Stable water-in-oil emulsion is essential to digital PCR and many other bioanalytical reactions that employ droplets as microreactors. We developed a novel technology to produce monodisperse emulsion ...droplets with high efficiency and high throughput using a bench-top centrifuge. Upon centrifugal spinning, the continuous aqueous phase is dispersed into monodisperse droplet jets in air through a micro-channel array (MiCA) and then submerged into oil as a stable emulsion. We performed dPCR reactions with a high dynamic range through the MiCA approach, and demonstrated that this cost-effective method not only eliminates the usage of complex microfluidic devices and control systems, but also greatly suppresses the loss of materials and cross-contamination. MiCA-enabled highly parallel emulsion generation combines both easiness and robustness of picoliter droplet production, and breaks the technical challenges by using conventional lab equipment and supplies.
Cephalopods have remarkable ability to change their body color across a wide range of wavelengths, yet the structural basis remains largely unknown. Reflectin, a protein family assumed to be ...responsible for structural color in cephalopods, has unique features of higher-order assembly that are tightly regulated by aromatic molecules. Here, we reconstructed the dynamic and reversible color change using purified reflectin protein and demonstrated how the conformational change and the status of assembly led to the change in optical properties. In addition, optical spectral and structural analyses indicated that the "cephalopod-blue" primarily resulted from wavelength-dependent light scattering rather than reflection. Our results suggest a possible role of reflectin in color dynamics. The in vitro reconstruction system we present here may serve as an initial step for designing bio-inspired optical materials based on reflectin protein.
Atherosclerosis (AS) is a serious threat to human health and the main pathological basis of cardiovascular disease. Hyperoside (Hyp), a flavonoid found mainly in traditional Chinese herbs, can exert ...antitumor, anti-inflammatory, antioxidant, and cardiovascular-protective effects. Herein, we prepared hybrid nanomicelles (HFT) comprising Hyp loaded into pluronic F-127 and polyethylene glycol 1000 vitamin E succinate and assessed their effects on AS. To establish an AS model, apolipoprotein-E-deficient (ApoE
) mice were fed a high-fat diet. We then analyzed the effects of HFT on AS-induced changes in aortic tissues and metabolic markers, simultaneously assessing changes in gut flora community structure. In mice with AS, HFT significantly reduced the aortic plaque area; decreased levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, inflammatory factors, and inducible nitric oxide synthase (NOS); increased high-density lipoprotein cholesterol, endothelial NOS, superoxide dismutase, catalase, and glutathione levels; and promoted the proliferation of beneficial gut bacteria. HFT could regulate intestinal flora structure and lipid metabolism and inhibit inflammatory responses. These beneficial effects may be mediated by inhibiting nuclear factor kappa B signal activation, reducing inflammatory factor expression and improving gut microflora structure and dyslipidemia. The present study provides an empirical basis for the development and clinical application of new dosage forms of Hyp.
Single-cell whole-genome sequencing (scWGS) is mainly used to probe intercellular genomic variations, focusing on the copy number variations or alterations and the single-nucleotide variations (SNVs) ...occurring within single cells. Single-cell whole-genome amplification (scWGA) needs to be applied before scWGS but is challenging due to the low copy number of DNA. Besides, many genomic variations are rare within a population of cells, so the throughput of currently available scWGA methods is far from satisfactory. Here, we integrate a one-step micro-capillary array (MiCA)-based centrifugal droplet generation technique with emulsion multiple displacement amplification (eMDA) and demonstrate a high-throughput scWGA method, MiCA-eMDA. MiCA-eMDA increases the single-run throughput of scWGA to a few dozen, and enables the assessment of copy number variations and alterations at 50-kb resolution. Downstream target enrichment further enables the detection of SNVs with 20% allele drop-out.
Background Ancient classic prescription play a crucial role in the preservation and advancement of traditional Chinese medicine (TCM) theories. They represent a significant milestone in the ongoing ...development and transmission of TCM knowledge and practices and are considered one of the breakthroughs in the development of TCM inheritance. In the process of developing ancient classic prescriptions, many problems may still arise in ensuring quality consistency between traditional methods and modern production processes, among which the extraction process poses major challenges. This paper introduces a practical approach extracting an ancient classic prescription using a modern extraction process. The technique is demonstrated through the study of the extraction process of Shenshou Taiyi powder (STP). Methods This study focuses on optimising the STP extraction process to ensure consistency in the quality of the product obtained through ancient and modern processes using the standard relation and fuzzy analytic hierarchical process (FAHP) and criteria importance through intercriteria correlation (CRITIC) method integrated weights combined with the Box-Behnken response surface test. Using the contents of rosmarinic acid, isoimperatorin, puerarin, as well as the extract yield and fingerprint similarity as evaluation indexes of STP, the Box-Behnken response surface method was employed to examine the varying extraction parameters, including water addition ratio, extraction duration, and number of extractions. The weighted coefficients for each parameter were calculated by combining the benchmark correlation and FAHP-CRITIC method, deriving a comprehensive score. Results The optimal extraction process for STP consisted of a two extractions, each using at a tenfold quantity of water, performed for one hour. Process verification across three separate batches yielded a comprehensive score of 94.7, with a relative standard deviation of 0.76%. Conclusions The application of the Box-Behnken response surface method combined with standard relation and FAHP-CRITIC approach proved to be stable and feasible for optimising the extraction process of STP. Keywords: Ancient formulas, Content determination, Optimization of process, Response surface, Fuzzy analytic hierarchy process, CRITIC method
Dynamic contact angle (DCA) is of crucial importance in the numerical investigation of water management problems in proton exchange membrane fuel cells (PEMFCs). In order to well predict the ...gas-liquid two-phase flow in the complex flow field in PEMFCs, first, it is very critical to build a robust DCA model that is capable of simulating droplet behaviors on a single surface under various conditions. In our previous research work, an advancing-receding DCA (AR-DCA) model is developed and has been successfully validated against a series of experiments from the available literature for droplet impact on surfaces. In this study, the AR-DCA model is further applied to simulate droplet behaviors on inclined surfaces with different droplet impact velocities, impact angles and viscosities. It is found that the droplet spreading and deformation from the simulations have excellent agreement with those captured in the corresponding experiments. The results also indicate that higher impact velocity and impact angle can facilitate the spreading trend at the droplet trailing edge and have no notable effects on the leading edge. In addition, the increase of droplet viscosity leads to a transition from droplet deposition phenomenon to partial rebound on the surface.
•Droplet behaviors on inclined surfaces are simulated based on AR-DCA model.•Effects of impact velocity, impact angle and viscosity are investigated.•The numerical results have excellent agreement with the experiments.•AR-DCA model is capable of predicting droplet behaviors under various conditions.
Liquid water flow behavior in the microchannel is of crucial importance to the water management in proton exchange membrane fuel cells (PEMFCs). In this study, the liquid water flow regimes in a ...single straight microchannel are numerically investigated using the volume of fluid (VOF) method with the dynamic contact angle (DCA). Various air and liquid water inlet flow velocities are considered in the simulation to study their effects on the gas-liquid behaviors and flow structure. It was found that the liquid water injection rate is the dominant factor for the formation of different flow regimes: the increase of water inlet velocity will lead to the transition from squeezing flow to partial-jetting flow and jetting flow. Meanwhile, the air inlet velocity can also significantly affect the flow patterns: the higher inertial air flow will facilitate the detachment of liquid water under the squeezing flow, and greatly accelerate the transition process from liquid water blob to the film under the jetting flow.
•Liquid water flow regimes in a microchannel are simulated using VOF method.•Dynamic contact angle model is employed to conduct numerical simulation.•Various air and water inlet flow velocities are considered in the simulation.•Squeezing flow, partial-jetting flow and jetting flow are observed and discussed.
Dynamic contact angle (DCA) plays a critical role in the numerical investigation of gas-liquid two-phase flow problem in proton exchange membrane fuel cells (PEMFCs). In our previous study, an ...advancing-receding DCA (AR-DCA) model was developed based on Hoffman function and has been successfully validated. This study aims to further modify the contact line velocity evaluation method in the AR-DCA model and an improved-AR-DCA (i-AR-DCA) model is proposed. The simulations of droplet impact on inclined surface and liquid water behaviors in microchannel are conducted based on these two models and the results show that the improved methodology has no significant effects on general droplet spreading process on inclined surface; whereas it can facilitate the liquid water detachment in the microchannel. In addition, the Hoffman function is modified into three different forms based on the original experimental data points in order to test the sensitivity of different formulae on the numerical results. It is indicated that the modified forms of Hoffman function can induce notable changes in the liquid water slug elongation in the microchannel.
•The contact line velocity evaluation method in AR-DCA model is modified.•An improved AR-DCA model is proposed and employed in the simulation.•Original Hoffman function is modified into different forms for numerical test.
In the numerical simulation of water management for proton exchange membrane fuel cells (PEMFCs), the static contact angle (SCA) model is generally used. However, an empirical correlation for dynamic ...contact angle (DCA), known as Hoffman function or Kistler's law, was recently employed to numerically simulate the droplet behaviors either in a microchannel or on a surface. In this paper, for the first time, a DCA evolution map is created based on Hoffman function and related experiments to better understand the DCA evolving mechanism; based on this evolution map, the Advancing-Receding DCA (AR-DCA) model is proposed and explained, in addition to the Advancing DCA (A-DCA) model that is based on the original Hoffman's experiments; using user defined function (UDF), the A-DCA and AR-DCA models are implemented with Volume of Fluid (VOF) method in ANSYS Fluent; a series of numerical simulations are conducted with the SCA, A-DCA and AR-DCA models for droplet impact on horizontal and inclined surfaces; the validations of these contact angle models are performed, qualitatively and quantitatively, by comparing the numerical simulation results with the corresponding experimental results from the literature. It is indicated that the AR-DCA model can better simulate the droplet deformation and evolvement, showing its potential for the DCA simulations in a more complex gas-liquid flow domain such as the cathode of PEMFCs.
•DCA evolution map is created to better understand the DCA evolving mechanism.•The concept of A-DCA and AR-DCA models are proposed for the first time.•Comparisons of A-DCA, AR-DCA and SCA models are conducted for the first time.•Validations of contact angle models are performed qualitatively and quantitatively.•AR-DCA model has potential to better capture DCA features in PEMFC-simulations.
In this paper, the Volume of Fluid (VOF) method for tracking the gas-liquid interface is employed to investigate the carbon dioxide (CO2) behaviors inside the anode of a direct methanol fuel cell ...(DMFC). The CO2 bubble emergence processes from the catalyst layer (CL) to the gas diffusion layer (GDL) and then to the flow channels are studied with two different strategies. In the first strategy, the CL and GDL are modeled as a uniform porous layer; in the second strategy, they are modeled as a well-ordered-path GDL and a uniform CL. The simulation results show that the second modeling strategy can better capture and match the fundamental phenomena of CO2 bubble formation and evolvement observed from the experiments inside a DMFC anode.
•VOF method is employed to investigate CO2 behaviors inside the anode of a DMFC.•Two different anode modeling strategies (AMS1, AMS2) are proposed and implemented.•The results from AMS2 are better in agreement with those from experiments.
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