An optical microwave waveform generator using a polarization modulator (PolM) in a Sagnac loop is proposed and experimentally demonstrated. Microwave waveforms including a triangular waveform, a ...sawtooth waveform, and a square waveform, can be generated using a sinusoidal signal to modulate a light wave at a PolM in a Sagnac loop. In the proposed microwave waveform generator, a sinusoidal microwave signal is applied to the PolM in the Sagnac loop. Due to the velocity mismatch, only the clockwise light wave in the Sagnac loop is effectively modulated by the sinusoidal microwave signal at the PolM, and the counter-clockwise light wave is not modulated. Along the clockwise direction, the powers of the odd- and even-order sidebands can be controlled separately by tuning a polarization controller after the PolM. In addition, the output power of the optical carrier can be independently controlled by combining the counter-clockwise and clockwise optical carriers at the output of a polarization beam splitter. As a result, a modulated signal with controllable odd- and even-order sidebands is generated. By applying the modulated signal to a photodetector, a microwave signal with fully controllable odd- and even-order harmonics is generated, which corresponds to a desired microwave waveform. A theoretical analysis is developed, which is validated by an experiment. A triangular, sawtooth, and square waveform with a repetition rate tunable from 2 to 4 GHz is experimentally generated.
Wound dressing with the capacities of antioxidation, antiinflammation, and efficient angiogenesis induction is expected for effectively promoting wound healing. Herein, a novel core‐shell hyaluronic ...acid (HA) microneedle (MN) patch with ferrum‐mesenchymal stem cell‐derived artificial nanovesicles (Fe‐MSC‐NVs) and polydopamine nanoparticles (PDA NPs) encapsulated in the needle tips is presented for wound healing. Fe‐MSC‐NVs containing multifunctional therapeutic cytokines are encapsulated in the inner HA core of the MN tips for accelerating angiogenesis. The PDA NPs are encapsulated in the outer methacrylated hyaluronic acid (HAMA) shell of the MN tips to overcome the adverse impacts from reactive oxygen species (ROS)‐derived oxidative stress. With the gradual degradation of HAMA patch tips in the skin, the PDA NPs are sustainably released at the lesion to suppress the ROS‐induced inflammation reaction, while the Fe‐MSC‐NVs significantly increase the migration, proliferation, and tube formation of human umbilical vein endothelial cells (HUVEC). More attractively, the combination of PDA NPs and Fe‐MSC‐NVs further promotes M2 macrophage polarization, thereby suppressing wound inflammation. Through in vivo experiment, the Fe‐MSC‐NVs/PDA MN patch shows an excellent effect for diabetic wound healing. These features of antioxidation, antiinflammation, and pro‐angiogenesis indicate the proposed composite core‐shell MN patch is valuable for clinical wound healing applications.
Core‐shell microneedle (MN) patches with ferrum‐mesenchymal stem cell‐derived nanovesicles (Fe‐MSC‐NVs) and polydopamine nanoparticles (PDA NPs) encapsulated in different layers of tips are developed for promoting wound healing. Their desired features of antioxidation, anti‐inflammation, and pro‐angiogenesis indicate that the proposed composite core‐shell MN patches are valuable for comprehensively handling the complicated process in diabetic wound healing.
Photonic signal processing has been considered a solution to overcome the inherent electronic speed limitations. Over the past few years, an impressive range of photonic integrated signal processors ...have been proposed, but they usually offer limited reconfigurability, a feature highly needed for the implementation of large-scale general-purpose photonic signal processors. Here, we report and experimentally demonstrate a fully reconfigurable photonic integrated signal processor based on an InP-InGaAsP material system. The proposed photonic signal processor is capable of performing reconfigurable signal processing functions including temporal integration, temporal differentiation and Hilbert transformation. The reconfigurability is achieved by controlling the injection currents to the active components of the signal processor. Our demonstration suggests great potential for chip-scale fully programmable all-optical signal processing.
A transdermal drug delivery system was prepared by high methoxyl pectin (HMP) or low methoxyl pectin (LMP) coated vitamin C liposomes. HMP coated vitamin C liposomes (HMP-L) and LMP coated vitamin C ...liposomes (LMP-L) exhibited an increase in average diameter (from 66.9 nm to 117.3 nm and 129.6 nm, respectively), a decrease in zeta potential (from -2.3 mV to -23.9 mV and -35.5 mV, respectively), and a similar entrapment efficiency (48.3-50.1%). Morphology and FTIR analysis confirmed that pectin was successfully coated on the surface of vitamin C liposomes mainly through the hydrogen bonding interactions. Besides, HMP-L and LMP-L exhibited an obvious improvement in storage stability, with lower aggregation, oxidation of lipid and leakage ratio of vitamin C from liposomes, and LMP-L showed better physicochemical stability than HMP-L. Moreover, skin permeation of vitamin C was improved 1.7-fold for HMP-L and 2.1-fold for LMP-L after 24 h, respectively, compared with vitamin C nanoliposomes. Therefore, this study suggested that pectin coated liposomes, especially the LMP-L, could be a promising transdermal drug delivery system with better storage stability and skin permeation.
To improve lipid membrane stability and prevent leakage of encapsulated food ingredients, a polyelectrolyte delivery system (PDS) based on sodium alginate (AL) and chitosan (CH) coated on the surface ...of nanoliposomes (NLs) has been prepared and optimized using a layer-by-layer self-assembly deposition technique. Morphology and FTIR observation confirmed PDS has been successfully coated by polymers. Physical stability studies (pH and heat treatment) indicated that the outer-layer polymers could protect the core (NLs) from damage, and PDS showed more intact structure than NLs. Further enzymic digestion stability studies (particle size, surface charge, free fatty acid, and model functional component release) demonstrated that PDS could better resist lipolytic degradation and facilitate a lower level of encapsulated component release in simulated gastrointestinal conditions. This work suggested that deposition of polyelectrolyte on the surface of NLs can stabilize liposomal structure, and PDS could be developed as a formulation for delivering functional food ingredients in the gastrointestinal tract.
Liposomes loaded with positively charged lactoferrin (LF) were prepared from milk fat globule membrane-derived phospholipids using a thin-layer dispersion method. The entrapment efficiency of LF in ...the liposomes and the stability during in vitro gastrointestinal digestion were characterized and examined using dynamic light scattering, transmission electron microscopy, and PAGE. The entrapment efficiency of LF encapsulated in the liposomes was about 46%. The entrapped LF remained unchanged as a function of time and pepsin concentration when the liposome samples were digested in a simulated gastric environment, suggesting that the liposomes prepared from milk fat globule membrane-derived phospholipids were stable and protected the entrapped LF from pepsin hydrolysis. In simulated intestinal fluid, the entrapped LF was more susceptible to hydrolysis by the protease in pancreatin, as shown by changes in the diameter and membrane structure of the liposomes. The release of free fatty acids from the liposomes during digestion in simulated intestinal fluid revealed that the phospholipids in the liposomes were partly hydrolyzed by pancreatic lipase. It was suggested that liposomes may prevent the gastric degradation of LF and reduce the rate of hydrolysis of LF in intestinal conditions.
Frequency quadrupling for tunable microwave and sub-terahertz generation using a single polarization modulator (PolM) in a Sagnac loop without using an optical filter or a wideband microwave phase ...shifter is proposed and experimentally demonstrated. In the proposed system, a linearly polarized continuous wave from a tunable laser source (TLS) is split into two orthogonally polarized optical waves by a polarization beam splitter (PBS) and sent to the Sagnac loop traveling along the clockwise and counter-clockwise directions. A PolM to which a reference microwave signal is applied is incorporated in the loop. The PolM is a traveling-wave modulator, due to the velocity mismatch only the clockwise light wave is effectively modulated by the reference microwave signal, and the counter-clockwise light wave is not modulated. This is the key point that ensures the cancelation of the optical carrier without the need of an optical filter. Along the clockwise direction, the joint operation of the PolM, a polarization controller (PC), and a polarizer corresponds to a Mach-Zehnder modulator (MZM) with the bias point controlled to suppress the odd-order sidebands. The optical carrier is then suppressed by the counter-clockwise light wave at the polarizer. As a result, only two ±2nd-order sidebands are generated, which are applied to a photodetector (PD) to generate a microwave signal with a frequency that is four times that of the reference microwave signal. A theoretical analysis is developed, which is validated by an experiment. A frequency-quadrupled electrical signal with a large tunable range from 2.04 to 100 GHz is generated. The performance of the proposed system in terms of stability and phase noise is also evaluated.
Zn–air battery is considered as one of the most promising candidates for next-generation batteries for energy storage due to safety, high energy density, and low cost. There are many challenges in ...electrolytes for developing high-performance rechargeable Zn–air cells as well as electrocatalysts. An electrolyte is the crucial part of the rechargeable Zn–air batteries that determine their capacity, cycling stability, and lifetime. This paper reviews the most recent progress in designing and fabricating electrolytes in aqueous and flexible Zn–air batteries. The discussion on the surface reaction relationships was covered between air–catalyst–electrolyte and electrolyte–zinc reaction mechanism. We highlight the recent developments of three different electrolytes in zinc–air battery: aqueous electrolyte, room temperature ionic liquid, and quasi-solid flexible electrolyte. Furthermore, the general perspective is proposed for designing and fabricating electrolytes to improve the performance and prolong the lifetime of Zn–air batteries.
In this study, calcium carbonate (CaCO
) microparticles having pH-sensitive properties were loaded with sodium lignosulfonate (SLS), a corrosion inhibitor. Scanning electron microscope (SEM), UV-VIS ...spectrophotometer (UV-vis), X-ray diffraction (XRD), and attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR) were applied to evaluate the properties of the synthetic microparticles. This material could lead to the release of corrosion inhibitor under different pH conditions of the aqueous media. However, the extent of release of the corrosion inhibitor in the acidic media was higher, leading to enhanced shielding effect of the Q235 steel. These microparticles can serve as anti-corrosion additive for epoxy resin-coated Q235 steel. Electrochemical experiments were used to assess the anti-corrosive ability of the epoxy coatings in simulated concrete pore (SCP) solution, confirming the superior corrosion inhibition of the epoxy coating via incorporation of 5 wt % calcium carbonate microparticles loaded with SLS (SLS/CaCO
). The physical properties of coating specimens were characterized by water absorption, contact angle, adhesion, and pencil hardness mechanical tests.
Crude liposomes and nanoliposomes, respectively, formed both from a milk fat globule membrane (MFGM) phospholipid fraction and from soybean phospholipid were prepared by thin layer dispersion and ...dynamic high pressure microfluidization methods. The structure and the integrity of the liposomes were evaluated in terms of average diameter, zeta potential, microstructure, lipolysis, and membrane permeability during in vitro digestion as a function of time. The physical and chemical properties of the liposomes were little influenced in SGF containing pepsin. However, the liposomes exhibited lower stability in simulated intestinal fluid (SIF) than in simulated gastric fluid (SGF). The liposomes obtained from the MFGM phospholipid fraction were more stable than the soybean-based liposomes, with less change in average diameter, surface charge, morphology, and free fatty acid release, and better membrane integrity during digestion in SIF. However, no differences in the stability between nanoliposomes and crude liposomes were observed during digestion. These results systematically demonstrated the relationship between the stability of liposomes and in vitro digestion, and provided some information for further developing more stable liposomes in the gastrointestinal tract.
► Crude liposomes and nanoliposomes formed with MFGM or soybean phospholipid fraction. ► The structure and integrity of liposomes were evaluated during in vitro digestion. ► The physical and chemical properties of liposomes were little influenced in SGF. ► Liposomes exhibited lower stability in simulated intestinal fluid (SIF). ► The MFGM liposomes were more stable than the soybean phospholipid liposomes.
PDF
