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Sample records for glucose analogs measured

  1. PET measurement of glucose membrane transport using labeled analogs: Distinction of transport from metabolic processes

    Carrier mediated glucose transport rates across brain capillary and myocardial cell membranes are many times higher than those expected for simple diffusion, and transport regulation can be an important determinant of tissue metabolic status. The authors have investigated the use of glucose analogs and dynamic positron tomography for the non-invasive measurement of unidirectional membrane transport rates. If analog extraction is sufficiently low, transport rates can be inferred directly from fitted kinetic rate constants. Fitting calculations were seen to be sensitive to the difficult to measure rapid components of the arterial input curves, to contributions from blood-borne label in the early data points, and to interference from other chemical forms in cases of significant phosphorylation. This last uncertainty was studied using serial scans of normal brain after venous injection of the well-transported but poorly phosphorylated analog 3-deoxy-3-fluoroglucose. Transport rate constants derived from 4-parameter fits of three hours of data were compared to those derived from 2-parameter fits of the first 12-20 minutes of data. Errors due to trapped label were absorbed primarily into the apparent distribution volume, allowing accurate estimation of transport rate constants from a brief data acquisition period. The study of the distinction of transport from phosphorylation also bears on the important question of the significance of the individual rate constants in the four-parameter fitting of brief dynamic scan sequences in studies of metabolic rate using 2-deoxy-2-fluoroglucose

  2. Liver kinetics of glucose analogs measured in pigs by PET: importance of dual-input blood sampling

    Munk, O L; Bass, L; Roelsgaard, K; Bender, D; Hansen, S B; Keiding, S

    2001-01-01

    parameters, because of ignorance of the dual blood supply from the hepatic artery and the portal vein to the liver. METHODS: Six pigs underwent PET after [15O]carbon monoxide inhalation, 3-O-[11C]methylglucose (MG) injection, and [18F]FDG injection. For the glucose scans, PET data were acquired for 90 min......Metabolic processes studied by PET are quantified traditionally using compartmental models, which relate the time course of the tracer concentration in tissue to that in arterial blood. For liver studies, the use of arterial input may, however, cause systematic errors to the estimated kinetic....... Hepatic arterial and portal venous blood samples and flows were measured during the scan. The dual-input function was calculated as the flow-weighted input. RESULTS: For both MG and FDG, the compartmental analysis using arterial input led to systematic underestimation of the rate constants for rapid blood...

  3. Analog to Digital Conversion in Physical Measurements

    Kapitaniak, T.; Zyczkowski, K.; Feudel, U.; Grebogi, C.

    1999-01-01

    There exist measuring devices where an analog input is converted into a digital output. Such converters can have a nonlinear internal dynamics. We show how measurements with such converting devices can be understood using concepts from symbolic dynamics. Our approach is based on a nonlinear one-to-one mapping between the analog input and the digital output of the device. We analyze the Bernoulli shift and the tent map which are realized in specific analog/digital converters. Furthermore, we d...

  4. [Long acting insulin analogs: possibly more stable glucose regulation

    Huvers, F.C.

    2004-01-01

    A better diabetes regulation seems possible, with the aid of the recently available insulin analogs than with isophane insulin, for patients with diabetes mellitus type 1 or 2. The glycaemic regulation can be improved and/or the chances of hypoglycaemia can be reduced by reduced variability in the r

  5. Reusable glucose fiber sensor for measuring glucose concentration in serum

    Cheng-Chih Hsu; Yi-Cheng Chen; Ju-Yi Lee; Chyan-Chyi Wu

    2011-01-01

    We demonstrate a glucose fiber sensor for measuring glucose concentration in serum. High resolution and rapid measurement are achieved through the integration of highly selective enzymes and heterodyne interferometry. The best resolution and response time obtained are 0.14mg/dL and 1.3 s, respectively. The stability of the sensor is also verified by investigating the initial phase variation. Experimental results show that the fiber sensor can be reused more than 10 times.%We demonstrate a glucose fiber sensor for measuring glucose concentration in serum.High resolution and rapid measurement are achieved through the integration of highly selective enzymes and heterodyne interferometry.The best resolution and response time obtained are 0.14 mg/dL and 1.3 s,respectively.The stability of the sensor is also verified by investigating the initial phase variation.Experimental results show that the fiber sensor can be reused more than 10 times.Fiber sensors have attracted considerable attention over the past two decades.Various kinds of fiber sensors have been proposed for measnring specific chemical concentrations[1-8].Most previously reported methods[1-5] involved measuring the variations in fluorescence intensity[2-4] or transmitted light[3,4].Hence,avoiding the inflnence of snrrounding light and the use of expensive photon detection equipment are important requirements.Furthermore,procedures for manufacturing optical biosensors are complicated[3] and qualitv is difficult to control[4]..

  6. A bioluminescent assay for measuring glucose uptake.

    Valley, Michael P; Karassina, Natasha; Aoyama, Natsuyo; Carlson, Coby; Cali, James J; Vidugiriene, Jolanta

    2016-07-15

    Identifying activators and inhibitors of glucose uptake is critical for both diabetes management and anticancer therapy. To facilitate such studies, easy-to-use nonradioactive assays are desired. Here we describe a bioluminescent glucose uptake assay for measuring glucose transport in cells. The assay is based on the uptake of 2-deoxyglucose and the enzymatic detection of the 2-deoxyglucose-6-phosphate that accumulates. Uptake can be measured from a variety of cell types, it can be inhibited by known glucose transporter inhibitors, and the bioluminescent assay yields similar results when compared with the radioactive method. With HCT 116 cells, glucose uptake can be detected in as little as 5000 cells and remains linear up to 50,000 cells with signal-to-background values ranging from 5 to 45. The assay can be used to screen for glucose transporter inhibitors, or by multiplexing with viability readouts, changes in glucose uptake can be differentiated from overall effects on cell health. The assay also can provide a relevant end point for measuring insulin sensitivity. With adipocytes and myotubes, insulin-dependent increases in glucose uptake have been measured with 10- and 2-fold assay windows, respectively. Significant assay signals of 2-fold or more have also been measured with human induced pluripotent stem cell (iPSC)-derived cardiomyocytes and skeletal myoblasts. PMID:27130501

  7. Nonlinear optical measurements of glucose concentration

    Yakovlev, V. V.

    2008-02-01

    Diabetes mellitus is a metabolic disease that currently affects about 7% of the US population, or roughly about 20 million people. Effectively controlling diabetes requires regular measurements of the blood sugar levels to ensure the one time insulin injection when the concentration of glucose reaches a critical level. In this report, nonlinear Raman microspectroscopy is demonstrated to be a promising new way of continuous and noninvasive way of measuring the glucose concentration.

  8. Measurement of glucose and 2-deoxy-2-[18F]fluoro-D-glucose transport and phosphorylation rates in myocardium using dual-tracer kinetic experiments

    To examine the use of 2-deoxy-2-[18F]fluoro-D-glucose (2-FDG) as a glucose analog for measuring glucose utilization rate in myocardium, dual-tracer kinetic experiments with 2-FDG and 2-[3H]glucose were performed in the perfused, isolated rabbit interventricular septum to measure simultaneously the transport and phosphorylation rates of glucose and 2-FDG. Results of the present study indicated that, in the septum, (i) the transport rate constants of 2-FDG and glucose were similar in magnitude, (ii) the phosphorylation rate constant for 2-FDG was about 60% of that of glucose, (iii) hypoxia caused an increase in phosphorylation rates of glucose and 2-FDG without affecting transport. 9 refs.; 1 figure; 3 tabs

  9. Blood Glucose Measurement Using Bioimpedance Technique

    Kamat, D. K.; Dhanashri Bagul; Patil, P. M.

    2014-01-01

    Bioimpedance measurement is gaining importance in wide field of bioresearch and biomedical systems due to its noninvasive nature. Noninvasive measurement method is very important to decrease infection and physical injuries which result due to invasive measurement. This paper presents basic principle of bioimpedance along with its application for blood glucose analysis and effect of frequency on impedance measurement. Input from bioimpedance sensor is given to amplifier and signal conditioner ...

  10. Non-Invasive Optical Blood Glucose Measurement

    Megha C.Pande

    2013-07-01

    Full Text Available The method for noninvasively blood glucose monitoring system is discussed in this paper. Lot of research work has been done in developing the device which is completely noninvasive to avoid the pros & cons because of frequent pricking. In this paper we are trying to analyze the noninvasive blood glucose measurement study in the near infrared region which is the most suitable region for blood glucose measurement. For this purpose we use a technique which is similar to pulseoximetry based on near infrared spectrometry .An infrared light of particular wavelength is passed through fingertip containing an arterial pulse component are derived,thus minimizing influences of basal components such as resting blood volume,skin, muscle and bone.

  11. Estimation of glucose utilization in a type 2 diabetes mellitus patient on insulin analogs with tumor hypoglycemia induced by IGF-II.

    Chode, Suresh; Albert, Stewart G; Shoemaker, James D; Green, Aileen L

    2016-02-01

    We present a 38-year-old male patient with insulin requiring type 2 diabetes mellitus (DM) who had fasting hypoglycemia caused by a non-pancreatic-islet-cell mesenchymal tumor producing IGF-II. The evaluation was confounded in that there was pre-existing DM being treated with insulin analogs. Insulin levels were assessed with an immunoassay with cross reactivity with the insulin analogs. An 18-Fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) scan localized the 19.7×18.0×17.8cm retroperitoneal mass. A 3.25kg tumor was resected. Post-operatively insulin treatment was resumed and circulating IGF-II levels returned to normal. The maximum standardized uptake values of FDG (SUVmax) along with a steady state glucose infusion of 17.5g/h were used to determine the components of glucose utilization due to IGF-II induced muscle glucose uptake (utilization, 62%) whereas the tumor itself was responsible for approximately 22% of measurable glucose uptake. Whereas tumor induced hypoglycemia has been ascribed to preferential glucose utilization by the tumor, the predominant hypoglycemic effect was due to hormonal IGF-II induced total body glucose uptake. PMID:26774399

  12. Blood Glucose Measurement Using Bioimpedance Technique

    D. K. Kamat

    2014-01-01

    Full Text Available Bioimpedance measurement is gaining importance in wide field of bioresearch and biomedical systems due to its noninvasive nature. Noninvasive measurement method is very important to decrease infection and physical injuries which result due to invasive measurement. This paper presents basic principle of bioimpedance along with its application for blood glucose analysis and effect of frequency on impedance measurement. Input from bioimpedance sensor is given to amplifier and signal conditioner AD5933. AD5933 is then interfaced with microcontroller LPC1768 using I2C bus for displaying reading on LCD. Results can also be stored in database using UART interface of LPC1768.

  13. Measurement of tear glucose levels with amperometric glucose biosensor/capillary tube configuration.

    Yan, Qinyi; Peng, Bo; Su, Gang; Cohan, Bruce E; Major, Terry C; Meyerhoff, Mark E

    2011-11-01

    An amperometric needle-type electrochemical glucose sensor intended for tear glucose measurements is described and employed in conjunction with a 0.84 mm i.d. capillary tube to collect microliter volumes of tear fluid. The sensor is based on immobilizing glucose oxidase on a 0.25 mm o.d. platinum/iridium (Pt/Ir) wire and anodically detecting the liberated hydrogen peroxide from the enzymatic reaction. Inner layers of Nafion and an electropolymerized film of 1,3-diaminobenzene/resorcinol greatly enhance the selectivity for glucose over potential interferences in tear fluid, including ascorbic acid and uric acid. Further, the new sensor is optimized to achieve very low detection limits of 1.5 ± 0.4 μM of glucose (S/N = 3) that is required to monitor glucose levels in tear fluid with a glucose sensitivity of 0.032 ± 0.02 nA/μM (n = 6). Only 4-5 μL of tear fluid in the capillary tube is required when the needle sensor is inserted into the capillary. The glucose sensor was employed to measure tear glucose levels in anesthetized rabbits over an 8 h period while also measuring the blood glucose values. A strong correlation between tear and blood glucose levels was found, suggesting that measurement of tear glucose is a potential noninvasive substitute for blood glucose measurements, and the new sensor configuration could aid in conducting further research in this direction. PMID:21961809

  14. Importance of correction for intravascular radioactivity in dynamic PCT studies using glucose analogs

    Recently, there has been considerable controversy concerning the accuracy of single scan approaches for estimating glucose metabolic rate. An alternative is to acquire a dynamic sequence of PCT data to estimate the individual rate constants of the conventional 4-parameters model. A model developed that accounts not only for the arterial blood radioactivity, but also for the venous blood radioactivity which itself depends on the local blood flow value, the individual plasma and RBC components of the blood radioactivity, the hematocrit, and the transport rate constants k/sub 1/ and k/sub 2/. Computer simulations predict overestimation in k/sub 1/, k/sub 2/ and k/sub 3/ of 30%, 40%, and 20%, respectively. The overestimation in the estimated metabolic rate, which is proportional to the term k/sub 1/k/sub 3//(k/sub 2/+k/sub 3/), was less than 16%. Parameter values for PCT studies on human subjects using 2-FDG and 3-FDG were evaluated with and without corrections for blood-horns radioactivity. Percent overestimations were similar for both analogs. Results from human studies are in good agreement with those predicted by computer simulation

  15. Activity of P536, a UDP-glucose analog, against Trypanosoma cruzi

    P536, a UDP-glucose analog which was previously described as an antiviral agent, has a potent and selective activity against the intracellular and extracellular stages of Trypanosoma cruzi in vitro. It had a 50% inhibitory concentration of less than 5 micrograms/ml for T. cruzi extracellular cultured forms (epimastigote) and of 25 micrograms/ml for T. cruzi intracellular forms (amastigote) growing inside J774G8 macrophage-like cells. In contrast, the 50% inhibitory concentration was 100 micrograms/ml or greater for cultured mammalian cells and 180 micrograms/ml for the proliferation of mouse spleen lymphocytes. Furthermore, the addition of P536 (50 micrograms/ml) to T. cruzi-infected J774G8 cells cured the infected macrophages, making them able to grow and function normally. Studies on the mechanism of action of this drug indicated that it inhibited incorporation of [35S]methionine, [3H]thymidine, [3H]mannose, [14C]-N-acetylglucosamine, and [3H]uridine into macromolecules by T. cruzi epimastigotes, the last being the most sensitive

  16. Potentiometric measurement of glucose concentration with an immobilized glucose oxidase/catalase electrode.

    Wingard, L B; Liu, C C; Wolfson, S K; Yao, S J; Drash, A L

    1982-01-01

    A series of enzyme electrodes for measurement of glucose have been constructed. The electrodes contain glucose oxidase immobilized on platinum, either with or without co-immobilization of catalase. When placed in buffered glucose, the enzyme electrodes show a potentiometric response to glucose with respect to a Ag/AgCl reference electrode. This response is reproducible in the physiologic range of glucose concentrations. The immobilization technique, some of the environmental variables such as oxygen concentration and pH, and several compounds that might interfere with the selectivity of the enzyme electrodes for glucose have received preliminary study. This direct potentiometric approach is undergoing further evaluation to determine the basic electrochemical mechanism responsible for the potentiometric signal and whether it can be adapted for continuous in vivo monitoring of the glucose concentration in body fluids. PMID:7172983

  17. Interaction of uridine diphosphate glucose analogs with calf liver uridine diphosphate glucose dehydrogenase. Influence of substituents at C-5 of pyrimidine nucleus.

    Shibaev, V N; Eliseeva, G I; Kochetkov, N K

    1975-09-22

    The interaction of alpha-D-glucopyranosyl pyrophosphates of 5-X-uridines (X = CH3, NH2, CH3O, I, Br, Cl, OH) with uridine diphosphate glucose (UDPGlc) dehydrogenase (EC 1.1.1.22) from calf liver has been studied. All the derivatives investigated were able to serve as substrates for the enzyme. The apparent Michaelis constants for UDPGlc-analogs were dependent both on electronic and steric factors. Increase of substituent negative inductive effect lead to decrease of pKa for ionization of the NH-group in the uracil nucleus and, consequently, to a diminishing of the proportion of the active analog species under the conditions of assay. After correction for the ionization effect, the Km values were found to depend on the van der Waals radius of the substituent. The value of 1.95 A seems to be critical, as the analogs with bulkier substituents at C-5 showed a decreased affinity to the enzyme. The maximal velocity values of the analogs were also dependent on nature of the substituent. Good linear correlation between log V and substituent hydrophobic phi-constant was observed for a number of the analogs, although V values for the nucleotides with X = H, OH or NH2 were higher than would be expected on the basis of the correlation. The significance of the results for understanding of the topography of UDPGlc dehydrogenase active site is discussed. PMID:1174552

  18. Contribution to a decision making model for analogical measurement validation

    In limits of studies taken on validity of analogic measures in nuclear power plant's operation, the present thesis takes aim at establishment of a model to reaching a decision on the indice of probability on measures obtained by preliminary validation system. In a first step, it is proposed to retain a system made by redundant measures in which the calcul of measures is based on the coherence between measures themselves and logic vote. In the second step, one equation is proposed to compute the index of probability of measures taken in account, the characteristics of the system

  19. Analogy between gambling and measurement-based work extraction

    Vinkler, Dror A.; Permuter, Haim H.; Merhav, Neri

    2016-04-01

    In information theory, one area of interest is gambling, where mutual information characterizes the maximal gain in wealth growth rate due to knowledge of side information; the betting strategy that achieves this maximum is named the Kelly strategy. In the field of physics, it was recently shown that mutual information can characterize the maximal amount of work that can be extracted from a single heat bath using measurement-based control protocols, i.e. using ‘information engines’. However, to the best of our knowledge, no relation between gambling and information engines has been presented before. In this paper, we briefly review the two concepts and then demonstrate an analogy between gambling, where bits are converted into wealth, and information engines, where bits representing measurements are converted into energy. From this analogy follows an extension of gambling to the continuous-valued case, which is shown to be useful for investments in currency exchange rates or in the stock market using options. Moreover, the analogy enables us to use well-known methods and results from one field to solve problems in the other. We present three such cases: maximum work extraction when the probability distributions governing the system and measurements are unknown, work extraction when some energy is lost in each cycle, e.g. due to friction, and an analysis of systems with memory. In all three cases, the analogy enables us to use known results in order to obtain new ones.

  20. Blood-brain transport of new glucose analogs and their effect on yeast hexokinase

    Dihalogen derivates of D-glucal were formed by the direct addition of halogen to the unsaturated double-bond between C atoms 1 and 2 in D-glucal. 82Br-glucal and 36Cl-glucal were injected into the carotid artery of rats and brain uptake studied and compared with uptake for D-glucose and 2-deoxy-D-glucose. Investigations with enzymes have shown D-glucal dihalides to be good substrates for hexokinase. (U.K.)

  1. An Integrated Analog Readout for Multi-Frequency Bioimpedance Measurements

    Kassanos, P.; Constantinou, L.; Triantis, I. F.; Demosthenous, A.

    2014-01-01

    Bioimpedance spectroscopy is used in a wide range of biomedical applications. This paper presents an integrated analog readout, which employs synchronous detection to perform galvanostatic multi-channel, multi-frequency bioimpedance measurements. The circuit was fabricated in a 0.35-μm CMOS technology and occupies an area of 1.52 mm2. The effect of random dc offsets is investigated, along with the use of chopping to minimize them. Impedance measurements of a known RC load and skin (using comm...

  2. Temperature influence on non-invasive blood glucose measurement

    Zhang, Xiqin; Yeo, Joon Hock

    2009-02-01

    Regular monitoring of blood sugar level is important for the management of diabetes. The Near-Infra-Red (NIR) spectroscopy method is a promising approach and this involves some form of contact with the body skin. It is noted that the skin temperature does fluctuate with the environment and physiological conditions and the temperature has an influence on the glucose measurement. In this paper, in-vitro and in-vivo investigations on the temperature influence on blood glucose measurement were studied. The in-vitro results from FTIR spectrometer show that sample temperature has significant influence on water absorption, which significantly affects the glucose absorption measurement. The in-vivo results show that when skin temperature around the measurement site is taken into consideration, the prediction of blood glucose level greatly improves.

  3. Study on optical measurement conditions for noninvasive blood glucose sensing

    Xu, Kexin; Chen, Wenliang; Jiang, Jingying; Qiu, Qingjun

    2004-05-01

    Utilizing Near-infrared Spectroscopy for non-invasive glucose concentration sensing has been a focusing topic in biomedical optics applications. In this paper study on measuring conditions of spectroscopy on human body is carried out and a series of experiments on glucose concentration sensing are conducted. First, Monte Carlo method is applied to simulate and calculate photons" penetration depth within skin tissues at 1600 nm. The simulation results indicate that applying our designed optical probe, the detected photons can penetrate epidermis of the palm and meet the glucose sensing requirements within the dermis. Second, we analyze the influence of the measured position variations and the contact pressure between the optical fiber probe and the measured position on the measured spectrum during spectroscopic measurement of a human body. And, a measurement conditions reproduction system is introduced to enhance the measurement repeatability. Furthermore, through a series of transmittance experiments on glucose aqueous solutions sensing from simple to complex we found that though some absorption variation information of glucose can be obtained from measurements using NIR spectroscopy, while under the same measuring conditions and with the same modeling method, choices toward measured components reduce when complication degree of components increases, and this causes a decreased prediction accuracy. Finally, OGTT experiments were performed, and a PLS (Partial Least Square) mathematical model for a single experiment was built. We can easily get a prediction expressed as RMSEP (Root Mean Square Error of Prediction) with a value of 0.5-0.8mmol/dl. But the model"s extended application and reliability need more investigation.

  4. Novel analog switching circuit for van der Pauw measurements

    David, T.; Molchadsky, I.; Somechi, A.; Rosenbaum, R.

    2005-01-01

    A simple electronic circuit is described using four common and very inexpensive analog multiplexer/demultiplexer chips. These analog switches are used to select eight different wiring configurations to a van der Pauw sample. Several interfacing schemes to a PC are suggested. The van der Pauw resistivity and Hall voltage expressions are also summarized.

  5. Fluorescence lifetime measurements of boronate derivatives to determine glucose concentration

    Gable, J H

    2000-06-01

    A novel investigation into the fluorescence lifetimes of molecules, both established and newly designed, was performed. These molecules are the basis of a continuous, minimally invasive, glucose sensor based on fluorescence lifetime measurements. This sensor, if coupled with an automated insulin delivery device, would effectively create an artificial pancreas allowing for the constant monitoring and control of glucose levels in a person with diabetes. The proposed sensor includes a fluorescent molecule that changes its' fluorescence properties upon binding selectively and reversibly to glucose. One possible sensor molecule is N-methyl-N-(9-methylene anthryl)-2-methylenephenylboronic acid (AB). The fluorescence intensity of AB was shown to change in response to changing glucose concentrations. (James, 1994) James proposed that when glucose binds to AB the fluorescence intensity increases due to an enhancement of the N{yields}B dative bond which prevents photoinduced electron transfer (PET). PET from the amine (N) to the fluorophore (anthracene) quenches the fluorescence. The dative bond between the boron and the amine can prevent PET by involving the lone pair of electrons on the amine in interactions with the boron rather than allowing them to be transferred to the fluorophore. Results of this research show the average fluorescence lifetime of AB also changes with glucose concentration. It is proposed that fluorescence is due to two components: (1) AB with an enhanced N{yields}B interaction, and no PET, and (2) AB with a weak N{yields}B interaction, resulting in fluorescence quenching by PET. Lifetime measurements of AB as a function of both the pH of the solvent and glucose concentration in the solution were made to characterize this two component system and investigate the nature of the N{yields}B bond. Measurements of molecules similar to AB were also performed in order to isolate behavior of specific AB constituents. These molecules are 9

  6. Near-infrared spectral methods for noninvasively measuring blood glucose

    Fei, Sun; Kong, Deyi; Mei, Tao; Tao, Yongchun

    2004-05-01

    Determination of blood glucose concentrations in diabetic patients is a frequently occurring procedure and an important tool for diabetes management. Use of noninvasive detection techniques can relieve patients from the pain of frequent finger pokes and avoid the infection of disease via blood. This thesis discusses current research and analyzes the advantages and shortages of different measurement methods, including: optical methods (Transmission, Polarimetry and scattering), then, we give emphasis to analyze the technology of near-infrared (NIR) spectra. NIR spectral range 700 nm ~2300 nm was used because of its good transparency for biological tissue and presence of glucose absorption band. In this work, we present an outline of noninvasive blood glucose measurement. A near-infrared light beam is passed through the finger, and the spectral components of the emergent beam are measured using spectroscopic techniques. The device includes light sources having the wavelengths of 600 nm - 1800 nm to illuminate the tissue. Receptors associated with the light sources for receiving light and generating a transmission signal representing the light transmitted are also provided. Once a transmission signal is received by receptors, and the high and low values from each of the signals are stored in the device. The averaged values are then analyzed to determine the glucose concentration, which is displayed on the device.

  7. In Alzheimer’s Disease, 6-Month Treatment with GLP-1 Analog Prevents Decline of Brain Glucose Metabolism: Randomized, Placebo-Controlled, Double-Blind Clinical Trial

    Gejl, Michael; Gjedde, Albert; Egefjord, Lærke; Møller, Arne; Hansen, Søren B.; Vang, Kim; Rodell, Anders; Brændgaard, Hans; Gottrup, Hanne; Schacht, Anna; Møller, Niels; Brock, Birgitte; Rungby, Jørgen

    2016-01-01

    In animal models, the incretin hormone GLP-1 affects Alzheimer’s disease (AD). We hypothesized that treatment with GLP-1 or an analog of GLP-1 would prevent accumulation of Aβ and raise, or prevent decline of, glucose metabolism (CMRglc) in AD. In this 26-week trial, we randomized 38 patients with AD to treatment with the GLP-1 analog liraglutide (n = 18), or placebo (n = 20). We measured Aβ load in brain with tracer [11C]PIB (PIB), CMRglc with [18F]FDG (FDG), and cognition with the WMS-IV scale (ClinicalTrials.gov NCT01469351). The PIB binding increased significantly in temporal lobe in placebo and treatment patients (both P = 0.04), and in occipital lobe in treatment patients (P = 0.04). Regional and global increases of PIB retention did not differ between the groups (P ≥ 0.38). In placebo treated patients CMRglc declined in all regions, significantly so by the following means in precuneus (P = 0.009, 3.2 μmol/hg/min, 95% CI: 5.45; 0.92), and in parietal (P = 0.04, 2.1 μmol/hg/min, 95% CI: 4.21; 0.081), temporal (P = 0.046, 1.54 μmol/hg/min, 95% CI: 3.05; 0.030), and occipital (P = 0.009, 2.10 μmol/hg/min, 95% CI: 3.61; 0.59) lobes, and in cerebellum (P = 0.04, 1.54 μmol/hg/min, 95% CI: 3.01; 0.064). In contrast, the GLP-1 analog treatment caused a numerical but insignificant increase of CMRglc after 6 months. Cognitive scores did not change. We conclude that the GLP-1 analog treatment prevented the decline of CMRglc that signifies cognitive impairment, synaptic dysfunction, and disease evolution. We draw no firm conclusions from the Aβ load or cognition measures, for which the study was underpowered. PMID:27252647

  8. Tunable laser diode system for noninvasive blood glucose measurements.

    Olesberg, Jonathon T; Arnold, Mark A; Mermelstein, Carmen; Schmitz, Johannes; Wagner, Joachim

    2005-12-01

    Optical sensing of glucose would allow more frequent monitoring and tighter glucose control for people with diabetes. The key to a successful optical noninvasive measurement of glucose is the collection of an optical spectrum with a very high signal-to-noise ratio in a spectral region with significant glucose absorption. Unfortunately, the optical throughput of skin is low due to absorption and scattering. To overcome these difficulties, we have developed a high-brightness tunable laser system for measurements in the 2.0-2.5 microm wavelength range. The system is based on a 2.3 microm wavelength, strained quantum-well laser diode incorporating GaInAsSb wells and AlGaAsSb barrier and cladding layers. Wavelength control is provided by coupling the laser diode to an external cavity that includes an acousto-optic tunable filter. Tuning ranges of greater than 110 nm have been obtained. Because the tunable filter has no moving parts, scans can be completed very quickly, typically in less than 10 ms. We describe the performance of the present laser system and avenues for extending the tuning range beyond 400 nm. PMID:16390586

  9. Effects of gamma-rays and glucose analogs on the energy metabolism of a cell line derived from human cerebral glioma

    Effects of gamma-rays and glucose analogs, 2-deoxy-D-glucose (2-DG), 5-thio-D-glucose (5-TG) and 3-O-methyl glucose (3-O-MG) on cellular energy metabolism have been studied in a cell line, derived from a human cerebral glioma, by analysing intermediates of glycolysis and some important nucleotides (ATP, NAD etc.) using the technique of isotachophoresis. Gamma-irradiation induced a transient decrease in the nucleotide levels accompanied by an accumulation of sugar phosphates, the nucleotide levels recovering in a few hours post-irradiation. 2-DG inhibited glycolysis and reduced the nucleotide levels of irradiated as well as unirradiated cells in a concentration-dependent manner both in presence and absence of respiration, whereas 5-TG and 3-OMG did not show significant effects in the presence of respiration. Reduced energy status observed with 2-DG under respiratory proficient conditions was completely reversed in 2 hr following its removal, whereas such a recovery was not observed in the absence of respiration. These results have important implications in the energy-linked modifications of tumor radiation response using glucose analogs. (author). 36 refs., 6 figs., 4 tabs

  10. Capillary Bedside Blood Glucose Measurement in Neonates: Missing a Diagnosis of Galactosemia

    Özbek, Mehmet Nuri; Öcal, Murat; Tanrıverdi, Sibel; Baysal, Birsen; Deniz, Ahmet; Öncel, Kahraman; Demirbilek, Hüseyin

    2015-01-01

    A number of factors may lead to inaccuracy in measurement of capillary blood glucose with a glucometer. Measurement of other carbohydrate molecules such as galactose and fructose along with glucose can potentially be a cause of error. We report a newborn patient who was referred to our hospital with conjugated bilirubinemia, hepatomegaly and high capillary blood glucose levels measured with a glucometer. Simultaneous biochemical measurements revealed normal blood glucose levels. Further inves...

  11. Investigation of [18F]2-fluoro-2-deoxyglucose for the measure of myocardial glucose metabolism

    Fluorine-18-labeled 2-deoxyglucose (FDG) was studied as a glucose analog for the measure of myocardial glucose metabolism. Myocardial uptake and retention, blood clearance, species dependence (dog, monkey, man), and effect of diet on uptake were investigated. Normal myocardial uptake of FDG was 3 to 4% of injected dose in dog and monkey, and 1 to 4% in man, compared with brain uptakes of 1.5 to 3% in dog, 5 to 6% in monkey, and 4 to 8% in man. The myocardial metabolic rate (MR) for glucose in the nonfasting (glycolytic) state was 2.8 times that in the fasting (ketogenic) state. Human subjects showed higher myocardial uptake after a normal meal than after a meal containing mostly free fatty acids (FFA). Blood clearance was rapid with initial clearance t/sub 1/2/ of 0.2 to 0.3 min, followed by a t/sub 1/2/ of 8.4 +- 1.2 min in dog and 11.6 +- 1.1 min in man. A small third component had half-times of 59 +- 10 min and 88 +- 4 min in dog and man, respectively. With the ECAT positron tomograph, high image-contrast ratios were found between heart and blood (dog 3.5/1, man 14/1), heart and lung (dog 9/1, man 20/1), and heart and liver (dog 15/1, man 10/1). The FDG was taken up rapidly by the myocardium without any significant tissue clearance over a 4-hr period. The FDG exhibited excellent imaging properties. Average counting rates of 12K, 20K, and 40K c/min-mCi injected are obtained in human subjects with high, medium, and low resolutions of the ECAT tomograph. Determination of glucose and FFA MR in vivo with EACT provides a method for investigation and assessment of changing aerobic and anaerobic metabolic rates in ischemic heart disease in man

  12. Modeling and Measurement of Correlation between Blood and Interstitial Glucose Changes

    Shi, Ting; Li, Dachao; Li, Guoqing; Zhang, Yiming; Xu, Kexin; Lu, Luo

    2016-01-01

    One of the most effective methods for continuous blood glucose monitoring is to continuously measure glucose in the interstitial fluid (ISF). However, multiple physiological factors can modulate glucose concentrations and affect the lag phase between blood and ISF glucose changes. This study aims to develop a compensatory tool for measuring the delay in ISF glucose variations in reference to blood glucose changes. A theoretical model was developed based on biophysics and physiology of glucose transport in the microcirculation system. Blood and interstitial fluid glucose changes were measured in mice and rats by fluorescent and isotope methods, respectively. Computer simulation mimicked curves were fitted with data resulting from fluorescent measurements of mice and isotope measurements of rats, indicating that there were lag times for ISF glucose changes. It also showed that there was a required diffusion distance for glucose to travel from center of capillaries to interstitial space in both mouse and rat models. We conclude that it is feasible with the developed model to continuously monitor dynamic changes of blood glucose concentration through measuring glucose changes in ISF with high accuracy, which requires correct parameters for determining and compensating for the delay time of glucose changes in ISF.

  13. Capillary bedside blood glucose measurement in neonates: missing a diagnosis of galactosemia.

    Özbek, Mehmet Nuri; Öcal, Murat; Tanrıverdi, Sibel; Baysal, Birsen; Deniz, Ahmet; Öncel, Kahraman; Demirbilek, Hüseyin

    2015-03-01

    A number of factors may lead to inaccuracy in measurement of capillary blood glucose with a glucometer. Measurement of other carbohydrate molecules such as galactose and fructose along with glucose can potentially be a cause of error. We report a newborn patient who was referred to our hospital with conjugated bilirubinemia, hepatomegaly and high capillary blood glucose levels measured with a glucometer. Simultaneous biochemical measurements revealed normal blood glucose levels. Further investigation led to a diagnosis of classical galactosemia. Capillary blood glucose level measured with glucometer also dropped to normal values following cessation of breastfeeding and initiation of feeding with a lactose-free formula. PMID:25800483

  14. Combined use of basal insulin analog and acarbose reduces postprandial glucose in patients with uncontrolled type 2 diabetes

    Kim, Ji-Hyun; Ahn, Ji-Hyun; Kim, Soo-Kyung; Lee, Dae-Ho; Kim, Hye-Soon; Shon, Ho-Sang; Jeon, Hyun-Jeong; Kim, Tae-Hwa; Cho, Yong-Wook; Kim, Jae-Taek; Han, Sung-Min; Chung, Choon-Hee; Ryu, Ohk-Hyun; Lee, Jae-Min; Lee, Soon-Hee

    2014-01-01

    Aims/Introduction Early initiation of basal insulin therapy is recommended for normalizing fasting blood glucose in type 2 diabetes mellitus. However, basal insulin treatment might not adequately control postprandial glucose levels. The present study evaluated whether the combination of the α-glucosidase inhibitor, acarbose, and basal insulin improved blood glucose control under daily-life treatment conditions in a large sample of Korean patients. Materials and Methods The present study was a...

  15. Synthesis and characterization of 1-deoxy-β-D-glucopyranosyl-methanephosphonyl-5'-uridine monophosphate: a phosphono analog of UDP-glucose

    The phosphono analog of UDP-glucose (UDPG) has been synthesized as a first entry into potential dead-end inhibitors of glycosyltransferases using UDP-sugars such as UDP-glucuronyltransferase and possible alternative substrates for UDPG dehydrogenase and epimerase. 1-Deoxy-β-D-glucopyranosylmethanephosphonate (G-1-CH2P) was synthesized by modifications of literature procedures and characterized by 1H, 31P and 13C NMR. Condensation of G-1-CH2P with UMP morpholidate gave the expected phosphono analog of UDPG (UDPCH2G) in low yield. G-1-CH2P was found to be a substrate for UTP: glucose-1-phosphate pyrophosphoyrlase. Thus, UDPCH2G can be prepared enzymatically from G-1-CH2P and UTP by the coupled action of the pyrophosphoyrlase and inorganic pyrophosphatase. Preliminary evidence suggests UDPCH2G is a very poor substrate for UDPG dehydrogenase. Thus, efficient enzymatic synthesis of the phosphono analog (UDPCH2GA) of UDP-glucuronate appears unlikely

  16. Non-invasive measurement of glucose uptake of skeletal muscle tissue models using a glucose nanobiosensor.

    Obregón, Raquel; Ahadian, Samad; Ramón-Azcón, Javier; Chen, Luyang; Fujita, Takeshi; Shiku, Hitoshi; Chen, Mingwei; Matsue, Tomokazu

    2013-12-15

    Skeletal muscle tissues play a significant role to maintain the glucose level of whole body and any dysfunction of this tissue leads to the diabetes disease. A culture medium was created in which the muscle cells could survive for a long time and meanwhile it did not interfere with the glucose sensing. We fabricated a model of skeletal muscle tissues in vitro to monitor its glucose uptake. A nanoporous gold as a high sensitive nanobiosensor was then successfully developed and employed to detect the glucose uptake of the tissue models in this medium upon applying the electrical stimulation in a rapid, and non-invasive approach. The response of the glucose sensor was linear in a wide concentration range of 1-50 mM, with a detection limit of 3 μM at a signal-to-noise ratio of 3.0. The skeletal muscle tissue was electrically stimulated during 24 h and glucose uptake was monitored during this period. During the first 3 h of stimulation, electrically stimulated muscle tissue consumed almost twice the amount of glucose than counterpart non-stimulated sample. In total, the glucose consumption of muscle tissues was higher for the electrically stimulated tissues compared to those without applying the electrical field. PMID:23856563

  17. Development of a fluorescent method for simultaneous measurement of glucose concentrations in interstitial fluid and blood

    Continuous blood glucose monitoring is of great clinical significance to patients with diabetes. One of the effective methods to monitor blood glucose is to measure glucose concentrations of interstitial fluid (ISF). However, a time-delay problem exists between ISF and blood glucose concentrations, which results in difficulty in indicating real-time blood glucose concentrations. Therefore, we developed a fluorescent method to verify the accuracy and reliability of simultaneous ISF and blood glucose measurement, especially incorporating it into research on the delay relationship between blood and ISF glucose changes. This method is based on a competitive reaction among borate polymer, alizarin and glucose. When glucose molecules combine with borate polymers in alizarin–borate polymer competitively, changes in fluorescence intensity demonstrate changes in glucose concentrations. By applying the measured results to the blood and ISF glucose delay relationship, we were able to calculate the time delay as an average of 2.16 ± 2.05 min for ISF glucose changes with reference to blood glucose concentrations. (paper)

  18. Evaluation of the appropriateness of using glucometers for measuring the blood glucose levels in mice.

    Togashi, Yu; Shirakawa, Jun; Okuyama, Tomoko; Yamazaki, Shunsuke; Kyohara, Mayu; Miyazawa, Ayumi; Suzuki, Takafumi; Hamada, Mari; Terauchi, Yasuo

    2016-01-01

    Glucometers are also widely used in diabetes research conducted using animal models. However, the appropriateness of measuring blood glucose levels using glucometers in animal models remains unclear. In this study, we evaluated the consistency between the blood glucose levels measured by 11 models of glucometers and plasma glucose levels measured by a laboratory biochemical test in blood samples collected by retro-orbital sinus puncture or tail-tip amputation. In both blood samples obtained by retro-orbital sinus puncture and those obtained by tail-tip amputation, 10 of the 11 models of glucometers yielded higher glucose values, while 1 yielded lower glucose values, than the plasma glucose values yielded by the laboratory test, the differences being in direct proportion to the plasma glucose values. Most glucometers recorded higher blood glucose levels after glucose loading and lower blood glucose levels after insulin loading in retro-orbital sinus blood as compared to tail vein blood. Our data suggest that the blood glucose levels measured by glucometers in mice tended to be higher than the plasma glucose levels yielded by the biochemical test under the hyperglycemic state, and that differences in the measured levels were observed according to the blood collection method depending on the glycemia status. PMID:27151424

  19. Differential half-maximal effects of human insulin and its analogs for in situ glucose transport and protein synthesis in rat soleus muscle

    Weinstein, Randi B.; Eleid, Noura; LeCesne, Catherine; Durando, Bianca; Crawford, Julie T.; Heffner, Michelle; Layton, Christle; O'Keefe, Matthew; Robinson, Jennifer; Rudinsky, Suzy; Henriksen, Erik J.; Tischler, Marc E.

    2002-01-01

    Analogs of human insulin have been used to discriminate between responses of metabolic and mitogenic (growth-related) pathways. This study compared the stimulatory effects of human insulin (HI) and 2 analogs (X2, B-Asp(9), B-Glu(27) and H2, A-His(8),B-His(4),B-Glu(10), B-His(27)) on glucose uptake and protein synthesis in rat soleus muscle in situ. Glucose uptake, estimated by intramuscular (IM) injection of 2-deoxy[1,2-3H]glucose with or without insulin, was maximally increased at 10(-6) mol/L for HI and X2 and 10(-7) mol/L for H2. HI had a larger effect (318%) than either X2 (156%) or H2 (124%). The half-maximal effect (ED(50)) values for HI, X2, and H2 were 3.3 x10(-8) mol/L, 1.7 x 10(-7) mol/L, and 1.6 x 10(-9) mol/L, respectively. Protein synthesis, estimated by protein incorporation of [(3)H]phenylalanine injected into muscles with or without insulin, was maximally increased at 10(-5) mol/L for HI and 10(-6) for X2 and H2. HI had a larger effect in stimulating protein synthesis (34%) than either X2 (25%) or H2 (19.8%). The ED(50) values for HI, X2, and H2 were 3.0 x 10(-7) mol/L, 3.2 x 10(-7) mol/L, and 1.0 x 10(-9) mol/L, respectively. The biological potency of each analog (ED(50)insulin/ED(50)analog) showed X2 to be less potent than HI for both glucose uptake (0.2) and protein synthesis (0.9), whereas H2 is more potent than HI with ratios of 20 and 300, respectively. These data suggest that this approach for studying insulin responsiveness in a single muscle in situ may be a useful tool for investigating insulin signaling in muscle in vivo. Copyright 2002, Elsevier Science (USA). All rights reserved.

  20. Relationship between fluctuations in glucose levels measured by continuous glucose monitoring and vascular endothelial dysfunction in type 2 diabetes mellitus

    Torimoto Keiichi

    2013-01-01

    Full Text Available Abstract Background Fluctuations in blood glucose level cause endothelial dysfunction and play a critical role in onset and/or progression of atherosclerosis. We hypothesized that fluctuation in blood glucose levels correlate with vascular endothelial dysfunction and that this relationship can be assessed using common bedside medical devices. Methods Fluctuations in blood glucose levels were measured over 24 hours by continuous glucose monitoring (CGM on admission day 2 in 57 patients with type 2 diabetes mellitus. The reactive hyperemia index (RHI, an index of vascular endothelial function, was measured using peripheral arterial tonometry (EndoPAT on admission day 3. Results The natural logarithmic-scaled RHI (L_RHI correlated with SD (r=−0.504; PPP=0.001 and percentage of time ≥200 mg/dl (r=−0.292; P=0.028. In 12 patients with hypoglycemia, L_RHI also correlated with the percentage of time at hypoglycemia (r=−0.589; P=0.044. L_RHI did not correlate with HbA1c or fasting plasma glucose levels. Furthermore, L_RHI did not correlate with LDL cholesterol, HDL cholesterol, and triglyceride levels or with systolic and diastolic blood pressures. Finally, multivariate analysis identified MAGE as the only significant determinant of L_RHI. Conclusions Fluctuations in blood glucose levels play a significant role in vascular endothelial dysfunction in type 2 diabetes. Trial registration UMIN000007581

  1. Analog voltmeter for measuring oxygen concentration in fast reactor sodium circuits

    An analog voltmeter designed for oxygen concentration measurement in the sodium coolant of fast reactors and thus the determination of oxygen corrosion action on the reactor core materials was tested in a sodium loop. The oxygen concentration is determined from the measurements of voltage across a solid electrolyte galvanic cell and of ambient temperature measured by a thermocouple. Thermocouple voltage ranges within 10 and 21 mV while the input from the galvanic cell within 0.2 and 0.45 V. The measured values of both quantities are combined at the analog voltmeter output according to a certain relation shown and give oxygen concentration. (Z.M.)

  2. Development of an Amperometric-Based Glucose Biosensor to Measure the Glucose Content of Fruit

    Lee Fung Ang; Lip Yee Por; Mun Fei Yam

    2015-01-01

    An amperometric enzyme-electrode was introduced where glucose oxidase (GOD) was immobilized on chitosan membrane via crosslinking, and then fastened on a platinum working electrode. The immobilized enzyme showed relatively high retention activity. The activity of the immobilized enzyme was influenced by its loading, being suppressed when more than 0.6 mg enzyme was used in the immobilization. The biosensor showing the highest response to glucose utilized 0.21 ml/cm2 thick chitosan membrane. T...

  3. Effects of hyperglycemia on glucose production and utilization in humans. Measurement with [3H]-2-, [3H]-3-, and [14C]-6-glucose

    Studies with tritiated isotopes of glucose have demonstrated that hyperglycemia per se stimulates glucose utilization and suppresses glucose production in humans. These conclusions rely on the assumption that tritiated glucose provides an accurate measure of glucose turnover. However, if in the presence of hyperglycemia the isotope either loses its label during futile cycling or retains its label during cycling through glycogen, then this assumption is not valid. To examine this question, glucose utilization and glucose production rates were measured in nine normal subjects with a simultaneous infusion of [3H]-2-glucose, an isotope that may undergo futile cycling but does not cycle through glycogen; [14C]-6-glucose, an isotope that may cycle through glycogen but does not futile cycle; and [3H]-3-glucose, an isotope that can both undergo futile cycling and cycle through glycogen. In the postabsorptive state at plasma glucose concentration of 95 mg X dl-1, glucose turnover determined with [14C]-6-glucose (2.3 +/- 0.1 mg X kg-1 X min-1) was greater than that determined with [33H]glucose (2.1 +/- 0.1 mg X kg-1 X min-1, P = 0.002) and slightly less than that determined with [3H]-2-glucose (2.7 +/- 0.2 mg X kg-1 X min-1, P = 0.08). Plasma glucose was then raised from 95 to 135 to 175 mg X dl-1 while insulin secretion was inhibited, and circulating insulin, glucagon, and growth hormone concentrations were maintained constant by infusion of these hormones and somatostatin. Glucose production and utilization rates determined with [14C]-6-glucose continued to be less than those determined with [3H]-2-glucose and greater than those seen with [3H]-3-glucose

  4. Picosecond time measurement using ultra fast analog memories

    Breton, D.; Delagnes, E.; Maalmi, J.

    2009-01-01

    International audience The currently existing electronics dedicated to precise time measurement is mainly based on the use of constant fraction discriminators (CFD) associated with Time to Digital Converters (TDC). The constant fraction technique minimizes the time walk effect (dependency of timing on the pulse amplitude). Several attempts have been made to integrate CFD in multi-channel ASICs. But the time resolution measured on the most advanced one is of the order of 30 ps rms. Two main...

  5. Combined use of basal insulin analog and acarbose reduces postprandial glucose in patients with uncontrolled type 2 diabetes

    Kim, Ji-Hyun; Ahn, Ji-Hyun; Kim, Soo-Kyung; Lee, Dae-Ho; Kim, Hye-Soon; Shon, Ho-Sang; Jeon, Hyun-Jeong; Kim, Tae-Hwa; Cho, Yong-Wook; Kim, Jae-Taek; Han, Sung-Min; Chung, Choon-Hee; Ryu, Ohk-Hyun; Lee, Jae-Min; Lee, Soon-Hee; Kwon, Min-Jeong; Kim, Tae-kyun; Namgoong, Il-Seong; Kim, Eun-Sook; Jung, In-Kyung; Moon, Sung-Dae; Han, Je-Ho; Kim, Chong-Hwa; Cho, Eun-Hee; Kim, Ki-Young; Park, Hee-Baek; Lee, Ki-Sang; Lee, Sung-Woo; Lee, Sang-Cheol; Kang, Cheol-Min; Jeon, Byung-Sook; Song, Min-Seop; Yun, Seung-Baik; Chung, Hyung-Keun; Seong, Jong-Ho; Jeong, Jin-Yi; Cha, Bong-Yun

    2015-01-01

    Aims/Introduction Early initiation of basal insulin therapy is recommended for normalizing fasting blood glucose in type 2 diabetes mellitus. However, basal insulin treatment might not adequately control postprandial glucose levels. The present study evaluated whether the combination of the α-glucosidase inhibitor, acarbose, and basal insulin improved blood glucose control under daily-life treatment conditions in a large sample of Korean patients. Materials and Methods The present study was a multicenter, prospective, observational study under daily-life treatment conditions. A total of 539 patients with type 2 diabetes who were treated with basal insulin and additional acarbose were enrolled and followed up for 20 weeks. Changes in hemoglobin A1c, fasting and postprandial blood glucose were evaluated at baseline and at the end of the observation period. The physician and patient satisfaction of the combination treatment and safety were assessed. Results Hemoglobin A1c decreased by 0.55 ± 1.05% from baseline (P < 0.0001). Fasting and postprandial blood glucose levels were reduced by 0.89 ± 3.79 and 2.59 ± 4.77 mmol/L (both P < 0.0001). The most frequently reported adverse drug reactions were flatulence (0.37%) and abnormal gastrointestinal sounds (0.37%), and all were mild in intensity and transient. In the satisfaction evaluation, 79.0% of physicians and 77.3% of patients were ‘very satisfied’ or ‘satisfied’ with the combined basal insulin and acarbose therapy. Conclusions Combination therapy of basal insulin and acarbose in patients with type 2 diabetes improved glucose control, and had no drug-specific safety concerns, suggesting that the treatment might benefit individuals who cannot control blood glucose with basal insulin alone. PMID:25802730

  6. Noninvasive diagnostic devices for diabetes through measuring tear glucose.

    Zhang, Jin; Hodge, William; Hutnick, Cindy; Wang, Xianbin

    2011-01-01

    This article reviews the development of a noninvasive diagnostic for diabetes by detecting ocular glucose. Early diagnosis and daily management are very important to diabetes patients to ensure a healthy life. Commercial blood glucose sensors have been used since the 1970s. Millions of diabetes patients have to prick their finger for a drop of blood 4-5 times a day to check blood glucose levels--almost 1800 times annually. There is a strong need to have a noninvasive device to help patients to manage the disease easily and painlessly. Instead of detecting the glucose in blood, monitoring the glucose level in other body fluids may provide a feasible approach for noninvasive diagnosis and diabetes control. Tear glucose has been studied for several decades. This article reviews studies on ocular glucose and its monitoring methods. Attempts to continuously monitor the concentration of tear glucose by using contact lens-based sensors are discussed as well as our current development of a nanostructured lens-based sensor for diabetes. This disposable biosensor for the detection of tear glucose may provide an alternative method to help patients manage the disease conveniently. PMID:21303640

  7. Development of an amperometric-based glucose biosensor to measure the glucose content of fruit.

    Lee Fung Ang

    Full Text Available An amperometric enzyme-electrode was introduced where glucose oxidase (GOD was immobilized on chitosan membrane via crosslinking, and then fastened on a platinum working electrode. The immobilized enzyme showed relatively high retention activity. The activity of the immobilized enzyme was influenced by its loading, being suppressed when more than 0.6 mg enzyme was used in the immobilization. The biosensor showing the highest response to glucose utilized 0.21 ml/cm2 thick chitosan membrane. The optimum experimental conditions for the biosensors in analysing glucose dissolved in 0.1 M phosphate buffer (pH 6.0 were found to be 35°C and 0.6 V applied potential. The introduced biosensor reached a steady-state current at 60 s. The apparent Michaelis-Menten constant ([Formula: see text] of the biosensor was 14.2350 mM, and its detection limit was 0.05 mM at s/n > 3, determined experimentally. The RSD of repeatability and reproducibility of the biosensor were 2.30% and 3.70%, respectively. The biosensor was showed good stability; it retained ~36% of initial activity after two months of investigation. The performance of the biosensors was evaluated by determining the glucose content in fruit homogenates. Their accuracy was compared to that of a commercial glucose assay kit. There was no significance different between two methods, indicating the introduced biosensor is reliable.

  8. Development of an amperometric-based glucose biosensor to measure the glucose content of fruit.

    Ang, Lee Fung; Por, Lip Yee; Yam, Mun Fei

    2015-01-01

    An amperometric enzyme-electrode was introduced where glucose oxidase (GOD) was immobilized on chitosan membrane via crosslinking, and then fastened on a platinum working electrode. The immobilized enzyme showed relatively high retention activity. The activity of the immobilized enzyme was influenced by its loading, being suppressed when more than 0.6 mg enzyme was used in the immobilization. The biosensor showing the highest response to glucose utilized 0.21 ml/cm2 thick chitosan membrane. The optimum experimental conditions for the biosensors in analysing glucose dissolved in 0.1 M phosphate buffer (pH 6.0) were found to be 35°C and 0.6 V applied potential. The introduced biosensor reached a steady-state current at 60 s. The apparent Michaelis-Menten constant ([Formula: see text]) of the biosensor was 14.2350 mM, and its detection limit was 0.05 mM at s/n > 3, determined experimentally. The RSD of repeatability and reproducibility of the biosensor were 2.30% and 3.70%, respectively. The biosensor was showed good stability; it retained ~36% of initial activity after two months of investigation. The performance of the biosensors was evaluated by determining the glucose content in fruit homogenates. Their accuracy was compared to that of a commercial glucose assay kit. There was no significance different between two methods, indicating the introduced biosensor is reliable. PMID:25789757

  9. Development of reconfigurable analog and digital circuits for plasma diagnostics measurement systems

    In long pulse discharge tokamak, a large number of diagnostic channels are being used to understand the complex behavior of plasma. Different diagnostics demand different types of analog and digital processing for plasma parameters measurement. This leads to variable requirements of signal processing for diagnostic measurement. For such types of requirements, we have developed hardware with reconfigurable electronic devices, which provide flexible solution for rapid development of measurement system. Here the analog processing is achieved by Field Programmable Analog Array (FPAA) integrated circuit while reconfigurable digital devices (CPLD/FPGA) achieve digital processing. FPAA's provide an ideal integrated platform for implementing low to medium complexity analog signal processing. With dynamic reconfigurability, the functionality of the FPAA can be reconfigured in-system by the designer or on the fly by a microprocessor. This feature is quite useful to manipulate the tuning or the construction of any part of the analog circuit without interrupting operation of the FPAA, thus maintaining system integrity. The hardware operation control logic circuits are configured in the reconfigurable digital devices (CPLD/FPGA) to control proper hardware functioning. These reconfigurable devices provide the design flexibility and save the component space on the board. It also provides the flexibility for various setting through software. The circuit controlling commands are either issued by computer/processor or generated by circuit itself. (author)

  10. Measure and category a survey of the analogies between topological and measure spaces

    Oxtoby, John C

    1980-01-01

    In this edition, a set of Supplementary Notes and Remarks has been added at the end, grouped according to chapter. Some of these call attention to subsequent developments, others add further explanation or additional remarks. Most of the remarks are accompanied by a briefly indicated proof, which is sometimes different from the one given in the reference cited. The list of references has been expanded to include many recent contributions, but it is still not intended to be exhaustive. John C. Oxtoby Bryn Mawr, April 1980 Preface to the First Edition This book has two main themes: the Baire category theorem as a method for proving existence, and the "duality" between measure and category. The category method is illustrated by a variety of typical applications, and the analogy between measure and category is explored in all of its ramifications. To this end, the elements of metric topology are reviewed and the principal properties of Lebesgue measure are derived. It turns out that Lebesgue integration is not es...

  11. Glycolysis-induced discordance between glucose metabolic rates measured with radiolabeled fluorodeoxyglucose and glucose

    We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered [18F]fluorodeoxyglucose (FDG) and [14C]-6-glucose (GLC). FDG-6-phosphate accumulation is proportional to the rate of glucose phosphorylation, which occurs before the divergence of glycolytic (GMg) and oxidative (GMo) glucose metabolism and is therefore related to total cerebral glucose metabolism GMt: GMg + GMo = GMt. With oxidative metabolism, the 14C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the 14C label is lost from the brain via lactate production and efflux from the brain. Thus, cerebral GLC metabolite concentration may be more closely related to GMo than to GMt. If true, the glycolytic metabolic rate will be related to the difference between FDG- and GLC-derived LCMRglc. Thus far, we have studied normal awake rats, rats with limbic activation induced by kainic acid (KA), and rats visually stimulated with 16-Hz flashes. In KA-treated rats, significant discordance between FDG and GLC accumulation, which we attribute to glycolysis, occurred only in activated limbic structures. In visually stimulated rats, significant discordance occurred only in the optic tectum

  12. Glycolysis-induced discordance between glucose metabolic rates measured with radiolabeled fluorodeoxyglucose and glucose

    Ackermann, R.F.; Lear, J.L. (UCLA School of Medicine (USA))

    1989-12-01

    We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered ({sup 18}F)fluorodeoxyglucose (FDG) and ({sup 14}C)-6-glucose (GLC). FDG-6-phosphate accumulation is proportional to the rate of glucose phosphorylation, which occurs before the divergence of glycolytic (GMg) and oxidative (GMo) glucose metabolism and is therefore related to total cerebral glucose metabolism GMt: GMg + GMo = GMt. With oxidative metabolism, the {sup 14}C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the {sup 14}C label is lost from the brain via lactate production and efflux from the brain. Thus, cerebral GLC metabolite concentration may be more closely related to GMo than to GMt. If true, the glycolytic metabolic rate will be related to the difference between FDG- and GLC-derived LCMRglc. Thus far, we have studied normal awake rats, rats with limbic activation induced by kainic acid (KA), and rats visually stimulated with 16-Hz flashes. In KA-treated rats, significant discordance between FDG and GLC accumulation, which we attribute to glycolysis, occurred only in activated limbic structures. In visually stimulated rats, significant discordance occurred only in the optic tectum.

  13. Glycolysis-induced discordance between glucose metabolic rates measured with radiolabeled fluorodeoxyglucose and glucose.

    Ackermann, R F; Lear, J L

    1989-12-01

    We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered [18F]fluorodeoxyglucose (FDG) and [14C]-6-glucose (GLC). FDG-6-phosphate accumulation is proportional to the rate of glucose phosphorylation, which occurs before the divergence of glycolytic (GMg) and oxidative (GMo) glucose metabolism and is therefore related to total cerebral glucose metabolism GMt: GMg + GMo = GMt. With oxidative metabolism, the 14C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the 14C label is lost from the brain via lactate production and efflux from the brain. Thus, cerebral GLC metabolite concentration may be more closely related to GMo than to GMt. If true, the glycolytic metabolic rate will be related to the difference between FDG- and GLC-derived LCMRglc. Thus far, we have studied normal awake rats, rats with limbic activation induced by kainic acid (KA), and rats visually stimulated with 16-Hz flashes. In KA-treated rats, significant discordance between FDG and GLC accumulation, which we attribute to glycolysis, occurred only in activated limbic structures. In visually stimulated rats, significant discordance occurred only in the optic tectum. PMID:2584274

  14. Noninvasive Diagnostic Devices for Diabetes through Measuring Tear Glucose

    Zhang, Jin; Hodge, William; Hutnick, Cindy; Wang, Xianbin

    2011-01-01

    This article reviews the development of a noninvasive diagnostic for diabetes by detecting ocular glucose. Early diagnosis and daily management are very important to diabetes patients to ensure a healthy life. Commercial blood glucose sensors have been used since the 1970s. Millions of diabetes patients have to prick their finger for a drop of blood 4–5 times a day to check blood glucose levels—almost 1800 times annually. There is a strong need to have a noninvasive device to help patients to...

  15. Non-invasive Glucose Measurements Using Wavelength Modulated Differential Photothermal Radiometry (WM-DPTR)

    Guo, X.; Mandelis, A.; Zinman, B.

    2012-11-01

    Wavelength-modulated differential laser photothermal radiometry (WM-DPTR) is introduced for potential development of clinically viable non-invasive glucose biosensors. WM-DPTR features unprecedented glucose-specificity and sensitivity by combining laser excitation by two out-of-phase modulated beams at wavelengths near the peak and the baseline of a prominent and isolated mid-IR glucose absorption band. Measurements on water-glucose phantoms (0 to 300 mg/dl glucose concentration) demonstrate high sensitivity to meet wide clinical detection requirements ranging from hypoglycemia to hyperglycemia. The measurement results have been validated by simulations based on fully developed WM-DPTR theory. For sensitive and accurate glucose measurements, the key is the selection and tight control of the intensity ratio and the phase shift of the two laser beams.

  16. High glucose causes delayed fetal lung maturation as measured by fluorescence anisotropy.

    Gewolb, I H; Unger, M E; Merdian, W; Deutsch, J; Cavalieri, R L

    1993-06-15

    Fluorescence anisotropy has been used to estimate the microviscosity of the surfactant phospholipid bilayer and no predict fetal lung maturity in human amniotic fluid; its usefulness in in vitro systems has been recently demonstrated. To investigate the effect of high glucose on lung development, anisotropy measurements were performed on 20-day fetal rat lung explant homogenates and culture media after culture for 48 hours in medium containing final concentrations of 10, 50, and 100mM glucose. Anisotropy of lung tissue cultured in 100mM glucose was significantly increased when compared to those cultured in 10mM glucose (p < .01). After 48 hours, the media from samples grown in 100mM glucose had significantly higher anisotropy (.2210 +/- .0031) than did media from explants grown in 50mM glucose (.2027 +/- .0079; p < .05), or in 10mM glucose (.1886 +/- .0046; p < .001). Relative fluorescence intensity of explants grown in 100mM glucose was 74.4 +/- 5.7% of those grown in 10mM glucose (p < .01). Fluorescence intensity of media was also decreased by 15-30% under higher glucose considerations (p < .05). These data suggest that surfactant synthesized and secreted under high glucose conditions, such as exist in the infant of the diabetic gestation, may have qualitative as well as quantitative changes. PMID:8512578

  17. Application of transcutaneous diffuse reflectance spectroscopy in the measurement of blood glucose concentration

    Wenliang Chen(陈文亮); Rong Liu(刘蓉); Houxin Cui(崔厚欣); Kexin Xu(徐可欣); Lina Lü(吕丽娜)

    2004-01-01

    In this paper, the propagation characteristics of near-infrared (NIR) light in the palm tissue are analyzed,and the principle and feasibility of using transcutaneous diffuse reflectance spectroscopy for non-invasive blood glucose detection are presented. An optical probe suitable for measuring the diffuse reflectance spectrum of human palm and a non-invasive blood glucose detection system using NIR spectroscopy are designed. Based on this system, oral glucose tolerance tests are performed to measure the blood glucose concentrations of two young healthy volunteers. The partial least square calibration model is then constructed by all individual experimental data. The final result shows that correlation coefficients of the two experiments between the predicted blood glucose concentrations and the reference blood glucose concentrations are 0.9870 and 0.9854, respectively. The root mean square errors of prediction of full cross validation are 0.54 and 0.52 mmol/1, respectively.

  18. An Analog-Digital Mixed Measurement Method of Inductive Proximity Sensor

    Yi-Xin Guo; Zhi-Biao Shao; Ting Li

    2015-01-01

    Inductive proximity sensors (IPSs) are widely used in position detection given their unique advantages. To address the problem of temperature drift, this paper presents an analog-digital mixed measurement method based on the two-dimensional look-up table. The inductance and resistance components can be separated by processing the measurement data, thus reducing temperature drift and generating quantitative outputs. This study establishes and implements a two-dimensional look-up table that red...

  19. Underestimation of glucose turnover measured with [6-3H]- and [6,6-2H]- but not [6-14C]glucose during hyperinsulinemia in humans

    Recent studies indicate that hydrogen-labeled glucose tracers underestimate glucose turnover in humans under conditions of high flux. The cause of this underestimation is unknown. To determine whether the error is time-, pool-, model-, or insulin-dependent, glucose turnover was measured simultaneously with [6-3H]-, [6,6-2H2]-, and [6-14C]glucose during a 7-h infusion of either insulin (1 mU.kg-1.min-1) or saline. During the insulin infusion, steady-state glucose turnover measured with both [6-3H]glucose (8.0 +/- 0.5 mg.kg-1.min-1) and [6,6-2H2]glucose (7.6 +/- 0.5 mg.kg-1.min-1) was lower (P less than .01) than either the glucose infusion rate required to maintain euglycemia (9.8 +/- 0.7 mg.kg-1.min-1) or glucose turnover determined with [6-14C]glucose and corrected for Cori cycle activity (9.8 +/- 0.7 mg.kg-1.min-1). Consequently negative glucose production rates (P less than .01) were obtained with either [6-3H]- or [6,6-2H2]- but not [6-14C]glucose. The difference between turnover estimated with [6-3H]glucose and actual glucose disposal (or 14C glucose flux) did not decrease with time and was not dependent on duration of isotope infusion. During saline infusion, estimates of glucose turnover were similar regardless of the glucose tracer used. High-performance liquid chromatography of the radioactive glucose tracer and plasma revealed the presence of a tritiated nonglucose contaminant. Although the contaminant represented only 1.5% of the radioactivity in the [6-3H]glucose infusate, its clearance was 10-fold less (P less than .001) than that of [6-3H]glucose. This resulted in accumulation in plasma, with the contaminant accounting for 16.6 +/- 2.09 and 10.8 +/- 0.9% of what customarily is assumed to be plasma glucose radioactivity during the insulin or saline infusion, respectively (P less than .01)

  20. Simultaneous measurement of peritoneal glucose and free water osmotic conductances.

    La Milia, V; Limardo, M; Virga, G; Crepaldi, M; Locatelli, F

    2007-09-01

    Ultrafiltration (UF) failure is one of the most important causes of long-term peritoneal dialysis (PD) failure in patients. Osmotic forces acting across small and ultra-small pores generate a UF with solutes through the small pore and free water transport (FWT) through the ultra-small pore. The ability of glucose to exert an osmotic pressure sufficient to cause UF is the so-called 'osmotic conductance to glucose' (OCG) of the peritoneal membrane. Our study proposes a simple method to determine both the OCG and FWT. In 50 patients on PD, a Double Mini-Peritoneal Equilibration Test (Double Mini-PET), consisting of two Mini-PET, was performed consecutively. A solution of 1.36% glucose was used for the first test, whereas a solution of 3.86% glucose was used for the second test. The sodium removal values and the differences in UF between the two tests were used to calculate FWT and the OCG. Patients with UF failure showed significant reductions not only in the OCG and the FWT but also of UF of small pores. The Double Mini-PET is simple, fast, and could become useful to evaluate patients on PD in everyday clinical practice. PMID:17609692

  1. Multiple Silicon Nanowires with Enzymatic Modification for Measuring Glucose Concentration

    Cheng-Chih Hsu

    2015-08-01

    Full Text Available This study fabricated a multiple poly-Si nanowires sensor through a top-down method and immobilized glucose oxidase on the multiple nanowires for determining glucose concentration. The proposed sensor is 340 nm in width and uses five physically identical and parallel nanowires. The sensor contained nanowires of various lengths (3, 5, and 10 μm. Experimental results showed that sensor sensitivity is inversely proportional to nanowire length. The sensor with 3 μm in nanowire length exhibited a theoretical resolution of 0.003 mg/dL and the highest sensitivity of 0.03 μA/(mg/dL. Furthermore, the proposed sensor retains this performance when reused for up to 10 applications.

  2. Measurement of deuterium-labeled glucose flux in newborn infants by the continuous isotope infusion technique

    Although hypoglycemia is a frequent neonatal problem, direct estimates of glucose turnover in newborn infants have not been possible before the advent of practical, stable isotope microtechniques. Using the well-established constant isotopic infusion procedure, glucose flux has been measured in newborn infants for the first time with the metabolically non-recycling tracer, glucose-6,6-d2. Nineteen infants from 650 to 4330 grams (25 to 44 weeks gestation) were studied at various times during the first week of postnatal life. 100 to 200 microliter capillary blood samples, obtained at appropriate intervals during the course of a 150 to 240 minute infusion of dideuterioglucose, were processed by rapid ion exchange purification and the glucose converted to the 6-0-acetyl-1,2 : 3,5-di-O-(n-butane-boronyl)-α-D-glucofuranose derivative for subsequent measurement of isotopic enrichment by combined GC-MS with selected ion recording using an AVA:Voltage Sweeping circuit. Glucose flux rates were calculated by steady-state equations, where appropriate, or by non steady-state approximations when blood glucose concentration and/or glucose isotopic enrichment changed during the course of the investigation. Total glucose flux ranged from 3 to 43 mg/min (3.7 to 11.1 mg/kg.min) and was directly correlated with body weight, estimated brain weight, and average blood sugar concentration during the course of the study. These data agree closely with previous indirect estimates of glucose metabolism in the newborn period and represent the first direct measurements of new glucose production and utilization in the human neonate

  3. Maximum-likelihood reconstruction of photon returns from simultaneous analog and photon-counting lidar measurements

    Veberic, Darko

    2011-01-01

    We present a novel method for combining the analog and photon-counting measurements of lidar transient recorders into reconstructed photon returns. The method takes into account the statistical properties of the two measurement modes and estimates the most likely number of arriving photons and the most likely values of acquisition parameters describing the two measurement modes. It extends and improves the standard combining ("gluing") methods and does not rely on any ad hoc definitions of the overlap region nor on any ackground subtraction methods.

  4. The measurement of the nigrostriatal dopaminergic function and glucose metabolism in patients with movement disorders

    The nigrostriatal dopaminergic function and glucose metabolism were evaluated in 34 patients with various movement disorders by using positron emission tomography with 18F-Dopa and 18F-FDG respectively. The 18F-Dopa uptake in the striatum (the caudate head and the putamen) decreased in patients with Parkinson's disease but was relatively unaffected in the caudate. The cerebral glucose metabolism was normal in patients with Parkinson's disease. The 18F-Dopa uptake in the striatum also decreased in cases of atypical parkinsonism and in cases of progressive supranuclear palsy, but there was no difference in the uptake between the caudate and the putamen. The glucose metabolism decreased in the cerebral hemisphere including the striatum; this finding was also different from those of Parkinson's disease. A normal 18F-Dopa uptake in the striatum with a markedly decreased striatal glucose metabolism and a mildly decreased cortical glucose metabolism was observed in cases of Huntington's disease and Wilson's disease. The 18F-Dopa uptake in the striatum increased and the glucose metabolism was normal in cases of idiopathic dystonia. Various patterns of 18F-Dopa uptake and glucose metabolism were thus observed in the various movement disorders. These results suggest that the measurements of the 18F-Dopa uptake and the cerebral glucose metabolism would be useful for the evaluation of the striatal function in various movement disorders. (author)

  5. An optofluidic system with volume measurement and surface plasmon resonance sensor for continuous glucose monitoring.

    Li, Dachao; Lu, Bingyu; Zhu, Rui; Yu, Haixia; Xu, Kexin

    2016-01-01

    The traditional technology of glucose monitoring is painful and invasive because of the frequent blood collection. Nowadays, the enzyme electrode sensor is mainly used for continuous glucose monitoring in clinic, but it has inherent disadvantages of significant signal drift of current due to bioelectricity in body and the missing of hypoglycemia resulting from the irreversible consumption of glucose at the process of enzyme catalytic reaction. Interstitial fluid (ISF) transdermal extraction can be nearly unsensible which effectively reduces the pain caused by invasive detection so that it may provide a new way to monitor glucose. MEMS technology has been used to produce devices for transdermal ISF extraction, but there is a lack of on-chip ISF volume measurement capabilities, which are required to compensate skin permeability variations. This paper presents a lab-on-a-chip system for ISF transdermal extraction, ISF volume measurement, and optical glucose sensing towards the application of continuous glucose monitoring. The device significantly incorporates a MEMS volume sensor, which measures extracted ISF volume via conductance monitoring, and integrates a fiber-optic surface plasmon resonance sensor to measure glucose concentration in microchannel. The fiber-based technique provides an excellent approach to overcome the above two drawbacks of the enzyme electrode based glucose sensing. Six different volumes were tested, and the standard deviation of every sample is less than 0.05 μl, The resonance wavelength moves from 549.081 nm to 592.914 nm while the concentration ranges from 0 to 200 mg/dl. The feasibility of the single-chip device for accurate and continuous monitoring of subcutaneous ISF glucose concentrations is verified. PMID:26958100

  6. Comparison of protocols for measuring and calculating postmortem submersion intervals for human analogs in fresh water.

    Humphreys, Michael K; Panacek, Edward; Green, William; Albers, Elizabeth

    2013-03-01

    Protocols for determining postmortem submersion interval (PMSI) have long been problematic for forensic investigators due to the wide variety of factors affecting the rate of decomposition of submerged carrion. Likewise, it has been equally problematic for researchers to develop standardized experimental protocols to monitor underwater decomposition without artificially affecting the decomposition rate. This study compares two experimental protocols: (i) underwater in situ evaluation with photographic documentation utilizing the Heaton et al. total aquatic decomposition (TAD) score and (ii) weighing the carrion before and after submersion. Complete forensic necropsies were performed as a control. Perinatal piglets were used as human analogs. The results of this study indicate that in order to objectively measure decomposition over time, the human analog should be examined at depth using the TAD scoring system rather than utilizing a carrion weight evaluation. The acquired TAD score can be used to calculate an approximate PMSI. PMID:23278272

  7. Cerebral glucose transport and metabolism with dynamic PET

    A comprehensive model describing the response of the steady-state tissue distribution of glucose to changes in plasma glucose concentration was developed. In the model, the steady-state glucose content can be used to predict the steady-state distribution spaces of both phosphorylatable and non-phosphorylatable glucose analogs, and thus the value of the lumped constant (LC) required to convert measured rates of analog metabolism to the desired rate of glucose metabolism. Models of the sensitivity of the kinetic rate constants for phosphorylatable glucose analogs to tissue glucose content were developed. The use of the measured distribution space of a non-phosphorylatable analog such as methyl glucose as an indicator of the LC, is only useful for hyperglycemia. We determined that a particular aspect of the kinetics of phosphorylatable analogs, the ratio of the phosphorylation rate constant to the membrane transport rate constant, is very sensitive to glucose content over the entire physiological range of values. Considerable effort is being made to optimize the use of venous blood that is ''arterialized'' by limb warming methods. Similarly, final refinements have been made to the non-linear least squares fitting routines, allowing for blood-borne radioactivity and for the loss of phosphorylation product

  8. Measurement of tissue optical properties with optical coherence tomography: Implication for noninvasive blood glucose concentration monitoring

    Larin, Kirill V.

    Approximately 14 million people in the USA and more than 140 million people worldwide suffer from diabetes mellitus. The current glucose sensing technique involves a finger puncture several times a day to obtain a droplet of blood for analysis. There have been enormous efforts by many scientific groups and companies to quantify glucose concentration noninvasively using different optical techniques. However, these techniques face limitations associated with low sensitivity, accuracy, and insufficient specificity of glucose concentrations over a physiological range. Optical coherence tomography (OCT), a new technology, is being applied for noninvasive imaging in tissues with high resolution. OCT utilizes sensitive detection of photons coherently scattered from tissue. The high resolution of this technique allows for exceptionally accurate measurement of tissue scattering from a specific layer of skin compared with other optical techniques and, therefore, may provide noninvasive and continuous monitoring of blood glucose concentration with high accuracy. In this dissertation work I experimentally and theoretically investigate feasibility of noninvasive, real-time, sensitive, and specific monitoring of blood glucose concentration using an OCT-based biosensor. The studies were performed in scattering media with stable optical properties (aqueous suspensions of polystyrene microspheres and milk), animals (New Zealand white rabbits and Yucatan micropigs), and normal subjects (during oral glucose tolerance tests). The results of these studies demonstrated: (1) capability of the OCT technique to detect changes in scattering coefficient with the accuracy of about 1.5%; (2) a sharp and linear decrease of the OCT signal slope in the dermis with the increase of blood glucose concentration; (3) the change in the OCT signal slope measured during bolus glucose injection experiments (characterized by a sharp increase of blood glucose concentration) is higher than that measured in

  9. Accuracy of Continuous Glucose Monitoring Measurements in Normo-Glycemic Individuals

    Akintola, Abimbola A; Noordam, Raymond; Jansen, Steffy W;

    2015-01-01

    24-hour period. Validity of CGM-derived individual glucose measurements, calculated measures of glycemia over daytime (09:00h-23:00h) and nighttime (23:00h-09:00h), and calculated measures of glycemic variability (e.g. 24h standard deviation [SD]) were assessed by Pearson correlation coefficients......, mean absolute relative difference (MARD) and paired t-tests. RESULTS: The median correlation coefficient between CGM and venous glucose measurements per participant was 0.68 (interquartile range: 0.40-0.78), and the MARD was 17.6% (SD = 17%). Compared with venous sampling, the calculated measure of...

  10. Value of fructosamine measurement in pregnant women with abnormal glucose tolerance

    LI Kui; YANG Hui-xia

    2006-01-01

    Background The concentration of serum fructosamine is correlated with plasma glucose level. The aim of this study was to determine whether the level of serum fructosamine can be diagnostic for abnormal glucose tolerance in pregnant women.Methods Serum samples were collected from 161 pregnant women between November 2004 and April 2005.The women were divided into three groups according to the gestational age (16-20 weeks group, 56 patients; 28-34 weeks group, 72; and 37-41 weeks group, 33). Each group was subdivided into normal and abnormal glucose tolerance subgroups. The levels of serum fructosamine were measured. Differences among the groups were assessed by ANOVA and Student-Newman-Keuls test. Correlations between the level of fructosamine and other variables including the results of glucose challenge test (GCT), oral glucose tolerance test (OGTT), and glycosylated hemoglobin (HbA1c) test, and infant's birth weight were analyzed by Pearson correlation.Results The level of serum fructosamine decreased with gestational age [(223.25 ±48.90) μmol/L, (98.44±29.57)μmol/L, and (53.99±29.94) μmol/L, respectively. P<0.05]. It was higher in women with abnormal glucose tolerance than that in women with normal glucose tolerance, however, the difference reached statistical significance only in the 28-34 weeks group (P<0.05). In this group, the level of serum fructosamine correlated positively with the GCT result (r=0.28, P<0.05). No correlation was found between fructosamine level and OGTT result, HbA1c level, or neonatal weight.Conclusions Fructosamine can be used to monitor the glucose level of pregnant women with abnormal glucose tolerance, and to identify the patients at high risk of abnormal glucose tolerance, but can not be used to predict gestational diabetes mellitus (GDM) in early stage of pregnancy.

  11. A Novel Method to Measure Glucose Uptake and Myosin Heavy Chain Isoform Expression of Single Fibers From Rat Skeletal Muscle

    MacKrell, James G.; Gregory D. Cartee

    2012-01-01

    Skeletal muscle includes many individual fibers with diverse phenotypes. A barrier to understanding muscle glucose uptake at the cellular level has been the absence of a method to measure glucose uptake by single fibers from mammalian skeletal muscle. This study’s primary objective was to develop a procedure to measure glucose uptake by single fibers from rat skeletal muscle. Rat epitrochlearis muscles were incubated ex vivo with [3H]-2-deoxy-d-glucose, with or without insulin or AICAR, befor...

  12. Chance correlation in non-invasive glucose measurement using near-infrared spectroscopy

    Although the non-invasive glucose measurement technique based on near-infrared (NIR) spectroscopy has been an active research area for over twenty years, a reliable monitoring method has not been established yet. The key problem is that the spectral variations due to glucose concentration are extremely small compared to that from other biological components. In addition, there are also some ambiguous time-dependent physiological processes, which make the explanation of the model more difficult, especially in the universal calibration. Therefore, in order to produce a model that is related to the actual spectral variation of glucose, reproducible measurements and clinical validation experiments that improve the selectivity and signal to noise ratio of glucose measurement are needed. In this paper, chance correlation in spectroscopy analysis is investigated, which is one of the obstacles to achieving successful NIR spectroscopy analysis, especially in in vivo measurement. The reasons for chance correlation in the in vitro and in vivo experiments are analysed. Methods to avoid it are suggested accordingly and verified with the in vitro experiments. We also investigate the chance correlation for the in vivo NIR diffuse reflectance spectroscopy monitoring blood. Results show that there is significant signal variation after glucose is taken, and the potential chance correlation factors including the instrument-related and physiology-related variations during the in vivo experiments do not contribute to the multivariate model for glucose concentration

  13. The Analog Revolution and Its On-Going Role in Modern Analytical Measurements.

    Enke, Christie G

    2015-12-15

    The electronic revolution in analytical instrumentation began when we first exceeded the two-digit resolution of panel meters and chart recorders and then took the first steps into automated control. It started with the first uses of operational amplifiers (op amps) in the analog domain 20 years before the digital computer entered the analytical lab. Their application greatly increased both accuracy and precision in chemical measurement and they provided an elegant means for the electronic control of experimental quantities. Later, laboratory and personal computers provided an unlimited readout resolution and enabled programmable control of instrument parameters as well as storage and computation of acquired data. However, digital computers did not replace the op amp's critical role of converting the analog sensor's output to a robust and accurate voltage. Rather it added a new role: converting that voltage into a number. These analog operations are generally the limiting portions of our computerized instrumentation systems. Operational amplifier performance in gain, input current and resistance, offset voltage, and rise time have improved by a remarkable 3-4 orders of magnitude since their first implementations. Each 10-fold improvement has opened the doors for the development of new techniques in all areas of chemical analysis. Along with some interesting history, the multiple roles op amps play in modern instrumentation are described along with a number of examples of new areas of analysis that have been enabled by their improvements. PMID:26629976

  14. An Analog-Digital Mixed Measurement Method of Inductive Proximity Sensor

    Yi-Xin Guo

    2015-12-01

    Full Text Available Inductive proximity sensors (IPSs are widely used in position detection given their unique advantages. To address the problem of temperature drift, this paper presents an analog-digital mixed measurement method based on the two-dimensional look-up table. The inductance and resistance components can be separated by processing the measurement data, thus reducing temperature drift and generating quantitative outputs. This study establishes and implements a two-dimensional look-up table that reduces the online computational complexity through structural modeling and by conducting an IPS operating principle analysis. This table is effectively compressed by considering the distribution characteristics of the sample data, thus simplifying the processing circuit. Moreover, power consumption is reduced. A real-time, built-in self-test (BIST function is also designed and achieved by analyzing abnormal sample data. Experiment results show that the proposed method obtains the advantages of both analog and digital measurements, which are stable, reliable, and taken in real time, without the use of floating-point arithmetic and process-control-based components. The quantitative output of displacement measurement accelerates and stabilizes the system control and detection process. The method is particularly suitable for meeting the high-performance requirements of the aviation and aerospace fields.

  15. An Analog-Digital Mixed Measurement Method of Inductive Proximity Sensor.

    Guo, Yi-Xin; Shao, Zhi-Biao; Li, Ting

    2015-01-01

    Inductive proximity sensors (IPSs) are widely used in position detection given their unique advantages. To address the problem of temperature drift, this paper presents an analog-digital mixed measurement method based on the two-dimensional look-up table. The inductance and resistance components can be separated by processing the measurement data, thus reducing temperature drift and generating quantitative outputs. This study establishes and implements a two-dimensional look-up table that reduces the online computational complexity through structural modeling and by conducting an IPS operating principle analysis. This table is effectively compressed by considering the distribution characteristics of the sample data, thus simplifying the processing circuit. Moreover, power consumption is reduced. A real-time, built-in self-test (BIST) function is also designed and achieved by analyzing abnormal sample data. Experiment results show that the proposed method obtains the advantages of both analog and digital measurements, which are stable, reliable, and taken in real time, without the use of floating-point arithmetic and process-control-based components. The quantitative output of displacement measurement accelerates and stabilizes the system control and detection process. The method is particularly suitable for meeting the high-performance requirements of the aviation and aerospace fields. PMID:26729118

  16. Precision analog signal processor for beam position measurements in electron storage rings

    Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y position entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM

  17. Low power analog readout front-end electronics for time and energy measurements

    We report on the design and measurements of an analog front-end readout electronics dedicated for silicon microstrip detectors with relatively large capacitance of the order of tens pF for time and energy measurements of incoming pulses. The front-end readout electronics is required to process input pulses with an average rate of 150 kHz/channel with low both power consumption and noise at the same time. In the presented solution the single channel is built of two different parallel processing paths: fast and slow. The fast path includes the fast CR–RC shaper with the peaking time tp=40 ns and is optimized to determine the input charge arrival time. The slow path, which consists of the slow CR–(RC)2 shaper with the peaking time tp=80 ns, is dedicated for low noise accurate energy measurement. The analog front-end electronics was implemented in UMC 180 nm CMOS technology as a prototype ASIC AFE. The AFE chip contains 8 channels with the size of 58 μm×1150 μm each. It has low power dissipation Pdiss=3.1 mW per single channel. The article presents the details of the front-end architecture and the measurement results

  18. Real-time estimation of plasma insulin concentration from continuous glucose monitor measurements.

    de Pereda, Diego; Romero-Vivo, Sergio; Ricarte, Beatriz; Rossetti, Paolo; Ampudia-Blasco, Francisco Javier; Bondia, Jorge

    2016-07-01

    Continuous glucose monitors can measure interstitial glucose concentration in real time for closed-loop glucose control systems, known as artificial pancreas. These control systems use an insulin feedback to maintain plasma glucose concentration within a narrow and safe range, and thus to avoid health complications. As it is not possible to measure plasma insulin concentration in real time, insulin models have been used in literature to estimate them. Nevertheless, the significant inter- and intra-patient variability of insulin absorption jeopardizes the accuracy of these estimations. In order to reduce these limitations, our objective is to perform a real-time estimation of plasma insulin concentration from continuous glucose monitoring (CGM). Hovorka's glucose-insulin model has been incorporated in an extended Kalman filter in which different selected time-variant model parameters have been considered as extended states. The observability of the original Hovorka's model and of several extended models has been evaluated by their Lie derivatives. We have evaluated this methodology with an in-silico study with 100 patients with Type 1 diabetes during 25 h. Furthermore, it has been also validated using clinical data from 12 insulin pump patients with Type 1 diabetes who underwent four mixed meal studies. Real-time insulin estimations have been compared to plasma insulin measurements to assess performance showing the validity of the methodology here used in comparison with that formerly used for insulin models. Hence, real-time estimations for plasma insulin concentration based on subcutaneous glucose monitoring can be beneficial for increasing the efficiency of control algorithms for the artificial pancreas. PMID:26343364

  19. A dielectric inverse problem applied to human skin measurements during glucose excursions

    A fringing field capacitive sensor has been used to measure the dielectric properties of human skin and underlying tissue in the MHz frequency range. It has recently been shown in clinical experimental studies that these dielectric properties can be related to the effects of in vivo glucose variations of the test subject. Previously, the relationship between electrical impedance and the glucose level has been established via statistical methods, such as the regression method. In this work, we explored a different approach, namely the resolution of the so-called inverse problem. First we applied the method on an artificial two-layer lossy system in order to test the sensitivity of the solution to forced changes in the layer properties and its stability to a constant setting. After validation of this method on artificial systems, a similar inverse problem was set and solved for dielectric measurements on human skin during an induced glucose excursion, where the skin is also modelled as a double-layer system. The changes of the measured permittivity and conductivity of the second layer versus the glucose changes are calculated for 22 study days. The statistical distribution shows that the median slopes of both dielectric properties are negative. These results can be used to test our hypothesis and to continue building potential explanations for the phenomena induced by the glucose changes on the skin layer dielectric parameters

  20. Analog of Formula of Total Probability for Quantum Observables Represented by Positive Operator Valued Measures

    Khrennikov, Andrei

    2016-09-01

    We represent Born's rule as an analog of the formula of total probability (FTP): the classical formula is perturbed by an additive interference term. In this note we consider practically the most general case: generalized quantum observables given by positive operator valued measures and measurement feedback on states described by atomic instruments. This representation of Born's rule clarifies the probabilistic structure of quantum mechanics (QM). The probabilistic counterpart of QM can be treated as the probability update machinery based on the special generalization of classical FTP. This is the essence of the Växjö interpretation of QM: statistical realist contextual and local interpretation. We analyze the origin of the additional interference term in quantum FTP by considering the contextual structure of the two slit experiment which was emphasized by R. Feynman.

  1. Introduction to Non-Invasive Glucose Measurement - A Physicist's Perspective

    Blakley, Daniel; Simske, Steven; Vadgama, Pankaj

    2011-10-01

    The Quest, The Elusive Art and Science, Many Efforts and Investments, Physiology of Blood and Epidermal Regions, Some Methods including Eyes, Breath, Skin Coupling using Spectroscopy, Ring-down Spectroscopy, IR Measurement, Florescence - all as General Introductory Material.

  2. Novel approach for non-invasive glucose sensing using vibrational contrast CD absorption measurements (Conference Presentation)

    Yakovlev, Vladislav V.; Tovar, Carlos; Hokr, Brett; Petrov, Georgi I.

    2016-03-01

    Noninvasive glucose sensing is a Holy Grail of diabetes mellitus management. Unfortunately, despite a number of innovative concepts and a long history of continuous instrumental improvements, the problem remains largely unsolved. Here we propose and experimentally demonstrate the first successful implementation of a novel strategy based on vibrational overtone circular dichroism absorption measurements. Such an approach uses a short-wavelength infrared excitation (1000-2000 nm), which takes the advantage of lower light scattering and intrinsic chemical contrast provided by the chemical structure of D-glucose molecule. We model the propagation of circular polarized light in scattering medium using Monte Carlo simulations to show the feasibility of such approach in turbid medium and demonstrate the proof of principle using optical detection. We also investigate the possibility of using ultrasound detection through circular dichroism absorption measurements to achieve simple and sensitive glucose monitoring.

  3. The Balloon Analog Insurance Task (BAIT: a behavioral measure of protective risk management.

    Brian G Essex

    Full Text Available Prior methods used to assess individual differences related to risk have not focused on an important component of risk management: how willing individuals are to pay for or take actions to insure what they already have. It is not clear whether this type of protective risk management taps into the same individual differences as does risk taking propensity measured by existing risk taking tasks. We developed a novel task to assess protective risk management, the Balloon Analog Insurance Task (BAIT, which is modeled after the Balloon Analog Risk Task (BART. In the BAIT, individuals are forced to decide how much money they are willing to pay in order to insure a specific fraction of their prior winnings given changing but imprecise levels of risk of monetary loss. Participants completed the BART and BAIT for real monetary rewards, and completed six self report questionnaires. The amount of insurance purchased on the BAIT was positively correlated with scores on the Intolerance of Uncertainty Scale and on the Checking scale of the revised Obsessive Compulsive Inventory. Conversely, the amount of insurance purchased was negatively correlated with scores on the Domain Specific Risk Taking Questionnaire, and on the Psychopathic Personality Inventory (PPI. Furthermore, relationships between insurance purchased and these scales remained significant after controlling for the BART in linear regression analyses, and the BART was only a significant predictor for measures on one scale--the PPI. Our results reveal that behavior on the BAIT taps into a number of individual differences that are not related to behavior on another measure of risk taking. We propose that the BAIT may provide a useful complement to the BART in the assessment of risk management style.

  4. A simple method for measuring glucose utilization of insulin-sensitive tissues by using the brain as a reference

    A simple method, without measurement of the plasma input function, to obtain semiquantitative values of glucose utilization in tissues other than the brain with radioactive deoxyglucose is reported. The brain, in which glucose utilization is essentially insensitive to plasma glucose and insulin concentrations, was used as an internal reference. The effects of graded doses of oral glucose loading (0.5, 1 and 2 mg/g body weight) on insulin-sensitive tissues (heart, muscle and fat tissue) were studied in the rat. By using the brain-reference method, dose-dependent increases in glucose utilization were clearly shown in all the insulin-sensitive tissues examined. The method seems to be of value for measurement of glucose utilization using radioactive deoxyglucose and positron emission tomography in the heart or other insulin-sensitive tissues, especially during glucose loading. (orig.)

  5. A new visual analog scale to measure distinctive well-being effects of LED photobiomodulation

    Michel, François; Barolet, Daniel

    2016-03-01

    LED photobiomodulation is known mostly for its restorative effects on skin and joints. While providing LED photobiomodulation aesthetic treatments of the face, not only the skin condition was improved, but a subjective well-being effect was observed, obvious both in photographs of the treated areas and in patient behaviour. This has been supported by studies showing the beneficial effects of transcranial lasers and LEDs on neurological and psychological conditions, providing great insight. LED therapy can now be used as a standalone procedure to regulate neuronal function. To measure such neurological outcomes in humans, we developed a visual analog scale questionnaire with the purpose of having a convenient tool for the assessment of quality of life following facial LED photobiomodulation.We also gauged patients' emotional state regarding overall aesthetic improvement.

  6. Glucose metabolism in chronic diabetic foot ulcers measured in vivo using microdialysis

    Simonsen, L; Holstein, P; Larsen, K;

    1998-01-01

    Ten subjects with diabetes mellitus and unilateral chronic foot ulcer were investigated. Local tissue concentrations of glucose and lactate were measured using the microdialysis method at a distance of 0.5-1 cm from the edge of the ulcer and in normal skin in the contralateral foot. Subcutaneous...

  7. Glucose transport carrier of human erythrocytes. Radiation target size measurement based on flux inactivation

    Intact human erythrocytes frozen in the presence of cryoprotective reagents and irradiated with an electron beam retained their diffusion barrier to L-glucose. The carrier-mediated flux of D-glucose, on the other hand, was inactivated as a simple exponential function of the radiation dose. Classical target size analysis of this data yielded a molecular size of 185,000 daltons for the carrier. This represents the first measurement of the functional size of a transport protein based directly on flux inactivation

  8. Glucose transport in human erythrocytes measured using 13C NMR spin transfer

    The authors present the results of a new NMR-based procedure for measuring the fast transmembrane exchange of D-[1-13C]glucose in human erythrocytes. The method relies on different rates of exchange between the α- and β-anomers of glucose inside and outside the cells; the rate outside the cells is greatly increased by the addition of mutarotase to the suspension. Theory is developed to describe nuclear-spin transfer in the present system and is used to analyse the data to yield estimates of transmembrane-exchange rate constants and their statistical uncertainties. For a total glucose concentration of 25.5 mmol/l at 400C the first order efflux rate constants for the α- and β-anomers were 1.20 ± 0.40 s-1 and 0.71 ± 0.30 s-1, respectively. 17 refs.; 4 figs

  9. Activating efficiency of Ca2+ and cross-bridges as measured by phosphate analog release.

    Yamaguchi, M.; Takemori, S

    2001-01-01

    To assess the activating efficiency of Ca2+ and cross-bridges, the release rates of phosphate analogs from skinned fibers were estimated from the recovery of contractility and that of stiffness. Estimations were performed based on the assumptions that contractility was indicative of the population of analog-free myosin heads and that stiffness reflected the population of formed cross-bridges. Aluminofluoride (AlFx) and orthovanadate (Vi) were used as phosphate analogs with mechanically skinne...

  10. IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS

    The organic haze produced from complex CH4/N2 chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH4 concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

  11. IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS

    Hoerst, S. M.; Tolbert, M. A, E-mail: sarah.horst@colorado.edu [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO (United States)

    2013-06-10

    The organic haze produced from complex CH{sub 4}/N{sub 2} chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH{sub 4} concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

  12. A Novel Analog Integrated Circuit Design Course Covering Design, Layout, and Resulting Chip Measurement

    Lin, Wei-Liang; Cheng, Wang-Chuan; Wu, Chen-Hao; Wu, Hai-Ming; Wu, Chang-Yu; Ho, Kuan-Hsuan; Chan, Chueh-An

    2010-01-01

    This work describes a novel, first-year graduate-level analog integrated circuit (IC) design course. The course teaches students analog circuit design; an external manufacturer then produces their designs in three different silicon chips. The students, working in pairs, then test these chips to verify their success. All work is completed within…

  13. Advancement in polarimetric glucose sensing: simulation and measurement of birefringence properties of cornea

    Malik, Bilal H.; Coté, Gerard L.

    2011-03-01

    Clinical guidelines dictate that frequent blood glucose monitoring in diabetic patients is critical towards proper management of the disease. Although, several different types of glucose monitors are now commercially available, most of these devices are invasive, thereby adversely affecting patient compliance. To this end, optical polarimetric glucose sensing through the eye has been proposed as a potential noninvasive means to aid in the control of diabetes. Arguably, the most critical and limiting factor towards successful application of such a technique is the time varying corneal birefringence due to eye motion artifact. We present a spatially variant uniaxial eye model to serve as a tool towards better understanding of the cornea's birefringence properties. The simulations show that index-unmatched coupling of light is spatially limited to a smaller range when compared to the index-matched situation. Polarimetric measurements on rabbits' eyes indicate relative agreement between the modeled and experimental values of corneal birefringence. In addition, the observed rotation in the plane of polarized light for multiple wavelengths demonstrates the potential for using a dual-wavelength polarimetric approach to overcome the noise due to timevarying corneal birefringence. These results will ultimately aid us in the development of an appropriate eye coupling mechanism for in vivo polarimetric glucose measurements.

  14. A Method for Manipulating Blood Glucose and Measuring Resulting Changes in Cognitive Accessibility of Target Stimuli.

    Prokosch, Marjorie L; Hill, Sarah E

    2016-01-01

    Much research in social psychology has investigated the impact of bodily energy need on cognition and decision-making. As such, blood glucose, the body's primary energy source, has been of special interest to researchers for years. Fluctuations in blood glucose have been linked to a variety of changes in cognitive and behavioral processes, such as self-control, political attitudes, and eating behavior. To help meet growing interest in the links between bodily energy need and these processes, this manuscript offers a simple methodology to experimentally manipulate blood glucose using a fasting procedure followed by administration of a sugar-sweetened, unsweetened, or artificially-sweetened beverage. This is followed by presentation of a method for measuring resulting changes in implicit cognition using a lexical decision-task. In this task, participants are asked to identify whether strings of letters are words or non-words and response latencies are recorded. Sample results from a recent publication are presented as an example of the applications for the experimental manipulation of blood glucose and the lexical decision task measures. PMID:27585282

  15. Analog earthquakes

    Hofmann, R.B. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

    1995-09-01

    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

  16. Applying the reference-wavelength method to improve the precision of glucose measurement by near infrared spectroscopy

    Wenliang Chen; Kexin Xu; Yu Li; Yun Chen

    2007-01-01

    The reference-wavelength method is proposed to diminish the influence of noises on glucose measurement by differentially processing two signals at the reference and measuring wavelengths. At the reference wavelength, the radiation intensity is insensitive to the changes of glucose concentration. Therefore, it can be used as the internal reference to estimate the noise and then to extract the effective glucose signal at the other wavelengths. The validation experiments are constructed in the non-scattering samples with the reference wavelength of glucose at 1525 nm. The results show that the reference-wavelength-based glucose-specific signal extracting method can largely improve the glucose prediction precision from 17.56 to 8.87 mg/dL in the two-component experiment and from 26.82 to 9.94 mg/dL in the three-component experiment.

  17. Development of portable health monitoring system for automatic self-blood glucose measurement

    Kim, Huijun; Mizuno, Yoshihumi; Nakamachi, Eiji; Morita, Yusuke

    2010-02-01

    In this study, a new HMS (Health Monitoring System) device is developed for diabetic patient. This device mainly consists of I) 3D blood vessel searching unit and II) automatic blood glucose measurement (ABGM) unit. This device has features such as 1)3D blood vessel location search 2) laptop type, 3) puncturing a blood vessel by using a minimally invasive micro-needle, 4) very little blood sampling (10μl), and 5) automatic blood extraction and blood glucose measurement. In this study, ABGM unit is described in detail. It employs a syringe type's blood extraction mechanism because of its high accuracy. And it consists of the syringe component and the driving component. The syringe component consists of a syringe itself, a piston, a magnet, a ratchet and a micro-needle whose inner diameter is about 80μm. And the syringe component is disposable. The driving component consists of body parts, a linear stepping motor, a glucose enzyme sensor and a slider for accurate positioning control. The driving component has the all-in-one mechanism with a glucose enzyme sensor for compact size and stable blood transfer. On designing, required thrust force to drive the slider is designed to be greater than the value of the blood extraction force. Further, only one linear stepping motor is employed for blood extraction and transportation processes. The experimental result showed more than 80% of volume ratio under the piston speed 2.4mm/s. Further, the blood glucose was measured successfully by using the prototype unit. Finally, the availability of our ABGM unit was confirmed.

  18. Brain glucose concentrations in poorly controlled diabetes mellitus as measured by high-field magnetic resonance spectroscopy

    Seaquist, Elizabeth R.; Tkac, Ivan; Damberg, Greg; Thomas, William; Gruetter, Rolf

    2005-01-01

    Hyperglycemia and diabetes alter the function and metabolism of many tissues. The effect on the brain remains poorly defined, but some animal data suggest that chronic hyperglycemia reduces rates of brain glucose transport and/or metabolism. To address this question in human beings, we measured glucose in the occipital cortex of patients with poorly controlled diabetes and healthy volunteers at the same levels of plasma glucose using proton magnetic resonance spectroscopy. Fourteen patients w...

  19. Measurement of glucose utilization by Pseudomonas fluorescens that are free-living and that are attached to surfaces

    The assimilation and respiration of glucose by attached and free-living Pseudomonas fluorescens were compared. The attachment surfaces were polyvinylidene fluoride, polyethylene, and glass. Specific uptake of [1C]glucose was determined after bacterial biomass was measured by (1) microscopic counts or (2) prelabelling of cells by providing [3H]leucine as substrate, followed by dual-labelling scintillation counting. The glucose concentration was 1.4, 3.5, 5.5, 7.6, or 9.7 μM. Glucose assimilation by cells which became detached from the surfaces during incubation with glucose was also measured after the detached cells were collected by filtration. The composition of the substratum had no effect on the amount of glucose assimilated by attached cells. Glucose assimilation by attached cells exceeded that by free-living cells by a factor of between 2 and 5 or more, and respiration of glucose by surface-associated cells was greater than that by free-living bacteria. Glucose assimilation by detached cells was greater than that by attached bacteria. Measurements of biomass by microscopic counts gave more consistent results than those obtained with dual-labelling, but in general, results obtained by both methods were corroborative

  20. Isobaric analog states of neutron-rich nuclei. Doppler shift as a measurement tool for resonance excitation functions

    We present a new approach for the measurement of resonance excitation functions of neutron-rich nuclei using Doppler shift information. Preliminary data from the first application of the method is presented in the spectroscopy studies of 7He isobaric analog states in 7Li. (orig.)

  1. High power high linearity waveguide photodiodes : measurement, modeling, and characterization for analog optical links

    Draa, Meredith Nicole

    2010-01-01

    As analog optical links continue to mature and fulfill communication needs, the requirements for output power and linearity continue to be a main focus. The receiver end of a link is a limiting factor for such applications, and therefore photodiode research continues to be at the forefront of these issues. In order to compete, photodiodes need to be able to maintain high bandwidth, high power and high linearity simultaneously. The study of photodiodes for analog links has focused on linearity...

  2. Real-time measurement of glucose using chrono-impedance technique on a second generation biosensor.

    Mayorga Martinez, Carmen C; Treo, Ernesto F; Madrid, Rossana E; Felice, Carmelo C

    2011-11-15

    Chrono-impedance technique (CIT) was implemented as a new transduction method for real time measurement of glucose in a biosensor system based in carbon paste (CP)/Ferrocene (FC)/glucose oxidase (GOx). The system presents high selectivity because the optimal stimulation signal composed by a 165mV DC potential and 50mV(RMS) AC signal at 0.4Hz was used. The low DC potential used decreased the interfering species effect and the biosensor showed a linear impedance response toward glucose detection at concentrations from 0mM to 20mM,with 0.9853 and 0.9945 correlation coefficient for impedance module (|Z|) and phase (Φ), respectively. The results of quadruplicate sets reveal the high repeatability and reproducibility of the measurements with a relative standard deviation (RSD) less than 10%. CIT presented good accuracy (within 10% of the actual value) and precision did not exceed 15% of RSD for high concentration values and 20% for the low concentration ones. In addition, a high correlation coefficient (R(2)=0.9954) between chrono-impedance and colorimetric methods was obtained. On the other hand, when two samples prepared at the same conditions were measured in parallel with both methods (the measurement was repeated four times), it should be noticed that student's t-test produced no difference between the two mentioned methods (p=1). The biosensor system hereby presented is highly specific to glucose detection and shows a better linear range than the one reported on the previous article. PMID:21907557

  3. Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography. [Dogs

    Schelbert, H.R.; Phelps, M.E.

    1980-06-01

    While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography (/sup 13/N-ammonia) are promising, their utility and value remains to be determined in man. If this technique can be applied to patients with acute myocardial ischemia or infarction it may permit delineation of regional myocardial segments with altered, yet still active metabolism. Further, it may become possible to evaluate the effects of interventions designed to salvage reversibly injured myocardium by this technique.

  4. Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography

    While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography (13N-ammonia) are promising, their utility and value remains to be determined in man. If this technique can be applied to patients with acute myocardial ischemia or infarction it may permit delineation of regional myocardial segments with altered, yet still active metabolism. Further, it may become possible to evaluate the effects of interventions designed to salvage reversibly injured myocardium by this technique

  5. Effects of glucose and insulin levels on adipose tissue glucose measurement by microdialysis probes retained for three weeks in Type 1 diabetic patients

    Hullegie, LM; Lutgers, HL; Dullaart, RPF; Sluiter, WJ; Wientjes, KJ; Schoonen, AJM; Hoogenberg, K

    2000-01-01

    Background: To evaluate the effects of acute hyperglycaemia and hyperinsulinaemia on adipose tissue glucose measurements by microdialysis probes inserted for a 3-week period. Methods: Microdialysis probes were implanted pairwise in abdominal adipose tissue in seven Type 1 diabetic patients and remai

  6. Association between DNA Methylation in Whole Blood and Measures of Glucose Metabolism: KORA F4 Study

    Wahl, Simone; Kunze, Sonja; Molnos, Sophie; Volkova, Nadezda; Schramm, Katharina; Carstensen-Kirberg, Maren; Waldenberger, Melanie; Gieger, Christian; Peters, Annette; Illig, Thomas; Prokisch, Holger; Roden, Michael; Grallert, Harald

    2016-01-01

    Epigenetic regulation has been postulated to affect glucose metabolism, insulin sensitivity and the risk of type 2 diabetes. Therefore, we performed an epigenome-wide association study for measures of glucose metabolism in whole blood samples of the population-based Cooperative Health Research in the Region of Augsburg F4 study using the Illumina HumanMethylation 450 BeadChip. We identified a total of 31 CpG sites where methylation level was associated with measures of glucose metabolism after adjustment for age, sex, smoking, and estimated white blood cell proportions and correction for multiple testing using the Benjamini-Hochberg (B-H) method (four for fasting glucose, seven for fasting insulin, 25 for homeostasis model assessment-insulin resistance [HOMA-IR]; B-H-adjusted p-values between 9.2x10-5 and 0.047). In addition, DNA methylation at cg06500161 (annotated to ABCG1) was associated with all the aforementioned phenotypes and 2-hour glucose (B-H-adjusted p-values between 9.2x10-5 and 3.0x10-3). Methylation status of additional three CpG sites showed an association with fasting insulin only after additional adjustment for body mass index (BMI) (B-H-adjusted p-values = 0.047). Overall, effect strengths were reduced by around 30% after additional adjustment for BMI, suggesting that this variable has an influence on the investigated phenotypes. Furthermore, we found significant associations between methylation status of 21 of the aforementioned CpG sites and 2-hour insulin in a subset of samples with seven significant associations persisting after additional adjustment for BMI. In a subset of 533 participants, methylation of the CpG site cg06500161 (ABCG1) was inversely associated with ABCG1 gene expression (B-H-adjusted p-value = 1.5x10-9). Additionally, we observed an enrichment of the top 1,000 CpG sites for diabetes-related canonical pathways using Ingenuity Pathway Analysis. In conclusion, our study indicates that DNA methylation and diabetes-related traits

  7. Changing from analog to digital images: Does it affect the accuracy of alignment measurements of the lower extremity?

    Lohman, Martina; Tallroth, Kaj; Kettunen, Jyrki A.; Remes, Ville

    2011-01-01

    Background and purpose Medical imaging has changed from analog films to digital media. We examined and compared the accuracy of orthopedic measurements using different media. Methods Before knee arthroplasty, full-length standing radiographs of 52 legs were obtained. The mechanical axis (MA), tibio-femoral angle (TFA), and femur angle (FA) were measured and analyzed twice, by 2 radiologists, using (1) true-size films, (2) short films, (3) a digital high-resolution workstation, and (4) a web-b...

  8. Biosensor-based analyser. Measurement of glucose, sucrose, lactose, L-lactate and alcohol

    Williams, F.T. Jr. (YSI, Inc., Yellow Springs, OH (United States))

    1992-05-01

    This paper describes an instrument, the YSI 2700, for the measurement of glucose, sucrose, lactose, L-lactate, and alcohol by means of biosensors. Each biosensor consists of an amperometric, hydrogen peroxide sensitive electrode combined with an immobilized oxidase enzyme trapped between two membranes. Each biosensor differs from the others only in its enzyme layer. The instrument can be used to measure these analytes in complex sample matrices; often directly, e.g. in whole blood and fermentations, after dilution with water, e.g. in molasses and corn syrup, or after extraction into water, e.g. in cheese and cereal products. (orig.).

  9. Preliminary Broadband Measurements of Dielectric Permittivity of Planetary Regolith Analog Materials Using a Coaxial Airline

    Boivin, A.; Tsai, C. A.; Ghent, R. R.; Daly, M. G.

    2014-12-01

    When considering radar observations of airless bodies containing regolith, the radar backscatter coefficient is dependent upon the complex dielectric permittivity of the regolith materials. In many current applications of imaging radar data, uncertainty in the dielectric permittivity precludes quantitative estimates of such important parameters as regolith thickness and depth to buried features (e.g., lava flows on the Aristarchus Plateau on the Moon and the flows that surround the Quetzalpetlatl Corona on Venus). For asteroids, radar is an important tool for detecting and characterizing regoliths. Many previous measurements of the real and/or complex parts of the dielectric permittivity have been made, particularly for the Moon (on both Apollo samples and regolith analogues). However, no studies to date have systematically explored the relationship between permittivity and the various mineralogical components such as presence of FeO and TiO2. For lunar materials, the presence of the mineral ilmenite (FeTiO3), which contains equal portions FeO and TiO2, is thought to be the dominant factor controlling the loss tangent (tanδ, the ratio of the imaginary and real components of the dielectric permittivity). Ilmenite, however, is not the only mineral to contain iron in the lunar soil and our understanding of the effect of iron on the loss tangent is insufficient. Beyond the Moon, little is known about the effects on permittivity of carbonaceous materials. This is particularly relevant for missions to asteroids, such as the OSIRIS-REx mission to (101955) Bennu, a carbonaceous asteroid whose regolith composition is largely unknown. Here we present preliminary broadband (300 Mhz to 14 GHz) measurements on materials intended as planetary regolith analogs. Our ultimate goal is to establish a database of the effects of a wide range mineralogical components on dielectric permittivity, in support of the OSIRIS REx mission and ongoing Earth-based radar investigation of the Moon

  10. Hollow optical-fiber based infrared spectroscopy for measurement of blood glucose level by using multi-reflection prism.

    Kino, Saiko; Omori, Suguru; Katagiri, Takashi; Matsuura, Yuji

    2016-02-01

    A mid-infrared attenuated total reflection (ATR) spectroscopy system employing hollow optical fibers and a trapezoidal multi-reflection ATR prism has been developed to measure blood glucose levels. Using a multi-reflection prism brought about higher sensitivity, and the flat and wide contact surface of the prism resulted in higher measurement reproducibility. An analysis of in vivo measurements of human inner lip mucosa revealed clear signatures of glucose in the difference spectra between ones taken during the fasting state and ones taken after ingestion of glucose solutions. A calibration plot based on the absorption peak at 1155 cm(-1) that originates from the pyranose ring structure of glucose gave measurement errors less than 20%. PMID:26977373

  11. Simultaneous measurement of blood flow and glucose metabolism by autoradiographic techniques

    Mies, G.; Niebuhr, I.; Hossmann, K.A.

    A double tracer autoradiographic technique using 131I-iodo-antipyrine and 14C-deoxyglucose is presented for the simultaneous measurement of blood flow and cerebral glucose utilization in the same animal. 131I is a gamma emitting isotope with a half life of 8.06 days and can be detected with adequate resolution on standard autoradiographic films. Autoradiograms are made before and after decay of 131I; the time interval between the 2 exposures and the concentration of the 2 tracers is adjusted to avoid significant cross-contamination. In this way, 2 film exposures are obtained which can be processed quantitatively like single tracer autoradiograms. The validity of the method for the investigation of local coupling of flow and metabolism was tested under various physiological and pathophysiological conditions. Coupling was tight in barbiturate-anesthetized healthy animals, but not under halothane anesthesia where uncoupling occurred in various subcortical structures. Focal seizures induced by topical application of penicillin on the cortical surface led to a coupled increase of metabolism and flow in thalamic relay nuclei but not at the site of penicillin administration where increased glucose utilization was not accompanied by similar increase in blood flow. Both coupled and uncoupled increases in local glucose utilization were observed in spreading depression and in circumscribed areas of experimental brain tumors. The results obtained demonstrate that double tracer autoradiography allows allows the very precise local assessment of cerebral blood flow and glucose utilization, and, therefore, is particularly suited to the study of regional coupling processes under various experimental conditions.

  12. Simultaneous measurement of blood flow and glucose metabolism by autoradiographic techniques

    A double tracer autoradiographic technique using 131I-iodo-antipyrine and 14C-deoxyglucose is presented for the simultaneous measurement of blood flow and cerebral glucose utilization in the same animal. 131I is a gamma emitting isotope with a half life of 8.06 days and can be detected with adequate resolution on standard autoradiographic films. Autoradiograms are made before and after decay of 131I; the time interval between the 2 exposures and the concentration of the 2 tracers is adjusted to avoid significant cross-contamination. In this way, 2 film exposures are obtained which can be processed quantitatively like single tracer autoradiograms. The validity of the method for the investigation of local coupling of flow and metabolism was tested under various physiological and pathophysiological conditions. Coupling was tight in barbiturate-anesthetized healthy animals, but not under halothane anesthesia where uncoupling occurred in various subcortical structures. Focal seizures induced by topical application of penicillin on the cortical surface led to a coupled increase of metabolism and flow in thalamic relay nuclei but not at the site of penicillin administration where increased glucose utilization was not accompanied by similar increase in blood flow. Both coupled and uncoupled increases in local glucose utilization were observed in spreading depression and in circumscribed areas of experimental brain tumors. The results obtained demonstrate that double tracer autoradiography allows allows the very precise local assessment of cerebral blood flow and glucose utilization, and, therefore, is particularly suited to the study of regional coupling processes under various experimental conditions

  13. Nucleic Acid Base Analog FRET-Pair Facilitating Detailed Structural Measurements in Nucleic Acid Containing Systems

    Börjesson, Karl; Preus, Søren; El-Sagheer, Afaf;

    2009-01-01

    We present the first nucleobase analog fluorescence resonance energy transfer (FRET)-pair. The pair consists of tCO, 1,3-diaza-2-oxophenoxazine, as an energy donor and the newly developed tC(nitro), 7-nitro-1,3-diaza-2-oxophenothiazine, as an energy acceptor. The FRET-pair successfully monitors d...

  14. MGS-TES Phase Effects and Thermal Infrared Directional Emissivity Field Measurements of Martian Analog Sites

    Pitman, K. M.; Bandfield, J. L.; Wolff, M. J.

    2006-03-01

    We present a set of on- and off-nadir thermal IR field and laboratory emissivity spectra for three undisturbed Mars terrain analog sites and analyze them for presence or absence of directional emissivity effects. Comparisons to moderate and low albedo surface MGS-TES EPF sequences are discussed.

  15. FRET measurements of intracellular cAMP concentrations and cAMP analog permeability in intact cells.

    Börner, Sebastian; Schwede, Frank; Schlipp, Angela; Berisha, Filip; Calebiro, Davide; Lohse, Martin J; Nikolaev, Viacheslav O

    2011-04-01

    Real-time measurements of second messengers in living cells, such as cAMP, are usually performed by ratiometric fluorescence resonance energy transfer (FRET) imaging. However, correct calibration of FRET ratios, accurate calculations of absolute cAMP levels and actual permeabilities of different cAMP analogs have been challenging. Here we present a protocol that allows precise measurements of cAMP concentrations and kinetics by expressing FRET-based cAMP sensors in cells and modulating them with an inhibitor of adenylyl cyclase activity and a cell-permeable cAMP analog that fully inhibits and activates the sensors, respectively. Using this protocol, we observed different basal cAMP levels in primary mouse cardiomyocytes, thyroid cells and in 293A cells. The protocol can be generally applied for calibration of second messenger or metabolite concentrations measured by FRET, and for studying kinetics and pharmacological properties of their membrane-permeable analogs. The complete procedure, including cell preparation and FRET measurements, takes 3-6 d. PMID:21412271

  16. Estimation of utility values from visual analog scale measures of health in patients undergoing cardiac surgery

    Oddershede L

    2014-01-01

    Full Text Available Lars Oddershede,1,2 Jan Jesper Andreasen,1 Lars Ehlers2 1Department of Cardiothoracic Surgery, Center for Cardiovascular Research, Aalborg University Hospital, Aalborg, Denmark; 2Danish Center for Healthcare Improvements, Faculty of Social Sciences and Faculty of Health Sciences, Aalborg University, Aalborg East, Denmark Introduction: In health economic evaluations, mapping can be used to estimate utility values from other health outcomes in order to calculate quality adjusted life-years. Currently, no methods exist to map visual analog scale (VAS scores to utility values. This study aimed to develop and propose a statistical algorithm for mapping five dimensions of health, measured on VASs, to utility scores in patients suffering from cardiovascular disease. Methods: Patients undergoing coronary artery bypass grafting at Aalborg University Hospital in Denmark were asked to score their health using the five VAS items (mobility, self-care, ability to perform usual activities, pain, and presence of anxiety or depression and the EuroQol 5 Dimensions questionnaire. Regression analysis was used to estimate four mapping models from patients' age, sex, and the self-reported VAS scores. Prediction errors were compared between mapping models and on subsets of the observed utility scores. Agreement between predicted and observed values was assessed using Bland–Altman plots. Results: Random effects generalized least squares (GLS regression yielded the best results when quadratic terms of VAS scores were included. Mapping models fitted using the Tobit model and censored least absolute deviation regression did not appear superior to GLS regression. The mapping models were able to explain approximately 63%–65% of the variation in the observed utility scores. The mean absolute error of predictions increased as the observed utility values decreased. Conclusion: We concluded that it was possible to predict utility scores from VAS scores of the five

  17. Measurement of glucose metabolism in rat spinal cord slices with dynamic positron autoradiography

    We attempted to measure the regional metabolic rate of glucose (MRglc) in sliced spinal cords in vitro. The thoracic spinal cord of a mature Wister rat was cut into 400-μm slices in oxygenated and cooled (1-4 deg. C) Krebs-Ringer solution. After at least 60 min of preincubation, the spinal cord slices were transferred into double polystyrene chambers and incubated in Krebs-Ringer solution at 36 deg. C, bubbled with 5% O2/5% CO2 gas. To measure MRglc, we used the dynamic positron autoradiography technique (dPAT) with F-18-2-fluoro-2-deoxy-D-glucose ([18F]FDG) and the net influx constant of [18F]FDG as an index. Uptake curves of [18F]FDG were well fitted by straight lines for more than 7 h after the slicing of the spinal cord (linear regression coefficient, r=0.99), indicating a constant uptake of glucose by the spinal cord tissue. The slope (K), which denotes MRglc, is affected by tetrodotoxin, and high K+ (50 mM) or Ca2+-free, high Mg2+ solution. After 10 min of hypoxia, the K value following reoxygenation was similar to the unloaded control value, but after 45 min of hypoxia, the K value was markedly lower than the unloaded control value, and after >90 min of reoxygenation it was nearly 0. Our results indicate that the living spinal cord slices used retained an activity-dependent metabolism to some extent. This technique may provide a new approach for measuring MRglc in sliced living spinal cord tissue in vitro and for quantifying the dynamic changes in MRglc in response to various interventions such as hypoxia

  18. Measurement of glucose metabolism in rat spinal cord slices with dynamic positron autoradiography

    Fan Xiaoping [Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People' s Hospital, Guangzhou 510100 (China); Asai, Tatsuya [Biomedical Imaging Research Center, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Morioka, Koichi [Department of Cardiovascular Surgery II, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Uchida, Kenzo; Baba, Hisatoshi [Department of Orthopaedics and Rehabilitation Medicine, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Tanaka, Kuniyoshi [Department of Cardiovascular Surgery II, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Zhuang Jian [Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People' s Hospital, Guangzhou 510100 (China); Okazawa, Hidehiko [Biomedical Imaging Research Center, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan); Fujibayashi, Yasuhisa [Biomedical Imaging Research Center, University of Fukui, Eiheiji-cho, Fukui 910-1193 (Japan)], E-mail: yfuji@u-fukui.ac.jp

    2009-02-15

    We attempted to measure the regional metabolic rate of glucose (MRglc) in sliced spinal cords in vitro. The thoracic spinal cord of a mature Wister rat was cut into 400-{mu}m slices in oxygenated and cooled (1-4 deg. C) Krebs-Ringer solution. After at least 60 min of preincubation, the spinal cord slices were transferred into double polystyrene chambers and incubated in Krebs-Ringer solution at 36 deg. C, bubbled with 5% O{sub 2}/5% CO{sub 2} gas. To measure MRglc, we used the dynamic positron autoradiography technique (dPAT) with F-18-2-fluoro-2-deoxy-D-glucose ([{sup 18}F]FDG) and the net influx constant of [{sup 18}F]FDG as an index. Uptake curves of [{sup 18}F]FDG were well fitted by straight lines for more than 7 h after the slicing of the spinal cord (linear regression coefficient, r=0.99), indicating a constant uptake of glucose by the spinal cord tissue. The slope (K), which denotes MRglc, is affected by tetrodotoxin, and high K{sup +} (50 mM) or Ca{sup 2+}-free, high Mg{sup 2+} solution. After 10 min of hypoxia, the K value following reoxygenation was similar to the unloaded control value, but after 45 min of hypoxia, the K value was markedly lower than the unloaded control value, and after >90 min of reoxygenation it was nearly 0. Our results indicate that the living spinal cord slices used retained an activity-dependent metabolism to some extent. This technique may provide a new approach for measuring MRglc in sliced living spinal cord tissue in vitro and for quantifying the dynamic changes in MRglc in response to various interventions such as hypoxia.

  19. Uncertainty estimation of non-ideal analog switches using programmable Josephson voltage standards for mutual inductance measurement in the joule balance

    Wang, Gang; Zhang, Zhonghua; Li, Zhengkun; Xu, Jinxin; You, Qiang

    2016-02-01

    Measurement of the mutual inductance is one of the key techniques in the joule balance to determine the Planck constant h, where a standard-square-wave compensation method was proposed to accurately measure the dc value of the mutual inductance. With this method, analog switches are used to compose an analog-switch signal generator to synthesize the excitation and compensation voltages. However, the accuracy of the compensation voltage is influenced by the non-ideal behaviors of analog-switches. In this paper, the effect from these non-ideal switches is analyzed in detail and evaluated with the equivalent circuits. A programmable Josephson voltage standard (PJVS) is used to generate a reference compensation voltage to measure the time integration of the voltage waveform generated by the analog-switch signal generator. Moreover, the effect is also evaluated experimentally by comparing the difference between the mutual inductance measured with the analog-switch signal generator and the value determined by the PJVS-analog-switch generator alternately in the same mutual inductance measurement system. The result shows that the impact of analog switches is 1.97  ×  10-7 with an uncertainty of 1.83  ×  10-7 (k  =  1) and confirms that the analog switch method can be used regularly instead of the PJVS in the mutual inductance measurement for the joule balance experiment.

  20. Associations between insulin and glucose concentrations and anthropometric measures of fat mass in Australian adolescents

    Denney-Wilson Elizabeth

    2010-08-01

    Full Text Available Abstract Background One of the most serious, yet common co-morbidities of obesity is insulin resistance, which if untreated may progress to type 2 diabetes. This paper describes the insulin and glucose concentration distributions, the prevalence of elevated insulin, the associations between insulin and body mass index (BMI, waist circumference, waist-to-height ratio (WHtR and fat mass index in a representative sample of Australian adolescents. Methods Cross-sectional population-based study of adolescent boys and girls (N = 496, mean age 15.3 years attending schools in metropolitan Sydney, Australia. Fasting venous blood collected and analysed for insulin and glucose concentrations. Height, weight, waist circumference measured, BMI and waist-to-height ratio calculated. Pubertal status self-reported. Results Glucose concentrations were normally distributed and were not associated with adiposity. Insulin concentrations were distributed logarithmically, were higher among girls than boys overall and within the same ranges of BMI and waist circumference, but were lower among girls than boys within the same ranges of fat mass adjusted for height. The prevalence of elevated insulin concentration (defined as > 100 pmol/L was 15.9% and 17.1% among boys and girls, respectively. Correlations between insulin concentration and BMI, waist circumference, WHtR and fat mass adjusted for height were 0.53, 0.49, 0.51 and 0.55, among boys, respectively, and 0.35, 0.40, 0.42 and 0.34, among girls, respectively. Conclusions Elevated insulin is highly correlated with adiposity in adolescents. BMI and WHtR are simple measures that can be used to identify young people who should be screened for insulin resistance and other co-morbidities.

  1. Detection of glucose variability in saline solutions from transmission and reflection measurements using V-band waveguides

    This paper presents experimental results that demonstrate the correlation of glucose concentration in water and saline solutions with transmitted electromagnetic (EM) energy in the frequency range of 50–75 GHz. The system is based on placing the aqueous solutions in acrylic holding tanks sandwiched between two open V-band waveguides. The measured samples have clinically relevant range of glucose concentrations, as low as 0.025 wt%. Our measurements show for the first time that it is possible to establish an approximately linear relationship between the signals transmitted through this simple waveguide-based system and the glucose content in the samples. Accurate full-wave EM simulations confirm this linear correlation. The results suggest the possibility of developing a miniaturized non-invasive glucose sensing device based on the transmission of radio waves in this frequency range. (paper)

  2. A self referencing platinum nanoparticle decorated enzyme-based microbiosensor for real time measurement of physiological glucose transport

    McLamore, E.S.; Shi, J.; Jaroch, David; Claussen, Jonathan; Uchida, A.; Jiang, Y.; W. Zhang; Donkin, Shawn S.; Banks, M.K.; Buhman, K.K.; Teegarden, D.; Rickus, Jenna; Porterfield, D. Marshall

    2010-01-01

    Glucose is the central molecule in many biochemical pathways, and numerous approaches have been developed for fabricating micro biosensors designed to measure glucose concentration in/near cells and/or tissues. An inherent problem for microsensors used in physiological studies is a low signal-to-noise ratio, which is further complicated by concentration drift due to the metabolic activity of cells. A microsensor technique designed to filter extraneous electrical noise and provide direct quant...

  3. Accuracy of bedside glucose measurement from three glucometers in critically ill patients.

    Hoedemaekers, C.W.E.; Gunnewiek, JM Klein; Prinsen, M.A.; Willems, J.L.; Hoeven, J.G. van der

    2008-01-01

    OBJECTIVE: Implementation of strict glucose control in most intensive care units has resulted in increased use of point-of-care glucose devices in the intensive care unit. The aim of this study was to determine the reliability of point-of-care testing glucose meters among critically ill patients und

  4. Detection accuracy of three glucose meters estimated by capillary blood glucose measurements compared with venous blood evaluated by the diabetes unit of the Hospital Evangélico de Curitiba, Brazil

    Camacho SL

    2012-05-01

    Full Text Available Mirnaluci Paulino Ribeiro Gama, Camile Fiorese Cruzeta, Ana Carolina Ossowski, Marina Rech Bay, Mariella Muller Michaelis, Stênio Lujan CamachoEndocrinology and Diabetes Service, Hospital Universitário Evangélico de Curitiba, BrazilObjective: To compare capillary blood glucose measurements between three different glucose meters and with the serum glucose values of inpatients at the diabetes unit of Hospital Universitário Evangélico de Curitiba, Brazil.Materials and methods: A total of 132 non-intensive care unit patients admitted for medical and surgical pathologies were evaluated. All patients reported a previous diagnosis of diabetes mellitus, were under 60 years of age, had no hematocrit alterations, remained hemodynamically stable during the time of data collection, and were given no ascorbic acid, acetaminophen, dopamine, or mannitol during follow-up. Capillary and serum blood glucose samples were collected simultaneously by finger-stick and venipuncture 2 hours after lunch, by the same observer, who was blinded to the serum glucose results. First, between July and November 2009, capillary glucose levels were measured using the blood glucose meters OneTouch SureStep® and MediSense Optium®. Between November 2009 and February 2010, capillary blood glucose levels were measured on the glucose meters OneTouch SureStep and Optium Xceed®. The capillary glucose readings were analyzed between meters and also in relation to the serum blood glucose values by the t-test for paired samples and the Mood two-sample test.Results: The patients’ mean age was 50.45 years. The blood glucose means obtained using the meters OneTouch SureStep, MediSense Optium, and Optium Xceed were, respectively, 183.87 mg/dL, 178.49 mg/dL, and 192.73 mg/dL, and the mean for the serum glucose values was 174.58 mg/dL. A significant difference was found between the capillary measurements taken by the glucose meters and the serum glucose measurements (P < 0.05, and no

  5. Issues in the in vivo measurement of glucose metabolism of human central nervous system tumors.

    Di Chiro, G; Brooks, R A; Patronas, N J; Bairamian, D; Kornblith, P L; Smith, B H; Mansi, L; Barker, J

    1984-01-01

    Over 150 cases of central nervous system tumors have been studied with positron emission tomography using fluorine-18-labeled fluorodeoxyglucose (18FDG) as a tracer. From this material 100 consecutive cases of cerebral glioma have been reviewed and analyzed. The results show a strong correlation of tumor grade with glycolytic rate, with visual "hot spots" present in all high-grade neoplasms and in only four low-grade tumors. The quantitative accuracy is limited by three basic factors. First, the measurement of tissue uptake, as compared with the parent technique, autoradiography, is more difficult because detection must be done outside the body. Effects such as scattered radiation and self-attenuation introduce errors unless properly corrected. A more serious problem when measuring small structures, such as a rim-shaped high-grade glioma, is the limited spatial resolution. The most advanced scanner, the Neuro-PET, has a resolution of 6 to 7 mm. Second, corrections are needed for backflow, including free tracer at the time of the scan that will return to the blood and "trapped" tracer that will backflow because of the presence of phosphatase. These corrections are calculated from the blood activity using nominal rate constants for 18FDG. Our study found no significant alteration in rate constants between normal and tumoral tissue. Finally, a lumped constant is needed to correct for kinetic differences between 18FDG and glucose. If there is a change in the mechanism of either membrane transport or the hexokinase reaction, the lumped constant may change. However, measurements of actual glucose utilization in tissue culture lines from six patients support the 18FDG results. PMID:6331282

  6. [Clinical research on improvement of glucose metabolic marker level by coffee drinking-validity of saliva caffeine concentration measurement].

    Okada, Tomoko; Kobayashi, Daisuke; Kono, Suminori; Shimazoe, Takao

    2010-05-01

    We measured both serum and saliva caffeine concentration using HPLC and assessed the correlation between them in volunteers with mild obesity. Significant correlation was shown between saliva and serum caffeine concentration. It may be necessary to measure caffeine metabolite concentration because its metabolites may also have an improving effect of glucose metabolism. In summary, we found that saliva caffeine concentration measurement was useful to assess caffeine intake level. Moreover, it will be helpful to know whether caffeine has an improving effect of glucose metabolism. PMID:20460869

  7. [18F]-2-fluoro-2-deoxyglucose transport kinetics as a function of extracellular glucose concentration in malignant glioma, fibroblast and macrophage cells in vitro

    FDG-PET is used to measure the metabolic rate of glucose. Transport and phosphorylation determine the amount of hexose analog that is phosphorylated and trapped. Competition occurs for both events, such that extracellular glucose concentration affects the FDG image. This study investigated the effect of glucose concentration on the rate of FDG accumulation in three cell lines. The results show that extracellular glucose concentration has a greater impact on the rate of FDG accumulation than the relative abundance of GLUT transporter subtypes

  8. Analog front-end measuring biopotential signal with effective offset rejection loop.

    Lim, Seunghyun; Kim, Hyunho; Song, Haryong; Cho, Dong-il Dan; Ko, Hyoungho

    2015-01-01

    This paper presents an analog front-end (AFE) IC design for recording biopotential signals. The AFE employs a capacitively coupled instrumentation amplifier to achieve a low-noise and high-common mode rejection ratio (CMRR) system. A ripple reduction loop is proposed to reduce the ripple generated by the up-modulating chopper. The low frequency noise is attenuated by an input AC coupling capacitor, and is attenuated again by a DC servo loop. The proposed AFE features a differential gain of 71 dB, and a CMRR of 89 dB, at 50 Hz. Furthermore, the proposed AFE can robustly acquire biopotential signals even in the presence of an input offset and ripples. PMID:26406095

  9. Preferred Presentation of the Visual Analog Scale for Measurement of Postoperative Pain

    Kjeldsen, Helle Birgitte; Klausen, Tobias Wirenfeldt; Rosenberg, Jacob

    2015-01-01

    scores than VAS, especially at low levels of pain. Patients preferred the NRS as compared to the VAS, and when choosing between the four different VAS presentations, they preferred the horizontal VAS with stop lines at the ends. CONCLUSION: For daily clinical practice for guiding postoperative analgesic......BACKGROUND: The aim of this study was to evaluate differences in pain scores with different visual analog scale (VAS) presentations and to compare those differences with a numeric rating scale. We also asked the patients for preference of the different methods. METHODS: Prior to the trial, we...... performed power calculations to estimate a preferred sample size, and 62 postoperative patients supplied a complete set of data to the study. Inclusion criteria were newly operated patients within the first 5 days after surgery. Every patient included was with 1-minute intervals and presented with one of...

  10. Reliability of point-of-care hematocrit, blood gas, electrolyte, lactate and glucose measurement during cardiopulmonary bypass.

    Steinfelder-Visscher, J.; Weerwind, P.W.; Teerenstra, S.; Brouwer, M.H.J.

    2006-01-01

    BACKGROUND: Recently, the GEM Premier blood gas analyser was upgraded to the GEM Premier 3000. In addition to pH, pCO2, pO2, Na+, K+, Ca2+, and hematocrit measurement, glucose and lactate can be measured on the GEM Premier 3000. In this prospective clinical study, the analytical performance of the G

  11. Blood Test: Glucose

    ... Things to Know About Zika & Pregnancy Blood Test: Glucose KidsHealth > For Parents > Blood Test: Glucose Print A A A Text Size What's in ... de sangre: glucosa What It Is A blood glucose test measures the amount of glucose (the main ...

  12. A Comparative Study of Blood Glucose Measurements Using Glucometer Readings and the Standard Method in the Diagnosis of Neonatal Hypoglycemia

    Mohammad Torkaman

    2016-03-01

    Full Text Available Background: Hypoglycemia is one of the most common neonatal disorders, associated with severe complications. There has been a great deal of controversy regarding the definition and screening of hypoglycemia. Therefore, in this study, we aimed to determine a cut-off value for blood glucose level in glucometer readings. Methods: This cross-sectional study was conducted on 238 newborns at risk of hypoglycemia, admitted to Baqiyatallah Hospital of Tehran, Iran in 2012; the subjects were selected via simple sampling. After obtaining informed consents from the newborns’ parents, 1 cc blood samples were sent to the laboratory for measuring the blood glucose level. Moreover, venous blood samples, as well as heel-stick blood samples, were obtained for glucometer measurements. Blood glucose measurements were used to determine the cut-off value by the receiver operating characteristic (ROC curve and make comparisons with the diagnostic criteria for hypoglycemia in the literature. Results: A total of 238 infants with the mean weight of 2869±821.9 g were enrolled in this study. The mean (±SD blood glucose levels were 65.1±22.9, 82.9±24.7, and 84.4±24.8 mg/dl, based on the standard laboratory method, glucometer reading of venous blood samples, and glucometer reading of heel-stick capillary blood samples, respectively. The optimal cut-off point for hypoglycemia was determined as 65 mg/dl, using glucometer-based assessment of heel-stick blood samples. Conclusion: The significant difference in blood glucose levels measured by the laboratory method and outpatient glucometer readings highlights the importance of a cut-off value for rapid assessment and control of blood glucose and timely detection of hypoglycemia. In fact, the cut-off value introduced in the present study could facilitate such measurements.

  13. Stability of regional cerebral glucose metabolism in the normal brain measured by positron emission tomography

    Cerebral glucose utilization (LCMRGI) was measured using the [18F]fluorodeoxyglucose method with PET in two groups of ten healthy young volunteers, each scanned in a resting state under different methodological conditions. In addition, five subjects had a second scan within 48 hr. Mean hemispheric values averaged 45.8 +/- 3.3 mumol/100 g/min in the right cerebral hemisphere and 47.0 +/- 3.7 mumol/100 g/min in the left hemisphere. A four-way analysis of variance (group, sex, region, hemisphere) was carried out on the results using three different methods of data manipulation: (a) the raw values of glucose utilization, (b) LCMRGI values normalized by the mean hemispheric gray matter LCMRGI value, and (c) log transformed LCMRGI values. For all analysis techniques, significantly higher LCMRGI values were consistently seen in the left mid and posterior temporal area and caudate nucleus relative to the right, and in the right occipital region relative to the left. The coefficient of variation of intrasubject regional differences (9.9%) was significantly smaller than the coefficient of variation for regions between subjects (16.5%). No differences were noted between the sexes and no effect of repeat procedures was seen in subjects having multiple scans. In addition, inter-regional LCMRGI correlations were examined both in values from the 20 normal subjects, as well as in a set of hypothetical abnormal values. Results were compared with those reported from other PET centers; despite certain methodological differences, the intersubject and inter-regional variation of LCMRGI is fairly constant

  14. Experimental study for cancer diagnosis with positron-labeled fluorinated glucose analogs: [18F]-2-fluoro-2-deoxy-D-mannose

    18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) and 18F-2-fluoro-2-deoxy-D-mannose (18F-FDM) were tested as tumor diagnostic agents in a transplantable rat tumor and rabbit tumors. Tissue distribution studies in rats showed high tumor uptakes of both radiopharmaceuticals. The tumor uptake reached 2.65+-0.61% dose 18F-FDG/g and 2.65+-0.81% dose 18F-FDM/g at 60 min and remained relatively constant until 120 min. Blood clearance of both 18F-FDG and 18F-FDM was very rapid and tumor-to-blood ratios reached 22.1 and 29.4 at 60 min, respectively. Tumor-to-tissue ratios of both radiopharmaceuticals were very high in most organs, especially in the liver, kidney, and pancreas. Positron emission tomography (PET) of rabbit tumor with 18F-FDM clearly delineated the main tumor, central necrosis, and lymph node metastases. These data suggested that 18F-FDM, which is a by-product of 18F-FDG synthesis, was also an excellent cancer diagnostic agent as well as 18-F-FDG. This is not only a new feature of 18F-FDM, but also an economical improvement on cancer diagnosis by PET. (orig.)

  15. Photoacoustic blood glucose and skin measurement based on optical scattering effect

    Zhao, Zuomin; Myllyla, Risto A.

    2002-07-01

    Non-invasive blood glucose determination has been investigated by more than 100 research groups in the world during the past fifteen years. The commonly optical methods are based on the capacity of near-IR light to penetrate a few hundreds micrometers or a few millimeters into human tissue where it interacts with glucose. A change of glucose concentration may modify the optical parameters in tissue, with the result that its glucose concentration can be extracted by analyzing the received optical signals. This paper demonstrates that glucose affects on the scattering coefficient of human blood, by applying the streak camera and pulsed photoacoustic techniques; and drinking water seems also affecting on PA signal from skin surface.

  16. The relationship between HbA(1c) and fasting plasma glucose in patients with increased plasma liver enzyme measurements

    Christiansen, R; Rasmussen, L Melholt; Nybo, H;

    2012-01-01

    Background:  HbA(1c) is currently being introduced for diagnostic purpose in diabetes. Previous studies have, however, indicated that patients with liver disease have false low HbA(1c) levels. We therefore investigated the correlation between HbA(1c) and plasma glucose in patients with different...... levels of increased liver enzyme concentrations. Methods:  Data from 10 065 patients with simultaneous measurement of HbA(1c) , venous fasting plasma glucose, alanine aminotransferase and γ-glutamyl transferase were extracted from our laboratory database. Correlations were investigated in four patient...... groups divided according to their liver enzyme concentrations. Results:  The correlation between HbA(1c) and plasma glucose was high in all groups, with r = 0.77 for men and r = 0.78 for women (P ...

  17. Experiments of glucose solution measurement based on the tunable pulsed laser induced photoacoustic spectroscopy method

    Ren, Zhong; Liu, Guodong; Xiong, Zhihua; Huang, Zhen

    2015-07-01

    Photoacoustic spectroscopy (PAS) is a hybrid, well-established and promising detection technique that has widely applied into a lot of fields such as bio-medical, material and environment monitoring etc. PAS has high contrast and resolution because of combining the advantages of the pure-optical and the pure-acoustic. In this paper, a photoacoustic experiment of glucose solution induced by 532nm pumped Nd:YAG tunable pulsed laser with repetition rate of 20Hz and pulse width of 10ns is performed. The time-resolved photoacoustic signals of glucose solution induced by pulsed laser in the average time of 512 are obtained. And the photoacoustic experiments of different concentrations of glucose solutions and different wavelengths of pulsed laser are carried out in this paper. Experimental results demonstrate that the bipolar sine-wave profiles for the time-resolved photoacoustic signal of glucose solution are in good agreement with the past reported literatures. And the different absorbing coefficients of glucose solution can be gotten according to the slope of the first part of the time-resolved photoacoustic signals. In addition, the different acoustic velocities of glucose solution can also be gotten according to the shift change of the time-resolved photoacoustic peak values. Research results illustrate that the characteristic wavelengths, different optical and acoustic properties of glucose solution can be interpreted by the time-resolved and peak-to-peak photoacoustic signals induced by the pulsed laser.

  18. Interferon Analogs

    Poelstra, Klaas; Prakash, Jai; Beljaars, Eleonora; Bansal, Ruchi

    2015-01-01

    The invention relates to the field of medicine. Among others, it relates to biologically active analogs of interferons (IFNs) which show less unwanted side-effects and to the therapeutic uses thereof. Provided is an IFN analog, wherein the moiety mediating binding to its natural receptor is at least

  19. Interferon Analogs

    Poelstra, Klaas; Prakash, Jai; Beljaars, Leonie; Bansal, Ruchi

    2010-01-01

    The invention relates to the field of medicine. Among others, it relates to biologically active analogs of interferons (IFNs) which show less unwanted side-effects and to the therapeutic uses thereof. Provided is an IFN analog, wherein the moiety mediating binding to its natural receptor is at least

  20. Age and sex differences in cerebral glucose consumption measured by pet using [18-F] fluorodeoxyglucose (FDG)

    Resting cerebral glucose metabolic rates (CMRglc) were measured in 23 subjects by PET using FDG. Subjects were divided into several groups (mean age +- S.D.) 5 young males (YM) (27 +- 6); 6 young females (YF)(33 +9); 5 elderly males (EM)(73 +- 5); 7 elderly females (EF)(69 +- 7). Additionally, from these groups 4 YM, 3YF, 5EM and 4EF were studied again within 6 weeks under identical conditions. CMRglc in the YF group again was significantly hider than YM (p 0.05). No obvious relationships of CMRglc to the phase of the menstrual cycle was found in this small group. There was a trend (p=0.06) toward a higher CMRglc in YF than EF. These results support the findings of higher CBF in YF versus YM. The differences between the results of Kuhl et al (J. Cereb. and a reduction of CMRglc with age was found in a mixed group of males and females (58and female), and where no age effect was found the males, are also resolved by these findings. The authors suggest that the apparent age effect, in females in this study, is principally a hormonal one

  1. 4-Phenylureido/thioureido-substituted 2,2-dimethylchroman analogs of cromakalim bearing a bulky 'carbamate' moiety at the 6-position as potent inhibitors of glucose-sensitive insulin secretion.

    Pirotte, Bernard; Florence, Xavier; Goffin, Eric; Medeiros, Marlen Borges; de Tullio, Pascal; Lebrun, Philippe

    2016-10-01

    The synthesis of 2,2-dimethylchromans bearing a 3/4-chloro/cyano-substituted phenylureido or phenylthioureido moiety at the 4-position and an alkoxycarbonylamino ('carbamate') group at the 6-position is described. These new analogs of the potassium channel opener (±)-cromakalim were further tested on rat pancreatic islets as putative inhibitors of insulin release and on rat aorta rings as putative vasorelaxants. All compounds inhibited insulin secretion and induced a myorelaxant activity. Compound 14o [R/S-N-3-cyanophenyl-N'-(6-tert-butoxycarbonylamino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)urea; BPDZ 711] emerged as the most potent inhibitor of the glucose-sensitive insulin releasing process (IC50 = 0.24 μM) and displayed selectivity towards the pancreatic endocrine tissue. Radioisotopic, fluorimetric and pharmacological investigations were performed on rat pancreatic islet and rat vascular smooth muscle cells in order to decipher its mechanism of action. Our findings suggest that the mechanism of action of 14o is rather unspecific. The compound behaves as a KATP channel opener, a Ca(2+) entry blocker, and promotes an intracellular calcium translocation. PMID:27267004

  2. Measurement of regional cerebral glucose utilization in man by positron emission tomography

    The various methods available for the study of regional cerebral glucose consumption in man by positron emission tomography are described and their applications, limitations and principal physiopathological results are presented

  3. The Glucose Measurement Industry and Hemoglobin A1c: An Opportunity for Creative Destruction.

    Cembrowski, George

    2016-01-01

    The MyStar Extra self-monitoring blood glucose (SMBG) system provides moving estimates of the patient's hemoglobin A1c (HbA1c). There is a treasure trove of highly accurate glucose data available from highly accurate SMBG, CGM and FGM along with highly accurate HPLC HbA1c. If Nathan's criteria are used to select subjects whose glucoses can be correlated to the HbA1c, then algorithms can be developed for robustly transforming glucose into HbA1c. These algorithms can then be implemented in any SMBG or with the CGM and FGM software. This calculated HbA1c would even be accurate with Nathan's excluded population thus reducing the use of fructosamine and glycated protein. Finally, the developer of these new algorithms is advised to use a specific approach for testing her algorithm. PMID:26481643

  4. Precision timing measurement of phototube pulses using a flash analog-to-digital converter

    Bennett, J. V.(Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA); Kornicer, M.(University of Hawaii, Honolulu, HI, 96822, USA); Shepherd, M. R.; Ito, M. M.

    2010-01-01

    We present the timing characteristics of the flash ADC readout of the GlueX forward calorimeter, which depends on precise measurement of arrival time of pulses from FEU 84-3 photomultiplier tubes to suppress backgrounds. The tests presented were performed using two different 250 MHz prototype flash ADC devices, one with eight-bit and one with twelve-bit sampling depth. All measured time resolutions were better than 1 ns, independent of signal size, which is the design goal for the GlueX forwa...

  5. Analysis of FTO Gene Variants with Measures of Obesity and Glucose Homeostasis in the IRAS Family Study

    Wing, Maria R; Ziegler, Julie; Langefeld, Carl D.; Ng, Maggie CY; Haffner, Steven M.; Norris, Jill M.; Goodarzi, Mark O; Donald W Bowden

    2009-01-01

    Multiple studies have identified FTO gene variants associated with measures of adiposity in European-derived populations. The study objective was to determine whether FTO variants were associated with adiposity, including visceral and subcutaneous adipose tissue (VAT; SAT), and glucose homeostasis measures in the Insulin Resistance Atherosclerosis Family Study (IRASFS). A total of 27 SNPs in FTO intron 1, including SNPs prominent in the literature (rs9939609, rs8050136, rs1121980, rs17817449,...

  6. Measurement of Faraday rotation in twisted optical fiber using rotating polarization and analog phase detection

    We demonstrated phase modulation of rotating linearly polarized light by current-induced Faraday rotation in a single mode optical fiber and used the technique to measure the current in ZT-40M, a Reversed-Field Pinch. We have also demonstrated the practicality of using twisted sensing fiber to overcome the problems associated with linear birefringence

  7. Effects of Zinc Supplementation on the Anthropometric Measurements, Lipid Profiles and Fasting Blood Glucose in the Healthy Obese Adults

    Sepide Mahluji

    2013-02-01

    Full Text Available Purpose: The aim of this study was to assess the effects of zinc supplementation on anthropometric measures, improving lipid profile biomarkers, and fasting blood glucose level in obese people. Methods: This randomized, double- blind clinical trial was carried out on 60 obese participants in the 18-45 age range for one month. The participants were randomly divided into the intervention group, who received 30 mg/d zinc gluconate, and the placebo group who received 30mg/d starch. Anthropometric measurements (body mass index (BMI, weight and waist circumference were recorded before and at the end of study. Lipid profile biomarkers and fasting blood glucose were determined using enzymatic procedure. Analysis of Covariance (ANCOVA test was run to compare the post-treatment values of the two groups, and t-test was conducted to compare within group changes. Results: Serum zinc concentration was increased significantly in intervention group (p=0.024. BMI and body weight was significantly decreased (p=0.030 and p=0.020, respectively. Lipid profile biomarkers and fating blood glucose did not change significantly but triglyceride level was significantly decreased (p=0.006 in the intervention group. Conclusion: The obtained results indicate that zinc supplementation improves BMI, body weight, and triglyceride concentration without considerable effects on lipid profile and glucose level. Zinc can be suggested as a suitable supplementation therapy for obese people, but more studies are needed to verify the results.

  8. Measurement of glucose metabolism in patients with dilated cardiomyopathy using positron emission tomography with 18F-FDG: Initial Experience

    Introduction: Fluorine18 deoxyglucose (18F-FDG) has been used in numerous studies to determine the cardiac rate of glucose metabolism in normal and pathological conditions. It is known that during heart failure the metabolic pattern is altered. Patlack's graphical analysis allows the assessment of heart muscle glucose consumption in patients with non-ischaemic heart failure and normal subjects. Methods: Standardized measurement of glucose metabolism was performed in four patients with dilated cardiomyopathy and three healthy subjects. All subjects received an oral load of carbohydrates (75gr) previous to scanning. Dynamic images of the thorax were acquired. Myocardial uptake was estimated from time-activity curves in the atrium and left ventricle using Patlack's graphical analysis. Results: All subjects studied were male. 18F-FDG uptake rate for the group with dilated cardiomyopathy was 1.31±0.2, versus 1.26±0.37 ml/100gr/min in the control group. Conclusion: Measurement of cardiac glucose metabolism by 18F-FDG PET is feasible in a clinical service, allowing impact evaluation of physiologic and metabolic changes in the myocardium in different pathologic scenarios in addition to therapy assessment

  9. Direct measurement of time-frequency analogs of sub-Planck structures

    Praxmeyer, Ludmila; Chen, Chih-Cheng; Yang, Popo; Yang, Shang-Da; Lee, Ray-Kuang

    2016-05-01

    Exploiting the correspondence between the Wigner distribution function and the frequency-resolved optical gating (FROG) measurement, we experimentally demonstrate the existence of chessboardlike interference patterns with a time-bandwidth product smaller than that of a transform-limited pulse in the phase-space representation of compass states. Using superpositions of four electric pulses as the realization of compass states, we have shown via direct measurements that displacements leading to orthogonal states can be smaller than limits set by uncertainty relations. In the experiment we observe an exactly chronocyclic correspondence to the sub-Planck structure in the interference pattern appearing for the superposition of two Schrödinger-cat-like states in a position-momentum phase space.

  10. Precision timing measurement of phototube pulses using a flash analog-to-digital converter

    Bennett, J.V.; Kornicer, M. [Indiana University, Bloomington, IN 47405 (United States); Shepherd, M.R., E-mail: mashephe@indiana.ed [Indiana University, Bloomington, IN 47405 (United States); Ito, M.M. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)

    2010-10-01

    We present the timing characteristics of the flash ADC readout of the GlueX forward calorimeter, which depends on precise measurement of arrival time of pulses from FEU 84-3 photomultiplier tubes to suppress backgrounds. The tests presented were performed using two different 250 MHz prototype flash ADC devices, one with eight-bit and one with 12-bit sampling depth. All measured time resolutions were better than 1 ns, independent of signal size, which is the design goal for the GlueX forward calorimeter. For pulses with an amplitude of 100 mV the timing resolution is 0.57{+-}0.18 ns, while for 500 mV pulses it is 0.24{+-}0.08 ns.

  11. Precision timing measurement of phototube pulses using a flash analog-to-digital converter

    We present the timing characteristics of the flash ADC readout of the GlueX forward calorimeter, which depends on precise measurement of arrival time of pulses from FEU 84-3 photomultiplier tubes to suppress backgrounds. The tests presented were performed using two different 250 MHz prototype flash ADC devices, one with eight-bit and one with 12-bit sampling depth. All measured time resolutions were better than 1 ns, independent of signal size, which is the design goal for the GlueX forward calorimeter. For pulses with an amplitude of 100 mV the timing resolution is 0.57±0.18 ns, while for 500 mV pulses it is 0.24±0.08 ns.

  12. Precision timing measurement of phototube pulses using a flash analog-to-digital converter

    Bennett, J V; Shepherd, M R; Ito, M M

    2010-01-01

    We present the timing characteristics of the flash ADC readout of the GlueX forward calorimeter, which depends on precise measurement of arrival time of pulses from FEU 84-3 photomultiplier tubes to suppress backgrounds. The tests presented were performed using two different 250 MHz prototype flash ADC devices, one with eight-bit and one with twelve-bit sampling depth. All measured time resolutions were better than 1 ns, independent of signal size, which is the design goal for the GlueX forward calorimeter. For pulses with an amplitude of 100 mV the timing resolution is 0.57 +- 0.18 ns, while for 500 mV pulses it is 0.24 +- 0.08 ns.

  13. Precision timing measurement of phototube pulses using a flash analog-to-digital converter

    Bennett, J. V.; Kornicer, M.; Shepherd, M. R.; Ito, M. M.

    2010-10-01

    We present the timing characteristics of the flash ADC readout of the GlueX forward calorimeter, which depends on precise measurement of arrival time of pulses from FEU 84-3 photomultiplier tubes to suppress backgrounds. The tests presented were performed using two different 250 MHz prototype flash ADC devices, one with eight-bit and one with 12-bit sampling depth. All measured time resolutions were better than 1 ns, independent of signal size, which is the design goal for the GlueX forward calorimeter. For pulses with an amplitude of 100 mV the timing resolution is 0.57±0.18 ns, while for 500 mV pulses it is 0.24±0.08 ns.

  14. Laser spectroscopic real time measurements of methanogenic activity under simulated Martian subsurface analog conditions

    Schirmack, Janosch; Böhm, Michael; Brauer, Chris; Löhmannsröben, Hans-Gerd; de Vera, Jean-Pierre; Möhlmann, Diedrich; Wagner, Dirk

    2014-08-01

    On Earth, chemolithoautothrophic and anaerobic microorganisms such as methanogenic archaea are regarded as model organisms for possible subsurface life on Mars. For this reason, the methanogenic strain Methanosarcina soligelidi (formerly called Methanosarcina spec. SMA-21), isolated from permafrost-affected soil in northeast Siberia, has been tested under Martian thermo-physical conditions. In previous studies under simulated Martian conditions, high survival rates of these microorganisms were observed. In our study we present a method to measure methane production as a first attempt to study metabolic activity of methanogenic archaea during simulated conditions approaching conditions of Mars-like environments. To determine methanogenic activity, a measurement technique which is capable to measure the produced methane concentration with high precision and with high temporal resolution is needed. Although there are several methods to detect methane, only a few fulfill all the needed requirements to work within simulated extraterrestrial environments. We have chosen laser spectroscopy, which is a non-destructive technique that measures the methane concentration without sample taking and also can be run continuously. In our simulation, we detected methane production at temperatures down to -5 °C, which would be found on Mars either temporarily in the shallow subsurface or continually in the deep subsurface. The pressure of 50 kPa which we used in our experiments, corresponds to the expected pressure in the Martian near subsurface. Our new device proved to be fully functional and the results indicate that the possible existence of methanogenic archaea in Martian subsurface habitats cannot be ruled out.

  15. Error in the measurement of the Telector monitor, model 6112B (analogic)

    This monitor is a portable equipment used with radiological protection ends in many areas where use of radioactive material is made, since account with a telescopic bar with two Geiger Mueller tubes (GM) to measure gamma radiation. The maker in his specifications indicates that the equipment is able to measure from 0.1 R/hr up to 1000 R/hr and their response doesn't depend on the energy in the interval of 300 keV to 3 MeV. However, personal of the Electronic Systems department carrying out tests in the Secondary Laboratory of Dosimetric Calibration (LSCD) of the ININ, it found that this monitor really presents an energy dependence for the energies of 60Co, in the scale of 2 R/hr. With base in an analysis of the equipment and the two GM detectors that it uses, was found that the origin of the problem is the point of saturation of the detector that uses for this scale, which coincides with the maximum measurement value that is of 2 R/hr. This flaw it can be solved using the detector that operates with the high scales, for which is required to make a modification to the electronic circuit in the part of the switch that selects the detector type. (Author)

  16. Thermal dilution measurement of cardiac output in dogs using an analog computer.

    Hendriks, F F; Schipperheyn, J J; Quanjer, P H

    1978-01-01

    Thermal dilution cardiac output determinations in dogs were compared to simultaneously performed Fick oxygen measurements. The purpose of this study was to validate in dog experiments a method for thermal dilution measurement which employs a double-thermistor catheter combined with an automatic computer as described by Olsson et al. Dilution and injectate temperature are entered directly into the calculation. The method does not employ logarithmic extrapolation, integration of the dilution signal being terminated when a preset cut-off level is reached. Errors due to recirculation, thermal capacitance of the right heart and heat exchange with the catheter's dead space require the use of an empirically derived correction factor, which in dogs was found to be significantly different from the factor used for human thermal dilution curves. With the appropriate cut-off level and correction factor a good agreement was found between the results of the thermal dilution and the Fick method. The regression equation for 47 experiments was found to be COtd = 0.95 COFick + 0.08; the correlation coefficient was 0.94. PMID:728031

  17. Measurements of Polyatomic Molecule Formation on an Icy Grain Analog Using Fast Atoms

    Chutjian, A.; Madsunkov, S.; Shortt, B. J.; MacAskill, J. A.; Darrach, M. R.

    2006-01-01

    Carbon dioxide has been produced from the impact of a monoenergetic O(P-3) beam upon a surface cooled to 4.8 K and covered with a CO ice. Using temperature-programmed desorption and mass spectrometer detection, we have detected increasing amounts of CO2 formation with O(P-3) energies of 2, 5, 10, and 14 eV. This is the first measurement of polyatomic molecule formation on a surface with superthermal atoms. The goal of this work is to detect other polyatomic species, such as CH3OH, which can be formed under conditions that simulate the grain temperature, surface coverage, and superthermal atoms present in shock-heated circumstellar and interstellar regions.

  18. Experimentally Measured Interfacial Area during Gas Injection into Saturated Porous Media: An Air Sparging Analogy

    Crandall, Dustin; Ahmadi, Goodarz; Smith, Duane H., Bromhal, Grant

    2010-01-01

    The amount of interfacial area (awn) between air and subsurface liquids during air-sparging can limit the rate of site remediation. Lateral movement within porous media could be encountered during air-sparging operations when air moves along the bottom of a low-permeability lens. This study was conducted to directly measure the amount of awn between air and water flowing within a bench-scale porous flow cell during the lateral movement of air along the upper edge of the cell during air injections into an initially water-saturated flow cell. Four different cell orientations were used to evaluate the effect of air injection rates and porous media geometries on the amount of awn between fluids. Air was injected at flow rates that varied by three orders of magnitude, and for each flow cellover this range of injection rates little change in awn was noted. A wider variation in awn was observed when air moved through different regions for the different flow cell orientations. These results are in good agreement with the experimental findings of Waduge et al. (2007), who performed experiments in a larger sand-pack flow cell, and determined that air-sparging efficiency is nearly independent of flow rate but highly dependent on the porous structure. By directly measuring the awn, and showing that awn does not vary greatly with changes in injection rate, we show that the lack of improvement to remediation rates is because there is a weak dependence of the awn on the air injection rate.

  19. Upconverting phosphors as an amplifier of a colorimetric signal in dry chemistry test strips for enzymatic measurement of glucose

    Valta, Timo; Horn, Carina

    2015-09-01

    We describe the use of upconverting phosphors (UCPs) as an amplifier of the colorimetric signal in enzymatic dry chemistry test strips for the determination of glucose. The indicator compound used in the strips attenuated both the emission and excitation wavelengths of the upconverting phosphors, thus taking advantage of the nonlinear relationship between the excitation and emission of these particles. By monitoring the emission of the UCPs under 978 nm excitation, we were able to obtain significantly higher signal response (a steeper calibration curve) from the colorimetric assay compared to a reflectance measurement. The limit of detection of the developed method was 2.1-fold lower than the reflectance-based reference method. The new method was able to determine glucose from a sample of water in the range of 5.7 μM to 22 mM, which covers the typical blood glucose range in newborns and adults. In low analyte concentrations we obtained up to 3-fold improvement in the slope of the assay calibration curve. This difference decreased with increasing analyte concentration and the effect was diminished by the highest glucose concentration. However, the analytical sensitivity (the ratio of slope and standard deviation) was practically identical between the two methods because of the higher deviation in the UCP emission signal.

  20. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions

  1. Effects of Zinc Supplementation on the Anthropometric Measurements, Lipid Profiles and Fasting Blood Glucose in the Healthy Obese Adults

    Sepide Mahluji; Mohammad Asghari Jafarabadi; Nazila Farrin; Yaser Khaje Bishak; Majid Mobasseri; Alireza Ostadrahimi; Laleh Payahoo

    2013-01-01

    Purpose: The aim of this study was to assess the effects of zinc supplementation on anthropometric measures, improving lipid profile biomarkers, and fasting blood glucose level in obese people. Methods: This randomized, double- blind clinical trial was carried out on 60 obese participants in the 18-45 age range for one month. The participants were randomly divided into the intervention group, who received 30 mg/d zinc gluconate, and the placebo group who received 30mg/d starch. Anthropo...

  2. The importance of glucose metabolism in the hypoxic cytotoxicity of Misonidazole

    The authors are investigating the mechanism of inhibition of glucose metabolism and its role in the hypoxic cytotoxicity of Misonidazole (Miso). Preincubation of hypoxic exponential EMT6/Ro cells with Miso and 5.5 mM glucose containing media caused a time-dependent inhibition of both glucose consumption and lactate formation. This inhibition began after 90 min, 45 min, and 15 min preincubation with 1mM, 2.5mM, and 5mM Miso respectively. The inhibition closely correlated with the kinetics and extent of decreased viability of these cells as measured by dye exclusion and colony forming efficiency. Miso does not inhibit glucose transport in these phloretin-sensitive cells. Transport was measured by the uptake of 3-0-methyl-D-glucose, a non-metabolized glucose analog. The initial rate was determined to be the same (1.66 +- 0.18 nmoles cell/second at 250C)

  3. Troubleshooting analog circuits

    Pease, Robert A

    1991-01-01

    Troubleshooting Analog Circuits is a guidebook for solving product or process related problems in analog circuits. The book also provides advice in selecting equipment, preventing problems, and general tips. The coverage of the book includes the philosophy of troubleshooting; the modes of failure of various components; and preventive measures. The text also deals with the active components of analog circuits, including diodes and rectifiers, optically coupled devices, solar cells, and batteries. The book will be of great use to both students and practitioners of electronics engineering. Other

  4. Analog circuits cookbook

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  5. In vivo cardiac glucose metabolism in the high-fat fed mouse: Comparison of euglycemic–hyperinsulinemic clamp derived measures of glucose uptake with a dynamic metabolomic flux profiling approach

    Rationale: Cardiac metabolism is thought to be altered in insulin resistance and type 2 diabetes (T2D). Our understanding of the regulation of cardiac substrate metabolism and insulin sensitivity has largely been derived from ex vivo preparations which are not subject to the same metabolic regulation as in the intact heart in vivo. Studies are therefore required to examine in vivo cardiac glucose metabolism under physiologically relevant conditions. Objective: To determine the temporal pattern of the development of cardiac insulin resistance and to compare with dynamic approaches to interrogate cardiac glucose and intermediary metabolism in vivo. Methods and results: Studies were conducted to determine the evolution of cardiac insulin resistance in C57Bl/6 mice fed a high-fat diet (HFD) for between 1 and 16 weeks. Dynamic in vivo cardiac glucose metabolism was determined following oral administration of [U-13C] glucose. Hearts were collected after 15 and 60 min and flux profiling was determined by measuring 13C mass isotopomers in glycolytic and tricarboxylic acid (TCA) cycle intermediates. Cardiac insulin resistance, determined by euglycemic–hyperinsulinemic clamp, was evident after 3 weeks of HFD. Despite the presence of insulin resistance, in vivo cardiac glucose metabolism following oral glucose administration was not compromised in HFD mice. This contrasts our recent findings in skeletal muscle, where TCA cycle activity was reduced in mice fed a HFD. Similar to our report in muscle, glucose derived pyruvate entry into the TCA cycle in the heart was almost exclusively via pyruvate dehydrogenase, with pyruvate carboxylase mediated anaplerosis being negligible after oral glucose administration. Conclusions: Under experimental conditions which closely mimic the postprandial state, the insulin resistant mouse heart retains the ability to stimulate glucose metabolism. - Highlights: • Insulin clamp was used to determine the evolution of cardiac insulin

  6. In vivo cardiac glucose metabolism in the high-fat fed mouse: Comparison of euglycemic–hyperinsulinemic clamp derived measures of glucose uptake with a dynamic metabolomic flux profiling approach

    Kowalski, Greg M., E-mail: greg.kowalski@deakin.edu.au [Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125 (Australia); De Souza, David P. [Metabolomics Australia, Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010 (Australia); Risis, Steve [Cellular and Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria 3004 (Australia); Burch, Micah L. [Brigham and Women' s Hospital, Department of Medicine, Boston, MA (United States); Hamley, Steven [Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125 (Australia); Kloehn, Joachim [Metabolomics Australia, Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010 (Australia); Selathurai, Ahrathy [Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125 (Australia); Lee-Young, Robert S. [Cellular and Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria 3004 (Australia); Tull, Dedreia; O' Callaghan, Sean; McConville, Malcolm J. [Metabolomics Australia, Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010 (Australia); Bruce, Clinton R. [Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125 (Australia)

    2015-08-07

    Rationale: Cardiac metabolism is thought to be altered in insulin resistance and type 2 diabetes (T2D). Our understanding of the regulation of cardiac substrate metabolism and insulin sensitivity has largely been derived from ex vivo preparations which are not subject to the same metabolic regulation as in the intact heart in vivo. Studies are therefore required to examine in vivo cardiac glucose metabolism under physiologically relevant conditions. Objective: To determine the temporal pattern of the development of cardiac insulin resistance and to compare with dynamic approaches to interrogate cardiac glucose and intermediary metabolism in vivo. Methods and results: Studies were conducted to determine the evolution of cardiac insulin resistance in C57Bl/6 mice fed a high-fat diet (HFD) for between 1 and 16 weeks. Dynamic in vivo cardiac glucose metabolism was determined following oral administration of [U-{sup 13}C] glucose. Hearts were collected after 15 and 60 min and flux profiling was determined by measuring {sup 13}C mass isotopomers in glycolytic and tricarboxylic acid (TCA) cycle intermediates. Cardiac insulin resistance, determined by euglycemic–hyperinsulinemic clamp, was evident after 3 weeks of HFD. Despite the presence of insulin resistance, in vivo cardiac glucose metabolism following oral glucose administration was not compromised in HFD mice. This contrasts our recent findings in skeletal muscle, where TCA cycle activity was reduced in mice fed a HFD. Similar to our report in muscle, glucose derived pyruvate entry into the TCA cycle in the heart was almost exclusively via pyruvate dehydrogenase, with pyruvate carboxylase mediated anaplerosis being negligible after oral glucose administration. Conclusions: Under experimental conditions which closely mimic the postprandial state, the insulin resistant mouse heart retains the ability to stimulate glucose metabolism. - Highlights: • Insulin clamp was used to determine the evolution of cardiac

  7. Continuous and simultaneous electrochemical measurements of glucose, lactate, and ascorbate in rat brain following brain ischemia.

    Lin, Yuqing; Yu, Ping; Hao, Jie; Wang, Yuexiang; Ohsaka, Takeo; Mao, Lanqun

    2014-04-15

    Developing new tools and technologies to enable recording the dynamic changes of multiple neurochemicals is the essence of better understanding of the molecular basis of brain functions. This study demonstrates a microfluidic chip-based online electrochemical system (OECS) for in vivo continuous and simultaneous monitoring of glucose, lactate, and ascorbate in rat brain. To fabricate the microfluidic chip-based detecting system, a microfluidic chip with patterned channel is developed into an electrochemical flow cell by incorporating the chip with three surface-modified indium-tin oxide (ITO) electrodes as working electrodes, a Ag/AgCl wire as reference electrode, and a stainless steel tube as counter electrode. Selective detection of ascorbate is achieved by the use of single-walled carbon nanotubes (SWNTs) to largely facilitate the electrochemical oxidation of ascorbate, while a dehydrogenase-based biosensing mechanism with methylene green (MG) adsorbed onto SWNTs as an electrocatalyst for the oxidation of dihydronicotiamide adenine dinucleotide (NADH) is employed for biosensing of glucose and lactate. To avoid the crosstalk among three sensors, the sensor alignment is carefully designed with the SWNT-modified electrode in the upstream channel and paralleled glucose and lactate biosensors in the downstream channels. With the microfluidic chip-based electrochemical flow cell as the detector, an OECS is successfully established by directly integrating the microfluidic chip-based electrochemical flow cell with in vivo microdialysis. The OECS exhibits a good linear response toward glucose, lactate, and ascorbate with less crosstalk. This property, along with the high stability and selectivity, enables the OECS for continuously monitoring three species in rat brain following brain ischemia. PMID:24621127

  8. Associations between insulin and glucose concentrations and anthropometric measures of fat mass in Australian adolescents

    Denney-Wilson Elizabeth; Cowell Christopher T; Okely Anthony D; Hardy Louise L; Aitken Robert; Dobbins Timothy

    2010-01-01

    Abstract Background One of the most serious, yet common co-morbidities of obesity is insulin resistance, which if untreated may progress to type 2 diabetes. This paper describes the insulin and glucose concentration distributions, the prevalence of elevated insulin, the associations between insulin and body mass index (BMI), waist circumference, waist-to-height ratio (WHtR) and fat mass index in a representative sample of Australian adolescents. Methods Cross-sectional population-based study ...

  9. Non-invasive detection of fasting blood glucose level via electrochemical measurement of saliva

    Malik, Sarul; Khadgawat, Rajesh; Anand, Sneh; Gupta, Shalini

    2016-01-01

    Machine learning techniques such as logistic regression (LR), support vector machine (SVM) and artificial neural network (ANN) were used to detect fasting blood glucose levels (FBGL) in a mixed population of healthy and diseased individuals in an Indian population. The occurrence of elevated FBGL was estimated in a non-invasive manner from the status of an individual’s salivary electrochemical parameters such as pH, redox potential, conductivity and concentration of sodium, potassium and calc...

  10. Potassium Measures and Their Associations with Glucose and Diabetes Risk: The Multi-Ethnic Study of Atherosclerosis (MESA)

    Chatterjee, Ranee; Zelnick, Leila; Mukamal, Kenneth J.; Nettleton, Jennifer A.; Kestenbaum, Bryan R.; Siscovick, David S.; Ix, Joachim H.; Tracy, Russell; Hoofnagle, Andrew N.; Svetkey, Laura P.; Edelman, David; de Boer, Ian H.

    2016-01-01

    Background Recent studies have found low-normal potassium (K) to be associated with increased diabetes risk. We sought to verify these associations in a multi-ethnic US cohort; and to determine if these associations extend to US Hispanics and Asian-Americans. Methods We analyzed data from Multi-Ethnic Study of Atherosclerosis (MESA) participants who were free-of-diabetes at baseline. We examined cross-sectional associations between measures of K—serum, dietary, and urine—with fasting glucose and HOMA-IR. We examined longitudinal associations between K and diabetes risk over 8 years. Findings In multivariable models, compared to those with higher serum K (≥4.5mmol/L), those with lower serum K (<4.0mmol/L) had significantly higher fasting glucose [1.3 mg/dL (95%CI 0.2, 2.4), P-value = 0.03]. Incident diabetes developed in 1281 of 5415 at-risk participants. In minimally-adjusted models, we found inverse associations between serum and dietary K and diabetes risk. Compared to those with higher serum K, those with lower serum K had an HR (95% CI) of incident diabetes of 1.23 (1.04, 1.47), P-value = 0.02. However, these associations were attenuated in fully-adjusted models. We found no significant interaction between potassium and ethnicity. Conclusions In this multi-ethnic cohort, we found a significant inverse association between serum K and fasting glucose but no significant association with longer-term diabetes risk. This inverse association between potassium and glucose must be studied further to understand the physiology and its potential impact on chronic health. PMID:27280455

  11. Glucose Tests

    ... be limited. Home Visit Global Sites Search Help? Glucose Tests Share this page: Was this page helpful? ... the meaning of other test results. Fasting Blood Glucose Glucose Level Indication From 70 to 99 mg/ ...

  12. A flow injection system, comprising a biosensor based on a screen-printed carbon electrode containing Meldola's Blue-Reinecke salt coated with glucose dehydrogenase, for the measurement of glucose.

    Piano, M; Serban, S; Biddle, N; Pittson, R; Drago, G A; Hart, J P

    2010-01-15

    A biosensor for the measurement of glucose in serum has been developed, based on a screen-printed carbon electrode modified with Meldola's Blue-Reinecke salt, coated with the enzyme glucose dehydrogenase (from Bacillus sp.), and nicotinamide adenine dinucleotide coenzyme (NAD+). A cellulose acetate layer was deposited on top of the device to act as a permselective membrane. The biosensor was incorporated into a commercially available, thin-layer, amperometric flow cell operated at a potential of only +0.05 V versus Ag/AgCl. The mobile phase consisted of 0.2 M phosphate buffer (pH 7.0) containing 0.1 M potassium chloride solution, and a flow rate of 0.8 ml min(-1) was used throughout the investigation. The biosensor response was linear over the range of 0.075-30 mM glucose, with the former representing the detection limit. The precision of the system was determined by carrying out 20 repeat injections of a 5-mM glucose standard, and the calculated coefficient of variation was 3.9%. It was demonstrated that this biosensor system could be applied to the direct measurement of glucose in serum without pretreatment. Therefore, this would allow high-throughput analysis, at low cost, for this clinically important analyte. PMID:19766585

  13. One-hour versus two-hour postprandial blood glucose measurement in women with gestational diabetes mellitus: which is more predictive?

    Ozgu-Erdinc, A Seval; Iskender, Cantekin; Uygur, Dilek; Oksuzoglu, Aysegul; Seckin, K Doga; Yeral, M Ilkin; Kalaylioglu, Zeynep I; Yucel, Aykan; Danisman, A Nuri

    2016-06-01

    The purpose of this study is to investigate postprandial 1-h (PP1) and 2-h (PP2) blood glucose measurements' correlation with adverse perinatal outcomes. This prospective cohort study consisted of 259 women with gestational diabetes mellitus. During each antenatal visit, HbA1c and fasting plasma glucose (FPG) as well as plasma glucose at PP1 and PP2 were analyzed. There were 144 patients on insulin therapy and 115 patients on diet therapy. A total of 531 blood glucose measurements were obtained at different gestational ages between 24 and 41 gestational weeks. PP2 plasma glucose measurements (but not PP1) were positively correlated with fetal macrosomia. But on adjusted analysis, neither PP1 nor PP2 measurements predicted perinatal complications. In addition to PP1 and PP2, neither FPG nor HbA1c were able to predict perinatal complications or fetal macrosomia when controlled for confounding factors except for a positive correlation between fetal macrosomia and HbA1c in patients on diet therapy. Postprandial 1-h and postprandial 2-h plasma glucose measurements were not superior to each other in predicting fetal macrosomia or perinatal complications. Based on our findings, it can be concluded that both methods may be suitable for follow-up as there are no clear advantages of one measurement over the other. PMID:26645814

  14. Combined Measurement of Fasting Plasma Glucose and A1C Is Effective for the Prediction of Type 2 Diabetes

    Sato, Kyoko Kogawa; Hayashi, Tomoshige; Harita, Nobuko; Yoneda, Takeshi; Nakamura, Yoshiko; Endo, Ginji; Kambe, Hiroshi

    2009-01-01

    OBJECTIVE We prospectively assessed whether the combined measurements of fasting plasma glucose (FPG) and A1C were effective for predicting type 2 diabetes. RESEARCH DESIGN AND METHODS Study participants included 6,736 nondiabetic Japanese men aged 40–55 years. Type 2 diabetes was diagnosed in those who had an FPG ≥126 mg/dl or who were being treated with an oral antidiabetic agent or insulin. The models including FPG, A1C, and both were compared using the area under the receiver operating ch...

  15. Functional expression of sodium-glucose transporters in cancer.

    Scafoglio, Claudio; Hirayama, Bruce A; Kepe, Vladimir; Liu, Jie; Ghezzi, Chiara; Satyamurthy, Nagichettiar; Moatamed, Neda A; Huang, Jiaoti; Koepsell, Hermann; Barrio, Jorge R; Wright, Ernest M

    2015-07-28

    Glucose is a major metabolic substrate required for cancer cell survival and growth. It is mainly imported into cells by facilitated glucose transporters (GLUTs). Here we demonstrate the importance of another glucose import system, the sodium-dependent glucose transporters (SGLTs), in pancreatic and prostate adenocarcinomas, and investigate their role in cancer cell survival. Three experimental approaches were used: (i) immunohistochemical mapping of SGLT1 and SGLT2 distribution in tumors; (ii) measurement of glucose uptake in fresh isolated tumors using an SGLT-specific radioactive glucose analog, α-methyl-4-deoxy-4-[(18)F]fluoro-D-glucopyranoside (Me4FDG), which is not transported by GLUTs; and (iii) measurement of in vivo SGLT activity in mouse models of pancreatic and prostate cancer using Me4FDG-PET imaging. We found that SGLT2 is functionally expressed in pancreatic and prostate adenocarcinomas, and provide evidence that SGLT2 inhibitors block glucose uptake and reduce tumor growth and survival in a xenograft model of pancreatic cancer. We suggest that Me4FDG-PET imaging may be used to diagnose and stage pancreatic and prostate cancers, and that SGLT2 inhibitors, currently in use for treating diabetes, may be useful for cancer therapy. PMID:26170283

  16. Glucose metabolism of fetal rat brain in utero, measured with labeled deoxyglucose

    Mammals have low cerebral metabolic rates immediately after birth and, by inference, also before birth. In this study, we extended the deoxyglucose method to the fetal rat brain in utero. Rate constants for deoxyglucose transfer across the maternal placental and fetal blood-brain barriers, and lumped constant, have not been reported. Therefore, we applied a new method of determining the lumped constant regionally to the fetal rat brain in utero. The lumped constant averaged 0.55 ± 0.15 relative to the maternal circulation. On this basis, we determined the glucose metabolic rate of the fetal rat brain to be one third of the corresponding maternal value, or 19 ± 2 μmol hg-1 min-1. (author)

  17. Effect of postprandial hyperglycaemia in non-invasive measurement of cerebral metabolic rate of glucose in non-diabetic subjects

    Tsuchida, Tatsuro; Itoh, Harumi [Department of Radiology, Fukui Medical University, Matsuoka (Japan); Sadato, Norihiro; Nishizawa, Sadahiko; Yonekura, Yoshiharu [Biomedical Imaging Research Center, Fukui Medical University (Japan)

    2002-02-01

    The aim of this study was to determine the effect of postprandial hyperglycaemia (HG) on the non-invasive measurement of cerebral metabolic rate of glucose (CMRGlc). Five patients who had a meal within an hour before a fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) examination were recruited in this study. They underwent intermittent arterial blood sampling (measured input function), and, based on this sampling, CMRGlc was calculated using an autoradiographic method (CMRGlc{sub real}). Simulated input functions were generated based on standardised input function, body surface area and net injected dose of FDG, and simulated CMRGlc (CMRGlc{sub sim}) was also calculated. Percent error of the area under the curve (AUC) between measured (AUC{sub real}) and simulated input function (AUC{sub IFsim}) and percent error between CMRGlc{sub real} and CMRGlc{sub sim} were calculated. These values were compared with those obtained from a previous study conducted under fasting conditions (F). The serum glucose level in the HG group was significantly higher than that in the F group (165{+-}69 vs 100{+-}9 mg/dl, P=0.0007). Percent errors of AUC and CMRGlc in grey matter and white matter in HG were significantly higher than those in F (12.9%{+-}1.3% vs 3.5%{+-}2.2% in AUC, P=0.0015; 18.2%{+-}2.2% vs 2.9%{+-}1.9% in CMRGlc in grey matter, P=0.0028; 24.0%{+-}4.6% vs 3.4%{+-}2.2% in CMRGlc in white matter, P=0.0028). It is concluded that a non-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions. (orig.)

  18. Effect of postprandial hyperglycaemia in non-invasive measurement of cerebral metabolic rate of glucose in non-diabetic subjects

    The aim of this study was to determine the effect of postprandial hyperglycaemia (HG) on the non-invasive measurement of cerebral metabolic rate of glucose (CMRGlc). Five patients who had a meal within an hour before a fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) examination were recruited in this study. They underwent intermittent arterial blood sampling (measured input function), and, based on this sampling, CMRGlc was calculated using an autoradiographic method (CMRGlcreal). Simulated input functions were generated based on standardised input function, body surface area and net injected dose of FDG, and simulated CMRGlc (CMRGlcsim) was also calculated. Percent error of the area under the curve (AUC) between measured (AUCreal) and simulated input function (AUCIFsim) and percent error between CMRGlcreal and CMRGlcsim were calculated. These values were compared with those obtained from a previous study conducted under fasting conditions (F). The serum glucose level in the HG group was significantly higher than that in the F group (165±69 vs 100±9 mg/dl, P=0.0007). Percent errors of AUC and CMRGlc in grey matter and white matter in HG were significantly higher than those in F (12.9%±1.3% vs 3.5%±2.2% in AUC, P=0.0015; 18.2%±2.2% vs 2.9%±1.9% in CMRGlc in grey matter, P=0.0028; 24.0%±4.6% vs 3.4%±2.2% in CMRGlc in white matter, P=0.0028). It is concluded that a non-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions. (orig.)

  19. Prediction of glucose intolerance at 24-28 weeks of gestation by glucose and insulin level measurements in the first trimester

    Fahami, Fariba; Torabi, Sahar; Abdoli, Samereh

    2015-01-01

    Background: Gestational diabetes is the second common disorder in pregnancy period, which is detected in 24-28 weeks of gestational age through screening tests in low-risk women. The women with gestational diabetes are prone to prenatal mortality and development of future diabetes. Therefore, detection of these individuals in the first trimester and conducting preventive interventions is of great importance. This study aimed to define the predictive value of fasting plasma glucose (FPG) and f...

  20. Glucose Sensing

    Geddes, Chris D

    2006-01-01

    Topics in Fluorescence Spectroscopy, Glucose Sensing is the eleventh volume in the popular series Topics in Fluorescence Spectroscopy, edited by Drs. Chris D. Geddes and Joseph R. Lakowicz. This volume incorporates authoritative analytical fluorescence-based glucose sensing reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. Glucose Sensing is an essential reference for any lab working in the analytical fluorescence glucose sensing field. All academics, bench scientists, and industry professionals wishing to take advantage of the latest and greatest in the continuously emerging field of glucose sensing, and diabetes care & management, will find this volume an invaluable resource. Topics in Fluorescence Spectroscopy Volume 11, Glucose Sensing Chapters include: Implantable Sensors for Interstitial Fluid Smart Tattoo Glucose Sensors Optical Enzyme-based Glucose Biosensors Plasmonic Glucose Sens...

  1. Non-invasive detection of fasting blood glucose level via electrochemical measurement of saliva.

    Malik, Sarul; Khadgawat, Rajesh; Anand, Sneh; Gupta, Shalini

    2016-01-01

    Machine learning techniques such as logistic regression (LR), support vector machine (SVM) and artificial neural network (ANN) were used to detect fasting blood glucose levels (FBGL) in a mixed population of healthy and diseased individuals in an Indian population. The occurrence of elevated FBGL was estimated in a non-invasive manner from the status of an individual's salivary electrochemical parameters such as pH, redox potential, conductivity and concentration of sodium, potassium and calcium ions. The samples were obtained from 175 randomly selected volunteers comprising half healthy and half diabetic patients. The models were trained using 70 % of the total data, and tested upon the remaining set. For each algorithm, data points were cross-validated by randomly shuffling them three times prior to implementing the model. The performance of the machine learning technique was reported in terms of four statistically significant parameters-accuracy, precision, sensitivity and F1 score. SVM using RBF kernel showed the best performance for classifying high FBGLs with approximately 85 % accuracy, 84 % precision, 85 % sensitivity and 85 % F1 score. This study has been approved by the ethical committee of All India Institute of Medical Sciences, New Delhi, India with the reference number: IEC/NP-278/01-08-2014, RP-29/2014. PMID:27350930

  2. Measurement of local glucose transport rate constant and free glucose pool in human brain using PET and CMG: First result in normals and Huntington patients

    Even in images reconstructed with the method of filtered backprojection it is possible to perform parametric images on a pixel by pixel base with use of appropriate stable algorithms. There is no doubt, that these analytical procedures are less efficient than the iterative ones, but they are doing well when relative values between pixels are of interest. The approach using a Lookup-Table was determined to be best and used in normals and Huntington patients. The first results show that in Huntington patients the transport of glucose is not regional affected, but globally reduced. Following studies on a large patient pool will challenge and proceed further this presented technique. (orig.)

  3. Associations between ultrasound measures of abdominal fat distribution and indices of glucose metabolism in a population at high risk of type 2 diabetes: the ADDITION-PRO study.

    Annelotte Philipsen

    Full Text Available Visceral adipose tissue measured by CT or MRI is strongly associated with an adverse metabolic risk profile. We assessed whether similar associations can be found with ultrasonography, by quantifying the strength of the relationship between different measures of obesity and indices of glucose metabolism in a population at high risk of type 2 diabetes.A cross-sectional analysis of 1342 participants of the ADDITION-PRO study. We measured visceral adipose tissue and subcutaneous adipose tissue with ultrasonography, anthropometrics and body fat percentage by bioelectrical impedance. Indices of glucose metabolism were derived from a three point oral glucose tolerance test. Linear regression of obesity measures on indices of glucose metabolism was performed.Mean age was 66.2 years, BMI 26.9kg/m2, subcutaneous adipose tissue 2.5cm and visceral adipose tissue 8.0cm. All measures of obesity were positively associated with indicators of glycaemia and inversely associated with indicators of insulin sensitivity. Associations were of equivalent magnitude except for subcutaneous adipose tissue and the visceral/subcutaneous adipose tissue ratio, which showed weaker associations. One standard deviation difference in BMI, visceral adipose tissue, waist circumference, waist/height ratio and body fat percentage corresponded approximately to 0.2mmol/l higher fasting glucose, 0.7mmol/l higher 2-hr glucose, 0.06-0.1% higher HbA1c, 30 % lower HOMA index of insulin sensitivity, 20% lower Gutt's index of insulin sensitivity, and 100 unit higher Stumvoll's index of beta-cell function. After adjustment for waist circumference visceral adipose tissue was still significantly associated with glucose intolerance and insulin resistance, whereas there was a trend towards inverse or no associations with subcutaneous adipose tissue. After adjustment, a 1cm increase in visceral adipose tissue was associated with ~5% lower insulin sensitivity (p≤0.0004 and ~0.18mmol/l higher 2-hr

  4. Leishmania amazonensis chemotaxis under glucose gradient studied by the strength and directionality of forces measured with optical tweezers

    de Ysasa Pozzo, Liliana; Fontes, Adriana; de Thomaz, André A.; Barbosa, Luiz Carlos; Ayres, Diana Copi; Giorgio, Selma; Cesar, Carlos Lenz

    2007-02-01

    Chemotaxis is the mechanism microorganisms use to sense the environment surrounding them and to direct their movement towards attractive, or away from the repellent, chemicals. The biochemical sensing is almost the only way for communication between unicellular organisms. Prokaryote and Eukaryote chemotaxis has been mechanically studied mainly by observing the directionality and timing of the microorganisms movements subjected to a chemical gradient, but not through the directionality and strength of the forces it generates. To observe the vector force of microorganisms under a chemical gradient we developed a system composed of two large chambers connected by a tiny duct capable to keep the chemical gradient constant for more than ten hours. We also used the displacements of a microsphere trapped in an Optical Tweezers as the force transducer to measure the direction and the strength of the propulsion forces of flagellum of the microorganism under several gradient conditions. A 9μm diameter microsphere particle was trapped with a Nd:YAG laser and its movement was measured through the light scattered focused on a quadrant detector. We observed the behavior of the protozoa Leishmania amazonensis (eukaryote) under several glucose gradients. This protozoa senses the gradient around it by swimming in circles for three to five times following by tumbling, and not by the typical straight swimming/tumbling of bacteria. Our results also suggest that force direction and strength are also used to control its movement, not only the timing of swimming/tumbling, because we observed a higher force strength clearly directed towards the glucose gradient.

  5. CMOS image sensors as an efficient platform for glucose monitoring.

    Devadhasan, Jasmine Pramila; Kim, Sanghyo; Choi, Cheol Soo

    2013-10-01

    Complementary metal oxide semiconductor (CMOS) image sensors have been used previously in the analysis of biological samples. In the present study, a CMOS image sensor was used to monitor the concentration of oxidized mouse plasma glucose (86-322 mg dL(-1)) based on photon count variation. Measurement of the concentration of oxidized glucose was dependent on changes in color intensity; color intensity increased with increasing glucose concentration. The high color density of glucose highly prevented photons from passing through the polydimethylsiloxane (PDMS) chip, which suggests that the photon count was altered by color intensity. Photons were detected by a photodiode in the CMOS image sensor and converted to digital numbers by an analog to digital converter (ADC). Additionally, UV-spectral analysis and time-dependent photon analysis proved the efficiency of the detection system. This simple, effective, and consistent method for glucose measurement shows that CMOS image sensors are efficient devices for monitoring glucose in point-of-care applications. PMID:23900281

  6. Analog model

    The invention relates to devices for modelling the space-dependent kinetics of a nuclear reactor. It can be advantageously used in studying the dynamics of the neutron field in the core to determine the effect of the control rods on the power distribution in the core, for training purposes. The proposed analog model of a nuclear reactor comprises operational amplifiers and a grid of resistors simulating neutron diffusion. Connected to the grid nodes are supply resistors modelling absorption and multiplication of neutrons. This is achieved by that, in the proposed model, all resistors through which power is supplied to the grid nodes are interconnected by their other leads and coupled to the output of the amplifier unit common for all nodes. Therewith, the amlifier unit models the transfer function of a ''point'' reactor. Connected to the input of this unit which includes two to four amplifiers are resistors for addition of signals with a grid node. Coupled to the grid nodes via additional resistors are voltage sources simulating reactivity

  7. Glucose effectiveness in nondiabetic relatives

    Egede, M B; Henriksen, J-E; Durck, T T;

    2014-01-01

    development of isolated impaired fasting glucose, glucose intolerance, and acute insulin release. METHODS: At 0 years, 19 RELs and 18 matched control subjects had glucose effectiveness (GE), insulin sensitivity, acute insulin release (AIR)IVGTT, and disposition index measured during an iv glucose tolerance...... test (IVGTT), using the minimal model analysis. At 0 and 10 years, oral glucose tolerance (OGTT) and AIROGTT were determined. RESULTS: At 0 years, fasting glucose (FG) and GE were raised in RELs, but insulin sensitivity and AIROGTT were reduced (P ≤ .05) compared with controls. At 10 years, RELs......AIMS: Reduced glucose effectiveness is a predictor of future glucose tolerance in individuals with a family history of type 2 diabetes. We examined retrospectively at 10 years in normoglycemic relatives of diabetic subjects (RELs) the pathophysiological role of glucose effectiveness in the...

  8. Evaluation of fasting state-/oral glucose tolerance test-derived measures of insulin release for the detection of genetically impaired β-cell function.

    Silke A Herzberg-Schäfer

    Full Text Available BACKGROUND: To date, fasting state- and different oral glucose tolerance test (OGTT-derived measures are used to estimate insulin release with reasonable effort in large human cohorts required, e.g., for genetic studies. Here, we evaluated twelve common (or recently introduced fasting state-/OGTT-derived indices for their suitability to detect genetically determined β-cell dysfunction. METHODOLOGY/PRINCIPAL FINDINGS: A cohort of 1364 White European individuals at increased risk for type 2 diabetes was characterized by OGTT with glucose, insulin, and C-peptide measurements and genotyped for single nucleotide polymorphisms (SNPs known to affect glucose- and incretin-stimulated insulin secretion. One fasting state- and eleven OGTT-derived indices were calculated and statistically evaluated. After adjustment for confounding variables, all tested SNPs were significantly associated with at least two insulin secretion measures (p≤0.05. The indices were ranked according to their associations' statistical power, and the ranks an index obtained for its associations with all the tested SNPs (or a subset were summed up resulting in a final ranking. This approach revealed area under the curve (AUC(Insulin(0-30/AUC(Glucose(0-30 as the best-ranked index to detect SNP-dependent differences in insulin release. Moreover, AUC(Insulin(0-30/AUC(Glucose(0-30, corrected insulin response (CIR, AUC(C-Peptide(0-30/AUC(Glucose(0-30, AUC(C-Peptide(0-120/AUC(Glucose(0-120, two different formulas for the incremental insulin response from 0-30 min, i.e., the insulinogenic indices (IGI(2 and IGI(1, and insulin 30 min were significantly higher-ranked than homeostasis model assessment of β-cell function (HOMA-B; p<0.05. AUC(C-Peptide(0-120/AUC(Glucose(0-120 was best-ranked for the detection of SNPs involved in incretin-stimulated insulin secretion. In all analyses, HOMA-β displayed the highest rank sums and, thus, scored last. CONCLUSIONS/SIGNIFICANCE: With AUC(Insulin(0

  9. Human blood glucose dynamics

    Rahaghi, Farbod N.

    2007-01-01

    The control of blood glucose concentration has become central to the prevention of morbidity in diabetes. Currently sensors are becoming available to make available near continuous measurements of tissue glucose concentrations. Frequently measured values provide an opportunity to analyze the dynamics of these measurements in addition to statistical analysis. The dynamics can be used to verify sensor validity, to provide a physiologic control target, and serve as a tool to diagnose and monitor...

  10. On-line measurements of oscillating mitochondrial membrane potential in glucose-fermenting Saccharomyces cerevisiae

    Andersen, Ann Zahle; Poulsen, Allan K; Olsen, Lars Folke;

    2007-01-01

    We employed the fluorescent cyanine dye DiOC(2)(3) to measure membrane potential in semi-anaerobic yeast cells under conditions where glycolysis was oscillating. Oscillations in glycolysis were studied by means of the naturally abundant nicotinamide adenine dinucleotide (NADH). We found that the...

  11. Optical Rotatory Dispersion Measurement of D-Glucose with Fixed Polarizer Analyzer Accessory in Conventional Spectrophotometer

    2013-01-01

    ABSTRACT In the sample compartment of a conventional spectrophotometer, mounting of a polarizer before sample and an analyzer behind sample allows the determination of the optical rotatory dispersion of optical active media by measurement of the transmission ratio of crossed and parallel arranged polarizer and analyzer. A formula for the determination of the angle of rotation is derived from the transmission ratio. The arrangement is applied to determine the molar optical rotation of D-gl...

  12. A MEMS Dielectric Affinity Glucose Biosensor

    Xian HUANG; Li, SiQi; Davis, Erin; Li, Dachao; Wang, Qian; Lin, Qiao

    2013-01-01

    Continuous glucose monitoring (CGM) sensors based on affinity detection are desirable for long-term and stable glucose management. However, most affinity sensors contain mechanical moving structures and complex design in sensor actuation and signal readout, limiting their reliability in subcutaneously implantable glucose detection. We have previously demonstrated a proof-of-concept dielectric glucose sensor that measured pre-mixed glucose-sensitive polymer solutions at various glucose concent...

  13. Associations between Ultrasound Measures of Abdominal Fat Distribution and Indices of Glucose Metabolism in a Population at High Risk of Type 2 Diabetes: The ADDITION-PRO Study

    Philipsen, Annelotte; Jørgensen, Marit E; Vistisen, Dorte;

    2015-01-01

    metabolism in a population at high risk of type 2 diabetes. METHODS: A cross-sectional analysis of 1342 participants of the ADDITION-PRO study. We measured visceral adipose tissue and subcutaneous adipose tissue with ultrasonography, anthropometrics and body fat percentage by bioelectrical impedance. Indices....... One standard deviation difference in BMI, visceral adipose tissue, waist circumference, waist/height ratio and body fat percentage corresponded approximately to 0.2mmol/l higher fasting glucose, 0.7mmol/l higher 2-hr glucose, 0.06-0.1% higher HbA1c, 30 % lower HOMA index of insulin sensitivity, 20...

  14. An Implantable RFID Sensor Tag toward Continuous Glucose Monitoring.

    Xiao, Zhibin; Tan, Xi; Chen, Xianliang; Chen, Sizheng; Zhang, Zijian; Zhang, Hualei; Wang, Junyu; Huang, Yue; Zhang, Peng; Zheng, Lirong; Min, Hao

    2015-05-01

    This paper presents a wirelessly powered implantable electrochemical sensor tag for continuous blood glucose monitoring. The system is remotely powered by a 13.56-MHz inductive link and utilizes an ISO 15693 radio frequency identification (RFID) standard for communication. This paper provides reliable and accurate measurement for changing glucose level. The sensor tag employs a long-term glucose sensor, a winding ferrite antenna, an RFID front-end, a potentiostat, a 10-bit sigma-delta analog to digital converter, an on-chip temperature sensor, and a digital baseband for protocol processing and control. A high-frequency external reader is used to power, command, and configure the sensor tag. The only off-chip support circuitry required is a tuned antenna and a glucose microsensor. The integrated chip fabricated in SMIC 0.13-μm CMOS process occupies an area of 1.2 mm ×2 mm and consumes 50 μW. The power sensitivity of the whole system is -4 dBm. The sensor tag achieves a measured glucose range of 0-30 mM with a sensitivity of 0.75 nA/mM. PMID:25823049

  15. Working Memory and Dynamic Measures of Analogical Reasoning as Predictors of Children's Math and Reading Achievement

    Stevenson, Claire E.; Bergwerff, Catharina E.; Heiser, Willem J.; Resing, Wilma C. M.

    2014-01-01

    Working memory and inductive reasoning ability each appear related to children's achievement in math and reading. Dynamic measures of reasoning, based on an assessment procedure including feedback, may provide additional predictive value. The aim of this study was to investigate whether working memory and dynamic measures of analogical…

  16. Foregut exclusion disrupts intestinal glucose sensing and alters portal nutrient and hormonal milieu.

    Pal, Atanu; Rhoads, David B; Tavakkoli, Ali

    2015-06-01

    The antidiabetes effects of Roux-en-Y gastric bypass (RYGB) are well-known, but the underlying mechanisms remain unclear. Isolating the proximal small intestine, and in particular its luminal glucose sensors, from the nutrient stream has been proposed as a critical change, but the pathways involved are unclear. In a rodent model, we tested the effects of isolating and then stimulating a segment of proximal intestine using glucose analogs to examine their impact on glucose absorption (Gabsorp) and hormone secretion after a glucose bolus into the distal jejunum. Analogs selective for sodium-glucose cotransporter (SGLT) family members and the sweet taste receptor were tested, and measurements of the portosystemic gradient were used to determine Gabsorp and hormone secretion, including GLP-1. Proximal intestinal isolation reduced Gabsorp and GLP-1 secretion. Stimulation of the glucose-sensing protein SGLT3 increased Gabsorp and GLP-1 secretion. These effects were abolished by vagotomy. Sweet taste receptor stimulation only increased GLP-1 secretion. This study suggests a novel role for SGLT3 in coordinating intestinal function, as reflected by the concomitant modulation of Gabsorp and GLP-1 secretion, with these effects being mediated by the vagus nerve. Our findings provide potential mechanistic insights into foregut exclusion in RYGB and identify SGLT3 as a possible antidiabetes therapeutic target. PMID:25576062

  17. Glucose allostasis

    Stumvoll, Michael; Tataranni, P Antonio; Stefan, Norbert;

    2003-01-01

    In many organisms, normoglycemia is achieved by a tight coupling of nutrient-stimulated insulin secretion in the pancreatic beta-cell (acute insulin response [AIR]) and the metabolic action of insulin to stimulate glucose disposal (insulin action [M]). It is widely accepted that in healthy...... individuals with normal glucose tolerance, normoglycemia can always be maintained by compensatorily increasing AIR in response to decreasing M (and vice versa). This has been mathematically described by the hyperbolic relationship between AIR and M and referred to as glucose homeostasis, with glucose...... chronic stress (insulin resistance), we propose to use the term "glucose allostasis." Allostasis (stability through change) ensures the continued homeostatic response (stability through staying the same) to acute stress at some cumulative costs to the system. With increasing severity and over time, the...

  18. Analog and VLSI circuits

    Chen, Wai-Kai

    2009-01-01

    Featuring hundreds of illustrations and references, this book provides the information on analog and VLSI circuits. It focuses on analog integrated circuits, presenting the knowledge on monolithic device models, analog circuit cells, high performance analog circuits, RF communication circuits, and PLL circuits.

  19. Science Teachers' Analogical Reasoning

    Mozzer, Nilmara Braga; Justi, Rosária

    2013-08-01

    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to introduce analogies in their lessons. Both aspects have been discussed in the literature in the last few decades. However, almost nothing is known about how teachers draw their own analogies for instructional purposes or, in other words, about how they reason analogically when planning and conducting teaching. This is the focus of this paper. Six secondary teachers were individually interviewed; the aim was to characterize how they perform each of the analogical reasoning subprocesses, as well as to identify their views on analogies and their use in science teaching. The results were analyzed by considering elements of both theories about analogical reasoning: the structural mapping proposed by Gentner and the analogical mechanism described by Vosniadou. A comprehensive discussion of our results makes it evident that teachers' content knowledge on scientific topics and on analogies as well as their pedagogical content knowledge on the use of analogies influence all their analogical reasoning subprocesses. Our results also point to the need for improving teachers' knowledge about analogies and their ability to perform analogical reasoning.

  20. Measurement of regional cerebral metabolic rate for glucose in the human subject with (F-18)-2-deoxy-2-fluoro-d-glucose and emission computed tomography: validation of the method

    Tracer techniques and models of in vitro quantitative autoradiography and tissue counting for the measure of regional metabolic rates (rMR) are combined with emission computed tomography (ECT). This approach, Physiologic Tomography (PT), provides atraumatic and analytical measurements of rMR. PT is exemplified with the regional measurement of the cerebral metabolic rate for glucose (CMRGlu) in man with (18F)-2-deoxy-2-fluoro-D-glucose (FDG) and positron ECT. Our model incorporates a k4* mediated hydrolysis of FDG-6-PO4 to FDG which then competes with phosphorylation (k3*) of FDG back to FDG-6-PO4 and reverse transport (k2*) back to blood. Although small, k4* is found to be significant. The ECAT positron tomograph was used to measure the rate constants (k1*→k4*), lumped constant (LC), stability, and reproducibility of the model in man. Since these parameters have not been measured for FDG in any species, comparisons are made to values for DG in rat and monkey. Compartmental concentrations of FDG and FDG-6-PO4 were determined and show that cerebral FDG-6-PO4 steadily accumulates for about 100 mins, plateaus and then slowly decreases due to hydrolysis. Cerebral blood FDG concentration was determined to be a minor contribution to tissue activity after 10 min. Regional CMRGlu measurements are reproducible to +- 5.5% over 5 hrs. PT allows the in vivo study ofregional biochemistry and physiology in normal and pathophysiologic states in man with a unique and fundamental capability

  1. Analog filters in nanometer CMOS

    Uhrmann, Heimo; Zimmermann, Horst

    2014-01-01

    Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

  2. High glucose concentrations partially release hexokinase from inhibition by glucose 6-phosphate.

    Fujii, S; Beutler, E

    1985-01-01

    The phosphorylation of glucose by human erythrocyte hexokinase follows classical Michaelis-Menten kinetics; hexokinase manifests maximum activity at 5 mM glucose, and no further increase in activity can be measured at higher glucose concentrations. However, the erythrocytes of diabetics and normal erythrocytes incubated with high concentrations of glucose contain increased concentrations of glucose 6-phosphate. To elucidate the mechanism of accumulation of glucose 6-phosphate when erythrocyte...

  3. The Usefulness of Homeostatic Measurement Assessment-Insulin Resistance (HOMA-IR) for Detection of Glucose Intolerance in Thai Women of Reproductive Age with Polycystic Ovary Syndrome

    Prasong Tanmahasamut; Surasak Angsuwathana; Kitirat Techatraisak; Suchada Indhavivadhana; Pichai Leerasiri; Manee Rattanachaiyanont; Thanyarat Wongwananuruk; Chongdee Dangrat

    2012-01-01

    Objectives. To study the cut-off point of Homeostatic Measurement Assessment-Insulin Resistance (HOMA-IR) as a screening test for detection of glucose intolerance in Thai women with polycystic ovary syndrome (PCOS). Study Design. Cross-sectional study. Setting. Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital. Subject. Two hundred and fifty Thai PCOS women who attended the Gynecologic Endocrinology Unit, during May 2007 to January 2009. Materials and Methods. The ...

  4. Intuitive analog circuit design

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  5. 21 CFR 862.1345 - Glucose test system.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Glucose test system. 862.1345 Section 862.1345....1345 Glucose test system. (a) Identification. A glucose test system is a device intended to measure glucose quantitatively in blood and other body fluids. Glucose measurements are used in the diagnosis...

  6. Enhancing the characterization of bedload transport in rivers using the analogy between the Hertz contact theory and plate hydrophone measurements

    Barrière, Julien; Oth, Adrien; Schenkluhn, Reimar; Krein, Andreas

    2014-05-01

    Vibration measurements performed with plate or pipe geophone/hydrophone systems are of growing interest for bedload transport monitoring since they allow performing high temporal resolution and continuous records. Our set-up is constituted by a piezoelectric hydrophone acting as a "sediment vibration sensor" in contact with a steel plate located on the streambed. With such an apparatus, the signal processing is generally reduced to power spectral analysis or impact counting. However, a large amount of useful information is contained in the waveform of the impact signal, which conveys the force and the contact time that the bedload imposes on the plate. The wave amplitude is not well constrained because it varies a lot with changing impact location and velocity. The wave frequency is a more relevant parameter, less sensitive to these variables. According to the Hertz contact theory the frequency of the first signal arrival (flexural wave) is directly proportional to the bed-material grain size. Then, an appropriate analysis of the frequency attributes (central frequency, modulation) is needed to estimate the size of bedload particles. In this way, we have developed a complete processing algorithm based on a high dimensional decomposition method (chirplet transform) to get an accurate estimation of the first arrival frequency content. Results on summer flood events in a lowland river show that impacts are well separated by their central frequency and that most of transport occurs during larger peak flows. The portion of coarser sediment which is characterized by low frequencies is preferentially transported during the rising limb whereas the finer sand fraction identified by higher frequencies is transported during both rising and falling limb. Such a processing offers the opportunity to better understand the bedload signature of vibration measurements and is promising in view of quantifying processes of bedload transport and deposition. This final objective of

  7. POF based glucose sensor incorporating grating wavelength filters

    Hassan, Hafeez Ul; Aasmul, Søren; Bang, Ole;

    2014-01-01

    AND RESEARCH IN POLYMER OPTICAL DEVICES; TRIPOD. Within the domain of TRIPOD, research is conducted on "Plastic Optical Fiber based Glucose Sensors Incorporating Grating Wavelength Filters". Research will be focused to optimized fiber tips for better coupling efficiency, reducing the response time of sensor......Medtronic has already developed a plastic fiber based optical sensor to detect the concentration of glucose both in vivo and in-vitro. The glucose sensor is based on a competitive glucose binding affinity assay consisting of a glucose receptor and glucose analog (ligand) contained in a compartment...

  8. Laboratory measurements of density-driven convection in analogy with solubility trapping of geologically sequestered CO2

    Rasmusson, Maria; Fagerlund, Fritjof; Rasmusson, Kristina; Niemi, Auli

    2016-04-01

    Density-driven convection is of interest to several areas of groundwater-science: nuclear waste storage, industrial waste disposal, deep geothermal energy extraction, and seawater intrusion into coastal aquifers. Lately it has been identified to accelerate the rate of CO2 solubility trapping for geological CO2 storage in deep saline aquifers. We present an experimental method based on the light transmission technique and an analogue system design that enable comprehensive study of solutally induced density-driven convection in saturated porous media. The system design affords an examination of the convective process in general as well as a two-dimensional laboratory analogue for field phenomena. Furthermore, the method can be used to verify numerical results from density-driven flow simulation codes as part of benchmarking. With application to geological CO2 storage, we show how the method is used to measure density-driven convection in both homogenous and heterogeneous porous media and for different Rayleigh numbers. The results demonstrate that the solute concentration distribution in the system can be accurately determined with high spatial and temporal resolution. Thus, the onset time of convection, mass flux and flow dynamics can be quantified for different systems under well-controlled conditions.

  9. Glucose-dependent Insulinotropic Polypeptide

    Christensen, Mikkel B; Calanna, Salvatore; Holst, Jens Juul;

    2014-01-01

    CONTEXT: Patients with type 2 diabetes mellitus (T2DM) have clinically relevant disturbances in the effects of the hormone glucose-dependent insulinotropic polypeptide (GIP). OBJECTIVE: We aimed to evaluate the importance of the prevailing plasma glucose levels for the effect of GIP on responses of...... glucagon and insulin and glucose disposal in patients with T2DM. DESIGN AND SETTING: We performed a single center, placebo-controlled, cross-over, experimental study. PATIENTS: We studied twelve patients with T2DM (age: 62 ± 1 years [mean ± SEM], body mass index: 29 ± 1 kg/m(2); glycosylated hemoglobin A1c......: 6.5 ± 0.1% [48 ± 2 mmol/mol]). INTERVENTION: We infused physiological amounts of GIP (2 pmol × kg(-1) × min(-1)) or saline. MAIN OUTCOME MEASURES: We measured plasma concentrations of glucagon, glucose, insulin, C-peptide, intact GIP, and amounts of glucose needed to maintain glucose clamps. RESULTS...

  10. Edentulism and dental prostheses in the elderly: impact on quality of life measured with EuroQol - visual analog scale (EQ-VAS).

    Cano-Gutiérrez, Carlos; Borda, Miguel G; Arciniegas, Antonio J; Borda, Claudia X

    2015-08-01

    The objective of this study was to measure the impact of edentulism and dental prostheses on quality of life (QOL) in older adults in Bogota, Colombia. Edentulism is a frequent condition in older adults and has great impact on their QOL. No epidemiological data are currently available on edentulism among older adults in Colombia. Data were obtained from the SABE-Bogota study, a cross-sectional study conducted in 2012, and used to analyze the EQ-VAS (Visual Analog Scale) from the EuroQol instrument to measure the perception of quality of life (QOL) in relation to edentulism. The study included 2,000 individuals over 60 years old. The Spearman-Rho correlation was used to analyze the correlation between EQ-VAS and edentulism. Chi-Square, ANOVA and t-test were used to study the differences in EQ-VAS scores between edentulous and healthy subjects. Statistical significance was set at psocial class and lower education were related to edentulism. Individuals with fewer teeth and dental prostheses had lower EQ-VAS scores (paffects QOL in older adults and the use of dental prosthesis does not improve the perception of QOL. PMID:26355885

  11. Structure and equilibria of Ca 2+-complexes of glucose and sorbitol from multinuclear ( 1H, 13C and 43Ca) NMR measurements supplemented with molecular modelling calculations

    Pallagi, A.; Dudás, Cs.; Csendes, Z.; Forgó, P.; Pálinkó, I.; Sipos, P.

    2011-05-01

    Ca 2+-complexation of D-glucose and D-sorbitol have been investigated with the aid of multinuclear ( 1H, 13C and 43Ca) NMR spectroscopy and ab initio quantum chemical calculations. Formation constants of the forming 1:1 complexes have been estimated from one-dimensional 13C NMR spectra obtained at constant ionic strength (1 M NaCl). Binding sites were identified from 2D 1H- 43Ca NMR spectra. 2D NMR measurements and ab initio calculations indicated that Ca 2+ ions were bound in a tridentate manner via the glycosidic OH, the ethereal oxygen in the ring and the OH on the terminal carbon for the α- and β-anomers of glucose and for sorbitol simultaneous binding of four hydroxide moieties (C1, C2, C4 and C6) was suggested.

  12. In vivo measurements of whole body (WB) and skeletal muscle glucose metabolism under basal and euglycemic insulin clamp (Clamp) by combined PET and stable isotope (SI) tracer studies

    Aim/Background: Primed-constant infusion of SI labeled tracers is a classic technique for studying metabolism at the WB level, however, this procedure provides no information about the metabolism of specific tissues. In contrast PET provides primarily tissue specific data. In this study, we combined PET with SI techniques to measure glucose metabolism in WB and lower limb skeletal muscle (LLM) of humans under Basal and Clamp conditions. Methods and Materials: Four healthy volunteers (73.0 ± 6.0 kg, mean ± sem) were studied. After fasting overnight, each subject was injected with 10 mCi of 18FDG and serial 1.0 min. PET images of the mid-thigh region were acquired over 90 min. Arterial blood samples were collected in parallel. Glucose metabolic rate (GM) was calculated with a 3-compartment / 4 rate constant model; LC assumed to be 1.0. A primed constant infusion of [6,6, 2H2]glucose was performed in parallel with the PET measurements. On another day, the PET and SI measurements were repeated under clamp conditions. All results are expressed as mean ± sem. Results: The glucose kinetics in whole body and in low limb skeletal muscles are shown. Under in vivo conditions, Clamp caused: 1) a 10.2 ± 2.3 fold increase in GM by LLM but only a 4.7 ± 0.4 fold increase in GM by MB. 2) Increased contribution of LLM to WB GM, indicating that LLM GM is more sensitive to insulin compared with anterior LLM (extensors). Discussion: The study demonstrated the unique advantages of using PET to study substrate metabolism in specific tissues in human subjects: i) It is less invasive than the conventional A-V difference and muscle biopsy method. ii) It provides a more detailed picture of substrate metabolism in different parts of the muscle in the same limb, as compared to one spot muscle biopsy. Data in demonstrated that GM in posterior LLM is more sensitive to insulin than that in anterior LLM. iii) It can detect substrate metabolism in deep muscles which cannot be reached by biopsy

  13. A Comparative Study of Blood Glucose Measurements Using Glucometer Readings and the Standard Method in the Diagnosis of Neonatal Hypoglycemia

    Mohammad Torkaman; Gholamreza Bagheri; Ahmad Ahmadi; Amin Saburi

    2016-01-01

    Background: Hypoglycemia is one of the most common neonatal disorders, associated with severe complications. There has been a great deal of controversy regarding the definition and screening of hypoglycemia. Therefore, in this study, we aimed to determine a cut-off value for blood glucose level in glucometer readings. Methods: This cross-sectional study was conducted on 238 newborns at risk of hypoglycemia, admitted to Baqiyatallah Hospital of Tehran, Iran in 2012; the subjects were selected ...

  14. Michaelis-Menten constraints improved cerebral glucose metabolism and regional lumped constant measurements with [18F]fluorodeoxyglucose

    In the three-compartment model of transfer of native glucose and [18F]fluorodeoxyglucose (FDG) into brain, both transport across the blood-brain barrier and phosphorylation by hexokinase can be described by the Michaelis-Menten equation. This permits the use of fixed transport (tau = K*1/K1) and phosphorylation (psi = k*3/k3) ratios and a common partition volume (Ve = K1/k2) for tracer and glucose. By substituting transfer constants of FDG for those of glucose, using tau and psi, the lumped constant was determined directly by positron tomography. The same constraints also eliminated k*2 and k*3 from the model, thus limiting the parameters to K* [equivalent to K*1k*3/(k*2 + k*3)], K*1, and the cerebral vascular volume (Vo). In six healthy elderly men (aged 61 +/- 5 years), time-activity records of cerebral cortical regions were analyzed with tau = 1.1 and psi = 0.3. The results were compared with those of the conventional FDG method. At 20 min, the goodness of fit by the new equation was as good as that of the conventional method at 45 min. The estimates obtained by the constrained method had stable coefficients of variation. After 20 min, regional differences between the estimates were independent of time, although we observed steady decreases of K* and (k*3). The decrease strongly suggested dephosphorylation of FDG-6-phosphate, particularly after 20 min. All estimates of variables with the constrained method were more accurate than those of the conventional method, including the cerebral glucose metabolic rate itself, as well as physiologically more meaningful, particularly with respect to k*2 and k*3

  15. Analog and hybrid computing

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  16. Biconical tapered optical fiber biosensor for measuring refractive index of a-amino acids in aqueous D-glucose and sucrose solution

    Zibaii, M. I.; Latifi, H.; Karami, M.; Gholami, M.; Hosseini, S. M.; Ghezelayagh, M. H.

    2010-04-01

    A single-mode biconical tapered optical fiber (BTOF) sensor was utilized for sensing the variation of refractive index (RI) with concentration of D-glucose in double distilled deionized water and measuring of RI of amino acids (AAs) in carbohydrate solutions. This method showed a rewarding ability in understanding the basis of biomolecular interactions in biological systems. The BTOF is fabricated by heat pulling method, utilizing a CO2 laser. The detection limit of the BTOF was 50 ppb for the D-glucose concentration ranging from 0 to 80 ppm, and RI detection limit corresponding to these concentrations in the range at 1.3333 to 1.3404 was 5.4×10-6 as a refractometer sensor. The response of the BTOF shows that the different kinds of interactions of various groups of AAs such as L-alanine, L-leucine, and L-cystein with D-glucose, sucrose and water molecules depend on functional groups in AAs such as OH, SH;CH2;NH3+ ,COO-. These results can be interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.

  17. Dexamethasone increases glucose cycling, but not glucose production, in healthy subjects

    We established that measurement of glucose fluxes through glucose-6-phosphatase (G-6-Pase; hepatic total glucose output, HTGO), glucose cycling (GC), and glucose production (HGP), reveals early diabetogenic changes in liver metabolism. To elucidate the mechanism of the diabetogenic effect of glucocorticoids, we treated eight healthy subjects with oral dexamethasone (DEX; 15 mg over 48 h) and measured HTGO with [2-3H]glucose and HGP with [6-3H]glucose postabsorptively and during a 2-h glucose infusion (11.1 mumol.kg-1.min-1). [2-3H]- minus [6-3H]glucose equals GC. DEX significantly increased plasma glucose, insulin, C peptide, and HTGO, while HGP was unchanged. In controls and DEX, glucose infusion suppressed HTGO (82 vs. 78%) and HGP (87 vs. 91%). DEX increased GC postabsorptively (three-fold) P less than 0.005 and during glucose infusion (P less than 0.05) but decreased metabolic clearance and glucose uptake (Rd), which eventually normalized, however. Because DEX increased HTGO (G-6-Pase) and not HGP (glycogenolysis + gluconeogenesis), we assume that DEX increases HTGO and GC in humans by activating G-6-Pase directly, rather than by expanding the glucose 6-phosphate pool. Hyperglycemia caused by peripheral effects of DEX can also contribute to an increase in GC by activating glucokinase. Therefore, measurement of glucose fluxes through G-6-Pase and GC revealed significant early effects of DEX on hepatic glucose metabolism, which are not yet reflected in HGP

  18. Optical imaging of tumor vascularity associated with proliferation and glucose metabolism in early breast cancer: clinical application of total hemoglobin measurements in the breast

    Near-infrared optical imaging targeting the intrinsic contrast of tissue hemoglobin has emerged as a promising approach for visualization of vascularity in cancer research. We evaluated the usefulness of diffuse optical spectroscopy using time-resolved spectroscopic (TRS) measurements for functional imaging of primary breast cancer. Fifty-five consecutive TNM stageI/II patients with histologically proven invasive ductal carcinoma and operable breast tumors (<5 cm) who underwent TRS measurements were enrolled. Thirty (54.5%) patients underwent 18F-fluoro-deoxy-glucose (FDG) positron emission tomography with measurement of maximum tumor uptake. TRS was used to obtain oxyhemoglobin, deoxyhemoglobin, and total hemoglobin (tHb) levels from the lesions, surrounding normal tissue, and contralateral normal tissue. Lesions with tHb levels 20% higher than those present in normal tissue were defined as “hotspots,” while others were considered “uniform.” The findings in either tumor type were compared with clinicopathological factors. “Hotspot” tumors were significantly larger (P = 0.002) and exhibited significantly more advanced TNM stage (P = 0.01), higher mitotic counts (P = 0.01) and higher levels of FDG uptake (P = 0.0004) compared with “uniform” tumors; however, other pathological variables were not significantly different between the two groups. Optical imaging for determination of tHb levels allowed for measurement of tumor vascularity as a function of proliferation and glucose metabolism, which may be useful for prediction of patient prognosis and potential response to treatment

  19. Glucose uptake-stimulatory activity of Tinospora cordifolia stem extracts in Ehrlich ascites tumor cell model system.

    Joladarashi, Darukeshwara; Chilkunda, Nandini D; Salimath, Paramahans Veerayya

    2014-01-01

    Diabetes mellitus is a multifunctional disorder with several causes and multiple consequences. Nutraceuticals play a vital role in ameliorating diabetic condition. The stems of the plant, Tinospora cordifolia (T. cordifolia) are often used in Ayurvedic medicine for the management of diabetes. Earlier studies have shown that T. cordifolia to be a potent antidiabetic plant material by virtue of being rich in nutraceuticals. In the present study we were interested to know if, T. cordifolia stem extracts are able to promote glucose uptake through glucose transporters, 1 (GLUT1) and 3 (GLUT3), which are responsible for basal glucose uptake. Hence, Ehrlich ascites tumor (EAT) cells were chosen as a model which harbours both GLUT1 and GLUT3 and glucose uptake was measured using a fluorescent analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG). Serially, solvent extracted T. cordifolia stems, especially water, ethanol and methanol extracts showed glucose uptake activity. Uptake was stimulated in a dose dependent manner at dosages of 1-100 μg. Glucose-stimulating activity does not seem to be solely due to polyphenol content since methanol extract, with high amount of polyphenol content (9.5 ± 0.1 g kg(-1)), did not stimulate higher glucose uptake activity when compared to water extract. PMID:24426067

  20. Nocturnal continuous glucose monitoring

    Bay, Christiane; Kristensen, Peter Lommer; Pedersen-Bjergaard, Ulrik;

    2013-01-01

    Abstract Background: A reliable method to detect biochemical nocturnal hypoglycemia is highly needed, especially in patients with recurrent severe hypoglycemia. We evaluated reliability of nocturnal continuous glucose monitoring (CGM) in patients with type 1 diabetes at high risk of severe...... from 23:00 to 07:00 h for plasma glucose (PG) measurements (gold standard). Results: Valid data were obtained in 217 nights. The sensitivity of CGM was 65% (95% confidence interval, 53-77%) below 4 mmol/L, 40% (24-56%) below 3 mmol/L, and 17% (0-47%) below 2.2 mmol/L. PG and CGM readings correlated in...

  1. Several Forms of Fuzzy Analogical Reasoning

    Bouchon-Meunier, B; Delechamp, J.; Marsala, C.; Rifqi, M.

    1997-01-01

    We present a general framework representing analogy, on the basis of a link between variables and measures of comparison between values of variables. This analogical scheme is proven to represent a common description of several forms of reasoning used in fuzzy control or in the management of knowledge-based systems, such as deductive reasoning, inductive reasoning or prototypical reasoning, gradual reasoning.

  2. Sucrose, glucose, and fructose extraction in aqueous carrot root extracts prepared at different temperatures by means of direct NMR measurements.

    Cazor, Anne; Deborde, Catherine; Moing, Annick; Rolin, Dominique; This, Hervé

    2006-06-28

    Solutions obtained by heating carrot roots in water (stocks) are widely used in the food industry, but little information is available regarding the metabolites (intermediates and products of metabolism) found in the stock. The effect of treatment temperature and duration on the sugar composition of stocks was investigated directly by quantitative (1)H NMR spectroscopy, to understand the extraction mechanism when processing at 100 degrees C. Stocks prepared at three different temperatures (50, 75, and 100 degrees C) were investigated for up to 36 h. Three sugars (sucrose, glucose, and fructose) were detected and quantified. The concentrations of these three sugars reached a maximum after 9 h when the temperature of treatment was 50 or 75 degrees C. At 100 degrees C, the sucrose concentration reached a maximum after 3 h, whereas the concentration of glucose and fructose was still increasing at that time. Comparison of the kinetic composition of these carrot stocks with that of model sugar solutions leads to the proposal that the changes in stock composition result from sugar diffusion, sucrose hydrolysis, and hydroxymethylfurfural (HMF) formation. PMID:16787015

  3. The Analogical Mind

    Holyoak, Keith J.; Thagard, P.

    1997-01-01

    We examine the use of analogy in human thinking from the perspective of a multiconstraint theory, which postulates three basic types of constraints: similarity, structure and purpose. The operation of these constraints is apparent in both laboratory experiments on analogy and in naturalistic settings, including politics, psychotherapy, and scientific research. We sketch how the multiconstraint theory can be implemented in detailed computational simulations of the analogical human mind.

  4. Insulin analogs and cancer

    Laura eSciacca

    2012-02-01

    Full Text Available Today, insulin analogs are used in millions of diabetic patients. Insulin analogs have been developed to achieve more physiological insulin replacement in terms of time course of the effect. Modifications in the amino acid sequence of the insulin molecule change the pharmacokinetics and pharmacodynamics of the analogs in respect to human insulin. However, these changes can also modify the molecular and biological effects of the analogs. The rapid-acting insulin analogs, lispro, aspart and glulisine, have a rapid onset and shorter duration of action. The long-acting insulin analogs glargine and detemir have a protracted duration of action and a relatively smooth serum concentration profile. Insulin and its analogs may function as growth factors and therefore have a theoretical potential to promote tumor proliferation. A major question is whether analogs have an increased mitogenic activity in respect to insulin. These ligands can promote cell proliferation through many mechanisms like the prolonged stimulation of the insulin receptor, stimulation of the IGF-1 receptor (IGF-1R, prevalent activation of the ERK rather than the AKT intracellular post-receptor pathways. Studies on in vitro models indicate that short-acting analogs elicit molecular and biological effects that are similar to those of insulin. In contrast, long-acting analogs behave differently. Although not all data are homogeneous, both glargine and detemir have been found to have a decreased binding to IR but an increased binding to IGF-1R, a prevalent activation of the ERK pathway, and an increased mitogenic effect in respect to insulin. Recent retrospective epidemiological clinical studies have suggested that treatment with long-acting analogs (specifically glargine may increase the relative risk for cancer. Results are controversial and methodologically weak. Therefore prospective clinical studies are needed to evaluate the possible tumor growth-promoting effects of these insulin

  5. Analog circuit design

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  6. Analog synthetic biology.

    Sarpeshkar, R

    2014-03-28

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  7. Thresholds of whole-blood β-hydroxybutyrate and glucose concentrations measured with an electronic hand-held device to identify ovine hyperketonemia.

    Pichler, M; Damberger, A; Schwendenwein, I; Gasteiner, J; Drillich, M; Iwersen, M

    2014-03-01

    Metabolic disorders, especially hyperketonemia, are very common in dairy sheep. The whole-blood concentrations of β-hydroxybutyrate (BHBA) and glucose can be determined by commercially available electronic hand-held devices, which are used in human medicine and for the detection of ketosis in dairy cows. The aim of this study was to evaluate the suitability of the hand-held device Precision Xceed (PX; Abbott Diabetes Care Inc., Abbott Park, IL) to detect hyperketonemia in ewes. An additional objective of this study was to evaluate the agreement between samples obtained by minimal invasive venipuncture of an ear vein and measurements of whole-blood samples from the jugular vein (vena jugularis, v. jug.). Blood samples taken from the v. jug. were collected from 358 ewes on 4 different farms. These samples and a blood drop obtained from an ear vein were analyzed simultaneously on farm with the PX. For method comparison, the samples obtained from the v. jug. were also analyzed by standard methods, which served as the gold standard at the Central Laboratory of the University of Veterinary Medicine Vienna, Austria. The correlation coefficients between the serum BHBA concentration and the concentrations measured with the hand-held meter in the whole blood from an ear vein and the v. jug. were 0.94 and 0.96, respectively. The correlation coefficients of plasma and whole-blood glucose concentration were 0.68 for the v. jug. and 0.47 for the ear vein. The mean glucose concentration was significantly lower in animals classified as hyperketonemic (BHBA ≥ 1.6 mmol/L) compared with healthy ewes. Whole-blood concentrations of BHBA and glucose measured with the PX from v. jug. showed a constant negative bias of 0.15 mmol/L and 8.4 mg/dL, respectively. Hence, a receiver operating characteristic analysis was performed to determine thresholds for the PX to detect hyperketonemia in ewes. This resulted in thresholds for moderate ketosis of BHBA concentrations of 0.7 mmol/L in blood

  8. Hydraulic Capacitor Analogy

    Baser, Mustafa

    2007-01-01

    Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding. According to Iding, analogies are consistent with the tenets of constructivist learning…

  9. Analog pulse processor

    Wessendorf, Kurt O.; Kemper, Dale A.

    2003-06-03

    A very low power analog pulse processing system implemented as an ASIC useful for processing signals from radiation detectors, among other things. The system incorporates the functions of a charge sensitive amplifier, a shaping amplifier, a peak sample and hold circuit, and, optionally, an analog to digital converter and associated drivers.

  10. Effects of 5 Thio-D-Glucose on cellular adenosine triphosphate levels and deoxyribonucleic acid rejoining in hypoxic and aerobic Chinese hamster cells

    Intracellular adenosine triphosphate (ATP) levels were measured in both hypoxic and aerobic cultures of V79 Chinese hamster cells treated with 5-thio-D-glucose (5-SH-D-Glc). This glucose analog, a known inhibitor of D-glucose transport and metabolism, reduced ATP in cell cultures allowed to become hypoxic by cell metabolism, but not in aerobic cultures treated similarly. Cells depleted of ATP were unable to rejoin x-ray induced deoxyribonucleic acid (DNA) strand breaks as measured by the alkaline sucrose gradient sedimentation technique. The inference for radiation therapy is that inhibition of glucose metabolism selectively depletes energy reserves in hypoxic cells, rendering these cells more radiosensitive and leading to a more effective tumor treatment

  11. Meat analog: a review.

    Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S

    2015-01-01

    The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers. PMID:24915320

  12. Microwave-Based Biosensor for Glucose Detection

    Salim, N. S. M.; Khalid, K.; Yusof, N. A.

    2010-07-01

    In this project, microwave-based biosensor for glucose detection has been studied. The study is based on the dielectric properties changes at microwave frequency for glucose-enzyme reaction. Glucose interaction with glucose oxidase (GOD) produced gluconic acid and hydrogen peroxide. The reaction of the glucose solutions with an enzyme was carried out in 1:3 of glucose and enzyme respectively. The measurements were done using the Open Ended Coaxial Probe (OECP) coupled with computer controlled software automated network analyzer (ANA) with frequency range from 200MHz to 20GHz at room temperature (25 °C). The differences of enzyme and glucose-enzyme reaction were calculated and plotted. In the microwave interaction with the glucose-enzyme reaction, ionic conduction and dipole molecules was detected at 0.99GHz and 16.44GHz respectively based on changes of dielectric loss factor.

  13. Predicting Plasma Glucose From Interstitial Glucose Observations Using Bayesian Methods

    Hansen, Alexander Hildenbrand; Duun-Henriksen, Anne Katrine; Juhl, Rune;

    2014-01-01

    One way of constructing a control algorithm for an artificial pancreas is to identify a model capable of predicting plasma glucose (PG) from interstitial glucose (IG) observations. Stochastic differential equations (SDEs) make it possible to account both for the unknown influence of the continuous...... glucose monitor (CGM) and for unknown physiological influences. Combined with prior knowledge about the measurement devices, this approach can be used to obtain a robust predictive model. A stochastic-differential-equation-based gray box (SDE-GB) model is formulated on the basis of an identifiable...

  14. The determination of solubility and diffusion coefficient for solids in liquids by an inverse measurement technique using cylinders of amorphous glucose as a model compound

    The importance of sugar and sugar-containing materials is well recognized nowadays, owing to their application in industrial processes, particularly in the food, pharmaceutical and cosmetic industries. Because of the large numbers of those compounds involved and the relatively small number of solubility and/or diffusion coefficient data for each compound available, it is highly desirable to measure the solubility and/or diffusion coefficient as efficiently as possible and to be able to improve the accuracy of the methods used. In this work, a new technique was developed for the measurement of the diffusion coefficient of a stationary solid solute in a stagnant solvent which simultaneously measures solubility based on an inverse measurement problem algorithm with the real-time dissolved amount profile as a function of time. This study differs from established techniques in both the experimental method and the data analysis. The experimental method was developed in which the dissolved amount of solid solute in quiescent solvent was investigated using a continuous weighing technique. In the data analysis, the hybrid genetic algorithm is used to minimize an objective function containing a calculated and a measured dissolved amount with time. This is measured on a cylindrical sample of amorphous glucose in methanol or ethanol. The calculated dissolved amount, that is a function of the unknown physical properties of the solid solute in the solvent, is calculated by the solution of the two-dimensional nonlinear inverse natural convection problem. The estimated values of the solubility of amorphous glucose in methanol and ethanol at 293 K were respectively 32.1 g/100 g methanol and 1.48 g/100 g ethanol, in agreement with the literature values, and support the validity of the simultaneously measured diffusion coefficient. These results show the efficiency and the stability of the developed technique to simultaneously estimate the solubility and diffusion coefficient. Also

  15. Challenges in Analogical Reasoning

    Lin, Shih-Yin

    2016-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same physics principle is involved but that is more difficult to handle. Here, we examine introductory physics students' ability to use analogies in solving problems involving Newton's second law. Students enrolled in an algebra-based introductory physics course were given a solved problem involving tension in a rope and were then asked to solve another problem for which the physics is very similar but involved a frictional force. They were asked to point out the similarities between the two problems and then use the analogy to solve the friction problem.

  16. TV Analog Station Transmitters

    Department of Homeland Security — This file is an extract from the Consolidated Database System (CDBS) licensed by the Media Bureau. It consists of Analog Television Stations (see Rule Part47 CFR...

  17. Glucose and fructose 6-phosphate cycle in humans

    We have determined the rate of glucose cycling by comparing turnovers of [2-3H]- and [6-3H]glucose under basal conditions and during a glucose infusion. Moreover, the activity of the fructose 6-phosphate cycle was assessed by comparing [3-3H]- and [6-3H]glucose. The study included eight lean subjects with normal glucose tolerance. They participated in two randomly performed investigations. In one experiment [2-3H]- and [6-3H]glucose were given simultaneously, while in the other only [3-3H]glucose was given. The basal rate of glucose cycling was 0.32 +/- 0.08 mg X kg-1 X min-1 or 17% of basal glucose production (P less than 0.005). During glucose infusion the activity of endogenous glucose cycling did not change but since glucose production was suppressed it amounted to 130% of glucose production. The basal fructose 6-phosphate cycle could be detected only in three subjects and was suppressed during glucose infusion. In conclusion, the glucose cycle is active in healthy humans both in basal conditions and during moderate hyperglycemia. In some subjects, the fructose 6-phosphate cycle also appears to be active. Thus it is preferable to use [6-3H]glucose rather than [3-3H]glucose when measuring glucose production and particularly when assessing glucose cycle

  18. The immediate effects of a single bout of aerobic exercise on oral glucose tolerance across the glucose tolerance continuum

    Knudsen, Sine H; Karstoft, Kristian; Pedersen, Bente K;

    2014-01-01

    We investigated glucose tolerance and postprandial glucose fluxes immediately after a single bout of aerobic exercise in subjects representing the entire glucose tolerance continuum. Twenty-four men with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or type 2 diabetes (T2D; age......: 56 ± 1 years; body mass index: 27.8 ± 0.7 kg/m(2), P > 0.05) underwent a 180-min oral glucose tolerance test (OGTT) combined with constant intravenous infusion of [6,6-(2)H2]glucose and ingestion of [U-(13)C]glucose, following 1 h of exercise (50% of peak aerobic power) or rest. In both trials......, plasma glucose concentrations and kinetics, insulin, C-peptide, and glucagon were measured. Rates (mg kg(-1) min(-1)) of glucose appearance from endogenous (RaEndo) and exogenous (oral glucose; Ra OGTT) sources, and glucose disappearance (Rd) were determined. We found that exercise increased RaEndo, Ra...

  19. Synthesis of Paclitaxel Analogs

    Xu, Zhibing

    2010-01-01

    Paclitaxel is one of the most successful anti-cancer drugs, particularly in the treatment of breast cancer and ovarian cancer. For the investigation of the interaction between paclitaxel and MD-2 protein, and development of new antagonists for lipopolysaccharide, several C10 A-nor-paclitaxel analogs have been synthesized and their biological activities have been evaluated. In order to reduce the myelosuppression effect of the paclitaxel, several C3â ² and C4 paclitaxel analogs have been synth...

  20. In vivo measurements of sulcal plaque pH in rats after topical applications of xylitol, sorbitol, glucose, sucrose, and sucrose plus 53 mM sodium fluoride.

    Firestone, A R; Navia, J M

    1986-01-01

    In two series of experiments, Sprague-Dawley-derived rats were infected orally with cariogenic micro-organisms and fed caries-promoting diets. By means of an antimony electrode, resting pH values were measured in the mesial sulcus of the maxillary left first molar. 100 or 200 microL of the test solutions were applied, and the change in pH (delta pH) was recorded for three min. Test solutions were: (a) 10% sucrose, 10% glucose, 10% sorbitol, or 10% xylitol; (b) 0%, 10%, 20%, or 40% sucrose; (c) 0%, 3%, 7%, or 10% sucrose; and (d) 10% sucrose, 10% sucrose + 53 mmol/L NaF (1000 ppmF-), or 10% sucrose + 53 mmol/L NaCl. Experimental design was a 4 X 4 Latin square (a, b, c) or a cross-over design (d). Solutions of sucrose and glucose gave significantly greater decreases in pH than did sorbitol or xylitol. pH fall was maximal for 10% sucrose and significantly less for 40% sucrose during the three-minute experimental period. For sucrose solutions ranging in concentration from 3 to 10%, pH fall was highest after application of 10% sucrose when plaque was previously rinsed with water, but this pH fall did not differ significantly from that obtained using a 7% sucrose solution. Adding 1000 ppmF- to a 10% sucrose solution caused an increase in pH. Rinsing the teeth to remove saliva resulted in significantly lower resting pH values. The results of these experiments are in agreement with the results of human plaque pH measurements. PMID:3455697

  1. Electrical Circuits and Water Analogies

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  2. Analog modelling of obduction processes

    Agard, P.; Zuo, X.; Funiciello, F.; Bellahsen, N.; Faccenna, C.; Savva, D.

    2012-04-01

    Obduction corresponds to one of plate tectonics oddities, whereby dense, oceanic rocks (ophiolites) are presumably 'thrust' on top of light, continental ones, as for the short-lived, almost synchronous Peri-Arabic obduction (which took place along thousands of km from Turkey to Oman in c. 5-10 Ma). Analog modelling experiments were performed to study the mechanisms of obduction initiation and test various triggering hypotheses (i.e., plate acceleration, slab hitting the 660 km discontinuity, ridge subduction; Agard et al., 2007). The experimental setup comprises (1) an upper mantle, modelled as a low-viscosity transparent Newtonian glucose syrup filling a rigid Plexiglas tank and (2) high-viscosity silicone plates (Rhodrosil Gomme with PDMS iron fillers to reproduce densities of continental or oceanic plates), located at the centre of the tank above the syrup to simulate the subducting and the overriding plates - and avoid friction on the sides of the tank. Convergence is simulated by pushing on a piston at one end of the model with velocities comparable to those of plate tectonics (i.e., in the range 1-10 cm/yr). The reference set-up includes, from one end to the other (~60 cm): (i) the piston, (ii) a continental margin containing a transition zone to the adjacent oceanic plate, (iii) a weakness zone with variable resistance and dip (W), (iv) an oceanic plate - with or without a spreading ridge, (v) a subduction zone (S) dipping away from the piston and (vi) an upper, active continental margin, below which the oceanic plate is being subducted at the start of the experiment (as is known to have been the case in Oman). Several configurations were tested and over thirty different parametric tests were performed. Special emphasis was placed on comparing different types of weakness zone (W) and the extent of mechanical coupling across them, particularly when plates were accelerated. Displacements, together with along-strike and across-strike internal deformation in all

  3. Low Blood Glucose (Hypoglycemia)

    ... Other Dental Problems Diabetic Eye Disease Low Blood Glucose (Hypoglycemia) What is hypoglycemia? Hypoglycemia, also called low ... actions can also help prevent hypoglycemia: Check blood glucose levels Knowing your blood glucose level can help ...

  4. Glucose test (image)

    ... person with diabetes constantly manages their blood's sugar (glucose) levels. After a blood sample is taken and tested, it is determined whether the glucose levels are low or high. If glucose levels ...

  5. Measurement and COrrelation on Viscosity and Apparent Molar Volume of Ternary System for L—ascorbic Acid in Aqueous D—Glucose and Sucrose Solutions

    赵长伟; 马沛生

    2003-01-01

    Visosities and densities at ,several temperatures from 293.15 K to 313.15K are reported for L-ascorbic acid in aqueous glucose and sucrose solutions at different concentrations.The parameters of density,Viscosity coefficient B and partial molar volume are calculated by regression.The experimental results show that densities and viscositis decrease as temperature increases at the same solute and solvent (glucose and sucrose aueous solution)concentrations,and increase with concentration of glucose and sucrose at the same solute concentration and temperature,B increases with concentration of glucose and sucrose and temaperature,L-ascorbic acid is sturcture-breaker or structure-making for the glucose and sucrose aqueous solutions ,Furthermore,the solute-solvent interactions in ternary systems of water-glucose-electrolyte and water-sucrose-electrolyte are discussed.

  6. Biological evaluation of two iodine-123-labeled D-glucose acetals prepared as glucose transporter radioligands

    Brunet-Desruet, Marie-Dominique; Ghezzi, Catherine; Morin, Christophe; Comet, Michel; Fagret, Daniel

    1998-07-01

    Two iodinated acetals of D-glucose, 4,6-(R)-O-(2'-iodoethylidene)-{alpha}, {beta}-D-glucose and 4,6-(R)-O-(4'-iodobenzylidene)-{alpha}, {beta}-D-glucose , were prepared and their potential as suitable SPECT radioligands for imaging of glucose transporters was studied. Both are analogs of acetal D-glucose derivatives, which are known to bind to the exofacial sites of the glucose transport protein (GluT). To assess whether iodinated acetals 1 and 2 interacted with the glucose transporter, they were tested in vitro in human erythrocytes (GluT1) and neonatal rat cardiomyocytes (GluT4). The results indicated that 1 and 2 had a very low affinity for the glucose transporter and probably accumulated in cells. Study of their tissue distribution was carried out in the mouse in vivo: Both compounds showed fast tissue clearance with preferential renal elimination. It is concluded that iodinated acetals of D-glucose 1 and 2 are not suitable for GluT targeting in vivo.

  7. A MEMS Dielectric Affinity Glucose Biosensor.

    Huang, Xian; Li, Siqi; Davis, Erin; Li, Dachao; Wang, Qian; Lin, Qiao

    2013-06-20

    Continuous glucose monitoring (CGM) sensors based on affinity detection are desirable for long-term and stable glucose management. However, most affinity sensors contain mechanical moving structures and complex design in sensor actuation and signal readout, limiting their reliability in subcutaneously implantable glucose detection. We have previously demonstrated a proof-of-concept dielectric glucose sensor that measured pre-mixed glucose-sensitive polymer solutions at various glucose concentrations. This sensor features simplicity in sensor design, and possesses high specificity and accuracy in glucose detection. However, lack of glucose diffusion passage, this device is unable to fulfill real-time in-vivo monitoring. As a major improvement to this device, we present in this paper a fully implantable MEMS dielectric affinity glucose biosensor that contains a perforated electrode embedded in a suspended diaphragm. This capacitive-based sensor contains no moving parts, and enables glucose diffusion and real-time monitoring. The experimental results indicate that this sensor can detect glucose solutions at physiological concentrations and possesses good reversibility and reliability. This sensor has a time constant to glucose concentration change at approximately 3 min, which is comparable to commercial systems. The sensor has potential applications in fully implantable CGM that require excellent long-term stability and reliability. PMID:24511215

  8. 21 CFR 862.1340 - Urinary glucose (nonquantitative) test system.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urinary glucose (nonquantitative) test system. 862... Test Systems § 862.1340 Urinary glucose (nonquantitative) test system. (a) Identification. A urinary glucose (nonquantitative) test system is a device intended to measure glucosuria (glucose in...

  9. Initial distribution volume of glucose can be approximated using a conventional glucose analyzer in the intensive care unit

    Ishihara, Hironori; Nakamura, Hitomi; Okawa, Hirobumi; Takase, Hajime; Tsubo, Toshihito; Hirota, Kazuyoshi

    2005-01-01

    Introduction We previously reported that initial distribution volume of glucose (IDVG) reflects central extracellular fluid volume, and that IDVG may represent an indirect measure of cardiac preload that is independent of the plasma glucose values present before glucose injection or infusion of insulin and/or vasoactive drugs. The original IDVG measurement requires an accurate glucose analyzer and repeated arterial blood sampling over a period of 7 min after glucose injection. The purpose of ...

  10. Glucose reactivity with filling materials as a limitation for using the glucose leakage model

    H. Shemesh; E.M. Souza; M.K. Wu; P.R. Wesselink

    2008-01-01

    Aim To evaluate the reactivity of different endodontic materials and sealers with glucose and to asses the reliability of the glucose leakage model in measuring penetration of glucose through these materials. Methodology Ten uniform discs (radius 5 mm, thickness 2 mm) were made of each of the follow