Search

Hydrofluorocarbons(HFCs) are potent greenhouse gases in refrigeration systems, and their contribution will accelerate climate change. In the context of global warming, low global warming refrigerants have to be reconsidered, these refrigerants are commonly flammable, so systems that use them can pose a risk. Thus, an analysis of potential pipe leaks in refrigeration systems is urgently needed. In existing research on refrigerant leak, most studies have examined holes as leak points. However, the true morphology of leak points is commonly long and extremely narrow. Therefore, a round-pipe microcrack leak model with crack opening displacement (COD) ranging from 10–50 µm were built to perform a simulation and experiment. The Fluent (v.20, ANSYS Inc.) software performed computational fluid dynamics analysis. The R290, R32, and R1234yf refrigerants were simulated, and the orifice flow equation was introduced to calculate leakage from the microcrack. An axial and circumferential microcrack model was constructed, and the experiment validated the simulation with largest relative error of 2.9%. The simulation results indicated that for side flow through the microcrack, using the conventional discharge coefficient ( C d ) in the orifice equation may be unsuitable. Accordingly, based on the simulation results, empirical equations for predicting the C d of axial microcrack when R290, R32, and R1234yf are leaking are obtained. Additionally, the effect of length-to-diameter ratio and orifice-to-pipe-diameter ratio on C d are also discussed. Compared with existing studies, a smaller infinity discharge coefficient value ( C d ∞ ) was observed when COD 30 μ m .

The active ingredients of Traditional Chinese Medicine are an important source of bioactive molecules and play an important role in the research and development of innovative drugs. FA-30, which is a derivative of natural product ferulic acid, inhibited cervical cancer cell proliferation and induced apoptosis as well. To understand the underlying mechanisms of FA-30, a complementary multi-omics study was conducted. Cysteine and methionine metabolism and aminoacyl-tRNA biosynthesis pathways were significantly changed both at the metabolic level and proteomic level. This may help us to get a better understanding of cervical cancer and FA-30 at the same time.

Five extracts of the aerial parts of

Since most anti-glioma drug candidates hardly permeate through the blood-brain barrier (BBB), preclinical models that can integrate the complexity of the tumor microenvironment and the structure and function of the BBB is urgently needed for the treatment of glioma. Herein, we constructed an in vitro BBB-glioma microfluidic chip model lined by primary human brain microvascular endothelial cells, pericytes, astrocytes and glioma cells, which could recapitulate the high level of barrier function of the in vivo human BBB and glioma microenvironment. The BBB unit in BBB-glioma microfluidic chip (BBB-U251 chip) displayed selective permeability to fluorescein isothiocyanate isomer-dextran (FITC-dextran) with different molecular weights and three model drugs with different permeability behavior across BBB, which indicated that this glioma model included a functional barrier. Six potential anti-glioma components in traditional Chinese medicine (TCM) were delivered into the blood channel and the permeated amount was quantified by high-performance liquid chromatography combined with ultraviolet (HPLC-UV). The permeated drugs then directly acted on 3D cultured glioma cells (U251) to evaluate the drug efficacy. The results of permeability coefficients of drugs showed that the data were closer to the in vivo data of traditional Transwell model. The effect of the drugs on U251 cells in the BBB-U251 chip was significantly lower due to the existence of BBB. Drug responses on glioma demonstrated the necessity to take BBB into account during the development of anti-glioma new drugs. Therefore, this 3D glioma microfluidic models integrating the BBB functionality can be a useful platform for screening the anticancer drug for brain tumors.

Docetaxel is one of the clinical first-line drugs and its combination with other chemotherapy agents for advanced or metastatic cancers has attracted widespread attention. Therefore, to promote the clinical application of docetaxel alone or in combination, a comprehensive investigation of the metabolic mechanism of docetaxel is of great importance. Here, we apply an integrative analysis of metabolomics and network pharmacology to elucidate the underlying mechanisms of docetaxel. After taking the intersection of the aforesaid two methods, five pathways including ABC (ATP-binding cassette) transporters, central carbon metabolism in cancer, glycolysis and gluconeogenesis, cysteine and methionine metabolism, and arginine biosynthesis have been screened. Concerning the interaction network of these pathways and the anti-apoptosis effect of docetaxel itself, the central carbon metabolism in cancer pathway was mainly focused on. This study may help delineate global landscapes of cellular protein-metabolite interactions, to provide molecular insights about their mechanisms of action as well as to promote their clinical applications.

Droplet manipulation is of paramount significance for microfluidics-based biochips, especially for bioanalytical chips. Despite great progresses made on droplet manipulation, the existing bioanalytical methods face challenges in terms of capturing minute doses toward hard-to-obtain samples and analyzing biological samples at low temperatures immediately. To circumvent these limitations, a self-propelled and electric stimuli synergetic droplet manipulator (SES-SDM) was developed by a femtosecond laser microfabrication strategy followed by post-treatment. Combining the inspiration from cactus and Nepenthes pitcher plants, the wedge structure with the microbowl array and silicone oil infusion was endowed cooperatively with the SES-SDM. With the synergy of the ultralow voltage (4.0 V) stimuli, these bioinspired features enable the SES-SDM to transport the droplet spontaneously and controllably, showing the maximum fast motion (15.7 mm/s) and long distance (96.2 mm). Remarkably, the SES-SDM can function at -5 °C without the freezing of the droplets, where the self-propelled motion and electric-responsive pinning can realize the accurate capture and real-time analysis of the microdroplets of the tested samples. More importantly, the SES-SDM can realize real-time diagnosis of excessive heavy metal in water by the cooperation of self-propulsion and electro-brake. This work opens an avenue to design a microsampling (5-20 μL) manipulator toward producing the minute samples for efficient bioanalysis and offers a strategy for microanalysis using the synergistic droplet manipulation.

Bioinspired functional structures or devices show great potential for harvesting water resources in the atmosphere. Despite the great advances made in the capture and transportation of the droplets, the efficient storage of harvested water for direct and cyclable utilization is rarely concerned towards real daily life. Inspired by the long-stem storage of water caused from the Triarrhena sacchariflora leaf sheath, a wearable fogdrop collector was developed via laser structuring and origami techniques for effectively nourishing the plants in a lower-evaporation condition. The collector shows an annular thin-wall with a superhydrophilic grooved inwall (SGI), and a circular array of spine with thorns and gradient channels (STGCs). These structural features enable the collector to capture fogdrop by STGC, and keep water inside the thin-wall for long-lasting moisture retention. Furthermore, due to the excellent flexibility and composability, multiple collectors can be easily assembled to a larger harvesting one, implying its scalability potential. The assembled devices show a higher collection efficiency and lower evaporation than the individual ones, reaching ∼8.4 mL per hour when using triple collectors. More interestingly, such devices can be directly used for the moisture retention of the fresh flower, showing water retention of more than 140 min, which is superior to the traditional watering or water spraying. This work gives a flexible design strategy of a portable scalable collector for water harvesting, and especially opens an avenue to the direct and actual utilization of the fogdrop collectors for the flower moisture retention and even agricultural irrigation.

Despite extensive efforts made in directional manipulation of water and oil microdroplets, challenges still remain in the ultrafast self-transportation and the rapid separation of droplets with different surface tensions due to the lack of driving force. The natural inspiration from fish medullary spines provides a potential way to realize directional oil movement by using an anisotropic surface with micropits. Herein, a fish-spine-like liquid splitter (FSLLS) is developed based on a precise 3D printing and subsequent femtosecond laser structuring. The liquid splitter enables directional transportation of various microdroplets, with the maximum velocity reaching 265.3 mm s−1. More interestingly, it can spontaneously transport liquids with the surface tension ranging from 15 to 48 mN m−1, achieving an outstanding selectivity of specific liquids. Moreover, the lower the surface tension for the liquid in the surface tension range, the faster the transport speed on the FSLLS. This feature can be attributed to the unique micro-pit structure on the FSLLS surface and its oleophilic properties. The combination of ultrafast directional transportation and peculiar selective ability makes the FSLLS achieve the pumping of microdroplets with lower surface tension. As a proof-of-concept, the separation of the mixed droplets with different surface tensions is demonstrated using the FSLLS and the scalable device. This study offers a new bionic design concept for selective microdroplet pumping devices and opens up an avenue for the separation and extraction of oil droplets in the field of multiphase separation, biomedical analysis, microfluidics, etc.

A liquid surface deformation sensor with high sensitivity based on a Mach–Zehnder interferometer (MZI) was demonstrated. The MZI was constructed by cascading two Bowknot Type Tapers (BTTs) with an ...

Photothermal effect has attracted widespread attention in anti-icing surfaces due to energy saving and environmental friendliness. However, the development of surfaces with excellent photothermal performance is still limited in real engineering applications like aerospace by cheap material, facile fabrication and highly photothermal efficiency. Inspired by the optical features of the moth eye, a black engineering aluminum with high-efficiency solar anti-icing ability was developed through an ultrafast laser texturing treatment. The resultant anti-icing aluminum surface had regular micro/nano-scaled protrusions, showing good photothermal ability together with superhydrophobicity. The superhydrophobicity enables this surface to delay the freezing time by 5 times than blank one while the photothermal ability increases its surface temperature by 53 °C under one sun irradiation. The synergy of two abilities let the ice on its surface melt within 4 min. Additionally, the self-cleaning ability of the prepared surface enhances the anti-icing efficiency by removing absorbed contaminants affecting the photothermal effect adversely. This all-in-one integration of superhydrophobicity and photothermal effect finally boosts improved anti-icing performance as compared to the traditional superhydrophobic surface or individual photothermal materials. The work provides new insights into the design of enhanced anti-icing surface on the engineering materials with an advanced laser microfabrication.

A hydrogen gas sensor based on cascaded TCF with WO 3 film was demonstrated to monitoring the hydrogen concentration. By detecting spectral shifts, the proposed sensor showed a high sensitivity of 2.074444 dB/% under the hydrogen concentration of 0.00% to 1.32%.

A hydrogen sensor based on a peanut-type fiber coated with a film of PDMS covered with WO 3 /SiO 2 hybird powder was proposed. Mach-Zehnder interferometer is composed of two peanut-type structures and a single-mode optical fiber. Two peanut-type surfaces were coated with PDMS films coated with WO 3 /SIO 2 powder. The proposed sensor has the sensitivity of 0.47db/% with a linear correlation of 98.3% in the concentration range of 0% - 0.901%.

An optical fiber temperature sensor by using a Mach-Zehner interferometer coated with a film of PDMS was proposed. The Mach-Zehner interferometer is made up of two Bowknot Type Tapers (BTTs) and a single mode fiber. The surface of the two BTTs was coated with a film of PDMS. The energy distribution of the two BTTs was simulated by using the finite element means. The proposed sensor structure has a linearity correlation of 98.46% in temperature responses. Temperature detection sensitivity of 0.1957nm/ °C was obtained under the temperature range from 40 °C to 120°C, which is about 10 times of the similar sensors with a sensitivity of tens pm/ °C.

Surface-enhanced Raman scattering (SERS) with unique molecular vibrational fingerprints for identifying analytes provides an effective spectroscopic approach for the detection of trace molecules in biomedical/analytical fields. Although a great amount of efforts has been devoted to developing various SERS substrates with hierarchical micro/nanostructures, challenges remain in completely concentrating the target molecules within a sensitive area and thereby enhancing detection sensitivity. Here, we report trace molecular detection using superhydrophobic microcrater array as surface-enhanced Raman substrate (SMA-SERS). The hierarchically ordered microcrater array with plasmonic nanoparticle clusters is quickly obtained by the two-step process of femtosecond laser texturing and magnetron sputtering. The resultant substrates with hierarchical micro-/nanostructures show excellent superhydrophobicity with a contact angle above 150° and satisfactory plasmonic nanostructures with the easily attainable Raman signal enhancement factor of ~4.82 × 108. The signals on the SMA-SERS maintain uniformity with a relative standard deviation of

Highly-performance fogdrop collection is of great practical importance in addressing the worldwide water shortages, especially in arid regions. Although great progresses have been made to solve this problem, there still are challenges in developing high-performance fogdrop collecting systems to satisfy efficient fogdrop capturing and fast transport simultaneously, which are two critical factors that determine the collection efficiency. The well-evolved water-collecting capacity of creatures that adapt to the harsh environment provides a great inspiration for the design of efficient collection systems. Here, inspired by the unique hierarchical structures and the excellent fogdrop collection ability of wheat awn, artificial awn-like hierarchical systems are developed via a precision 3D printing strategy which exhibit excellent fogdrop capture and fast transport. The presence of hierarchical structure composed of conical spine, gradient microgrooves, and oriented thorns enables the fogdrop collection to transform from dropwise mode on the thorns to filmwise one on the spine. Furthermore, the collection efficiency of such a bioinspired system is 5.90 g/cm−2·h, which is higher than individual ones and other bioinspired systems. Through the model of structure–function relationship, the mechanisms of diverse collecting behaviors are explored to address the origin of highly-performance collection. This work opens up new avenues to design systems and devices for dramatic fogdrop collection enhancement.

An optical fiber temperature sensor based on a Mach-Zehnder interferometer (MZI) coated with a film of polydimethylsiloxane (PDMS) was demonstrated. The MZI was fabricated by a fiber mismatch structure through core-offset fusion splicing method. The resonant dip wavelength of the MZI will shift with the changing of the environmental temperature own to the effects of expansion and thermo-optic of the PDMS. Experimental results showed that the proposed sensor shows the temperature sensitivity of 0.101 nm/°C under the temperature range of 20 °C to 100 °C, which is about 2 times of the existing similar temperature fiber sensors.

Recent advancement in micro-electronic technology makes the development of quadrotor fully possible. This paper elaborates on the complete designing process of a quadrotor control platform. Firstly a hardware structure with a microcontroller and embedded sensors is reported. Then through the implementation of a linear complementary filter, the real-time attitude estimation of the quadrotor is realized. Furthermore, aiming at the outdoor environment navigation, a barometer and a Global Positioning System (GPS) are also integrated within this platform. A multisensory data fusion algorithm is then proposed to combine these sensors for the outdoor navigation. Finally, a group of PID controllers are designed to stabilize the attitude and position. The experiment results demonstrate the capability of this platform to navigate autonomously through user-defined waypoints.