Application of Ni/SiCw Composite Material in MEMS Microspring.

The microspring is a typical type of device in MEMS devices, with a wide range of application scenarios and demands, among which a popular one is the microelectroformed nickel-based planar microspring prepared by the UV-LIGA technology based on the SU-8 adhesive. It is worth noting that the yield strength of the electrodeposited nickel microstructure is low, and the toughness of the structure is not high, which is unbeneficial for the enduring and stable operation of the spring. The paper mainly presents the methods of preparing high-aspect-ratio Ni/SiCw microstructures for MEMS devices based on UV-LIGA technology, developing Ni/SiCw-based microspring samples with a thickness of 300 µm, and applying a DMA tensile tester for mechanical property tests and characterization. In addition, the paper explores the influence of heat treatment at 300 °C and 600 °C on the tensile properties and microstructure of composite coatings. The results show that the W-form microspring prepared from Ni/SiCw composites not only has a wider linear range (about 1.2 times wider) than that of pure nickel material but also has a stronger resistance capacity to plastic deformation, which is competent for MEMS device applications in environments below 300 °C. The research provides a frame of reference and guidance for improving the stable cyclic operating life of such flat springs.

Engineered Switchable-Wettability Surfaces for Multi-Path Directional Transportation of Droplets and Subaqueous Bubbles.

Conventional engineered surfaces for fluid manipulation are hindered by the set wettability, and thus they can only achieve spontaneous transport of single-phase fluid, namely liquid or gas. Moreover, fluid transport systems that are robust to path defects have yet to be fully explored. Here, unprecedentedly, a universal wettability switching strategy is developed for achieving programmable directional transport of both droplets and subaqueous bubbles on a dumbbell-patterned functional surface (DPFS), featuring in strong robustness, high efficiency, and effective cost. By tuning the superwettability of DPFS through octadecyltrichlorosilane treatment and ultraviolet-C selective irradiation, the transport fluid can alternate between liquid and gas. The material's switchable superwettability regulates the fluid directed dynamics within the confined pattern, in which the sustaining fluid propelling relies on the surface energy difference between the starting and terminal sites. This enables the construction of multiple channels, which works synergistically with ultralow-volume-loss transport to impart the fluidic system with strong robustness against path defects. Underlying the completion of complex microfluidics tasks, spatially-selective cooling devices and subaqueous gas microreactors are successfully demonstrated. This energy-consumption-free fluid transport system opens a new avenue for on-chip programmable fluid manipulation, promoting innovative applications requiring rational control of two-phase fluid transport.

Pain in neuromyelitis optic spectrum disorder.

BACKGROUND: Pain is a common symptom of neuromyelitis optica spectrum disorder (NMOSD), but there are relatively few studies on NMOSD pain. METHODS: We retrospectively reviewed the medical records of 145 patients with NMOSD admitted to our hospital between July 2016 and June 2019. RESULTS: The clinical characteristics of pain and factors related to NMOSD were analyzed, revealing that the incidence of pain in NMOSD is high and can be used for disease localization. CONCLUSION: Different types of pain occur at different stages of the disease, and serum aquaporin-4 antibody (AQP4-ab) positivity is an independent risk factor for NMOSD pain. Hormones and biological immune agents may also be effective in some cases.

High-Performance Directional Water Transport Using a Two-Dimensional Periodic Janus Gradient Structure.

Numerous materials in micro- or nanoscale hierarchical structures with surface gradients serve as the enablers in directional liquid transportation. However, concurrent high-speed and long-range liquid transport is yet to be fully realized so far. Here, an overall-improved approach is achieved in both water transport distance and velocity aspects using a 2D periodic Janus gradient structure, which is inspired by the Janus-wettable desert beetle back, tapered asymmetric cacti spine, and periodic Nepenthes alata microcavity. This 2D channel can efficiently regulate the kinetics of liquid transport within its confined structure, in which the terminal potential well and periodic Janus topological structure enable sustaining water propelling through a long distance. In addition, the rapidly formed aqueous film facilitates a high initial momentum and fast transport of liquid droplets along the channel, achieving an averaged velocity of over 400 mm s-1 and a maximum normalized transport distance of 23.4 for a 3 µL droplet, as well as an ultralow liquid volume loss of 6.02% upon high-flux water transport. This scalable, controllable, and easy-fabricable 2D water transport system provides an insightful pathway in realizing high-performance water manipulation and possibly facilitates substantial innovative applications in multidisciplinary fields.

UCP1 modulates immune infiltration level and survival outcome in ovarian cancer patients.

BACKGROUND: The uncoupling proteins (UCPs) are critical genes associated with tumorigenesis and chemoresistance. However, little is known about the molecular mechanism of the UCPs in ovarian cancer (OV). MATERIAL AND METHODS: UCPs expression analysis was conducted using Gene Expression Profiling Interactive Analysis (GEPIA), and its potential in clinical prognosis was analyzed using Kaplan- Meier analyses. The influence of UCPs on immune infiltration was analyzed by TIMER. In addition, the correlation between UCPs expression and molecular mechanisms was investigated by TIMER and Cancer Single-cell State Atlas (CancerSEA). RESULTS: UCP1, UCP2, UCP3 and UCP5 expression levels correlated with a favorable prognosis and tumor progression. Moreover, UCP1 expression correlated to several immune cell markers and regulated tumorigenesis, such as tumor invasion, EMT, metastasis and DNA repair. In addition, UCP1 potentially involved in genes expression of SNAI2, MMP2, BRCA1 and PARP1. CONCLUSIONS: These results implied a critical role of UCP1 in the prognosis and immune infiltration of ovarian cancer. In addition, UCP1 expression participated in regulating multiple oncogenes and tumorigenesis.

Factors Influencing the Degree of Disability in Patients With Multiple Sclerosis.

Objective: To explore the factors influencing the degree of disability in patients with multiple sclerosis (MS), and to provide evidence for its early diagnosis, prognostic evaluation and clinical intervention. Methods: This retrospective observational study included 72 patients with relapsing-remitting multiple sclerosis (RRMS) at the First Hospital of Shanxi Medical University. All patients completed craniocerebral and spinal cord MRI (with or without Gd enhancement) and were evaluated for Expanded Disability Status Score (EDSS) scores before receiving treatment. Results: Among 72 patients with RRMS, 45 (62.5%) had an EDSS score ≤3; A total of 27 patients (37.5%) had an EDSS score >3 points. Univariate analysis showed that age, annual recurrence rate (ARR), drug use, albumin (ALB), triglycerides (TG), and total number of lesions in groups with EDSS score ≤3 were significantly different from those with an EDSS score > 3 points (P < 0.05). Multivariate logistic regression analysis showed that ALB, total number of lesions, and drug use were independent influencing factors of the degree of disability in patients with MS, and the difference was statistically significant (P < 0.05). An ROC curve was constructed using ALB and the total number of lesions. The AUC of ALB was 0.681, P < 0.05, and the best cut-off value was 44.2 g/L. Its sensitivity to predict the degree of disability in patients with multiple sclerosis was 85.2%, while its specificity was 51.1%. The AUC of the total number of lesions was 0.665 (P < 0.05) and the best cut-off value was 5.5. Its sensitivity to predict the degree of disability in patients with multiple sclerosis was 70.4%, while its specificity was 64.4%. The AUC of the combined ALB, total number of lesions, and drug use was 0.795 (P < 0.05), sensitivity was 77.8, and specificity was 73.3%. The optimal diagnostic cut-off value of the regression equation for the EDSS score of patients with multiple sclerosis was 0.420. Conclusion: Serum ALB, total number of lesions, and drug use in patients with multiple sclerosis were independent factors influencing the degree of disability. These findings provide clinical evidence for the prognostic evaluation and early intervention of patients with multiple sclerosis.

Polydopamine/graphene/MnO2 composite-based electrochemical sensor for in situ determination of free tryptophan in plants.

The in vivo detection of small active molecules in plant tissues is essential for the development of precision agriculture. Tryptophan (Trp) is an important precursor material for auxin biosynthesis in plants, and the detection of Trp levels in plants is critical for regulating the plant growth process. In this study, an electrochemical plant sensor was fabricated by electrochemically depositing a polydopamine (PDA)/reduced graphene oxide (RGO)-MnO2 nanocomposite onto a glassy carbon electrode (GCE). PDA/RGO-MnO2/GCE exhibited high electrocatalytic activity for the oxidation of Trp owing to the combined selectivity of PDA and catalytic activity of RGO-MnO2. To address the pH variability of plants, a reliable Trp detection program was proposed for selecting an appropriate quantitative detection model for the pH of the plant or plant tissue of interest. Therefore, a series of linear regression curves was constructed in the pH range of 4.0-7.0 using the PDA/RGO-MnO2/GCE-based sensor. In this pH range, the linear detection range of Trp was 1-300 µM, the sensitivity was 0.39-1.66 µA µM-1, and the detection limit was 0.22-0.39 µM. Moreover, the practical applicability of the PDA/RGO-MnO2/GCE-based sensor was successfully demonstrated by determining Trp in tomato fruit and juice. This sensor stably and reliably detected Trp levels in tomatoes in vitro and in vivo, demonstrating the feasibility of this research strategy for the development of electrochemical sensors for measurements in various plant tissues.

Research on a New Type of Rigid-Flexible Coupling 3-DOF Micro-Positioning Platform.

A new type of rigid-flexible coupling three degrees of freedom (3-DOF) micro-positioning platform with high positioning accuracy and high bearing capacity is developed, which consists of flexible drive mechanism and rigid platform. The flexible drive mechanism consists of three sets of symmetrical parallel round flexible hinge structures, each with a wedge structure in the middle of the symmetrical parallel flexible hinge. The rigid platform has an inclined plane with the same angle as the wedge, while the wedge structure is used to achieve the self-locking effect. The flexibility matrix method and ANSYS are used to analyze the statics of the flexible drive mechanism. The first four natural frequencies of the platform are obtained by dynamic simulation analysis. A symmetrical rigid flexible coupling micro-positioning platform experimental system is developed. Output characteristics, positioning accuracy, relationship between frequency and amplitude, and bearing performance of the micro-positioning platform are tested. These experimental results obviously show that the micro-positioning platform has good motion characteristics, high positioning accuracy, large movement distance, and large load bearing capacity performance.

Effects of Anisotropy on Single Crystal Silicon in Polishing Non-Continuous Surface.

A molecular dynamics model of the diamond abrasive polishing the single crystal silicon is established. Crystal surfaces of the single crystal silicon in the Y-direction are (010), (011), and (111) surfaces, respectively. The effects of crystallographic orientations on polishing the non-continuous single crystal silicon surfaces are discussed from the aspects of surface morphology, displacement, polishing force, and phase transformation. The simulation results show that the Si(010) surface accumulates chips more easily than Si(011) and Si(111) surfaces. Si(010) and Si(011) workpieces are deformed in the entire pore walls on the entry areas of pores, while the Si(111) workpiece is a local large deformation on entry areas of the pores. Comparing the recovery value of the displacement in different workpieces, it can be seen that the elastic deformation of the A side in the Si(011) workpiece is larger than that of the A side in other workpieces. Pores cause the tangential force and normal force to fluctuate. The fluctuation range of the tangential force is small, and the fluctuation range of the normal force is large. Crystallographic orientations mainly affect the position where the tangential force reaches the maximum and minimum values and the magnitude of the decrease in the tangential force near the pores. The position of the normal force reaching the maximum and minimum values near the pores is basically the same, and different crystallographic orientations have no obvious effect on the drop of the normal force, except for a slight fluctuation in the value. The high-pressure phase transformation is the main way to change the crystal structure. The Si(111) surface is the cleavage surface of single crystal silicon, and the total number of main phase transformation atoms on the Si(111) surface is the largest among the three types of workpieces. In addition, the phase transformation in Si(010) and Si(011) workpieces extends to the bottom of pores, and the Si(111) workpiece does not extend to the bottom of pores.

The Blood Gene Expression Signature for Kawasaki Disease in Children Identified with Advanced Feature Selection Methods.

Kawasaki disease (KD) is an acute vasculitis, accompanied by coronary artery aneurysm, coronary artery dilatation, arrhythmia, and other serious cardiovascular diseases. So far, the etiology of KD is unclear; it is necessary to study the molecular mechanism and related factors of KD. In this study, we analyzed the expression profiles of 75 DB (identifying bacteria), 122 DV (identifying virus), 71 HC (healthy control), and 311 KD (Kawasaki disease) samples. 332 key genes related to KD and pathogen infections were identified using a combination of advanced feature selection methods: (1) Boruta, (2) Monte-Carlo Feature Selection (MCFS), and (3) Incremental Feature Selection (IFS). The number of signature genes was narrowed down step by step. Subsequently, their functions were revealed by KEGG and GO enrichment analyses. Our results provided clues of potential molecular mechanisms of KD and were helpful for KD detection and treatment.

A New Approach to Decoupled Non-Resonant Polishing.

Two-dimensional vibration-assisted polishing (2D-VAP) is a new polishing approach proposed in recent years, which is considered to be very suitable for the polishing of micro-optical parts and micro-structured surfaces. The advantages of the 2D-VAP approach are as follows: A very high relative velocity can be obtained between the workpiece and the polishing tool; the desired motion trajectory can be formed in one polishing cycle. However, there are still some problems to be solved in the 2D-VAP approach, mainly involving: The vibration frequency of the resonant excitation cannot be regulated, which makes it difficult to adapt to the processing demands of different materials; the theoretical model of removal function has been studied in few papers; and motion coupling occurs easily between the horizontal and vertical directions, which affects the trajectory synthesized at the polishing tool. In order to solve these problems, a new approach to decoupled non-resonant polishing is developed in this paper, and its effectiveness is investigated by the theoretical analysis and polishing experiments. Theoretical studies of removal function show that the vibration frequency, vibration amplitude and loading force are proportional to the removal depth. The comparison of experimental and modeling results of removal function show that they have good coherence, and the correctness of the theoretical model of removal function is verified. In addition, the stability experiments of removal function prove that the polishing approach has better stability and is beneficial to the convergence of workpiece surface.

Research on a 3-DOF Motion Device Based on the Flexible Mechanism Driven by the Piezoelectric Actuators.

This paper describes the innovative design of a three-dimensional (3D) motion device based on a flexible mechanism, which is used primarily to produce accurate and fast micro-displacement. For example, the rapid contact and separation of the tool and the workpiece are realized by the operation of the 3D motion device in the machining process. This paper mainly concerns the device performance. A theoretical model for the static performance of the device was established using the matrix-based compliance modeling (MCM) method, and the static characteristics of the device were numerically simulated by finite element analysis (FEA). The Lagrangian principle and the finite element analysis method for device dynamics are used for prediction to obtain the natural frequency of the device. Under no-load conditions, the dynamic response performance and linear motion performance of the three directions were tested and analyzed with different input signals, and three sets of vibration trajectories were obtained. Finally, the scratching experiment was carried out. The detection of the workpiece reveals a pronounced periodic texture on the surface, which verifies that the vibration device can generate an ideal 3D vibration trajectory.

[Correlation between cerebrovascular hemodynamic index accumulative score and subclinical arteriosclerosis indicators].

OBJECTIVE: To explore the correlation between cerebrovascular hemodynamic index (CVHI)accumulative score and subclinical arteriosclerosis indicators.
 Methods: A total of 27 184 cases were collected from the Health Management Center, the Third Xiangya Hospital, Central South University. Linear regression analysis was carried out to confirm the correlations between CVHI accumulative score and the modified Framingham stroke profile (FSP), as well as between CVHI accumulative score and cerebrovascular diseases (ICVD) scale. The correlation between CVHI accumulative score and brachial-ankle pulse wave velocity (baPWV), carotid plaque orcarotid intima-media thickness (CIMT) was analyzed by multifactor logistic regression model in 11 580 cases. Moreover, the correlation between CVHI accumulative score and microalbuminuria or serum cystatin C was performed by multifactor logistic regression model in 9 860 cases.
 Results: In this study, the people whose CVHI accumulative score was less than 75 accounted for 12.98%. The CVHI accumulative score was negatively related with the modified FSP score (r=-0.484, P<0.01) or ICVD score (r=-0.455, P<0.01). The multifactor logistic regression model found that the baPWV, carotid plaque, microalbuminuria and serum cystatin C were independent predictors for CVHI accumulative score.
 Conclusion: The CVHI accumulative score is correlated with the modified FSP score, ICVD score and indexes of subclinical arteriosclerosis (baPWV, carotid plaque, microalbuminuria and serum cystatin C). The CVHI accumulative score could be used as a tool for zero-level and primary prevention of cerebral stroke.

Effectiveness of low dose of rituximab compared with azathioprine in Chinese patients with neuromyelitis optica: an over 2-year follow-up study.

Neuromyelitis optical (NMO) and neuromyelitis optical spectrum disorder (NMOSD) are inflammatory autoimmune demyelination diseases affecting the central nervous system. We investigated the efficiency of low-dose rituximab treatment in 31 Chinese patients with NMO/NMOSD across a median period of 2.29 ± 0.97 years and azathioprine combined with corticosteroid treatment in 34 Chinese patients with NMO/NMOSD across a median period of 2.61 ± 0.94 years. Among the rituximab-treated patients, the mean Expanded Disability Status Scale (EDSS) was 5.62 ± 1.35 before treatment and 4.48 ± 0.78 at last follow-up, and the mean annualized relapse rate (ARR) was 1.39 ± 0.42 before treatment and 0.03 ± 0.13 at last follow-up. Among the azathioprine-treated patients, the mean EDSS was 5.63 ± 1.29 before treatment and 5.05 ± 1.00 at last follow-up, and the mean ARR was 1.28 ± 0.34 before treatment and 0.49 ± 0.21 at last follow-up. In this study, we showed that using low-dosage rituximab could benefit Chinese patients with NMO by reducing the new occurrence of relapses dramatically. Compared with the azathioprine-treated patients, we concluded that rituximab is more effective in preventing NMO relapse and could improve the symptoms.

Accumulative effects of indoor air pollution exposure on leukocyte telomere length among non-smokers.

Indoor air pollution is an important environmental factor that contributes to the burden of various diseases. Long-term exposure to ambient air pollution is associated with telomere shortening. However, the association between chronic indoor air pollution from household fuel combustion and leukocyte telomere length has not been studied. In our study, 137 cancer-free non-smokers were recruited. Their exposure levels to indoor air pollution from 1985 to 2014 were assessed using a face-to-face interview questionnaire, and leukocyte telomere length (LTL) was measured using a monochrome multiplex quantitative PCR method. Accumulative exposure to solid fuel usage for cooking was negatively correlated with LTL. The LTL of residents who were exposed to solid fuel combustion for three decades (LTL = 0.70 ± 0.17) was significantly shorter than that of other populations. In addition, education and occupation were related to both exposure to solid fuel and LTL. Sociodemographic factors may play a mediating role in the correlation between leukocyte telomere length and environmental exposure to indoor air pollution. In conclusion, long-term exposure to indoor air pollution may cause LTL dysfunction.

Anisotropy of Single-Crystal Silicon in Nanometric Cutting.

The anisotropy exhibited by single-crystal silicon in nanometric cutting is very significant. In order to profoundly understand the effect of crystal anisotropy on cutting behaviors, a large-scale molecular dynamics model was conducted to simulate the nanometric cutting of single-crystal silicon in the (100)[0-10], (100)[0-1-1], (110)[-110], (110)[00-1], (111)[-101], and (111)[-12-1] crystal directions in this study. The simulation results show the variations of different degrees in chip, subsurface damage, cutting force, and friction coefficient with changes in crystal plane and crystal direction. Shear deformation is the formation mechanism of subsurface damage, and the direction and complexity it forms are the primary causes that result in the anisotropy of subsurface damage. Structurally, chips could be classified into completely amorphous ones and incompletely amorphous ones containing a few crystallites. The formation mechanism of the former is high-pressure phase transformation, while the latter is obtained under the combined action of high-pressure phase transformation and cleavage. Based on an analysis of the material removal mode, it can be found that compared with the other crystal direction on the same crystal plane, the (100)[0-10], (110)[-110], and (111)[-101] directions are more suitable for ductile cutting.

Heat transfer and friction characteristics of the microfluidic heat sink with variously-shaped ribs for chip cooling.

This paper experimentally and numerically investigated the heat transfer and friction characteristics of microfluidic heat sinks with variously-shaped micro-ribs, i.e., rectangular, triangular and semicircular ribs. The micro-ribs were fabricated on the sidewalls of microfluidic channels by a surface-micromachining micro-electro-mechanical system (MEMS) process and used as turbulators to improve the heat transfer rate of the microfluidic heat sink. The results indicate that the utilizing of micro-ribs provides a better heat transfer rate, but also increases the pressure drop penalty for microchannels. Furthermore, the heat transfer and friction characteristics of the microchannels are strongly affected by the rib shape. In comparison, the triangular ribbed microchannel possesses the highest Nusselt number and friction factor among the three rib types.

Community-wide survey of physicians' knowledge of cholesterol management.

BACKGROUND: An elevated serum lipid is one of the major risk factors for coronary heart disease (CHD). Physicians' awareness contributes to successful adoption of practice guidelines. Community medical centers are the primary defense against chronic disease. This study aimed to investigate community physicians' awareness of cholesterol guidelines and their utilization. METHODS: Six hundred and one community physicians were randomly selected from four different regions, and completed a confidential and semi-structured questionnaire. Four hundred and ninety-one completed the questionnaire, and 486 valid questionnaires were available. RESULTS: The physicians' fundamental knowledge of lipids was astonishingly poor, while the awareness of cholesterol guidelines was low. Only 24% and 14% of the physicians reported the right optimal low-density lipoprotein cholesterol (LDL-C) level for CHD and diabetes patients respectively. More than half of the physicians (55.8%) mistakenly considered elevated transaminases to be the lethal side effect of statins. More than half of the physicians (51.9%) would give up statin treatment in the case of transaminase elevation. CONCLUSION: Educational interventions to improve cholesterol knowledge and to publicize standard treatment are needed among Chinese community physicians.

[Prevalence of dyslipidemia and borderline dyslipidemia and other risk factors of coronary heart disease in residents from Beijing communities].

OBJECTIVE: To investigate the prevalence of dyslipidemia and borderline dyslipidemia and other coronary heart disease (CHD) risk factors in residents from Beijing communities. METHODS: Resident samples were selected by random cluster multistage method. Serum lipid level and CHD factors were obtained through questionnaire, physical examination and biochemical analysis during June 2007 to August 2007 from 10 054 residents. RESULTS: Age- and sex-adjusted standardized prevalence of hypercholesterolemia, high low-density lipoprotein cholesterolemia, low high-density lipoprotein cholesterolemia, and triglyceridemia were 9.3%, 2.56%, 18.79% and 16.84%, respectively. Incidence of borderline hypercholesterolemia was 23.96%. Incidence of dyslipidemia and borderline dyslipidemia was 31.23% and 23.30% respectively, 71.17% residents have at least 1 CHD major risk factor and 20.23% residents were in borderline CHD risks. Prevalence of hypertension, diabetes, smoking and obese was 41.57%, 11.08%, 35.81% and 22.89%, respectively. The odds ratio for dyslipidemia (95% confidence interval) in residents having 1 borderline CHD risk factor (RF), 2 RF, and 3 RF versus none RF was 1.668, (95%CI: 1.319 - 2.110), 2.537 (95%CI: 1.989 - 3.235), and 3.203 (95%CI: 2.007 - 5.114). CONCLUSIONS: The prevalence of dyslipidemia of residents from Beijing communities is higher the average level of China (25.1%). Over 1 out of 5 residents were in increased risk for borderline dyslipidemia or CHD risks. Intensive control of dyslipidemia and CHD risk factors are warranted in Beijing residents.

[The smoking status of patients with acute coronary syndrome and effect of simple intervention on smoking cessation.].

OBJECTIVE: To evaluate the abstinence rate and relapse rate of smoker with ACS after discharged from hospital, to evaluate the effect of simple smoking cessation interventions. METHODS: 150 smokers with ACS were collected and was divided into simple intervention group (n = 87) and control group (n = 63), respectively, followed up for 6 months. 2 months, 6 months abstinence rate, relapse rate were compared between two groups, logistic regression model was used to analyzed the relevant factors for relapse. RESULTS: The smoking rate in patients with ACS was 31.14%, 6-month continuous abstinence rate and 6-month relapse rate was 64.6%, 36.4%, respectively. 6-month continuous abstinence rate and relapse rate between simple quit-smoking intervention group and control group showed no difference. Nicotine dependence score more than 4 points can be used as predictor of relapse. CONCLUSIONS: The smoking rate and the abstinence rate of smoker with ACS is higher than the general population, simple quit-smoking intervention do not increase the success rate of quit-smoking, indicated the need to strengthen the intervention in patients with ACS and smoking.