were no serious adverse events noticed, during the study period., Conclusion: Long-term use of atorvastatin seemed to be safe and effective in reducing blood lipids in patients with type 2 diabetes thus could delay the development of atherosclerosis.

A detailed three-dimensional nonlinear finite element model of lumbar segment L3-L5 was developed to investigate the influence of vibration on the components of human spine. The results show that the vibration effects of different spinal components are not exactly the same, and the stress near the posterior region of L4-L5 annulus is higher than that of its anterior region. The vibration exerts a great influence on the facet joint of L4-L5 segment. The changing amplitudes of stress and deformation of spine reduce by 50% on the condition that the damping ratio is 0.08.

This study was intended to observe the biological properties of primary human embryonic skeletal myoblasts cultured in vitro and to inquire about the possible differentiation mechanism. Isolated human embryonic myoblasts were identified by morphology and myosin immunohischemical staining. The proliferating myoblasts were shifted to DM (DMEM supplemented with 3% fetal bovine serum) to induce differentiation. The control group was cultured in GM (DMEM supplemented with 10% fetal bovine serum). The differentiation was tested by the rate of myotube formation (RMF); The change of cell cycle was tested by flow cytometry; the morphological features were observed by use of inverted microscope and TEM. The myogenic regulatory factors (MRFs) such as MyoD, Myogenin and Myf5 were assayed by RT-PCR. Results showed that the primary myoblasts cultured in DM, in comparison with those cultured in GM, had higher rate of myotube formation (RMF) and myofilament formation, and more of the myoblasts cultured in DM exited the S phase. The expression level of Myogenin mRNA was obviously higher than that of the control group, the increase of MyoD mRNA expression level was not so high, however, the expression of Myf5 mRNA was decreased. These data indicate that there is a possible mechanism between differentiation and cell cycle. Besides, the mRNA expression of myogenic regulatory factors (MRFs) occurs in different phase of differentiating myoblastes and implicates the diverse biological function.

Objective: To evaluate the surgical outcomes of spinal tuberculosis treated with transpedicular instrumentation and interbody auto-grafting., Methods: Thirty-four patients of thoracolumbar tuberculosis were treated with transpedicular instrumentation, radical focus resection and interbody auto-grafting, combined with 6- or 9-month antituberculous medication from October 1996 to November 1998. All patients were followed-up prospectively for 3 to 5 years postoperatively., Results: The back pain and tuberculous symptoms were relieved about one week postoperatively. The erythrocyte sedimentation rate came back to normal level from 4 to 6 weeks postoperatively. The solid interbody arthodesis was achieved from 4 to 6 months postoperatively. All patients were cured of tuberculous lesions in spinal column or in other region, and there were no tuberculous recurrence. In 12 patients, average preoperative kyphosis angle was 24 degrees (range 10 degrees approximately 32 degrees ), and that was 9 degrees (range 5 degrees approximately 13 degrees ) immediately after surgery. The average correction of kyphotic deformity was 15 degrees and was maintained unchanged in follow-up period postoperatively. Nine patients who had type-C or type-D neurological lesions, according to Frankel gradation, had complete recovery one year postoperatively., Conclusion: In spinal tuberculous operation, transpedicular instrumentation and interbody fusion are essential in providing rigid stabilization of spinal column, correcting or preventing kyphotic deformity, accelerating focus healing up and shortening chemotherapy period. Transpedicular instrumentation is necessary in short segments fixation and preserving functional unit of spine.