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A human vestibular system is a group of devices in the inner ear that govern the balancing movement of the head, in which the saccule is responsible for sensing gravity accelerations. Imitating the sensing principle and structure of the Sensory Hair (SH) cell in the saccule, a Bionic Sensory Hair (BSH) was developed, and 9 BSH arrays were arranged in the bionic macular at the bottom of the spherical shell to prepare a Bionic Saccule (BS). Based on the piezoelectric equation, the electromechanical theoretical models of the BSH cantilever and BS were deduced. They were subjected to impact oscillations using an exciter, and their output charges were analyzed to check their sensing ability. The results showed that BSH could sense its bending deflection, and the BS could sense its position change in the sagittal plane and in space. They exhibited a sensitivity of 1.6104 Pc s2/m and a fast response and similar sensing principles and low resonance frequency to those of the human saccule. The BS is expected to be used in the field of robotics and clinical disease diagnosis as a part of the artificial vestibular system in the future. [ABSTRACT FROM AUTHOR]

To date, there are three main hypotheses explaining why the human semicircular canals (HSCCs) cannot sense linear accelerations. To further study this issue, we designed a bionic ampulla (BA) instrumented with a symmetrical metal core polyvinylidene fluoride fiber as a bionic sensor, which imitates the structure and function of the human ampulla. The BA was confirmed to have a good sensing ability in experiments with a straight tube. Additionally, we designed a bionic semicircular canal model, a blocking model, and a square model. We compared the perception performance of these three models to test the "density hypothesis," the "closed loop hypothesis," and the "circular hypothesis." The outcomes of these experiments verified the "density hypothesis" and "circular hypothesis," but did not support the "closed loop hypothesis," shedding light on why the HSCC is sensitive to angular acceleration, but not to linear acceleration. [ABSTRACT FROM AUTHOR]

Recently, the CNC/GEL (cellulose nanocrystals/gelatin) composite hydrogel has been used as a biomaterial for 3D printing of tissue engineering scaffolds. Rheological properties of hydrogel have been regarded as one of the most important factors affecting printing quality, especially the viscosity recover time. However, there is still a lack of comprehensive research on the rheology property of the CNC/GEL hydrogel in the process of 3D printing. In this study, the CNC was isolated from Humulus japonicus, and a CNC/GEL hydrogel system was prepared. The rheological properties of CNC/GEL hydrogel were evaluated using a rotary rheometer. The viscosity recovery time of the CNC/GEL hydrogel was measured using a special method. The optimal ratio of hydrogel was obtained by rheology experiment and mechanical test. The flow field distribution of the hydrogel in the flow passage of 3D printer was analyzed using fluent simulation. The rheological parameters of a hydrogel can be adjusted by changing the printing conditions. Thus, the effect of printing conditions on the formation of CNC/GEL filaments was also investigated. Finally, the biocompatibility of the printed CNC/GEL scaffold after crosslinking treatment was verified using CCK-8 and Hoechst 33342/PI double-staining assays. The present study shows a new approach for the analysis of rheological properties of CNC/GEL and also provides some suggestions for 3D printing of CNC/GEL scaffolds. [ABSTRACT FROM AUTHOR]

An electronic skin (ES) is developed by embedding a liquid-core poly(vinylidene fluoride) fiber into a silicone rubber. The experimental results show that the ES can detect the waveform, frequency, amplitude, and other parameters of the surface vibration pressure. The ES can sense the surface pressure amplitude over a range of 1.5–2.5 kPa and exhibits a sensitivity of 0.0472 fC/Pa when the pressure is less than 60 Pa. The resonant frequency of the ES is 0.4 Hz. The ES can also detect the elongation strain, and its sensitivity is 0.0058 fC/με. The ES has the characteristics of flexibility, high sensitivity, and a wide measuring range. Therefore, the ES can be used as a robot finger skin, which enables the robot to have touch perception capabilities. [ABSTRACT FROM AUTHOR]

Early reports have demonstrated the feasibility of oxidized dextran/gelatin (OD/GEL) hydrogel for tissue engineering applications and the printability of OD/GEL hydrogel for 3D printing scaffolds, but adequate insight into fabricated OD/GEL scaffolds is lacking. In the present study, we prepared (cellulose nanocrystal) CNC/OD/GEL hydrogels and fabricated CNC/OD/GEL scaffolds by 3D printing. The properties of CNC/OD/GEL hydrogels were investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. The process of 3D printing of hydrogels was optimized, and the influence of the OD and CNC contents on the printability of CNC/OD/GEL hydrogels was investigated by studying the width of the printed filaments. The uniaxial compression test was performed to study the effects of the OD and CNC contents on the breaking strength and elastic modulus of CNC/OD/GEL scaffolds. In addition, the uniaxial compression test was also performed to determine the optimum mass ratio and crosslinking time of OD and GEL. The effects of the CNC content on scaffold shrinkage, scaffold swelling and scaffold porosity were further studied. The biocompatibility of a CNC0.4OD2G2 scaffold was also investigated by Cell Counting Kit-8 (CCK-8) and Hoechst 33342/PI double-staining assays. Collectively, the results confirmed the good potential of the CNC/OD/GEL hydrogels as 3D bioink for application in tissue repair. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing, used to fabricate modular and patient-specific scaffolds with high structural complexity and design flexibility, has drawn wide attentions in the tissue engineering area. However, one of the key problems hindering the application and development of 3D printing in TE area is the poor mechanical property of bio-inks. In this work, we aimed to design a high-strength hydrogel system based on dialdehyde cellulose nanocrystals (DAC) and gelatin (GEL) as a new bio-ink for 3D printing of scaffolds. The DAC were prepared and used as a natural crosslinker to interact with the GEL through a Schiff base reaction. The mechanical test results indicated that the breaking strength of the optimal 4:8-DAC/GEL sample was almost 41.3-fold greater than that of the GEL hydrogel. According to the rheological test results, the 4:8-DAC/GEL sample incubated for 3 h was proposed as a bio-ink for 3D printing. Then, the printing conditions, including the printing pressure and nozzle speed, as well as additional crosslinking conditions for a freshly printed scaffold, i.e., the crosslinking time and temperature, were optimized. Crosslinked scaffolds with adjustable porosity and good fidelity were successfully obtained. The biocompatibility of 4:8-DAC/GEL was also investigated by CCK-8 and Hoechst 33342/PI double-staining assays. Collectively, these results confirm the good potential of the 4:8-DAC/GEL hydrogel as a 3D bio-ink for application in tissue repair. [ABSTRACT FROM AUTHOR]

As one of the most abundant wild herbs in nature, the Humulus japonicus stem (HJS) is a new low-cost source of cellulosic material. In this work, cellulose nanocrystals (CNCs) were isolated from HJS using acid hydrolysis. The influence of high temperature pretreatment (HT pretreatment) on the properties and yields of these HT-HJS (HJS fibers after HT pretreatment at different temperatures) and HT-CNCs (CNCs prepared from the HT-HJS) was studied. The results showed that there was no variation of the chemical structure among the HT-HJS and HT-CNCs. The thermal stabilities and crystallinities of the HT-HJS were higher than bleached HJS. The average diameters of the HT-CNCs were significantly smaller while the average aspect ratios of them were obviously bigger than the CNCs, and the biggest average aspect ratio of HT140-CNCs (63.40) was almost twice of CNCs (32.00). Compared with the CNCs (70.05%, 212.8 °C), the crystallinity and initial degradation temperature also showed increase for the HT-CNCs and increased up to maximum of 86.93% and 227.5 °C for the HT160-CNCs. [ABSTRACT FROM AUTHOR]

Danggui Buxue Decoction is a classic formula for replenishing qi and nourishing blood. Despite its widespread use, its dynamic metabolism involved remains unclear. Based on the sequential metabolism strategy, blood samples from different metabolic sites were obtained via in situ closed intestine ring integrated with a jugular venous continuous blood supply technique. An ultra‐high‐performance liquid chromatography‐linear triple quadruple‐Orbitrap‐tandem mass spectrometry method was developed for the identification of prototypes and metabolites in rat plasma. The dynamic absorption and metabolic landscape of flavonoids, saponins, and phthalides were characterized. Flavonoids could be deglycosylated, deacetylated, demethylated, dehydroxylated, and glucuronicated in the gut and then absorbed for further metabolism. Jejunum is an important metabolic site for saponins biotransformation. Saponins that are substituted by Acetyl groups tend to lose their acetyl groups and convert to Astragaloside IV in the jejunum. Phthalides could be hydroxylated and glucuronidated in the gut and then absorbed for further metabolism. Seven components serve as crucial joints in the metabolic network and are potential candidates for the quality control of Danggui Buxue Decoction. The sequential metabolism strategy described in this study could be useful for characterizing the metabolic pathways of Chinese medicine and natural products in the digestive system. [ABSTRACT FROM AUTHOR]

For tissue engineering applications tissue scaffolds need to have a porous structure to meet the needs of cell proliferation/differentiation, vascularisation and sufficient mechanical strength for the specific tissue. Here we report the results of a study of the 3D printing process for composite materials based on oxidized nanocellulose and gelatin, that was optimised through measuring rheological properties of different batches of materials after different crosslinking times, simulation of the pneumatic extrusion process and 3D scaffolds fabrication with Solidworks Flow Simulation, observation of its porous structure by SEM, measurement of pressure-pull performance, and experiments aimed at finding out the vitro cytotoxicity and cell morphology. The materials printed are highly porous scaffolds with good mechanical properties. [ABSTRACT FROM AUTHOR]

Objective To use the high-performance liquid chromatography (HPLC) method and desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) method to study the dynamic accumulation and distribution of secondary metabolites of Coptis chinensis in different growth years. Methods Using the samples of one-, three-, and five-year Coptis chinensis as the research object, the HPLC method was used to determine the contents of seven index components (jatrorrhizine hydrochloride, columbamine, epiberberine, coptisine hydrochloride, palmatine hydrochloride, berberine hydrochloride, and magnoflorine) as the secondary metabolites of Coptis chinensis. Further, the distribution of seven index components in the one-, three- and five-year Coptis chinensis slices were qualitatively analyzed by using the DESI-MSI method. Results The HPLC result showed that the contents of berberine hydrochloride and palmatine hydrochloride, jatrorrhizine hydrochloride, columbamine, and magnoflorine in five-year Coptis chinensis were the highest; coptisine hydrochloride and epiberberine reached the highest level in 3- year Coptis chinensis, while the contents of magnoflorine and jatrorrhizine hydrochloride were the lowest in three-year Coptis chinensis; and berberine hydrochloride, palmatine hydrochloride, columbamine, epiberberine, and coptisine hydrochloride were the lowest in one-year Coptis chinensis. The hydrochloride of each alkaloid was dissociated in the process of mass spectrometry and appeared in the prototype form. The result obtained by the DESI-MSI method show that berberine and epiberberine were concentrated in the whole-slices section, the distribution area of the one-year sample was the smallest, and the distribution areas of the three- and five-year samples were similar. Jatrorrhizine and columbamine were distributed in the phloem and pith, and the five-year sample distribution area was the largest; palmatine and coptisine were distributed in the phloem and pith, and the one-year sample distribution area was the smallest. Magnoflorine was only distributed in the wood, and the distribution areas in the one-, three-, and five-year Coptis chinensis were similar. Conclusion The accumulation of secondary metabolites in the one-year samples was the least, indicating that the first year is the main stage of the growth and development of Coptis chinensis. The accumulation of secondary metabolites of three-year samples was higher than those of the one-year sample, indicating that the following one to two years are the main stage for the accumulation of secondary metabolites of Coptis chinensis. The five-year plant sample had the highest content of total components, and berberine accumulated the most, which is consistent with the market usage rules of Coptis chinensis being cultivated for at least five years. [ABSTRACT FROM AUTHOR]

To study the sensing process of the human semicircular canals (HSCs) during head rotation, which is difficult to directly measure due to physiological reasons. A 1-BSC (one-dimensional bionic semicircular canal) and 3-BSC were prepared with soft SMPFs (symmetric electrode metal core polyvinylidene difluoride fibers), which could sense deformations similar to human sensory cells. Based on these models, experiments were carried out to study the principle of the HSCs. Deformations of the bionic ampulla (BA) depended on the angular acceleration. Gravity had a strong influence on the deformation of the BA in the vertical plane. When the 3-BSC was subjected to angular acceleration around one of its centerlines, the three BAs all deformed. The deformation of the BAs was linearly related to the angular acceleration. The deformation of the BA in the main semicircular canal was exactly three times that of the other two BAs. [ABSTRACT FROM AUTHOR]

[Display omitted] • ATR-FTIR and 2DCOS were combined to study the volatilization of microemulsions. • Different volatilization stages can be segmented by PCA and moving-window 2DCOS. • The successive volatilizations of ethanol, water and menthone were observed. • Microemulsion with peppermint essential oil and composite herbal extract is feasible. Microemulsion is usually a transparent and isotropic liquid mixture composed of oil phase, water phase, surfactant and cosurfactant. The surfactant-framed nanoscale droplets in the microemulsion can penetrate into the skin surface to reduce its barrier function. This makes microemulsion an ideal preparation for the transdermal drug delivery. The permeability of microemulsion may be further enhanced when botanical essential oils that can dissolve the stratum corneum are used as the oil phase. However, the volatility of essential oils is possible to shorten the retention time of the microemulsion on the skin surface. Therefore, analytical methods are required to understand the volatilization process of the microemulsion composed of essential oils to develop the reasonable topical drug carrier system. In this research, Fourier transform infrared (FTIR) spectroscopy with an attenuated total reflection (ATR) accessory cooperated with two-dimensional correlation spectroscopy (2DCOS) to elucidate the volatilization processes of some microemulsions composed of peppermint essential oil. Principal component analysis (PCA) and moving-window two-dimensional correlation spectroscopy (MW2DCOS) revealed the multiple stages of the volatilization processes of the microemulsions. Synchronous 2D correlation infrared spectra indicated the compositional changes during each stage. It was found that the successive volatilizations of ethanol, water and menthone were the major events during the volatilization process of the microemulsion composed of peppermint essential oil. Ethanol can accelerate the volatilization of water, while the composite herbal extract seemed to not influence the volatilization of the other ingredients. After a 20-min-long volatilization process, the remaining microemulsion still contained considerable peppermint essential oil to affect the skin. The above results showed the feasibility of developing the microemulsion composed of peppermint essential oil for the transdermal drug delivery of composite herbal extract. This research also proved that the combination of ATR-FTIR spectroscopy and 2DCOS was valuable to study the volatilization process of the microemulsion. [ABSTRACT FROM AUTHOR]

Tissue scaffolds need to have anisotropic mechanical properties and a porous structure to meet the needs of different tissues and organs. This report presents results of a study on an especially-designed 3D printing method with oxidized nanocellulose and gelatin, analyzes the servo principle of pneumatic condensing extrusion 3D printer, and proposes a hexagonal algorithm. For the purpose of this study, a printing process file was written by G code, physical and mechanical performance of the 3D scaffolds was evaluated with Solidworks simulation, the porous structure and pressure-pull performance of the printed 3D scaffolds was observed by SEM, and experiments were conducted to measure their bio-compatibility. The study draws the conclusion that scaffolds thus printed have a highly porous structure and anisotropic mechanical properties. [ABSTRACT FROM AUTHOR]

Coptis chinensis Franch. (CC), as a commonly used heat-clearing and toxin-resolving traditional Chinese herbal medicine, has gained increased attention for its anti-tumor activity. However, little is known about the anti-tumor angiogenesis effect of CC and its possible bioactive components. Also, it has been shown that temperature affects the quality of CC, albeit whether and how it affects the anti-angiogenic activity of CC is currently unknown. To determine the processing temperatures (40, 60, 80, 120, 140, 150, 160 and 200 °C) at which CC has the strongest anti-angiogenic effect and speculate the possible bioactive components. The q-CAM model was constructed to explore the anti-angiogenesis agents of CC. The angiogenesis inhibition effects of CC samples at different processing temperatures and its seven alkaloids were determined based on morphological observation and vascular area proportion analysis. UPLC-MS/MS was employed to screen the potent active components of CC on anti-angiogenesis. All the intervention by CC at different processing temperatures and its seven alkaloids could inhibit angiogenesis on q-CAM vessels, as evidenced by a poor vasular development in morphological observation and a low vascular area proportion in vascular quantitative analysis, most evident in CC processed at 40 °C and palmatine. LC-MS revealed that palmatine displayed strongest inhibitory effect on q-CAM vessels with a high absorption due to its stable structure. And the maternal nucleus transformation phenomenon of CC alkaloids was found in the quail embryo metabolism. The q-CAM models in conjunction with the UPLC-MS/MS technique could be a useful tool for assessing tumor angiogenesis and screening tumor-targeted medicines. Processing temperature can affect the anti-angiogenesis effect of CC because of its function on the content of alkaloids, and palmatine can be considered as a prospective anti-angiogenic drug. [Display omitted] • New sight on q-CAM models with UPLC-MS/MS for angiogenesis studies. • Temperature affect the anti-angiogenesis efficacy of Coptis chinensis. • In-depth analysis of alkaloids on vessels; palmatine inhibits angiogenesis better. • Performance of the metabolic transformation between protoberberine alkaloids. [ABSTRACT FROM AUTHOR]

Stigmatellin A, a natural product with a chromone ring structure, is a specific inhibitor of the mitochondrial respiratory chain cytochrome bc 1 complex at the Q o site. In the last two decades, researchers have carried out extensive and in-depth organic synthesis studies and biological evaluations of this molecule. Herein, we review the recent progress on the synthesis and structural modification of stigmatellin A and its application in fungicide discovery. This review is expected to provide valuable clues for the synthesis of natural products that contain the chromone motif. Stigmatellin A, a natural product bearing a chromone moiety as the core skeleton, has been identified as a representative inhibitor that binds to the Q o site of the cytochrome bc 1 complex. Due to its unique structure and diverse biological activities, numerous researchers have conducted systematic and extensive investigations. This paper mainly described the development and biological activities of stigmatellin A, and then summarized the recent results of its synthesis and structural modifications. [Display omitted] [ABSTRACT FROM AUTHOR]