Electrical impedance spectroscopy for electro-mechanical characterization of conductive fabrics.

When we use a conductive fabric as a pressure sensor, it is necessary to quantitatively understand its electromechanical property related with the applied pressure. We investigated electromechanical properties of three different conductive fabrics using the electrical impedance spectroscopy (EIS). We found that their electrical impedance spectra depend not only on the electrical properties of the conductive yarns, but also on their weaving structures. When we apply a mechanical tension or compression, there occur structural deformations in the conductive fabrics altering their apparent electrical impedance spectra. For a stretchable conductive fabric, the impedance magnitude increased or decreased under tension or compression, respectively. For an almost non-stretchable conductive fabric, both tension and compression resulted in decreased impedance values since the applied tension failed to elongate the fabric. To measure both tension and compression separately, it is desirable to use a stretchable conductive fabric. For any conductive fabric chosen as a pressure-sensing material, its resistivity under no loading conditions must be carefully chosen since it determines a measurable range of the impedance values subject to different amounts of loadings. We suggest the EIS method to characterize the electromechanical property of a conductive fabric in designing a thin and flexible fabric pressure sensor.

Bioelectrical Impedance Methods for Noninvasive Health Monitoring: A Review.

Under the alternating electrical excitation, biological tissues produce a complex electrical impedance which depends on tissue composition, structures, health status, and applied signal frequency, and hence the bioelectrical impedance methods can be utilized for noninvasive tissue characterization. As the impedance responses of these tissue parameters vary with frequencies of the applied signal, the impedance analysis conducted over a wide frequency band provides more information about the tissue interiors which help us to better understand the biological tissues anatomy, physiology, and pathology. Over past few decades, a number of impedance based noninvasive tissue characterization techniques such as bioelectrical impedance analysis (BIA), electrical impedance spectroscopy (EIS), electrical impedance plethysmography (IPG), impedance cardiography (ICG), and electrical impedance tomography (EIT) have been proposed and a lot of research works have been conducted on these methods for noninvasive tissue characterization and disease diagnosis. In this paper BIA, EIS, IPG, ICG, and EIT techniques and their applications in different fields have been reviewed and technical perspective of these impedance methods has been presented. The working principles, applications, merits, and demerits of these methods has been discussed in detail along with their other technical issues followed by present status and future trends.

Protective effect of aqueous extract of seed of Psoralea corylifolia (Somraji) and seed of Trigonella foenum-graecum L. (Methi) in streptozotocin-induced diabetic rat: A comparative evaluation.

BACKGROUND: Psoralea corylifolia (Somraji) and Trigonella foenum-graecum L. (Methi), important medicinal plants widely used in India as folk medicine. Local people of West Bengal traditionally used the seeds of these plants to cure diabetes. OBJECTIVE: Present study was designed to investigate the antidiabetic efficacy of aqueous extract of seeds of these plants in separate or in composite manner in streptozotocin (STZ)-induced diabetic rat. MATERIALS AND METHODS: Diabetes was induced by intramuscular injection of STZ at the dose of 40 mg/ml of citrate buffer/kg body weight. Fasting blood glucose (FBG), glyclated hemoglobin (HbA1C) and activities of hexokinase, glucose-6-phosphate dehydrogenase and glucose-6-phosphatase of liver in experimental animals were assessed. Hyperlipidemic state developed in the experimental diabetic rat was assessed by measuring the levels of total cholesterol, triglyceride, and lipoproteins in serum. RESULTS: There was significant increased in the levels of FBG, HbA1C and lipid profiles along with diminution (P < 0.001) in the activities of hepatic hexokinase, glucose-6-phosphate dehydrogenase and elevation in glucose-6-phosphatase in diabetic control animals in respect to the untreated control. Significant recovery (P < 0.05) in the activities of above mentioned enzymes along with the correction in the levels of FBG, HbA1C and serum lipid profiles were noted towards the control level after the treatment of composite extract (i.e. 100 mg of Somraji: 100 mg of Methi, total 200 mg/kg body weight) than the individual extract (i.e. 200 mg of Somraji or 200 mg of Methi, per kg body weight) treatment. CONCLUSION: Results suggest that composite extract of above plant parts has more potent antidiabetic efficacy than the individual extract.

Overweight and obesity among early adolescent school girls in urban area of west bengal, India: prevalence assessment using different reference standards.

BACKGROUND: Overweight and obesity are epidemic and a 'public health crisis' among adolescents worldwide. The rising trends in adolescent obesity in girl are poorly documented in India. The aim of this study was to compare and assess the extent of overweight and obesity in early adolescent school girls using three references [World Health Organization (WHO) 2007; the Center for Diseases Control (CDC) 2000 and the International Obesity Task Force (IOTF) 2000]. METHODS: A cross sectional study was designed in 1375 early adolescent girl (10-14 years), in five Government affiliated schools of Kharagpur Municipality of West Bengal, India. RESULTS: Results of this study are eloquent of the fact that the roots of obesity lies in early stage of adolescence. Incidence of overweight, including obesity of participants was 10.62%, 7.64% and 7.49% depending on the references used (WHO, CDC and IOTF) respectively. Both incidence and remission rates were higher among younger girls. CONCLUSIONS: Regarding the harmful ramifications of overweight and obesity, it is encourage to healthy eating patterns and increase physical activity among early adolescent girls.

Effective admittivity of biological tissues as a coefficient of elliptic PDE.

The electrical properties of biological tissues can be described by a complex tensor comprising a simple expression of the effective admittivity. The effective admittivities of biological tissues depend on scale, applied frequency, proportions of extra- and intracellular fluids, and membrane structures. The effective admittivity spectra of biological tissue can be used as a means of characterizing tissue structural information relating to the biological cell suspensions, and therefore measuring the frequency-dependent effective conductivity is important for understanding tissue's physiological conditions and structure. Although the concept of effective admittivity has been used widely, it seems that its precise definition has been overlooked. We consider how we can determine the effective admittivity for a cube-shaped object with several different biologically relevant compositions. These precise definitions of effective admittivity may suggest the ways of measuring it from boundary current and voltage data. As in the homogenization theory, the effective admittivity can be computed from pointwise admittivity by solving Maxwell equations. We compute the effective admittivity of simple models as a function of frequency to obtain Maxwell-Wagner interface effects and Debye relaxation starting from mathematical formulations. Finally, layer potentials are used to obtain the Maxwell-Wagner-Fricke expression for a dilute suspension of ellipses and membrane-covered spheres.

A MATLAB-Based Boundary Data Simulator for Studying the Resistivity Reconstruction Using Neighbouring Current Pattern.

Phantoms are essentially required to generate boundary data for studying the inverse solver performance in electrical impedance tomography (EIT). A MATLAB-based boundary data simulator (BDS) is developed to generate accurate boundary data using neighbouring current pattern for assessing the EIT inverse solvers. Domain diameter, inhomogeneity number, inhomogeneity geometry (shape, size, and position), background conductivity, and inhomogeneity conductivity are all set as BDS input variables. Different sets of boundary data are generated by changing the input variables of the BDS, and resistivity images are reconstructed using electrical impedance tomography and diffuse optical tomography reconstruction software (EIDORS). Results show that the BDS generates accurate boundary data for different types of single or multiple objects which are efficient enough to reconstruct the resistivity images for assessing the inverse solver. It is noticed that for the BDS with 2048 elements, the boundary data for all inhomogeneities with a diameter larger than 13.3% of that of the phantom are accurate enough to reconstruct the resistivity images in EIDORS-2D. By comparing the reconstructed image with an original geometry made in BDS, it would be easier to study the inverse solver performance and the origin of the boundary data error can be identified.

Antihyperglycemic and antihyperlipidemic effects of n-hexane fraction from the hydro-methanolic extract of sepals of Salmalia malabarica in streptozotocin-induced diabetic rats.

Bio-efficacy of n-hexane fraction of sepal of Salmalia malabarica was evaluated covering the biochemical sensors for the management of hyperglycemic and hyperlipidemic effects. Evaluation of n-hexane fraction of Salmalia malabarica (SMH) from hydro-methanolic (2:3) extract at the dose of 0.1 gm/kg body weight twice a day were investigated in normal and streptozotocin (STZ) induced diabetic rats. Normal and STZ-induced diabetic rats were divided into five groups. The effect of the fraction on fasting blood glucose (FBG), serum insulin, hemoglobin, glycated hemoglobin, total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDLc), low density lipoprotein cholesterol (LDLc), very low density lipoprotein cholesterol (VLDLc), phospholipids, free fatty acids, urea, uric acid, creatinine, albumin and transaminases were investigated in STZ-induced diabetic rat. A significant reduction of FBG level was observed after SMH treatment in STZ-induced diabetic rat. Treatment of diabetic rats with n-hexane fraction of this plant restored the levels of the above biochemical sensors significantly (p<0.001) in respect to the control. Histological studies of pancreas showed a qualitative diminution in the area of the islet's of Langerhans in diabetic group which was recovered by said fraction. Phytochemical screening of the fraction revealed the presence of flavonoids, terpenoids and steroids.

Antihyperglycemic and antioxidative effects of the hydro-methanolic extract of the seeds of Caesalpinia bonduc on streptozotocin-induced diabetes in male albino rats.

BACKGROUND: No satisfactory effective treatment is available yet to cure diabetes mellitus. Though, synthetic drugs are used but there are several drawbacks. The attributed antihyperglycemic effects of many traditional plants are due to their ability for the management of diabetes mellitus. MATERIALS AND METHODS: A hydromethanolic extract was administered orally at a dose of 250 mg/kg of body weight per day for 21 days. Its effects on the fasting blood glucose (FBG) level, activities of key carbohydrate metabolic enzymes like hexokinase, glucose-6-phosphatase, and glucose-6-phosphate dehydrogenase, and antioxidant enzymes like catalase and superoxide dismutase along with the effect on the lipid peroxidation level in hepatic tissues were measured. Glycogen levels were also assessed in hepatic and skeletal muscles and some toxicity parameters, such as serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and alkaline phosphates activities were measured. RESULTS: Treatment of the hydromethanolic extract of the seeds of Caesalpinia bonduc resulted in a significant (P < 0.05) recovery in the activities of carbohydrate metabolic enzymes along with correction in FBG and glycogen levels as compared with the untreated diabetic group. The extract also resulted in a significant (P < 0.05) recovery in the activities of toxicity assessment enzyme parameters. Activities of antioxidant enzymes like catalase and superoxide dismutase along with the lipid peroxidation levels were also recovered significantly (P < 0.05) after the treatment of the extract. The corrective effects produced by the extract were compared with the standard antidiabetic drug, glibenclamide. CONCLUSION: Our findings provide that the extract shows possible antihyperglycemic and antioxidative activities.

Inhibitory effect of hydro-methanolic extract of seed of Holarrhena antidysenterica on alpha-glucosidase activity and postprandial blood glucose level in normoglycemic rat.

ETHNOPHARMACOLOGICAL RELEVANCE: The present experiment was conducted to search out the effect of hydro-methanolic extract of seed of Holarrhena antidysenterica on intestinal α-glucosidase activity in dose dependent manner and on the management of postprandial hyperglycemia in starch loaded rats. MATERIALS AND METHODS: Activity of intestinal α-glucosidase was measured by in vitro method. Fasting blood glucose level was determined by single touch glucometer. Total phenol and flavonoids of seed extract of Holarrhena antidysenterica were estimated using gallic acid and quercetin standard curves, respectively. RESULTS: The degree of elevation in blood glucose level after starch administration was significantly (p<0.05) less by the extract in respect to the control. The said extract also inhibited α-glucosidase activity having an IC(50) of 0.52mg/ml. Phytochemical study revealed that the extract is rich in phenolic compounds (60.23mg of gallic acid equivalent/g of extract) and flavonoids (360.23mg of quercetin equivalent/g of the extract). CONCLUSION: The extract exerts its antihyperglycemic effect by retarding the carbohydrate absorption from intestine through the inhibition in α-glucosidase activity and therefore resists postprandial hyperglycemia.

Antidiabetic Potentiality of the Aqueous-Methanolic Extract of Seed of Swietenia mahagoni (L.) Jacq. in Streptozotocin-Induced Diabetic Male Albino Rat: A Correlative and Evidence-Based Approach with Antioxidative and Antihyperlipidemic Activities.

Antidiabetic, antioxidative, and antihyperlipidemic activities of aqueous-methanolic (2 : 3) extract of Swietenia mahagoni (L.) Jacq. (family Meliaceae) seed studied in streptozotocin-induced diabetic rats. Feeding with seed extract (25 mg 0.25 mL distilled water(-1)100 gm b.w.(-1)rat(-1) day(-1)) for 21 days to diabetic rat lowered the blood glucose level as well as the glycogen level in liver. Moreover, activities of antioxidant enzymes like catalase, peroxidase, and levels of the products of free radicals like conjugated diene and thiobarbituric acid reactive substances in liver, kidney, and skeletal muscles were corrected towards the control after this extract treatment in this model. Furthermore, the seed extract corrected the levels of serum urea, uric acid, creatinine, cholesterol, triglyceride, and lipoproteins towards the control level in this experimental diabetic model. The results indicated the potentiality of the extract of S. mahagoni seed for the correction of diabetes and its related complications like oxidative stress and hyperlipidemia. The extract may be a good candidate for developing a safety, tolerable, and promising neutraceutical treatment for the management of diabetes.

Antioxidant potential of hydro-methanolic extract of seed of Caesalpinia bonduc: An in vitro study.

It is well known that the over production of reactive oxygen species is harmful for living organisms and it damages major cellular constituents such as DNA, protein, and lipid. At present, searching of new plant sources having free radical scavenging activity is an important field of research in phytomedicine as natural products are safe and relatively low cost. In this respect, attention has been focused to evaluate the antioxidant potential of hydro-methanolic extract of seed of Caesalpinia bonduc (Caesalpenacae) using different in vitro models. To evaluate the antioxidant activity, extract was examined on 2, 2-diphenyl-1-picrylhydrazyl radical scavenging effect, scavenging of hydrogen peroxide, hydroxyl radical scavenging potential, and anti-lipid peroxidation activity by biochemical methods. Total phenol and flavonoids contents in the said extract were measured biochemically as per standard methods. Results were compared with butylated hydroxyl toluene and α-tocopherol. Results indicated that hydro-methanolic extract has strong scavenging activity on 2, 2-diphenyl-1-picrylhydrazyl radical with IC(50) value 157.4 µg/ml, hydroxyl radical with IC(50) value 61.9 µg/ml and hydrogen peroxide with IC(50) value 64.32 µg/ml. Hydro-methanolic extract also showed notable inhibition in lipid peroxidation having IC(50) value 58.87 µg/ml. Phytochemical study focused that the extract is rich in phenolic compounds (24.66 mg gallic acid equivalent/g dried extract) and flavonoids (136.65 mg quercetin equivalent/g dried extract). Findings of the experiment indicated that the hydro-methanolic extract of seed of Caesalpinia bonduc is a source of natural antioxidants.