Electrochemical behaviors of single microcrystals of iron Hexacyanides/NaCl solid solution.

Solid-state solution with excellent ionic conductivity and redox activity has potential applications in electrochemical microdevices, such as transistors, switches, sensors, and actuators, due to its controllable assembly, integration, and package in microchips. In this paper, we present an electrochemical method to synthesize single microcrystals of an iron hexacyanides/NaCl solid solution and to assemble them into microdevices based on scanning electrochemical cell microscopy. The redox behaviors of the single microcrystals were investigated systematically, especially in the "all-in-solid-state", that is, without exposure to any external liquid environment. The unique metal/solid solution interface has similar electrochemical properties as the conventional metal/liquid solution interface. The apparent concentration of ion hexacyanides (1.05 × 10(-3) mol/L), the diffusion coefficient of the counterion Na(+) (8.05 × 10(-8) cm(2)/s), and the electron transfer rate in the lattice (1.22 × 10(-4) cm/s) were evaluated from the data obtained through all-in-solid-state cyclic voltammetry and electrochemical impedance. All the results are comparable to the conventional metal/solution theory of electrochemistry.

Identifying mass transfer influences on Au nanoparticles growth process by centrifugation.

A comparative study of gold nanoparticles (Au NPs) growth employing cetyltrimethylammonium bromide (CTAB) adsorbent was performed. Au nanooctahedrons transformed into slightly truncated nanocubes without centrifugation, whereas they transformed into nanocubes with centrifugation. Our results indicate that the mass transfer of Au monomers can influence the shape evolution of NPs.

[An efficient method for simulating ventricular electrical activity based on anatomic structure by incorporating AP model].

Conventional medical experiments can hardly simulate cardiac excitation propagation and observe the evolvement of cardiac electrical activities firsthand as is possible with computer simulation. Based on the anatomic structure of the heart, simulation of cardiac electrical activity mainly consists of the emulation of the excitation process among the cardiac cells and calculation of the electrical activities of individual cardiac cells. In this study we establish a geometric ventricular structure model demonstrating the direction of the cardiac muscle fibers and the layers of the ventricular cells, and endow different action potential models to the ventricular cells of different layers, and observe the activation process of the ventricular parts in view of the three-dimensional anatomy. This method gives attention to both enough calculation amounts and efficiency, which achieves satisfactory simulation results of ventricular electrical activity based on the anatomic structure and cell electrophysiology through an improved algorithm on personal computer.

[Some insights into clinical detection and analysis of serum lipoprotein for studies on integrated traditional Chinese and western medicine].

Dyslipoproteinemia is correlated with the occurrence and development of atherosclerosis and cardiocerebral vascular diseases. The metabolism of serum lipoprotein, however, is a complicated and ordered metabolic process. On one hand, every organ, tissue and even cell of the body participates in and affects the state of serum lipoprotein dynamic balance (SLDB) in different degrees. On the other hand, SLDB is a direct factor for maintaining the normality of whole vascular system, especially the vascular endothelium system. The serum lipoprotein dynamic imbalance, as an inducement or even etiological factor, can bring about various clinical diseases. Therefore, integrated analysis is needed to appropriately assess the state of SLDB. It is suggested that serum lipoprotein dynamic imbalance syndrome should be the key risk factor for those related diseases. Serum lipoprotein electrophoretogram can ideally express the state of SLDB and be taken as a new index for cognizing the serum lipid metabolism and the function of speen-qi to distribute Jing (Essonse) in the integrated traditional Chinese and western medicine. Practice has showed that concrete integration and bilateral development should be one of the main tasks in current researches of integrated traditional Chinese and western medicine.

Features of serum beta-lipoprotein electrophoretogram in patients with coronary heart disease.

OBJECTIVE: To investigate the changes in serum beta-lipoprotein (beta Lp) electrophoretogram in the patients with coronary heart disease (CHD). METHODS: This study included 36 CHD patients, 28 non-CHD patients and 8 normal control subjects, from whom serum beta Lps (prestained with Sudan Black B) were isolated by means of the first double-gradient polyacrylamide gel electrophoresis (f-DGPAGE). The secondary DGPAGE was performed for isolating beta Lps into 4 subfractions (beta Lp1-4) in order to complete the quantitative analysis of beta Lp electrophoretogram. A parallel test to examine the serum concentration of low-density lipoprotein cholesterol (LDLc) was also carried out. RESULTS: The relative amount of beta Lp1 was significantly elevated in CHD patients (53.4+/-10.0%) as compared with normal subjects (39.3+/-6.7%) and non-CHD patients (42.8+/-6.8%, P < 0.05 for both comparisons) regardless of serum LDLc concentrations, and beta Lp1 content between the latter 2 groups showed no significant difference. CONCLUSION: Serum beta Lp subfraction imbalance evidenced by increased beta Lp1 level characterizes the patients with CHD.

[A new method for detecting serum beta-lipoprotein electrophoretogram].

OBJECTIVE: To establish a new method for isolating serum beta-lipoprotein (betaLp) subfractions using second double gradient polyacrylamide gel electrophoresis (s-DGPAGE). METHODS: After the betaLp subfractions were isolated by mechanisms of molecular sieving and isoelectric focusing due to density and pH grade in the non-linear density gradient polyacrylamide gel, the gels were acquired with a gel imaging system, the electrophoretograms were quantitatively analyzed with optical density scanner. The isolation of serum betaLp was completed through first DGPAGE. RESULTS: s-DGPAGE separated the serum betaLp into four subfractions, designated respectively as betaLp1, betaLp2, betaLp3 and betaLp4, and their amounts in the betaLp and in the whole lipoproteins could be quantified. CONCLUSION: s-DGPAGE is a simple and practical method to show the heterogeneity of serum betaLp and the quantitative variation of its subfractions.

[Fast elimination of 50-Hz noise in PC-based application system].

The interference by 50-Hz noise arising from the power supply cables is common in PC-based application system, often considerably affecting the detection of useful signals. On the basis of self-adapting correlation method, we attempt to address the problem of fast elimination of 50-Hz noise from the useful signals in PC-based application system such as digital ECG recording system.

Pathological Q-wave generation in light of the Q wave alteration resulting from myocardial infarction in the left ventricular lateral wall of New Zealand rabbits.

OBJECTIVE: To explore the mechanism of pathological Q-wave generation in light of Q-wave alteration recorded on body surface resulting from the myocardial infarction in left ventricular lateral wall of New Zealand rabbits. METHOD: Electrocardiogram (ECG) was recorded with Wilson lead system at the surface points of chest and back in 30 normal rabbits. The myocardiac infarction models were prepared with quantitative chemical damaging method, and the ECG was recorded at the same points. Through comparison with the recorded ECG in normal animals, cases with pathological Q-wave at the recorded sites were identified and counted. RESULT: Pathological Q waves appeared at the point toward the infarction region, which was not observed in the area of right ventricular lateral wall opposite to the infarction region, showing significant difference (P<0.05). CONCLUSION: Negative potential transmitting from the ventricular chamber to the body surface through the window of infarction region may be involved in the generation of pathological Q waves.

[Comparison of pseudo Q wave occurrence and distribution on the body surface in New Zealand rabbit recorded by Wilson lead and head-chest lead].

OBJECTIVE: To compare the occurrence and distribution of pseudo Q wave on the body surface of rabbits recorded by Wilson lead with those detected by head-chest (HC) lead. METHODS: ECGs were recorded at each of the 70 points on the thoracodorsal regions of the body surface in 30 normal New-Zealand rabbits. The diagnostic value of the 2 lead systems was assessed on the basis of the detection of occurrence and distribution of pseudo Q wave. RESULTS: Pseudo Q wave was recorded at many points extensively in the thoracodorsal regions by Wilson lead, and only a few testing points on the upper dorsal surface showed pseudo Q wave activity while by HC lead. At the same testing point, the instances of pseudo Q wave detection by the two lead systems respectively were shown to be significantly different by X(2) test (P<0.05). CONCLUSION: HC lead is superior to Wilson lead in terms of its low occurrence rate and limited distribution regions of pseudo Q wave recorded on the body surface of normal rabbits.

[Study on distribution of cardiac electric field around the isolated heart of guinea pig].

OBJECTIVE: To define the distribution of the cardiac electric field around the isolated heart of guinea pig. METHODS: The hearts of 26 guinea pigs were isolated and immersed in normal saline or distilled water, and the ECGs were recorded in 4 directions of every plane with 4 points deposited in every direction at different distances from the anterior, posterior and the laterals of both the ventricles of the heart. RESULT: In both media, ECGs were composed mainly of upright waves were recorded at all points in the 4 directions at the 3 levels. CONCLUSION: The uniformed outward distribution of the cardiac electric field suggests that it is not dipolar but a sphere-like single source when the interference of different potentials of the reference points over the body surface is excluded.