Linuo Zhou

Saturated Orientational Polarization of Polar Molecules in Giant Electrorheological Fluids

Many researches on polar-molecular electrorheological (PMER) fluids with giant electrorheological effects were reported in recent years. The particles of PMER fluids (PMER particles) are known to have a dielectric core with high dielectric constant and a shell of polar molecules. Our calculation of local electric fields using the finite element approach shows that the local electric field can cause an orientational polarization of the polar molecules. The saturation of the orientational polarization occurs on the outer shells of two nearby PMER particles. Then, it causes the strong outer shell-outer shell interaction between the two particles, and this kind of interaction is just responsible for the giant electrorheological effect. It is further realized that the PMER effect is mainly due to the interaction of the tail-head connected polar molecules within the two outer shells between the two PMER particles. Our theoretical results of static yield stresses are shown to be in excellent agreement with the reported experimental data by several groups. For general PMER fluids, the calculated static yield stress is nearly proportional to R(x-1). When h/R, the ratio between the thickness of shells and radius of PMER particles, changes from 0.05 to 0.5, the index x changes accordingly from 0.64 to 0.51. It is also found that particles with thinner thickness h and smaller radius R have larger electrorheological effects until the static yield stress shows a peak when R reaches about 10 nm.

High prevalence of chronic kidney disease in population-based patients diagnosed with type 2 diabetes in downtown Shanghai

OBJECTIVE This study aimed to evaluate the prevalence of chronic kidney disease (CKD) and the risk factors associated with CKD among Chinese patients diagnosed with type 2 diabetes aged over 30 in downtown Shanghai and to assess the relationship between CKD and diabetic retinopathy (DR). METHODS We investigated 1039 Chinese patients diagnosed with type 2 diabetes aged over 30 by randomized cluster sampling in downtown Shanghai, and 1009 patients in this study were analyzed based on data integrity. Body measurements including height, weight, waist circumference and hip circumference, resting blood pressure, fasting blood measures, and urinary albumin-to-creatinine ratio (ACR), as well as the digitally stored fundus images, were investigated. Glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault equation. The prevalence of CKD was calculated, and the risk factors associated with CKD were evaluated using stepwise logistic regression. The relationship between CKD and DR was evaluated using Spearman correlation and the chi-square test. RESULTS The following were the results found in this study: (a) The prevalence rate of CKD (Stages 1-5) was 63.9% in Chinese patients diagnosed with type 2 diabetes, 8.8% in those with CKD Stage 1, 22.3% in those with CKD Stage 2, and 32.8% in those with CKD Stages 3-5 (GFR<60 ml/min/1.73 m(2)). The prevalence of CKD increased with age. (b) CKD patients were older and had higher duration of diabetes, systolic blood pressure, urea nitrogen, uric acid, creatinine, and ACR of the first urine than those without CKD. (c) Male patients had a higher percentage of CKD Stages 3-5, and female patients had a higher percentage of CKD Stages 1-2. (d) CKD was significantly associated with duration of diabetes, older age, systolic blood pressure, and serum urea nitrogen based on logistic regression analysis. (e) Of the patients without CKD, 15.6% had DR, and of those with CKD, 27.6% had DR. The decrease in GFR was significantly correlated with DR after controlling for sex, age, and albuminuria staging. CONCLUSION The high prevalence of CKD observed in Chinese patients diagnosed with type 2 diabetes aged over 30 in downtown Shanghai was similar to that in Western patients, and the cause of CKD is likely to be any of the following: type 2 diabetes, IgA nephropathy, hypertension, or any combination of these. The screening program for GFR in type 2 diabetic patients should be performed even on those with normoalbuminuria. The decrease in GFR might predict the occurrence of DR among patients diagnosed with type 2 diabetes.

Determination of Peripheral Neuropathy Prevalence and Associated Factors in Chinese Subjects with Diabetes and Pre-Diabetes – ShangHai Diabetic neuRopathy Epidemiology and Molecular Genetics Study (SH-DREAMS)

Objective This study determined the prevalence and factors associated with peripheral neuropathy (PN) in subjects with diabetes mellitus, impaired glucose regulation (IGR), and normal glucose tolerance (NGT) in a community-based Chinese population. Research Design and Methods A total of 2035 subjects in Shanghai were classified as having NGT, IGR, or diabetes. All subjects underwent complete foot examination. PN was assessed according to the neuropathy symptom and neuropathy disability scores. Binary logistic regression was performed to analyze the contributions of factors to PN. Results The prevalence of PN was 8.4%, 2.8%, and 1.5% in diabetes mellitus, IGR, and NGT subjects, respectively (P<0.05 for diabetes vs. NGT, and IGR). The subjects with known diabetes had the highest frequency of PN (13.1%). Among the subjects without diabetes, those with PN were older, had a higher waist circumference and 2-h postprandial plasma glucose levels, and were more likely to be hypertensive. Among the IGR subjects, other than age, the 2-h postprandial plasma glucose level was an independent factor significantly associated with PN. Meanwhile, among the subjects with diabetes, PN was associated with fasting plasma glucose, duration of diabetes, and decreased estimated glomerular filtration rate. Conclusions The prevalence of PN is slightly higher in individuals with IGR than that in individuals with NGT, but small fibre damage in IGR as the earliest nerve fibre deficit may be underestimated in our study. As an independent risk factor, postprandial plasma glucose level may be an important target for strategies to prevent or improve PN in IGR subjects.

Prevalence, incidence and risk factors of chronic heart failure in the type 2 diabetic population: systematic review.

OBJECTIVES The aim of this review was to examine the prevalence, incidence and risk factors of chronic heart failure in the type 2 diabetic population. METHODS A systematic search of studies related to chronic heart failure (CHF) in the diabetic population was performed using medical databases. RESULTS 1) The prevalence of CHF in the diabetic population was approximately 10-23% in the large previously studied cohort. This was about three times higher than in non-diabetic control groups. 2) The incidence of CHF in diabetes varied greatly. It was influenced by the time of follow-up, the mean age of patients, the state of metabolic control and the complications of diabetes. The incidence of CHF in patients with diabetes was approximately two-fold greater than in the non-diabetic population. 3) The main risk factors of CHF in the type 2 diabetic population were age, hemoglobin A1c (HbA1c), coronary heart disease, hypertension, microalbuminuria and obesity. CONCLUSIONS The prevalence and incidence of CHF were found to be high in the diabetic population, and the risk factors of CHF were somewhat different from those in the general population.

Reduction of the buckling strength of carbon nanotubes resulting from encapsulation of C60 fullerenes

The effect of encapsulation of C60 fullerenes upon the buckling strength of hosting carbon nanotubes (CNTs) has been investigated, using molecular dynamics (MD) simulations. The simulation results show that encapsulating C60 fullerenes into some CNTs with diameters larger than that of the (10, 10) CNT, in particular the (14, 14) and (18, 18) CNTs, significantly reduces the buckling strength, in contrast to the conventional wisdom that fillings increase the mechanical strength of hollow structures. The simulations have also confirmed the previous findings that filling a (10, 10) CNT with C60 increases the buckling strength. Our detailed analysis reveals that the interaction between the C60 fullerenes and the hosting (10, 10) CNT is cylindrically symmetric, while the presence of a zigzag array of C60 inside the (14, 14) CNT breaks the cylindrical symmetry and so does the presence of the three arrays of C60 inside the (18, 18) CNT. The induced asymmetries cause one peak for the C60@(14, 14) system and three peaks for the C60@(18, 18) system in the corresponding force distribution along the circumferential direction. The force concentration leads to observed reduction in the buckling strength. The reduction is more severe for C60@(14, 14) than for C60@(18, 18), because the force distribution of the former system is more asymmetric.

Polar-molecules-driven enhanced colloidal electrostatic interactions and their applications in achieving high active electrorheological materials

We have fabricated a class of colloidal electrorheological (ER) fluids, in which suspended TiO2 particles were synthesized by a sol-gel method and modified by 1,4-butyrolactone molecules with a permanent molecular dipole moment of 4.524 D. Compared with pure TiO2 ER fluids, the quasi-static yield stress of the polarmolecules-modified ER fluid is enhanced as high as 48.1 kPa when subjected to an external electric field of 5 kV/mm. Also, it possesses other attractive characters such as low current density (<14 A/cm) and low sedimentation. Based on a Green’s function method, we present a first-principles approach to investigate colloidal electrostatic interactions. Excellent agreement between experiment and theory has been shown for the enhancement ratio of quasi-static yield stress, which quantitatively reveals that enough polar molecules oriented within the field-directed gap between the colloidal particles can unexpectedly enhance the interactions, thus yielding the unusual enhancement. This shows a promising and flexible direction for achieving more highly active ER materials.

Autonomic nervous function and baroreflex sensitivity in hypertensive diabetic patients

Objective Little is known about how the cardiac autonomic nervous function (CAN) changes with gradually increasing systolic blood pressure (SBP). This study investigated cardiac autonomic nervous function in diabetic patients and controls with different grades of SBP. Methods and results We measured heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS) by power spectral analysis in 118 Chinese type-2 diabetic patients and 137 age-matched controls. Subjects were further subdivided into 4 SBP groups. Results showed total HRV and BRS values were significantly lower in several diabetic SBP groups. Total HRV and BRS decreased with increasing SBP, with significant differences in the 140-159 mm Hg or 160-179 mm Hg groups compared with other groups of diabetic and control subjects. Conclusions We found that HRV and BRS can reflect cardiovascular autonomic dysfunction of diabetes when accompanied by hypertension. In our selected Chinese diabetic and control subjects, HRV and BRS parameters were influenced by gradually increasing SBP.

Comparison of Prediction Model for Cardiovascular Autonomic Dysfunction Using Artificial Neural Network and Logistic Regression Analysis

Background This study aimed to develop the artificial neural network (ANN) and multivariable logistic regression (LR) analyses for prediction modeling of cardiovascular autonomic (CA) dysfunction in the general population, and compare the prediction models using the two approaches. Methods and Materials We analyzed a previous dataset based on a Chinese population sample consisting of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN and LR analysis, and were tested in the validation set. Performances of these prediction models were then compared. Results Univariate analysis indicated that 14 risk factors showed statistically significant association with the prevalence of CA dysfunction (P<0.05). The mean area under the receiver-operating curve was 0.758 (95% CI 0.724–0.793) for LR and 0.762 (95% CI 0.732–0.793) for ANN analysis, but noninferiority result was found (P<0.001). The similar results were found in comparisons of sensitivity, specificity, and predictive values in the prediction models between the LR and ANN analyses. Conclusion The prediction models for CA dysfunction were developed using ANN and LR. ANN and LR are two effective tools for developing prediction models based on our dataset.

Relationship between N-terminal pro-B-type natriuretic peptide levels and metabolic syndrome.

Introduction Previous studies have shown that obese individuals have reduced natriuretic peptide levels. But conflicting data exist on the relation of natriuretic peptide levels to other metabolic risk factors. Material and methods We investigated the relationship between plasma N-terminal pro-B-type natriuretic peptide levels (NT-proBNP) and metabolic syndrome (MetS) and metabolic risk factors in 469 patients free of heart failure. Two hundred thirty diagnosed MetS cases and 239 non-MetS cases were included in this study. Echocardiography examinations were performed and left ventricular mass index was calculated according to the Devereux correction formula. NT-proBNP was measured by electrochemiluminescence. The log-transformed NT-proBNP levels were used for abnormal distribution. Multiple linear regression analysis was performed to assess the association between levels of NT-proBNP and metabolic factors. Covariance analysis was used for group comparisons. Results Log NT-proBNP levels were independently related to age, gender, body mass index, systolic blood pressure, diastolic blood pressure, fasting blood glucose, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol, left ventricular mass index and left ventricular ejection fraction in multiple linear regression analysis (p < 0.05). Adjusted log NT-proBNP levels were lower in persons with MetS compared with those without MetS (p < 0.05). Individuals with hyperlipidaemia, elevated body mass index, diastolic blood pressure and fasting plasma glucose had lower levels of log NT-proBNP than those without MetS (p < 0.05). Conclusions There is a relationship between metabolic components and lower plasma NT-proBNP concentration. These findings raise the possibility that reduced plasma NT-proBNP levels are a manifestation of MetS, which might possess significant clinical and pathophysiological implications.

Performance and comparison of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease formulae in estimating glomerular filtration rate in a Chinese Type 2 diabetic population.

Aims  Our aim was to assess performances of the Cockcroft–Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks.