The Real-Time Rendering of Gradient Media

In the real world, there are optical media that are difficult or impossible to simulate with classical real-time rendering methods. One of such media types is a gradient medium, in which light rays propagate along a curve. However, with advances in the capabilities of the real-time computer graphics rendering hardware, more sophisticated rendering algorithms, e.g., rendering based on the ray tracing technologies which uses a physically correct model of the light propagation and transformation, are becoming more widely used to achieve more realistic images. In the scope of the current article, the authors researched the capabilities of the current accelerated ray tracing-based realistic rendering technologies to perform the physically correct rendering of scenes containing the gradient medium. The presented method can operate in realtime which was proven by presenting the test images and aminations acquired from the implementation of the designed realistic rendering method of the gradient media with NVIDIA OptiX.

Parameter Optimization of Impedance Gradient Change Medium Based on Reinforcement Learning

Based on the relative researches, in order to solve the problem that the parameters of impedance gradient change medium are difficult to be optimized and generalized in different environments, an optimization method of the parameters of the impedance gradient change medium based on reinforcement learning was proposed. First, the propagation principle of sound wave in impedance gradient medium was analyzed. The sound field distribution in the medium was also studied, in order to master its acoustic characteristics. Second, the parameters of sound velocity and impedance distribution were optimized by DQN algorithm to reduce the sound reflection. Finally, the effectiveness of the proposed reinforcement learning model was verified by the traditional method. The experimental results show that the method presented in this paper was superior to the traditional method. The trained parameters are effective to reduce the acoustic reflection to a lower level.

Functional comparison of PBMCs isolated by Cell Preparation Tubes (CPT) vs. Lymphoprep Tubes

Background: Cryopreserved human peripheral blood mononuclear cells (PBMCs) are a commonly used sample type for a variety of immunological assays. Many factors can affect the quality of PBMCs, and careful consideration and validation of an appropriate PBMC isolation and cryopreservation method is important for well-designed clinical studies. A major point of divergence in PBMC isolation protocols is the collection of blood, either directly into vacutainers pre-filled with density gradient medium or the use of conical tubes containing a porous barrier to separate the density gradient medium from blood. To address potential differences in sample outcome, we isolated, cryopreserved, and compared PBMCs using parallel protocols differing only in the use of one of two common tube types for isolation. Methods: Whole blood was processed in parallel using both Cell Preparation Tubesä (CPT, BD Biosciences) and Lymphoprepä Tubes (Axis-Shield) and assessed for yield and viability prior to cryopreservation. After thawing, samples were further examined by flow cytometry for cell yield, cell viability, frequency of ten cell subsets, and capacity for stimulation-dependent CD4+ and CD8+ T cell intracellular cytokine production. Results: No significant differences in cell recovery, viability, frequency of immune cell subsets, or T cell functionality between PBMC samples isolated using CPT or Lymphoprep tubes were identified.Conclusion: CPT and Lymphoprep tubes are effective and comparable methods for PBMC isolation for immunological studies.

Functional comaparison of PBMCs isolated by Cell Preparation Tubes (CPT) vs Lymphoprep Tubes

Background : Cryopreserved human peripheral blood mononuclear cells (PBMCs) are a commonly used sample type for a variety of immunological assays. Many factors can affect the quality of PBMCs, and careful consideration and validation of an appropriate PBMC isolation and cryopreservation method is important for well-designed clinical studies. A major point of divergence in PBMC isolation protocols is the collection of blood, either directly into vacutainers pre-filled with density gradient medium or the use of conical tubes containing a porous barrier to separate the density gradient medium from blood. Results : To address potential differences in sample outcome, we isolated, cryopreserved, and compared frequency and functionality of PBMCs using parallel protocols differing only in the use of one of two common tube types for isolation. Whole blood was processed in parallel using both Cell Preparation Tubesä (CPT, BD Biosciences) and Lymphoprepä Tubes (Axis-Shield) and assessed for yield and viability prior to cryopreservation. After thawing, samples were further examined by flow cytometry for cell yield, cell viability, frequency of ten cell subsets, and capacity for stimulation-dependent CD4+ and CD8+ T cell intracellular cytokine production. Cell recovery, viability, frequency of immune cell subsets, and T cell functionality between PBMC samples isolated using CPT or Lymphoprep tubes were comparable. Conclusion : CPT and Lymphoprep tubes are both effective for PBMC isolation and may be used interchangeably for immunological studies involving T cell activation.

Purification Platelets from Mouse Blood with Sickle Cell Disease Using Iohexol Gradient Medium

Platelets are purified from whole blood to study their functional properties, which should be free from red blood cells (RBC), white blood cells (WBC), and plasma proteins. Since RBC and WBC contain significantly more RNA and proteins than platelets, the presence of even a small number of these cells can interfere with transcriptomic and proteomic analyses of RNA and proteins derived from platelets. Several protocols have described the isolation of platelets from human, dog, rat, and non-human primate by various methods. Some of the methods require multiple steps such as collection of platelet-rich plasma by centrifugation, filtration by separation column, negative selection of platelets with RBC- and WBC-specific antibody conjugated to magnetic beads, and so on, which are time-consuming and may degrade platelets and their contents. Moreover, mouse blood with sickle cell disease contains a significant level of fragments of RBC which should be removed from the platelet preparation. However, the mouse yields a relatively smaller volume of blood, which makes it difficult to purify platelets. If the same small volume of gradient medium and blood samples are used, the platelet layer cannot be clearly separated from RBC-WBC layer after centrifugation. We describe a simple method for purification of platelets from mouse blood with sickle cell disease using three-fold more iohexol gradient medium relative to blood sample volume and centrifugation in a swinging bucket rotor at 400 x g for 20 min at 20 °C. The platelet layer is collected and centrifuged again at 200 x g for 20 min at 20 °C to remove the residual fragments of RBC. The recovery/yield of the purified platelets were 10-17%, and the purified platelets were in a resting state, which did not contain any significant number of RBC and WBC. The purified platelets were activated with thrombin indicating their viability. We confirmed that the purified platelets were sufficiently pure using flow cytometric and microscopic evaluation. Although flow cytometric analysis of purified platelet from sickle cell disease mice showed a few RBC events after staining with anti-TER119 antibody, the microscopic study did not show any intact RBC or larger fragments indicating that these are smaller fragments of RBC which do not interfere with the biochemical and functional studies. This method can be used for purification of platelets from the blood of other species and disease models as well. Disclosures No relevant conflicts of interest to declare.

Conformally Mapped Multifunctional Acoustic Metamaterial Lens for Spectral Sound Guiding and Talbot Effect

We demonstrate a conformally mapped multifunctional acoustic metamaterial Mikaelian lens. Mikaelian lens is a gradient medium with a hyperbolic secant refractive index profile that can realize functions like beam self-focusing. Unlike the conventional design approaches, with a conformal transformation method, only isotropic material parameters with gradient refractive index profiles are required for the construction of such lens. To realize desired gradient index distribution, we carefully design a new type of cross-channel-shaped acoustic metamaterial, whose refractive index can be effectively modulated by simply changing the slit opening size. The distinct capabilities of the metamaterial Mikaelian lens in manipulating acoustic waves are experimentally verified with the fabricated sample. Simultaneous sound guiding and Talbot effects, which normally require respective geometrical and wave acoustic approximations, are observed in simulations and experiments. Furthermore, those effects of shaping acoustic wave propagations were validated within a relatively wide frequency range. Our study reveals how the conformal transformation method can help to bridge the ray acoustics with wave acoustics. It offers opportunities to the development of novel multifunctional acoustic devices for various applications, such as sound and particle manipulations.