We report a novel approach for the accurate measurement of glucose absorption in turbid media using a spectrally resolved reflectance setup. Our proposed reflectance setup with specialized variable source-detector separations enables scattering-independent absorption measurement, which is critical to in vivo long-term glucose concentration monitoring. Starting from the first-order approximation of the radiative transfer equation (RTE), we developed a scattering-independent glucose absorption measurement method and then evaluated this approach by Monte Carlo simulations as well as tissue-mimicking phantom studies in which glucose concentration was accurately measured. Our study demonstrates the potential of our proposed scattering-independent absorption measurement technique as an effective tool to quantify glucose levels in turbid media, which is an important step towards future in vivo long-term glucose concentration monitoring in human subjects.
For the non-invasive blood glucose concentration sensing by the near-infrared spectroscopy, the signal to noise ratio of the optical measurement system is very low. Both the content of glucose in body and the absorption coefficient of glucose in the near-infrared region are quite weak. More over, the structure of spectral noise is complicated and the variation of noise intensity is very large. The background correction is one of the most effective pre-processing methods to improve the signal to noise ratio of the near-infrared optical detection system. In this paper, the theory expression formula of traditional background correction method was induced firstly. Then in order to avoid the influence from the variation of optical characteristics in the sample and the drift in the optical system, the similar background correction method was proposed, that is, the background which has the similar optical characteristics with the sample was chosen as the reference. The in vitro experiments of pure absorption media and scattering media were conducted to validate the effect. The results showed that, for the glucose in the blood plasma solution and Intralipid-2% solution, after the correction of the background which has the similar optical characteristics with the sample, the prediction precision of multivariate model for glucose concentration has been improved by 25.9% and 40.1%, respectively.
We improved the thermal equivalent-circuit model of the laser diode module (LDM) to evaluate its thermal dynamic properties and calculate the junction temperature of the laser diode with a high accuracy. The thermal parameters and the transient junction temperature of the LDM are modeled and obtained according to the temperature of the thermistor integrated in the module. Our improved thermal model is verified indirectly by monitoring the emission wavelength of the laser diode against gas absorption lines, and several thermal parameters are obtained with the temperature uncertainty of 0.01 K in the thermal dynamic process.
Proteolytic targeting chimeras (PROTACs), as an emerging type of drug, function by proximity-based modalities that narrow the distance between a target protein and the E3 ubiquitin ligase to facilitate the ubiquitination labeling of the target protein for degradation. Although it is evidenced that the cooperativity of the PROTAC ternary interaction is one of the key factors affecting the degradation rate of a target protein, PROTAC design utilizing this indicator is still challenging because of the complicated/flexible interactions in a target-PROTAC-E3 ternary system. Therefore, developing reliable and practicable computational methods is of great interest for PROTAC design. Hence, in this study, we investigate the feasibility of using the end-point binding free energy calculation method, represented by molecular mechanics/Poisson-Boltzmann (generalized-Born) surface area (MM/PB(GB)SA), for characterizing cooperativity (including the stabilization and hook effects) of the PROTAC systems. The result shows that MM/GBSA is a good predictor in characterizing these effects under a relatively long molecular dynamics adjustment (50-100 ns) and low dielectric constant (ε
It is necessary to get optical information within tissue in order to improve the application of non-invasive blood glucose sensing. However, the light penetration depth is seriously limited due to high scattering effects of biological tissues, which restricts the detection precision of non-invasive blood glucose sensing. Tissue optical clearing technique is one of the effective approaches to reduce the scattering effect and increase the light penetration depth into biological tissues. In this talk, it is our aim to study the preliminary application of optical clearing to non-invasive blood glucose sensing based on Monte Carlo simulation. Firstly, optical properties of intralipid solutions mixing with different concentration of glucose were calculated within the wavelengths of 1000~1700nm. The transmittance spectra of intralipid solutions with and without glycerol as optical clearing agent were investigated through Monte Carlo simulation. Different concentrations of glycerol were taken into account. Furthermore, the root mean square error of prediction (RMSEP) was obtained by performing partial least squares (PLS) modelling. Simulation results showed that the transmittance increased gradually with the increase of glycerol concentration, which suggested that the optical clearing effect appeared. Meanwhile, the RMSEP decreased as the glycerol concentration increased. RMSEP has improved by 30.91% in the simulation, which showed the great potential of tissue optical clearing technique to effectively improve the predicting precision of non-invasive blood glucose sensing.
During a survey of culturable fungi in the coastal areas of China, three new species of Penicillium sect.Lanata-Divaricata were discovered and studied with a polyphasic taxonomic approach, and then named as P. donggangicum sp.nov.(ex-type AS3.15900 T = LN5H1-4), P. hepuense sp.nov.(ex-type AS3.16039 T = TT2-4X3, AS3.16040 = TT2-6X3) and P. jiaozhouwanicum
Noninvasive sensing of blood glucose based on near-infrared (NIR) spectroscopy is a research hotspot in the biomedical field. However, its accuracy is severely limited by the weak specific signal of glucose and the strong background variations caused by other constituents in the blood, the measuring instrument, and the environment. In this paper, special source-detector distances, defined as the floating reference position, are used to conduct relative measurements and correct for background variations. These floating reference positions are chosen so that the diffuse reflectance is not sensitive to the change in glucose concentration due to the combined effects of absorption and scattering. Nine 10% intralipid samples with glucose concentrations in the range of 1000-5000 mg dL-1 at an interval of 500 mg dL-1 were prepared. Using a custom-built, continuously moving, spatially resolving, double-fiber measurement system with a superluminescent diode (SLD) as the light source, the diffuse reflectance of intralipid samples containing glucose under different source-detector distances (0.2-5 mm, with intervals of 0.2 mm) were collected. Then, a correlation analysis between the spectra and the glucose concentration was carried out to determine the floating reference position and the optimal measuring position. The signal in the floating reference position was used to correct the background variation because it contains the same systematic drift and interference as the signal in the optimal measuring position. The results showed that the correlation between the diffuse reflectance and the glucose concentration was increased significantly compared with traditional correction by subtracting the nearest spectrum of pure 10% intralipid solution. The correlation between the diffuse reflectance and the concentration of glucose is significantly increased, which indicated that the combination of the correlation analysis and a floating reference is able to eliminate the influence of background variations.
The near infrared (NIR) spectroscopy analytical technique is one of the most advanced and promising tools in many domains. NIR acquisition is easily influenced by temperature, thereby affecting qualitative and quantitative analyses. In this paper, a temperature compensation model was established between NIR signals and output voltage values based on two-dimensional regression analysis. The effectiveness of the proposed compensation scheme was experimentally demonstrated by the measurement of six super luminescent diode sources at 293-313 K. The coefficient of variation was decreased 2-fold with this compensation algorithm. The results indicated that it was suitable for various NIR spectral acquisition systems with lower complexity and a higher signal-noise-ratio after being applied to an acousto-optic-tunable-filter system.
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