Transcriptomic analysis revealing the molecular response to arsenic stress in desert Eremostachys moluccelloides Bunge.

The saline, alkaline environment of arid soils is conducive to the diffusion of the metalloid arsenic (As). Desert plants in this area are of great ecological importance and practical value. However, there are few studies on the mechanism of arsenic action in desert plants. Therefore, in this study, Eremostachys moluccelloides Bunge was treated with different concentrations of As2O5 [As(V)] to analyze the physiological, biochemical, and transcriptomic changes of its roots and leaves and to explore the molecular mechanism of its response to As(Ⅴ) stress. The activities of catalase, superoxidase, peroxidase, and the contents of malondialdehyde and proline in roots and leaves first increased and then decreased under the As(Ⅴ) stress of different concentrations. The content of As was higher in roots than in leaves, and the As content was positively correlated with As(Ⅴ) stress concentration. In the differentially expressed gene analysis, the key enzymes of the oxidative stress response in roots and leaves were significantly enriched in the GO classification. In the KEGG pathway, genes related to the abscisic acid signal transduction pathway were co-enriched and up-regulated in roots and leaves. The related genes in the phenylpropanoid biosynthesis pathway were significantly enriched and down-regulated only in roots. In addition, the transcription factors NAC, HB-HD-ZIP, and NF-Y were up-regulated in roots and leaves. These results suggest that the higher the As(V) stress concentration, the more As is taken up by roots and leaves of E. molucelloides Bunge. In addition to causing greater oxidative damage, this may interfere with the production of secondary metabolites. Moreover, it may improve As(V) tolerance by regulating abscisic acid and transcription factors. The results will deepen our understanding of the molecular mechanism of As(Ⅴ) response in E. moluccelloides Bunge, lay the foundation for developing and applying desert plants, and provide new ideas for the phytoremediation of As pollution in arid areas.

Multifunctional Integrated Interdigital Microsupercapacitors and Self-Powered Iontronic Tactile Pressure Sensor for Wearable Electronics.

Multifunctionality and self-powering are key technologies for next-generation wearable electronics. Herein, an interdigitated MXene/TiS2-based self-powered intelligent pseudocapacitive iontronic sensor system is designed, realizing integration of energy storage and pressure-sensitive sensing function into one device. The intercalation of TiS2 nanosheet can effectively prevent self-stacking of MXene and results in mesoporous cross-linked framework, therefore exposing more active sites and broadening the electron/ion transport channels. The pressure sensing performance together with developed all-solid-state microsupercapacitor is explored systematically. When applied in a symmetrical microsupercapacitor, it presents a satisfactory energy density of 31.6 Wh/kg at 400 W/kg and 79.8% capacitance retention after 10 000 cycles. Meanwhile, with MXene/TiS2//MXene/TiS2 interdigitated structure as flexible self-powering pressure sensor, it illustrates outstanding pressure-sensing response toward external pressure, realizing accurate and continuous detection of human body motion signals. It is believed that this work proposes a feasible strategy by integrating pressure-sensing with a self-powering function for the next-generation self-powered E-skin electronics.

Three-dimensional printed lithium iron phosphate coated with magnesium oxide cathode with improved areal capacity and ultralong cycling stability for high performance lithium-ion batteries.

Three-dimensional (3D) printing of Li-ion batteries with unconventional 3D electrodes has attracted considerable attention in recent years. However, fabricating 3D electrodes with high specific capacity, high areal capacity, ultralong cycling stability, and improved rate performance remains a challenge to date. Novel 3D grid-patterned LiFePO4@MgO composite electrodes with thicknesses of 143, 306, and 473 µm were fabricated via 3D printing. The electrochemical performance of half cells was evaluated. The 3D-printed LiFePO4@MgO (143 µm) electrodes exhibit stable specific capacities of 142.8 mAh g-1 @ 1.0 C and 90.3 mAh g-1 @ 10.0 C after 800 and 1700 cycles, respectively. In addition, the 473 µm-thick 3D grid-patterned LiFePO4@MgO achieves an areal capacity of 3.01 mAh cm-2 @ 0.1 C after 20 cycles. The full cells comprised 143 µm-thick 3D-printed LiFePO4@MgO, and 217 µm Li4Ti5O12 electrodes show a capacity of 139.0 mAh g-1 @ 1.0 C after 400 cycles. These results indicate that, this type of thick 3D-printed LiFePO4@MgO electrode achieves high capacity, high-rate capability, and ultralong cycle stability. The outstanding performance ascribes the fast electrolyte infusion of 3D-printed electrodes and the enhanced electronic/ionic transport.

Engineering Homochiral MOFs in TiO2 Nanotubes as Enantioselective Photoelectrochemical Electrode for Chiral Recognition.

Enantioselective sensing of chiral molecules is an important issue for both biomedical research and the pharmaceutical industry. Here, an enantioselective photoelectrochemical (PEC) sensor was constructed by integrating TiO2 nanotubes (NTs) with metal-organic frameworks (MOFs) for the identification of enantiomers. TiO2 NTs prepared by electrochemical anodization can not only be used as the PEC platform but also as the metal-ion precursor to react with terephthalic acid (BDC) to form MIL-125(Ti) in situ. A postsynthetic exchange (PSE) method was used for exchanging the ligand of MIL-125 by 2-aminoterephthalic acid (BDC-NH2) for further functionalization. Homochirality was then successfully introduced into achiral MIL-125-NH2 by postsynthetic modification (PSM) with l-histidine (l-His). The resulting homochiral metal-organic frameworks (MOF)-in-NT architecture exhibits excellent discrimination ability for the chiral recognition of 3,4-dihydroxyphenylalanine (l/d-DOPA) enantiomers. Moreover, by adjusting the charge-carrier separation-induced photocurrent variation mechanism, the as-proposed homochiral PEC electrode exhibits a broad application potential for the discrimination of enantiomers. Because of the construction of binder-free monochiral MOF-in-NT structure directly on a Ti-metal substrate, the valuable feature is that the PEC sensing platform can be used directly, thereby providing a stable, simplified, and low-cost sensing device for the recognition of chiral enantiomers.

Tunable plasmonic filter based on parallel bulk Dirac semimetals at terahertz frequencies.

A plasmonic bandpass filter based on parallel bulk Dirac semimetals (BDSs) is proposed and numerically investigated using the finite-difference time-domain method. The proposed filter is realized by the evanescent coupling between the resonator and waveguide, and Fabry-Parot resonant theory is used to analyze its realization mechanism. The performance of the filter can be tuned by changing the coupling distance, length of the resonator, and Fermi levels of the BDSs. We further simulate a plasmonic broadband filter using coupling mode splitting by locating two identical resonators along the waveguide direction. The pass band of the proposed broadband filter can be tuned by adjusting the coupling distances between the resonators and waveguide.

Fiber reinforced GelMA hydrogel to induce the regeneration of corneal stroma.

Regeneration of corneal stroma has always been a challenge due to its sophisticated structure and keratocyte-fibroblast transformation. In this study, we fabricate grid poly (ε-caprolactone)-poly (ethylene glycol) microfibrous scaffold and infuse the scaffold with gelatin methacrylate (GelMA) hydrogel to obtain a 3 D fiber hydrogel construct; the fiber spacing is adjusted to fabricate optimal construct that simulates the stromal structure with properties most similar to the native cornea. The topological structure (3 D fiber hydrogel, 3 D GelMA hydrogel, and 2 D culture dish) and chemical factors (serum, ascorbic acid, insulin, and ß-FGF) are examined to study their effects on the differentiation of limbal stromal stem cells to keratocytes or fibroblasts and the phenotype maintenance, in vitro and in vivo tissue regeneration. The results demonstrate that fiber hydrogel and serum-free media synergize to provide an optimal environment for the maintenance of keratocyte phenotype and the regeneration of damaged corneal stroma.

A Novel Strategy for Creating Tissue-Engineered Biomimetic Blood Vessels Using 3D Bioprinting Technology.

In this work, a novel strategy was developed to fabricate prevascularized cell-layer blood vessels in thick tissues and small-diameter blood vessel substitutes using three-dimensional (3D) bioprinting technology. These thick vascularized tissues were comprised of cells, a decellularized extracellular matrix (dECM), and a vasculature of multilevel sizes and multibranch architectures. Pluronic F127 (PF 127) was used as a sacrificial material for the formation of the vasculature through a multi-nozzle 3D bioprinting system. After printing, Pluronic F127 was removed to obtain multilevel hollow channels for the attachment of human umbilical vein endothelial cells (HUVECs). To reconstruct functional small-diameter blood vessel substitutes, a supporting scaffold (SE1700) with a double-layer circular structure was first bioprinted. Human aortic vascular smooth muscle cells (HA-VSMCs), HUVECs, and human dermal fibroblasts⁻neonatal (HDF-n) were separately used to form the media, intima, and adventitia through perfusion into the corresponding location of the supporting scaffold. In particular, the dECM was used as the matrix of the small-diameter blood vessel substitutes. After culture in vitro for 48 h, fluorescent images revealed that cells maintained their viability and that the samples maintained structural integrity. In addition, we analyzed the mechanical properties of the printed scaffold and found that its elastic modulus approximated that of the natural aorta. These findings demonstrate the feasibility of fabricating different kinds of vessels to imitate the structure and function of the human vascular system using 3D bioprinting technology.

Capacitive Pressure Sensor with High Sensitivity and Fast Response to Dynamic Interaction Based on Graphene and Porous Nylon Networks.

Flexible pressure sensors are of great importance to be applied in artificial intelligence and wearable electronics. However, assembling a simple structure, high-performance capacitive pressure sensor, especially for monitoring the flow of liquids, is still a big challenge. Here, on the basis of a sandwich-like structure, we propose a facile capacitive pressure sensor optimized by a flexible, low-cost nylon netting, showing many merits including a high response sensitivity (0.33 kPa-1) in a low-pressure regime (<1 kPa), an ultralow detection limit as 3.3 Pa, excellent working stability after more than 1000 cycles, and synchronous monitoring for human pulses and clicks. More important, this sensor exhibits an ultrafast response speed (<20 ms), which enables its detection for the fast variations of a small applied pressure from the morphological changing processes of a droplet falling onto the sensor. Furthermore, a capacitive pressure sensor array is fabricated for demonstrating the ability to spatial pressure distribution. Our developed pressure sensors show great prospects in practical applications such as health monitoring, flexible tactile devices, and motion detection.

Construction of bionic tissue engineering cartilage scaffold based on three-dimensional printing and oriented frozen technology.

Articular cartilage (AC) has gradient features in both mechanics and histology as well as a poor regeneration ability. The repair of AC poses difficulties in both research and the clinic. In this paper, a gradient scaffold based on poly(lactic-co-glycolic acid) (PLGA)-extracellular matrix was proposed. Cartilage scaffolds with a three-layer gradient structure were fabricated by PLGA through three-dimensional printing, and the microstructure orientation and pore fabrication were made by decellularized extracellular matrix injection and directional freezing. The manufactured scaffold has a mechanical strength close to that of real cartilage. A quantitative optimization of the Young's modulus and shear modulus was achieved by material mechanics formulas, which achieved a more accurate mechanical bionic and a more stable interface performance because of the one-time molding process. At the same time, the scaffolds have a bionic and gradient microstructure orientation and pore size, and the stratification ratio can be quantitatively optimized by design of the freeze box and temperature simulation. In general, this paper provides a method to optimize AC scaffolds by both mechanics and histology as well as a bionic multimaterial scaffold. This paper is of significance for cell culture and clinical transplantation experiments. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1664-1676, 2018.

3D Printing Technologies for Flexible Tactile Sensors toward Wearable Electronics and Electronic Skin.

3D printing has attracted a lot of attention in recent years. Over the past three decades, various 3D printing technologies have been developed including photopolymerization-based, materials extrusion-based, sheet lamination-based, binder jetting-based, power bed fusion-based and direct energy deposition-based processes. 3D printing offers unparalleled flexibility and simplicity in the fabrication of highly complex 3D objects. Tactile sensors that emulate human tactile perceptions are used to translate mechanical signals such as force, pressure, strain, shear, torsion, bend, vibration, etc. into electrical signals and play a crucial role toward the realization of wearable electronics and electronic skin. To date, many types of 3D printing technologies have been applied in the manufacturing of various types of tactile sensors including piezoresistive, capacitive and piezoelectric sensors. This review attempts to summarize the current state-of-the-art 3D printing technologies and their applications in tactile sensors for wearable electronics and electronic skin. The applications are categorized into five aspects: 3D-printed molds for microstructuring substrate, electrodes and sensing element; 3D-printed flexible sensor substrate and sensor body for tactile sensors; 3D-printed sensing element; 3D-printed flexible and stretchable electrodes for tactile sensors; and fully 3D-printed tactile sensors. Latest advances in the fabrication of tactile sensors by 3D printing are reviewed and the advantages and limitations of various 3D printing technologies and printable materials are discussed. Finally, future development of 3D-printed tactile sensors is discussed.

Fabrication and Characterization of 3D-Printed Highly-Porous 3D LiFePO4 Electrodes by Low Temperature Direct Writing Process.

LiFePO4 (LFP) is a promising cathode material for lithium-ion batteries. In this study, low temperature direct writing (LTDW)-based 3D printing was used to fabricate three-dimensional (3D) LFP electrodes for the first time. LFP inks were deposited into a low temperature chamber and solidified to maintain the shape and mechanical integrity of the printed features. The printed LFP electrodes were then freeze-dried to remove the solvents so that highly-porous architectures in the electrodes were obtained. LFP inks capable of freezing at low temperature was developed by adding 1,4 dioxane as a freezing agent. The rheological behavior of the prepared LFP inks was measured and appropriate compositions and ratios were selected. A LTDW machine was developed to print the electrodes. The printing parameters were optimized and the printing accuracy was characterized. Results showed that LTDW can effectively maintain the shape and mechanical integrity during the printing process. The microstructure, pore size and distribution of the printed LFP electrodes was characterized. In comparison with conventional room temperature direct ink writing process, improved pore volume and porosity can be obtained using the LTDW process. The electrochemical performance of LTDW-fabricated LFP electrodes and conventional roller-coated electrodes were conducted and compared. Results showed that the porous structure that existed in the printed electrodes can greatly improve the rate performance of LFP electrodes.

Retinoic Acid promotes interleukin-4 plasmid-dimethylsulfoxide topical transdermal delivery for treatment of psoriasis.

BACKGROUND: Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1-dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. OBJECTIVE: We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14-VEGF) factor transgenic mice. METHODS: After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice. RESULTS: The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced. CONCLUSION: Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly.

On the constitutive model of nitrogen-containing austenitic stainless steel 316LN at elevated temperature.

The nitrogen-containing austenitic stainless steel 316LN has been chosen as the material for nuclear main-pipe, which is one of the key parts in 3rd generation nuclear power plants. In this research, a constitutive model of nitrogen-containing austenitic stainless steel is developed. The true stress-true strain curves obtained from isothermal hot compression tests over a wide range of temperatures (900-1250°C) and strain rates (10(-3)-10 s(-1)), were employed to study the dynamic deformational behavior of and recrystallization in 316LN steels. The constitutive model is developed through multiple linear regressions performed on the experimental data and based on an Arrhenius-type equation and Zener-Hollomon theory. The influence of strain was incorporated in the developed constitutive equation by considering the effect of strain on the various material constants. The reliability and accuracy of the model is verified through the comparison of predicted flow stress curves and experimental curves. Possible reasons for deviation are also discussed based on the characteristics of modeling process.

Development of a novel low-temperature deposition machine using screw extrusion to fabricate poly(l-lactide-co-glycolide) acid scaffolds.

Scaffolds are of great importance to the success of tissue engineering. Poly(l-lactide-co-glycolide) acid is one of the most commonly used biopolymers. This study develops a novel low-temperature deposition machine using screw extrusion to fabricate poly(l-lactide-co-glycolide) acid scaffolds. The screw extrusion process of poly(l-lactide-co-glycolide) acid is analysed, and the relationship between flow rate and processing parameters is examined. This relationship provides guidelines for optimizing the processing parameters. The major components and design strategy of the fabrication system are introduced. Measures are proposed to control the leakage of materials, and optimal processing parameters are determined. The machine is also equipped with a double-screw extrusion nozzle system; preliminary results demonstrate its capacity to fabricate gradient scaffolds. Porous structure characterization using mercury porosimetry demonstrates that the fabrication system is able to fabricate poly(l-lactide-co-glycolide) acid scaffolds that are both macroporous and microporous.

A novel transdermal plasmid-dimethylsulfoxide delivery technique for treatment of psoriasis.

BACKGROUND: Psoriasis is a chronic and relapsing inflammatory skin disease associated with various immunologic abnormalities. Repeated subcutaneous injection of interleukin-4 (IL-4) has been established as an effective treatment to counteract psoriasis. OBJECTIVE: We investigated whether gene therapy using IL-4 expression plasmid (pIL-4) via transdermal delivery was an alternative treatment for psoriasis. In our experiment, dimethylsulfoxide (DMSO) was used as a penetration enhancer. METHODS: At first, the penetration efficiency of the complex of reporter plasmid accompanied by DMSO was investigated both in vitro and in vivo. Then, the antipsoriasis efficiency of the treatment with pIL-4-DMSO was tested in mice. RESULTS: The expression of the reporter gene was detected in epidermis and dermis both in vitro and in vivo. More importantly, the psoriasis symptoms were relieved, and significant reductions in some psoriasis-associated factors were observed after pIL-4-DMSO treatment. CONCLUSION: We conclude that the topical application of pIL-4-DMSO can treat psoriasis to a significant extent.

Retinoic acid and dimethyl sulfoxide promote efficient delivery of transgenes to mouse skin by topically transdermal penetration.

Simple and efficient gene transfer to the skin would facilitate many local and systemic gene therapy applications. This study reports a novel approach that allows expression of plasmid DNA in epidermis and hair follicle cells with dimethyl sulfoxide (DMSO) after pre-treatment with depilation and retinoic acid (RA) for the purposes of gene therapy. This study investigated the transdermal efficacy of gene to mouse skin when utilizing DMSO after RA pre-treatment. Retinoic acid pre-treatment can increase the efficiency of transfection. This finding indicates that one can more effectively and much less expensively make use of genes therapy to treat diseases of the hair and skin.