Methods of objectivization of characteristics of cerebrospinal fluid and examples of their use

BACKGROUND: In modern research standards, a semi-quantitative evaluation scale with crosses is used to characterize turbid cerebrospinal fluid samples, where the absence of turbidity is evaluated as a clear cerebrospinal fluid (a variant of norm), and turbidity is evaluated, depending on the severity, by a different number of crosses. This approach is highly subjective. AIM: Development of a simple objective method for assessment of turbidity of the cerebrospinal fluid. MATERIALS AND METHODS: The optimal wavelength was determined by examination of the optical density of turbid samples of barium sulfate at various wavelengths on Stat Fax photometer (Awarenes, USA). Turbidity was standardized using Shank–Hoagland scale. The reference range was evaluated based on the results of 10 measurements of 10 samples of visually unchanged cerebrospinal fluid. At the same time, the stability and reproducibility of the measured parameters were evaluated. RESULTS: The optimal wavelength diabase is the range emitted by red light filter (λ = 670 nm). Stability of cerebrospinal fluid parameters is preserved for 2 hours after its obtaining. The reference range for normal cerebrospinal fluid samples does not exceed 0.1 units of turbidity on Shank–Hoagland scale. CONCLUSION: The presented methods demonstrate the importance and possibilities of objectivization of characterization of the properties of cerebrospinal fluid with use of the proposed method.

Hyperspectral Imaging to Characterize Table Grapes

Table grape quality is of importance for consumers and thus for producers. Its objective quality is usually determined by destructive methods mainly based on sugar content. This study proposed to evaluate the possibility of hyperspectral imaging to characterize table grapes quality through its sugar (TSS), total flavonoid (TF), and total anthocyanin (TA) contents. Different data pre-treatments (WD, SNV, and 1st and 2nd derivative) and different methods were tested to get the best prediction models: PLS with full spectra and then Multiple Linear Regression (MLR) were realized after selecting the optimal wavelengths thanks to the regression coefficients (β-coefficients) and the Variable Importance in Projection (VIP) scores. All models were good at showing that hyperspectral imaging is a relevant method to predict sugar, total flavonoid, and total anthocyanin contents. The best predictions were obtained from optimal wavelength selection based on β-coefficients for TSS and from VIPs optimal wavelength windows using SNV pre-treatment for total flavonoid and total anthocyanin content. Thus, good prediction models were proposed in order to characterize grapes while reducing the data sets and limit the data storage to enable an industrial use.

Analysis of the Optimal Wavelength for Oceanographic Lidar at the Global Scale Based on the Inherent Optical Properties of Water

Understanding the optimal wavelength for detecting the water column profile from a light detection and ranging (lidar) system is important in the design of oceanographic lidar systems. In this research, the optimal wavelength for detecting the water column profile using a lidar system at the global scale was analyzed based on the inherent optical properties of water. In addition, assuming that the lidar system had a premium detection characteristic in its hardware design, the maximum detectable depth using the established optimal wavelength was analyzed and compared with the mixed layer depth measured by Argo data at the global scale. The conclusions drawn are as follows: first, the optimal wavelengths for the lidar system are between the blue and green bands. For the open ocean, the optimal wavelengths are between 420 and 510 nm, and for coastal waters, the optimal wavelengths are between 520 and 580 nm. To obtain the best detection ability using a lidar system, the best configuration is to use a lidar system with multiple bands. In addition, a 490 nm wavelength is recommended when an oceanographic lidar system is used at the global scale with a single wavelength. Second, for the recommended 490 nm band, a lidar system with the 4 attenuating length detection ability can penetrate the mixed layer for 80% of global waters.

Long-term Brillouin imaging of live cells with reduced absorption-mediated damage at 660nm wavelength

In Brillouin microscopy, absorption-induced photodamage of incident light is the primary limitation on signal-to-noise ratio in many practical scenarios. Here we show that 660 nm may represent an optimal wavelength for Brillouin microscopy as it offers minimal absorption-mediated photodamage at high Brillouin scattering efficiency and the possibility to use a pure and narrow laser line from solid-state lasing medium. We demonstrate that live cells are ~80 times less susceptible to the 660 nm incident light compared to 532 nm light, which overall allows Brillouin imaging of up to more than 30 times higher SNR. We show that this improvement enables Brillouin imaging of live biological samples with improved accuracy, higher speed and/or larger fields of views with denser sampling.