Showing papers by "Xiao Dong Chen published in 2021"
TL;DR: In this paper, the microstructure, rheology, and starch hydrolysis of cooked normal (NAM) and high (HAM) amylose maize starch solutions with various dry matter contents were compared before and during simulated gastrointestinal digestion.
45 citations
25 Apr 2021
TL;DR: Topological photonics is an emerging field that attracts enormous interest for its novel ways to engineer the flow of light as mentioned in this paper, and with the help of topological protection, the surface modes of topologica...
Abstract: Topological photonics is an emerging field that attracts enormous interest for its novel ways to engineer the flow of light. With the help of topological protection, the surface modes of topologica...
45 citations
TL;DR: In this article, a 220-GHz four-channel, non-contiguous, and manifold-coupled waveguide multiplexer for future terahertz (THz) multichannel communication application is presented.
Abstract: This article presents a 220-GHz four-channel, noncontiguous, and manifold-coupled waveguide multiplexer for future terahertz (THz) multichannel communication application. The multiplexer is composed of four Chebyshev bandpass filters based on metal waveguide technology. Through a unique design in which the tuning dimensional variables are reduced to 14 and a co-design of low-order electromagnetic (EM) distributed models and full-wave EM models, the design optimization is achieved with a good computational efficiency and design accuracy. The proposed multiplexer is fabricated by high-precision computer numerical control (CNC) milling technology, in which the fabrication errors are evaluated to be within ±3 μm. The measured results exhibit 1.7 dB of in-band insertion loss and better than 15 dB of average common-port return loss for each of the channel filter. The measured results are all in good agreement with the simulated ones, thereby validating the complete design procedure.
38 citations
TL;DR: In this paper, a phase-controlled pattern-reconfigurable dielectric resonator antenna (DRA) is proposed for wide-angle beam scanning for a base station antenna.
Abstract: The function of passive wide-angle beam scanning is desired by the base station antenna to provide “green” cellular services. In this communication, such function is realized by designing a compact phase-controlled pattern-reconfigurable dielectric resonator antenna (DRA). The proposed DRA has a compact structure with a side length of $0.38 \boldsymbol {\lambda }_{\text {c}}$ and excites the fundamental TE and TM modes by diverse ports. By assigning phase between diverse ports, E-plane tilted patterns are synthesized with ±66° scan angles. Its pattern-reconfigurable capability makes contributions for increasing array beam scanning angle and minimizing gain fluctuation. A passive four-element array is verified to have an enhanced beam scanning angle of ±81° with a gain fluctuation of 1.25 dB. The maximum gain of the scanning beam is located on the off-axis angle of ±66° and achieves a wide 3 dB scan coverage of ±105°. Good agreements have been shown between the measured and simulated results. The proposed phase-controlled pattern reconfigurable DRA and DRA arrays have an impedance bandwidth of 3.33% (2.95–3.05 GHz) for a sub-6 GHz wireless system. They enable the wide-angle beam scanning for base station antenna and provide a cost-effective passive system for “green” communications.
38 citations
TL;DR: A benefit of incorporating the dandelion flavonoids in making functional foods in managing the diet of the diabetes is suggested, as the positive values of enthalpy and entropy change reveal that the binding was predominately driven by hydrophobic interactions.
27 citations
TL;DR: In this article, the mixing process in a human duodenum with circular folds was simulated using a multiphysics model, making it possible to track the evolution of mixing level distributions and enabling quantitative evaluation of the structural role of folds in mixing intensification.
22 citations
TL;DR: This study shows promise for facile and scalable production of high-quality nasal powder using combined complexation method with spray drying and spray freeze drying technique.
19 citations
TL;DR: In this paper, a novel activatable amphiphilic small molecular prodrug IR820-SS-CPT has been developed, which integrated multiple advantages of GSH-triggered drug release, high therapeutic agent content, and combined chemo-photothermal therapy into one drug delivery system.
Abstract: Background Nanoscale drug delivery systems have emerged as broadly applicable approach for chemo-photothermal therapy. However, these nanoscale drug delivery systems suffer from carrier-induced toxicity, uncontrolled drug release and low drug carrying capacity issues. Thus, to develop carrier-free nanoparticles self-assembled from amphiphilic drug molecules, containing photothermal agent and anticancer drug, are very attractive. Results In this study, we conjugated camptothecin (CPT) with a photothermal agent new indocyanine green (IR820) via a redox-responsive disulfide linker. The resulting amphiphilic drug-drug conjugate (IR820-SS-CPT) can self-assemble into nanoparticles (IR820-SS-CPT NPs) in aqueous solution, thus remarkably improving the membrane permeability of IR820 and the aqueous solubility of CPT. The disulfide bond in the IR820-SS-CPT NPs could be cleaved in GSH rich tumor microenvironment, leading to the on demand release of the conjugated drug. Importantly, the IR820-SS-CPT NPs displayed an extremely high therapeutic agent loading efficiency (approaching 100%). Besides, in vitro experimental results indicated that IR820-SS-CPT NPs displayed remarkable tumor cell killing efficiency. Especially, the IR820-SS-CPT NPs exhibited excellent anti-tumor effects in vivo. Both in vitro and in vivo experiments were conducted, which have indicated that the design of IR820-SS-CPT NPs can provide an efficient nanotherapeutics for chemo-photothermal therapy. Conclusion A novel activatable amphiphilic small molecular prodrug IR820-SS-CPT has been developed in this study, which integrated multiple advantages of GSH-triggered drug release, high therapeutic agent content, and combined chemo-photothermal therapy into one drug delivery system.
18 citations
TL;DR: In this paper, the authors showed that strain-specific cellular response toward variations in growth conditions is crucial to the intrinsic properties of LAB and to cell survival during spray drying and storage.
Abstract: Microencapsulation of lactic acid bacteria (LAB) via spray drying differs from that of common bioactive substances in that the intrinsic stress tolerance of cells can be modulated to improve cell survival. In this study, elevated growth temperatures that were 3–5 °C above the standard conditions were used to culture Lactococcus lactis subsp. cremoris, Lactobacillus rhamnosus GG (LGG), and Lactobacillus acidophilus for spray drying. The heat-adapted cultures showed lower bacterial population than the controls by 0.45 log at stationary growth phase and produced lactobacilli cells with elongated shape, while their metabolic activities were maintained similar to the controls. Heat-adapted L. cremoris and LGG demonstrated increases in survival by 0.7–1.5 log and 0.3 log, respectively, after heat treatment at 60 °C. The thermotolerance of L. acidophilus grown at 42 °C was dependent on growth phase, and the culture entered death phase within 24 h of incubation. The survival of heat-adapted L. cremoris and L. acidophilus after spray drying was increased by 21.0% and 13.7%, respectively, whereas the increase shown by LGG was relatively insignificant (9.9%). Spray-dried powders containing heat-adapted cells showed substantial reduction of viability at the first week of storage, reaching 1.03–1.23 log, compared to 0.87–0.90 log of reduction shown by the controls. The findings demonstrated that strain-specific cellular response toward variations in growth conditions is crucial to the intrinsic properties of LAB and to cell survival during spray drying and storage. Controlling cellular response is one of the key factors in developing a viable spray drying scheme for active LAB.
18 citations
TL;DR: In this paper, a topological nanophotonic corner state in a second-order topological photonic crystal (PC) cavity was investigated under in-plane excitation and the expectation values of a mirror-flip operation for the Bloch modes of a PC slab were used to characterize the topological phase.
Abstract: In silicon photonics, the cavity mode is a fundamental mechanism to design integrated passive devices for on-chip optical information processing. Recently, the corner state in a second-order topological photonic crystal (PC) rendered a global method to achieve an intrinsic cavity mode. It is crucial to explore such a topological corner state in silicon photonic integrated circuits (PICs) under in-plane excitation. Here, we study both theoretically and experimentally the topological nanophotonic corner state in a silicon-on-insulator PC cavity at a telecommunications wavelength. In theory, the expectation values of a mirror-flip operation for the Bloch modes of a PC slab are used to characterize the topological phase. Derived from topologically distinct bulk polarizations of two types of dielectric-vein PCs, the corner state is induced in a 90-deg-bend interface, localizing at the corner point of real space and the Brillouin zone boundary of reciprocal space. To implement in-plane excitation in an experiment, we fabricate a cross-coupled PC cavity based on the bend interface and directly image the corner state near 1383 nm using a far-field microscope. Finally, by means of the temporal coupled-mode theory, the intrinsic Q factor of a cross-coupled cavity (about 8000) is retrieved from the measured transmission spectra. This work gives deterministic guidance and potential applications for cavity-mode-based passive devices in silicon PICs, such as optical filters, routers, and multiplexers.
16 citations
TL;DR: This study proposed a strategy in which food ingredients containing hydrophobic bioactive small molecules can be incorporated into a food matrix to improve bioaccessibility and targeted release, without affecting their sensory properties.
TL;DR: The Maillard reaction products of whey protein isolate and xylooligosaccharides were prepared by a moist heat method for use as protectants to encapsulate Lactobacillus rhamnosus via spray drying and FTIR results indicated that MRPs were successfully prepared.
Abstract: The Maillard reaction products (MRPs) of whey protein isolate (WPI) and xylooligosaccharides (XOS) were prepared by a moist heat method for use as protectants to encapsulate Lactobacillus rhamnosus via spray drying. The protective effects of MRPs on bacterial cells during drying, storage, and in vitro digestion were explored. FTIR results indicated that MRPs were successfully prepared. All MRPs showed good thermo-protective effect on the bacteria, and the survival ratio achieved with 1 : 2 XOS–WPI as a wall material reached 99.83 ± 8.44%, which was around 2 times as high as that of the WPI wall material and 1.5 times as high as that of the 1 : 2 XOS–WPI mixture. The dried lactobacilli showed similar growth curves to the fresh culture. After 10 weeks of storage at 4 °C, the decrease in the bacterial activity was less than 1 log CFU g−1 for all types of microcapsules, while the microcapsules composed of all MRPs had better storage stability. MRPs improved the stability of microcapsules during in vitro digestion. The number of viable bacteria in 1 : 2 XOS–WPI MRPs microcapsules was maintained at 4.09 ± 0.59 × 109 CFU g−1 after simulated gastrointestinal digestion for 4 hours, which only decreased by 0.20 log CFU g−1.
TL;DR: In this paper, using time-domain measurements in the microwave regime, a sharply bended waveguide is constructed with the domain wall between two valley photonic crystal slabs for high-fidelity optical pulse signal transmission and the development of high-performance optical elements, such as photonic circuits or optical delay lines.
Abstract: A valley photonic crystal is one type of photonic topological insulator, the realization of which needs only P-symmetry breaking The domain wall between two valley-contrasting photonic crystals supports robust edge states, which can wrap around sharp corners without backscattering Using the robust edge states, one can achieve pulse transmission Here, using time-domain measurements in the microwave regime, we show distortionless pulse transmission in a sharply bended waveguide An \ensuremath{\Omega}-shaped waveguide with four 120\ifmmode^\circ\else\textdegree\fi{} bends is constructed with the domain wall between two valley photonic crystal slabs Experimental results show the progress of Gaussian pulse transmission without distortion, and the full width at half maximum of the output signal changes slightly in the \ensuremath{\Omega}-shaped waveguide By measuring the steady-state electric field distribution, we also confirm the confined edge states without out-of-plane radiation, which benefits from dispersion below the light line Our work provides a way for high-fidelity optical pulse signal transmission and the development of high-performance optical elements, such as photonic circuits or optical delay lines
TL;DR: In this paper, the authors proposed a wideband circular-polarized (CP) beam steering dielectric resonator antenna (DRA) using a gravitational ball lens, which offers a passive means for wall or ceiling mounted base station antennas to adjust their patterns by the gravity of ball lenses.
Abstract: This communication proposes a wideband circular-polarized (CP) beam steering dielectric resonator antenna (DRA) using a gravitational ball lens. It offers a passive means for wall or ceiling mounted base station antennas to adjust their patterns by the gravity of ball lenses. This novel antenna concept overcomes the difficulties of achieving wideband axial ratio versus the pattern reconfigurability of the existing antennas. The operation of the ball lens has been intensively studied. It is found that the ball lens provides 1.2 dB antenna gain enhancement, whereas enabling beam tilting via energy coupling to the offset direction. As a demonstration, a codesign of DRA and ball lens has been developed at 2.4 GHz, achieving 42% impedance bandwidth, 39% axial ratio bandwidth, and ±40° beam steering. Reasonable agreement between simulated and measured results is observed. The proposed DRA provides a low-cost solution for base stations to be mounted at an angle and effectively cover the indoor users.
TL;DR: Some considerations and recommendations for the in vitro-in vivo validation are proposed in order to show the way forward for the development of more physiologically relevant in vitro methods to predict bioaccessibility and even bioavailability.
Abstract: Measuring bioaccessibility before implementation of a fortification program are critical to fulfill the health benefits that the fortified food products are designed for. A number of in vitro approaches have been emerged and employed for assessing bioaccessibility of bioactive compounds or nutrients within the simulated human gastrointestinal tract (GIT). However, most of them developed so far have not been fully validated against in vivo studies on humans or animals mainly due to limitations in the availability of relevant in vivo data. This paper provides an overview of the most recent works on the assessments of bioaccessibility using in vitro approaches, as well as the current status of validation of typical static and dynamic GIT systems. In particular, some considerations and recommendations for the in vitro–in vivo validation are proposed, in order to show the way forward for the development of more physiologically relevant in vitro methods to predict bioaccessibility and even bioavailability.
TL;DR: In this article, the effect of protein isolate-polysaccharide combinations in aqueous phases on modulating the rheology and microstructural properties of 20-wt % oil-in-water emulsions was determined.
TL;DR: The current study demonstrates that a well-considered in vitro system can offer a reasonable approach for tracking the structural and physicochemical changes of foods during digestion in the stomach, which is practically meaningful.
Abstract: Nowadays, in vitro digestion models have received growing interest in recent years to track the digestive fate of foods in the gastrointestinal tract. A major challenge in the development of more physiologically relevant in vitro gastric models is to simulate realistic gastric emptying. In this study, an advanced dynamic in vitro human gastric system was investigated for its potential in achieving the above. The mechanisms for controlling the gastric emptying rate by modulations of the peristaltic moving distance, the pylorus opening size/frequency, and the stomach tilting angle in relation to time are illustrated. With solid cheese, a difficult food material for emptying, different combinations of the operational parameters of the stomach system were evaluated. The system was steered to attain consistent gastric emptying curve with the theoretical data by optimizing operational parameters. By fitting the gastric retention data with a power-exponential model, which is a common approach for describing gastric emptying, the total meal achieved an average emptying half-time (t1/2) of 84.5 min and a curve shape coefficient (β) of 1.69, similar to the theoretical data reported in the literature, where the values of t1/2 and β were 85 min and 1.8, respectively (p > 0.05). Furthermore, the mean median particle size was significantly decreased from the initial 2.80 mm (cheese cubes) to the final 1.35 mm (p < 0.05). There are few particles greater than 2 mm observed in the emptied cheese digesta throughout the digestion process. These suggest the powerful gastric grinding and sieving capacity exhibited by the in vitro system. The current study demonstrates that a well-considered in vitro system can offer a reasonable approach for tracking the structural and physicochemical changes of foods during digestion in the stomach, which is practically meaningful.
TL;DR: Under optimized conditions, Fe-TiO2 catalysts with iron lattice doping, well-dispersed ultrasmall α-Fe2O3 nanoparticles, appropriate anatase/rutile ratios and abundant OV sites work synergistically to improve the charge migration and interfacial activation of H2O2, leading to superior HPFO performance for MB degradation and mineralization.
TL;DR: In this article, a pyramidal double-ridged horn antenna with a high-dielectric material comprising a mixture of linseed oil and titanium oxide was used to measure abdominal fat layers of the human body.
Abstract: This article presents a novel 3-D-printed, pyramidal double-ridged horn antenna, filled with a high-dielectric material comprising a mixture of linseed oil and titanium oxide, for biomedical applications. In particular, this investigation explores the use of the antenna design to measure the abdominal fat layers of the human body. The antenna is designed to operate at the low-frequency microwave bands and complemented with an absorber layer at the aperture to improve directivity. The proposed method aims to assess the fat layer thicknesses based on an analysis of the variations of the reflection coefficients. The system has been calibrated and validated based on a number of numerical time-domain simulations, as well as experimental analysis. Assessment of the first transition point in the reflection coefficient spectrum has successfully predicted the rate of magnitude change caused by different layer thicknesses (e.g., oil and fat). Comparing coefficient spectra from various simulation experiments has allowed for eliminating the interferences arising from mismatches with the skin and muscle layers, resulting in the measurements of the fat layer thicknesses through the remaining power change rate.
TL;DR: In this paper, the authors investigated the skin rheological behavior during the different stages of the evaporation process, highlighting the specific role of each colloid, and interpreted the results in the light of drying-induced protein stratification, whose evidence is provided by direct observation of dry skin section structure.
TL;DR: In this article, the intrinsic stability and evolution of a series of metal-organic frameworks (MOFs) in aqueous ozone (O3) solution are studied. And the critical parameters that determine the stability and capability for post-synthesis of these MOFs in O3 solutions are discussed.
Abstract: Metal-organic frameworks (MOFs) are highly promising in many areas. Their application and postsynthesis under strong oxidative environments are emerging. However, the stability, physicochemical property evolution, and possible postmodification and postsynthesis of MOFs in strong oxidative solutions are largely unknown. In this paper, the behaviors of a series of MOFs in bubbled aqueous ozone (O3) solutions are studied. The chosen MOFs are categorized into trimesic type including MIL-101(Fe) and MIL-96(Al); terephthalic type including MOF-74(Co), UiO-66(Zr), MIL-53(Al), and MIL-101(Cr); and imidazole type including ZIF-67(Co) and ZIF-8(Zn), based on the ligand structure. The intrinsic stability and evolution of the physicochemical properties of these MOFs during aqueous O3 treatment are elucidated using structural, morphological, textural, thermal, and spectroscopic analyses. Several stable, metastable, and instable MOFs are identified. The critical parameters that determine the stability and capability for postsynthesis of these MOFs in aqueous O3 solutions are discussed. The stability follows the general order of trimesic-type > terephthalic-type ≫ imidazole-type MOFs because of the distinct antioxidation capability of the ligands. The effects of the ligand, metal cation, and their coordination number on stability are discussed. MIL-100(Fe), MIL-96(Al), and MOF-74(Co) are stable in aqueous O3. UiO-66(Zr), MIL-53(Al), and MIL-101(Cr) are metastable that their porosity, particle size, and crystallinity can be postmodified. ZIF-67(Co) and ZIF-8(Zn) are instable and can be gradually and completely disassembled. Their particle size and morphology and surface groups can be tuned by controlling the treatment time. Postsynthesis of metal hydroxides from ZIF-67(Co) and gradual release of dissolved zinc ion from ZIF-8(Zn) are achievable. The stable MIL-96(Al) shows promising performance in catalytic ozonation for degrading 4-nitrophenol, and the α-Co(OH)2 derived from treating ZIF-67(Co) shows highly promising performance in the electrocatalytic oxygen evolution reaction (OER).
TL;DR: In this paper, molecular dynamics simulations were utilized to separately elucidate the filtration effects of three typical edge functional groups, which were carboxyl (COOH), hydroxyl (OH), and hydrogen (H), on the LiCl, NaCl, and KCl solutions.
TL;DR: In this paper, a review of spray drying can be divided into three broad categories: the first category concerns mathematically describing the spray drying process using a plug-flow model which al...
Abstract: Recent initiatives covered in this review can be divided into three broad categories. The first category concerns mathematically describing the spray drying process using a plug-flow model which al...
TL;DR: In this paper, the authors simulated the process of mixing and emptying of gastric contents using a numerical method and found that a fast pathway is located close to the lesser curvature of the stomach when water is emptied.
TL;DR: In this paper, the effect of casein on β-lactoglobulin (BLG) denaturation at molecular level and subsequent fouling behavior in the pilot-scale plate heat exchanger during pasteurization treatment was investigated.
TL;DR: In this paper, a millimeter-wave (mm-wave) wideband circularly polarized (CP) horn antenna using iris polarizer is reported, which can achieve a better tolerance of manufacturing and assembly errors and is more suitable for highfrequency CP horn design.
Abstract: A novel millimeter-wave (mm-wave) wideband circularly polarized (CP) horn antenna using iris polarizer is reported. By introducing the metasurface concept, the electrical contact problem at the mm-wave band for waveguide-separated components of high-performance CP horn antenna is eliminated. The influence of air gaps on polarizer and whole horn antenna loaded and unloaded metasurface is analyzed and explained. According to simulation, small air gaps of the metal-to-metal contacting plane would not harm the horn performance after loading the metasurface, which means the proposed method can achieve a better tolerance of manufacturing and assembly errors and is more suitable for high-frequency CP horn design. For validation, the proposed horn antenna has been fabricated and its performance is evaluated. The measurement results are in good agreement with the simulation results. The experimental results of 37.8% bandwidth from 75 to 110 GHz for both the axial ratio (AR) $\vert S_{11}\vert dB are achieved.
TL;DR: In this article, four lactic acid bacteria (LAB) strains were cultured in reconstituted skim milk with different solids contents to compare the thermotolerance of resulting cultures.
01 Mar 2021
TL;DR: In this paper, a review comprehensively summarizes the existing studies on the galvanic effect of carbon fiber reinforced polymer (CFRP) on engineering metals, such as the involvement of crevice corrosion and self-corrosion in the damage of a metal/cFRP couple, the effect of micro-defects in the surface polymer layer of a CFRP, the polarization damage, and the electrochemical anisotropy of the reinforcing carbon fiber.
Abstract: Carbon fiber reinforced polymer (CFRP) as an advanced modern engineering material has found many applications in industry because of its high strength and lightweight. However, there has been a big concern that it may cause galvanic corrosion damage to the metal in contact. This review comprehensively summarizes the existing studies on the galvanic effect of CFRPs on engineering metals. Some recent achievements are particularly focused, such as the involvement of crevice corrosion and self-corrosion in the damage of a metal/CFRP couple, the effect of micro-defects in the surface polymer layer of a CFRP on the galvanic activity, the polarization damage in a CFRP, and the electrochemical anisotropy of the reinforcing carbon fiber (CF).
TL;DR: In this article, a spray-drying encapsulation and steaming transformation is used to obtain robust binder-free zeolite microspheres with hierarchical porosities.
TL;DR: In this paper, a millimeter-wave (mm-wave) wideband dual circularly polarized (CP) antipodal septum antenna is proposed, and the working principle of the generation process of dual CP is explained by a three-port model with three excitation conditions.
Abstract: A millimeter-wave (mm-Wave) wideband dual circularly polarized (CP) antipodal septum antenna is proposed. By introducing two antipodal septum blames in widened rectangular waveguide and the corresponding feeding network, the operating bandwidth of the septum antenna is enhanced. The working principle of the generation process of dual CP is explained by a three-port model with three excitation conditions. In addition, the asymmetrical radiation pattern of the classical polarizer consisting of square waveguide and single septum caused by the high-order modes is explained and eliminated. To verify the design, the proposed antenna has been fabricated and measured. An operating bandwidth of 37.4% for reflection coefficients less than −13.8 dB, isolation better than 22 dB, and axial ratio (AR) value less than 3 dB is achieved.