Espectroscopia de impedancia eléctrica, una herramienta para aplicaciones biotecnológicas con Lactobacillus casei ATCC 393 / Electrical impedance spectroscopy, a tool for biotechnological applications with Lactobacillus casei ATCC 393

RESUMEN La aplicación de espectroscopia de impedancia eléctrica (EIE), es una técnica que se utiliza para monitorear, detectar y cuantificar microorganismos de interés biotecnológico, con la medición de parámetros eléctricos de respuesta rápida de un medio inoculado a temperatura y agitación constante mediante electrodos sumergidos. Realizando una comparación del modelo de crecimiento y el recuento en placa con los parámetros eléctricos de respuesta, se puede dar una correlación para romper la barrera tecnológica entre la microbiología clásica y los métodos rápidos de detección. La comparación de ambas técnicas fue realizada para determinar el máximo crecimiento de Lactobacillus casei (L. casei) ATCC 393. Se encontró que tras la inoculación, después de 24 h en condiciones microaerofílicas (37 °C), el máximo crecimiento microbiano fue registrado por medio de la EIE, mediante los parámetros -Z- (29,1057) y Deg-Deg0 (24,555°). En contraste con la técnica de conteo en placa, el crecimiento máximo se estimó a las 9 h. Los datos experimentales obtenidos mediante la EIE fueron ajustados por un circuito RC en serie, posteriormente, las curvas generadas fueron ajustadas a los modelos de crecimiento de Gompertz y Boltzman. Usando la técnica de EIE, la impedancia del medio resultó el parámetro más eficiente para la estimación del pico máximo exponencial de crecimiento de L. casei. Se demostró que la EIE constituye una alternativa para la detección rápida de la concentración microbiana en procesos de producción de biomasa para la elaboración de productos alimenticios probióticos.

ABSTRACT The application of electrical impedance spectroscopy (EIS) is a technique used to monitor, detect and quantify microorganisms of biotechnological interest, with the measurement of electrical parameters of rapid response of a medium inoculated at temperature and constant agitation by submerged electrodes. By making a comparison of the growth model and the plate count with the electrical response parameters, a correlation can be made to break the technological barrier between classical microbiology and rapid detection methods. The comparison of both techniques was performed to determine the maximum growth of Lactobacillus casei (L. casei) ATCC 393. It was found that after inoculation, after 24 h under microaerophilic conditions (37 °C), the maximum microbial growth was recorded by medium of the EIE, using the parameters -Z- (29,1057) and Deg-Deg0 (24,555°). In contrast to the plate count technique, maximum growth was estimated at 9 h. The experimental data obtained through the EIE were adjusted by a series RC circuit; later, the generated curves were adjusted to the growth models of Gompertz and Boltzman. Using the EIE technique, the impedance of the medium was the most efficient parameter for the estimation of the maximum exponential growth peak of L. casei. It was demonstrated that the EIE constitutes an alternative for the rapid detection of the microbial concentration in biomass production processes for the elaboration of probiotic food products.

Preliminary observation on imbalance degree of impedance in extracellular fluid of cells in the twelve meridians in healthy subjects / 中国针灸

OBJECTIVE@#To calculate the imbalance degree (IBD) of left-right meridian (IBD-LRM), IBD of exterior-interior meridian (IBD-EIM) and IBD of hand-foot meridians (IBD-HFM) of impedance in extracellular fluid of cells in twelve meridians of healthy subjects, so as to provide foundation for meridian diagnosis.@*METHODS@#A total of 31 healthy volunteers were enrolled and bioelectrical impedance spectroscopy (BIS) was applied. The constant current (from 1 to 100 kHz, 200 μA) was connected into the bilateral twelve meridians through two excitation electrodes with a distance of 10 cm. Two measuring electrodes, with an interval of 5 cm, were set in between the two excitation electrodes to collect the voltage amplitude and phase. The Cole-Cole curve fitting was used to calculate the impedance of extracellular fluid of cells in the twelve meridians; the IBD-LRM, IBD-EIM and IBD-HFM as well as their absolute values were calculated.@*RESULTS@#The impedance of extracellular fluid in the left side was higher than that in right side in the large intestine meridian, the small intestine meridian and the bladder meridian (<0.05, <0.01). The mean value of IBD-LRM of extracellular fluid was (4.0±1.4) %; the mean value of absolute value of IBD-LRM was (15.0±1.1) %; the maximum absolute value of IBD-LRM was the bladder meridian. The mean value of IBD-EIM was (3.3±1.0) %; the mean value of absolute value of IBD-EIM was (17.9±1.6) %; the maximum absolute value of IBD-EIM was the bladder meridian and the kidney meridian. The impedance of extracellular fluid of hand meridian, hand meridian and hand meridian were lower than those of foot meridians. The mean value of IBD-HFM was (-2.6±1.1) %; the mean value of absolute value of IBD-HFM was (19.7±1.7) %; the maximum absolute value of IBD-HFM was meridian; the imbalance of meridians was greater than meridians. There were significant differences in impedance of extracellular fluid between left and right and between hands and feet (<0.05, <0.01).@*CONCLUSION@#The extracellular fluid of left-right meridians of healthy subjects is different, but the absolute value of IBD is low; the mean value of exterior meridian and interior meridian is very close, and the absolute value of IBD is medium; the impedance of the foot meridians are greater than the hand meridians, and the absolute value of IBD is relatively high.

Detection of biofilms formation by electrochemical impedance spectroscopy / 生物工程学报

Biofilms are microbial communities composed of bacteria cells and self-produced extracellular polymeric substances and lead to antibiotic resistance, forming a great threat in the fields of medicine, food industries and so on. The formation of biofilms is a multi-stage dynamic process regulated by multiple mechanisms. Recently, researchers paid much more attention to the related research areas of biofilms, especially the detection methods of biofilms. This paper introduced the characteristics and formation process of biofilms as well as the effects of quorum sensing on biofilms development. Meanwhile, we discussed the detection methods of biofilms, especially electrochemical impedance spectroscopy (EIS) in detection of biofilms in detail. Furthermore, we reviewed and predicted that microfluidic chips based EIS served as an in-situ and online monitoring method for biofilms growth.

Caracterización del tejido columnar del cérvix mediante espectroscopia de impedancia eléctrica y modelado computacional / Characterization of cervical columnar tissue through electrical impedance spectroscopy and computer modeling

RESUMEN Introducción: En este artículo se presenta la utilización de la espectroscopia de impedancia eléctrica (EIE) en la caracterización del tejido columnar cervical y como herramienta de apoyo a las técnicas diagnósticas del cáncer de cuello uterino. Métodos: Se realizó un estudio de validez diagnóstica a 30 pacientes no menopáusicas que presentaron ectopia cervical durante la colposcopia. Se obtuvieron 129 espectros de impedancia eléctrica de tejido columnar, que fueron diferenciados en cuatro zonas o puntos de toma de medidas, semejantes a las zonas horarias 12, 3, 6, y 9 de un reloj análogo. Los datos experimentales obtenidos fueron ajustados al modelo de Cole-Cole, que describe la fisiología y estructura del tejido mediante parámetros eléctricos de resistividad R y S, frecuencia característica Fc y capacitancia de membrana Cm. Resultados: La comparación entre tejidos columnares sanos y con lesión en cada uno de los puntos de medida se realizó mediante pruebas no paramétricas U de Mann-Whitney, que mostraron diferencias estadísticamente significativas (p <0,05) para las medianas de R y S, con un nivel de confianza del 95%. Los valores promedio de R y S para tejido columnar sano fueron 2,0 Ω-m y 11,36 Ω-m, con desviación estándar 0,41 y 0,51 respectivamente; mientras que para los tejidos con lesiones el valor promedio R y S fueron de 4,21 Ω-m y 7,03 Ω-m, con desviación estándar 0,40 para ambas medidas. Conclusión: Se encontró que la resistividad del líquido extracelular R y la resistividad de la matriz intracelular S son las que mejor discriminan entre epitelios columnares sanos y aquellos afectados por lesiones.

ABSTRACT Introduction: Thi s pape r shows the implementation of Electrical Impedance Spectroscopy (EIS) in the characterization of the cervical columnar tissue and as a supporting tool to the diagnostic techniques of cervical cáncer Methods: A diagnostic validity study was performed on 30 non-menopausal patients who presented cervical ectopy during colposcopy. A total of 129 electric impedance spectra of columnar tissue was obtained, which were differentiated into four measurement zones or points similar to time zones 12, 3, 6, and 9 of an analog clock. The experimental data obtained were adjusted to the Cole-Cole model which describes the physiology and structure of the tissue through electrical resistivity parameters R and S, characteristic frequency Fc and membrane capacitance Mc. Results: The comparison between healthy and damaged columnar tissue at each of the measurement points was performed using non-parametric Mann-Whitney U tests which showed statistically significant differences (p <0.05) for the R and S medians with a 95% confidence level. The average values of R and S for healthy columnar tissue were 2.0 Ω-m and 11.36 Ω-m, with 0.41 and 0.51 standard deviation respectively, whereas for a damaged tissue the average value of R and S were 4.21 Ω-m and 7.03 Ω-m, with 0.40 standard deviation for both measurements. Conclusions: It was found that the resistivity of the extracellular liquid R, and the resistivity of the intracellular matrix S, are the parameters that better discriminate between healthy columnar epithelia and those affected by lesions.

Rapid culture-based detection of living mycobacteria using microchannel electrical impedance spectroscopy (m-EIS)

BACKGROUND: Multiple techniques exist for detecting Mycobacteria, each having its own advantages and drawbacks. Among them, automated culture-based systems like the BACTEC-MGIT™ are popular because they are inexpensive, reliable and highly accurate. However, they have a relatively long "time-to-detection" (TTD). Hence, a method that retains the reliability and low-cost of the MGIT system, while reducing TTD would be highly desirable. METHODS: Living bacterial cells possess a membrane potential, on account of which they store charge when subjected to an AC-field. This charge storage (bulk capacitance) can be estimated using impedance measurements at multiple frequencies. An increase in the number of living cells during culture is reflected in an increase in bulk capacitance, and this forms the basis of our detection. M. bovis BCG and M. smegmatis suspensions with differing initial loads are cultured in MGIT media supplemented with OADC and Middlebrook 7H9 media respectively, electrical "scans" taken at regular intervals and the bulk capacitance estimated from the scans. Bulk capacitance estimates at later time-points are statistically compared to the suspension's baseline value. A statistically significant increase is assumed to indicate the presence of proliferating mycobacteria. RESULTS: Our TTDs were 60 and 36 h for M. bovis BCG and 20 and 9 h for M. smegmatis with initial loads of 1000 CFU/ml and 100,000 CFU/ml respectively. The corresponding TTDs for the commercial BACTEC MGIT 960 system were 131 and 84.6 h for M. bovis BCG and 41.7 and 12 h for M smegmatis, respectively. CONCLUSION: Our culture-based detection method using multi-frequency impedance measurements is capable of detecting mycobacteria faster than current commercial systems.

Caracterización de neoplasias mamarias mediante espectroscopia de impedancia eléctrica: modelo canino / Characterization of mammary neoplasia by electrical impedance spectroscopy: canine model

Introducción: La espectroscopia de impedancia eléctrica (EIE) es una técnica fácil de usar y de bajo costo que se puede utilizar para analizar tejidos biológicos en condiciones normales o patológicas. El objetivo de este trabajo fue caracterizar neoplasias de glándula mamaria benignas y malignas aplicando la técnica EIE en muestras extraídas de 45 caninos hembras (Canis lupus familiaris). Métodos: Se utilizó un medidor de impedancia eléctrica, Hioki 3532-50, para determinar los parámetros bioeléctricos: resistencia de la matriz extracelular (R), resistencia de la matriz intracelular (S), frecuencia característica (Fc) y capacitancia de membrana (Cm) en un rango de frecuencias entre 42 Hz y 5 MHz y se analizaron estadísticamente mediante la prueba no paramétrica U de Mann-Whitney (Wilcoxon) de dos colas. La precisión diagnóstica de la EIE se efectuó a través de curvas características de operación del receptor (COR) y tablas de doble entrada, con la histopatología como referencia. Resultados: Se encontraron diferencias estadísticamente significativas entre el tejido mamario sano y las neoplasias benignas para los parámetros R, Fc y Cm, p-value < 0,05. Entre tejido mamario sano y neoplasias mamarias malignas se encontraron diferencias estadísticamente significativas para R y Fc con un p-value < 0,05. La comparación entre lesiones tumorales benignas y malignas no presentó diferencias estadísticamente significativas, p-value > 0,05, para ninguna de las variables incluidas en este estudio. Conclusiones: De los parámetros analizados por EIE, la resistencia de la matriz extracelular es la que mejor permite diferenciar entre tejidos mamarios normales y neoplásicos. La EIE es una herramienta diagnóstica potencial que puede ser utilizada en la detección de cáncer mamario, con una precisión diagnóstica cercana al 80%.

Introduction: Electrical Impedance Spectroscopy (EIS) it is an easy to use and low-cost technique that can be used to analyze biological tissues in normal or pathological condition. The goal of this work was to characterize benign and malign mammary gland neoplasms applying the EIS technique in 45 female dogs (Canis lupus familiaris). Methods: An impedance meter Hioki 3532-50 was used to determine bioelectric parameters, extracellular matrix resistance (R), intracellular matrix resistance (S), characteristic frequency (Cf), and membrane capacitance (Mc), which were obtained in a 42 Hz and 5 MHz frequencies range. Were statistically analyzed with the non-parametric test of two-tailed MannWhitney (Wilcoxon). The diagnostic precision of the test was performed using receiver operating characteristics (ROC) and two-way tables using histopathology results as reference. Results: Significant differences between healthy mammary tissue and benign neoplasms were found for variables R, Cf and Mc (p < 0.05). There were statistically major differences between the healthy mammary tissue and malign mammary tumors groups for R and Cf (p < 0.05). The comparison between malign and benign tumor lesions did not show a statistically significant difference, p-value > 0.05, for any of the variables included in this study. Conclusion: Among all parameters analyzed for EIS, the extracellular matrix resistance R is the one that best allows differentiating between healthy and neoplastic mammary tissues. EIS is a diagnostic tool that can be used for breast cancer detection with a diagnostic precision close to 801%.

Conductividad iónica en nuevos compósitos (PEO)10(CF3COONa)-X% Al2O3 / Ionic conductivity of (PEO)10(CF3COONa)-X % Al2O3 composites

Se incrementó la conductividad iónica delelectrolito sólido polimérico (PEO)10CF3COONa medianteformación de nuevos compositos, adicionando partículasde óxido de aluminio (Al2O3) como relleno. Los compositosfueron preparados por disolución en solvente líquido y lacaracterización por espectroscopia de impedancias (EI)con configuración de electrodos Pt/electrolito/Pt. Reducciónde hasta dos órdenes de magnitud en la resistencia, seobservó en diagramas de Nyquist; combinando polióxido deetileno (PEO) con trifluoroacetato de sodio (CF3COONa).Al agregar partículas de Al2O3, la reducción en resistenciallego a ser hasta de tres órdenes de magnitud, a temperaturaambiente. Los gráficos de conductividad DC en función dela concentración, mostraron incremento de conductividadiónica a bajas concentraciones de alúmina. El compositoconductor iónico sintetizado mostró conductividadde 2.00x10-5 Scm-1 temperatura ambiente y 7.70x10-4Scm-1, temperatura de 383 K. Se presentó comportamientoArrhenius en dos regiones de diagramas de conductividadcon temperatura, indicando proceso térmicamenteactivado. Para altas concentraciones de Al2O3 se observócomportamiento Vogel-Tamman-Fulcher (VTF). Lasvariaciones de conductividad con concentración de Al2O3,están asociadas con número de sitios involucrados entrasporte iónico, a través de interacciones Lewis ácido–base,entre partículas de Al2O3 y especies iónicas del electrolito...

To increase the ionic conductivity of solid polymer electrolyte, (PEO)10CF3COONa, we formed newcomposites by adding alumina particles as a filler. We prepared these composites by dissolving them ina liquid solvent, and characterized them through impedance spectroscopy (IS), using a Pt/electrolyte/Ptelectrode configuration. The combination of polyethylene oxide (PEO) with sodium trifluoroacetate(CF3COONa) produced a reduction in resistance of up to two orders of magnitude in Nyquist plots, andup to three orders of magnitude when we added Al2O3 particles at room temperature. DC conductivityconcentration graphs show an increase in the ionic conductivity with low alumina concentrations. Thenew synthesized ionic conductor composite presented conductivity values of 2.00x10-5 Scm-1 at roomtemperature and of 7.70x10-4 Scm-1 at a temperature of 383 K. Two sections of the conductivity diagramsalso evidenced a temperature induced Arrhenius behavior, indicating a thermally activated process. Higherconcentrations of Al2O3 induced a Vogel-Tamman-Fulcher (VTF) behavior. Conductivity variationsproduced by Al2O3 concentration are linked to the number of sites involved in ion transport betweenAl2O3 ionic electrolyte species through Lewis acid-base interactions...

Foi Aumentada a condutividade iônica doeletrólito de polímero sólido (PEO)10CF3COONa, através daformação de um novo compósito, adicionando partículas deóxido de alumínio (Al2O3). Os compósitos foram preparadospor dissolução num solvente líquido e a caracterizaçãofoi feita por espectroscopia de impedância (EI) com aconfiguração utilizando eletrodo de platinum - Pt/eletrólito/Pt. A redução de até duas ordens de grandeza na resistênciaé observada em diagraamas de Nyquist quando se combinapoli (óxido de etileno) (PEO) com trifluoroacetato de sodioCF3COONa. Quando as partículas de Al2O3 são adicionadasao composição, é observado uma redução na resistênciade três ordens de grandeza à temperatura ambiente. Osgráficos do logaritmo da condutividade dc em função daconcentração, mostra um aumento da condutividade parabaixas concentrações de alumína. Do compósito condutorde íons sintetizado, apresenta valores de condutividade2.00x10-5 Scm-1 à temperatura ambiente e 7,70x10-4 Scm-1a uma temperatura de 383 K. Um comportamento do tipoArrhenius é apresentado em duas regiões dos diagramas decondutividade com a temperatura, indicando um processotermicamente ativado. Para concentrações elevadas deAl2O3, uma mudança de comportamento para Vogel-Tamman-Fulcher (VTF) foi observado. As variações nacondutividade com a concentração de Al2O3, está associadaa alteração do número dos sítios envolvidos no transportede íons através de interações do tipo ácido-base de Lewisentre partículas de Al2O3 e espécies iônicas...

Prediction of Treatment Outcome with Bioimpedance Measurements in Breast Cancer Related Lymphedema Patients

OBJECTIVE: To investigate the usefulness of bioimpedance measurement for predicting the treatment outcome in breast cancer related lymphedema (BCRL) patients. METHOD: Unilateral BCRL patients who received complex decongestive therapy (CDT) for 2 weeks (5 days per week) were enrolled in this study. We measured the ratio of extracellular fluid (ECF) volume by using bioelectrical impedance spectroscopy (BIS), and single frequency bioimpedance analysis (SFBIA) at a 5 kHz frequency before treatment. Arm circumferences were measured at 10 cm above and below the elbow before and after treatment. We also investigated whether there is correlation between ECF ratio and SFBIA ratio with the change of arm circumference after CDT. RESULTS: A total of 73 patients were enrolled in this study. The higher ECF ratio was significantly correlated with higher reduction of arm circumference at both above and below the elbow after treatment, but the higher SFBIA ratio was correlated only with the higher reduction of arm circumference below the elbow. CONCLUSION: These results show that ECF volume measurements and SFBIA before treatment are useful tools for predicting the outcome of patients with lymphedema. We concluded that ECF volume measure can be used as a screening tool for predicting treatment outcome of BCRL patients.

Immunosensor Based on Immobilizing Antibody of Aflatoxin B_1 Using Silica Sol-Gel Technology / 分析化学

In the presence of hydrochloric acid, tetraethoxysilicane was hydrolyzed and formed silica sol. Non-labeled immunosensor was fabricated by droping the mixture solution of the silica sol and antibody of aflatoxin B_1 on the surface of glassy carbon electrode. In this work, a Fe(CN)_6~(3-/4-) phosphate buffer solution) was employed as base solution for investigating cyclic voltammetry(CV) and electrochemical impedance spectroscopic(EIS) performances of the sensor, respectively. The experimental results t indicated that because of the complex formed by the immunoreaction hindered the diffusion of Fe(CN)_6~(3-/4-) on the electrode surface, the redox peak current of the immunosensor in CV obviously decreased, and its electron transfer impedance linearly) increased with increasing the concentration of aflantoxin B_1(AFB). When the medium acidit and incubation) time were pH 6.5 and 20 min, respectively, the biggest electron transfer impedance changed value before and after the immunoreaction was obtained. Under the optimal conditions, a linear range to concentration of aflatoxin B_1 was 1-10 μg/L with a detection limit of 0.1 μg/L(S/N=3). Proposed method is of high sensitivity and stability, it has been successfully applied to determine AFB_1 in maize, rice and peanut.

Electrochemical Deoxyribonucleic Acid Biosensor Based on Multi-walled Carbon Nanotubes/Ag-TiO_2 Composite Film for Label-free Phosphinothricin Acetyltransferase Gene Detection by Electrochemical Impedance Spectroscopy / 分析化学

A highly sensitive electrochemical deoxyribonucleic acid(DNA) biosensor based on multi-walled carbon nanotubes(MWNT)/Ag-TiO_2 composite film was developed. The solution containing Ag-TiO_2-MWNT composite was casted on the carbon paste electrode surface to form a robust film, which combine the advantages of the good biocompatibility of Ag-TiO_2 naocomposite and the fine conductivity, as well as the large active surface area of carbon nanotubes. The composite could greatly improve the immobilization capacity of the probe DNA. The morphologies and electrochemistry of the nanocomposite film were investigated by scanning electron microscopy and electrochemical techniques including electrochemical impedance spectroscopy and cyclic voltammetry, respectively. DNA hybridization events were monitored by a label-free method of electrochemical impedance spectroscopy. This label-free electrochemical impedance DNA biosensor showed high sensitivity and selectivity for phosphinothricin acetyltransferase gene sequence assay. The multicomponents films also displayed a high stability during repeated regeneration and hybridization process.

Experimental Study on Complex Impedance Spectra of Rabbit Whole Blood Cell / 医学研究杂志

Objective To establish characteristic parameters of plural impedance spectra of rabbit whole blood cell.Method The AC impedances of 30 blood samples from the 10 rabbits have been measured with the Agilent 4294A impedance analyzer at frequency range of 0.01～100MHz,then its characteristic data have been analyzed by the Bode plot,the Nyquist plot and the Nichols plot.Results(1)The impedance amplitude and phase angle of rabbit blood cell have a dependence of frequency.(2)The impedance spetroctra of rabbit blood cell have two characteristic frequency:the characteristic 1st frequency(fC1) was 2.58MHz,the characteristic 2nd frequency(fC2) was 5.21MHz.Conclusion The frequency properties of blood cells can be obtained by the analysis of impedance spectroscopy.

An Impedance Spectroscopy Analysis Method to measure RBC aggregation1 / 医学研究杂志

Objective From the Maxwell-Wagner theory for suspensions of spherical and the electrical property of blood,an equation has been derived to calculate RBC aggregate radius,a new method based on the impedance spectroscopy analysis has been developed to evaluate the Red Blood Cell (RBC) aggregation property. According the new method,the impedance spectroscopy of blood has been measured at first with the multi-frequency technique,then to get the impedance - frequency curve by a fit method,the time constant T has been extracted from the curve,at last,the RBC aggregate radius R has been gotten. According to the changes of R during the RBC aggregation,the measurement and evaluation of RBC aggregation property can be realized. The impedance spectroscopy analysis method introduced in this paper is a new,effective method to study RBC aggregation.

Experiment Study on the Impedance Spectroscopy Analysis Method t o measure RBC Aggregation / 医学研究杂志

In order to test validity and fea si bility of the impedance spectroscopy analysis method,a series of blood experime n ts have been carried out to study influences of the hematocrit,the plasma conc e ntration and the dextran concentration in suspend medium on the blood impedance and the RBC aggregation.The results show that the blood impedance of lower freq uency R_0 increases with increase of Hctc,the time constant T has little chang e when Hctc hange from 28.9 to 48.9;with the increase of plasma concentration ,t he RBC aggregation radius increases;When the dextran concentration is about 4g/ 100ml,the RBC aggregate reaches its maximum.It suggests that the impedance spe ctroscopy analysis method is a new,effective method to study RBC aggregation.

RELATION BETWEEN BODY COMPOSITION AND PHYSICAL ATHLETIC PERFORMANCE OF LONG DISTANCE RELAY RUNNERS PRODUCED BY A FOUR WEEK WEIGHT LOSS PROGRAM / 体力科学

The purpose of this study was to examine the relation between body composition and athletic performance of long distance relay runners in a four week weight reduction program. Six male collegiate runners, aged 19.0 ± 0.9 years, participated in this study. Body water content and fat free mass (FFM) were measured by bioelectrical impedance spectroscopy.The weight loss by 4.1% of the initial body weight consisted of decreases in FFM and fat mass (54% and 46% respectively). Percentage of body fat did not change significantly by the end of the fourth week. The total body water (TBW) loss comprised of intracellular water (ICW) and extracellular water (ECW) at the end of the fourth week, and TBW loss and FFM loss were nearly the same values. Isokinetic muscular strength of right thigh, maximal oxygen intake (VO₂max) and total treadmill running time (maximal workout time) measured did not show any significant change. These results indicate (1) half of the weight loss consisted of decrease in FFM, (2) TBW loss was due to the reduction of ICW and ECW, (3) the content of FFM loss was considered to be body water, and (4) there was no impact on muscular strength of right thigh, VO₂max or maximal workout time.

Research of effect of stray capacitance on measurement accuracy in tissue impedance spectroscopy measurement / 医疗卫生装备

In the tissue impedance spectroscopy measurements ,four-electrode method are normally used. A measurement error caused by stray capacitance between lines of drive electrode and receive electrode is not a trivial problem. This paper studied this error and reached the results This stray capacitance introduces errors which increase with frequency and has more effect on the imaginary part than on the real part in the measurement frequency range.

Design of impedance spectroscopy database frame based on ADD Technique / 医疗卫生装备

The author uses the database technique to manage the impedance spectroscopy data.In design of impedance spectroscopy database frame,ActiveX Data Object(ADO)technique is adopted to improve the agility and efficiency.It also enhances the efficiency to use data binding technique to avoid complex data type transformation in appending and amending.