Poly(vinyl alcohol) (PVA) can form intramolecular and intermolecular hydrogen bonds (H-bonds) within themselves or with others. These H-bonds exhibit remarkable influence on the nature of PVA, but ...the details about their respective effects are still unclear. Herein, the effect of intramolecular H-bonds on the single-chain elasticity of PVA has been studied by single-molecule atomic force microscopy (AFM) in the absence of intermolecular H-bonds. The average energy of intramolecular H-bonds has a positive correlation with the degree of alcoholysis (DA) of PVA, suggesting that there is a synergistic enhancement effect between the intramolecular H-bonds. Moreover, the higher the DA, the stronger the synergistic effect. Such a strong synergistic effect on PVA with a high DA may be the key factor to its low water solubility at room temperature. It is expected that this study will lay the foundation for future research on the influence of intermolecular H-bonds on the properties of PVA.
Ischemic stroke, producing a high mortality and morbidity rate, is a common clinical disease. Enhancing the prevention and control of ischemic stroke is particularly important. Baicalin and its ...aglycon baicalein are flavonoids extracted from
, an important traditional Chinese herb. In recent years, a growing body of evidences has shown that baicalin and baicalein could be effective in the treatment of cerebral ischemia. Pharmacokinetic studies have shown that baicalin could penetrate the blood-brain barrier and distribute in cerebral nuclei. Through a variety of
and
models of ischemic neuronal injury, numerous studies have demonstrated that baicalin and baicalein have salutary effect for neuroprotection. Especially, the studies on the pharmacological mechanism showed that baicalin and baicalein have several pharmacological activities, which include antioxidant, anti-apoptotic, anti-inflammatory and anti-excitotoxicity effects, protection of the mitochondria, promoting neuronal protective factors expression and adult neurogenesis effects and many more. This review focuses on the neuroprotective effects of baicalin and baicalein in ischemia or stroke-induced neuronal cell death. We aimed at collecting all important information regarding the neuroprotective effect and its pharmacological mechanism of baicalin and baicalein in various
and
experimental models of ischemic neuronal injury.
Decidualization is a critical event for the blastocyst implantation, placental development and fetal growth and the normal term. In mice, the embryo implantation to the uterine epithelial would ...trigger the endometrial stromal cells to differentiate into decidual stromal cells. However, decidualization in women takes place from the secretory phase of each menstrual cycle and continues to early pregnancy if there is conceptus. Deficient decidualization is often associated with pregnancy specific complications and reproductive disorders. Dramatic changes occur in the gene expression profiles during decidualization, which is coordinately regulated by steroid hormones, growth factors, and molecular and epigenetic mechanisms. Recently, emerging evidences showed that epigenetic modifications, mainly including DNA methylation, histone modification, and non-coding RNAs, play an important role in the decidualization process via affecting the target genes’ expression. In this review, we will focus on the epigenetic modifications in decidualization and open novel avenues to predict and treat the pregnancy complications caused by abnormal decidualization.
Organic near-infrared room temperature phosphorescence materials have unparalleled advantages in bioimaging due to their excellent penetrability. However, limited by the energy gap law, the ...near-infrared phosphorescence materials (>650 nm) are very rare, moreover, the phosphorescence lifetimes of these materials are very short. In this work, we have obtained organic room temperature phosphorescence materials with long wavelengths (600/657-681/732 nm) and long lifetimes (102-324 ms) for the first time through the guest-host doped strategy. The guest molecule has sufficient conjugation to reduce the lowest triplet energy level and the host assists the guest in exciton transfer and inhibits the non-radiative transition of guest excitons. These materials exhibit good tissue penetration in bioimaging. Thanks to the characteristic of long lifetime and long wavelength emissive phosphorescence materials, the tumor imaging in living mice with a signal to background ratio value as high as 43 is successfully realized. This work provides a practical solution for the construction of organic phosphorescence materials with both long wavelengths and long lifetimes.
We introduce the use of deep learning ensembles for real-time, gravitational wave detection of spinning binary black hole mergers. This analysis consists of training independent neural networks that ...simultaneously process strain data from multiple detectors. The output of these networks is then combined and processed to identify significant noise triggers. We have applied this methodology in O2 and O3 data finding that deep learning ensembles clearly identify binary black hole mergers in open source data available at the Gravitational-Wave Open Science Center. We have also benchmarked the performance of this new methodology by processing 200 hours of open source, advanced LIGO noise from August 2017. Our findings indicate that our approach identifies real gravitational wave sources in advanced LIGO data with a false positive rate of 1 misclassification for every 2.7 days of searched data. A follow up of these misclassifications identified them as glitches. Our deep learning ensemble represents the first class of neural network classifiers that are trained with millions of modeled waveforms that describe quasi-circular, spinning, non-precessing, binary black hole mergers. Once fully trained, our deep learning ensemble processes advanced LIGO strain data faster than real-time using 4 NVIDIA V100 GPUs.
Chitosan-based hydrogel has been widely used in the field of tissue engineering due to its favorable biocompatibility and good biodegradability. However, this kind of hydrogel generally exhibits poor ...mechanical stability, which greatly limits its application in the field of 3D bioprinting. In this study, we provided a hybrid bioink created from photocurable chitosan and acrylamide (AM) for digital light processing (DLP) based 3D bioprinting in tissue engineering applications. This hybrid bioink was facilely prepared by combining AM and chitosan modified with methacryloyl groups (CHIMA). The gelling point of the hybrid pre-hydrogel bioink was greatly dependent on the photoinitiators. Both the mechanical properties and cytocompatibility of the hydrogel formed by the bioink can be modulated by varying the AM contents. The hybridization of natural CHIMA and synthetic AM enables the hybrid hydrogels with desirable biological activity and mechanical properties. Utilizing the DLP based 3D printing, this hybrid bioink can be processed into complex 3D hydrogel constructs with high-strength and good biocompatibility. Therefore, the photocurable hybrid bioink composed of CHIMA and AM in proper proportion is well suitable for use in DLP based 3D bioprinting, which would play a promising role in constructing tissues and organs in the future.
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•A photocurable hybrid bioink composed of chitosan and AM is provided for DLP bioprinting.•Using DLP, the hybrid bioink can be processed into complex 3D hydrogel constructs.•The printed constructs are endowed with high-strength and good biocompatibility.
Beta-asarone (β-Asarone), the major component of Acorus tatarinowii Rhizoma, has been proved to be muti-pharmacological activities including anti-inflammation, and which is effective in protecting ...the central nervous system. However, the effect of β-Asarone on myocardial ischemia–reperfusion (I/R) injury is not yet clear. This study used a rat model with 45 min occlusion and 24 h releasing of proximal segment of left anterior descending coronary artery. The effects of β-Asarone on cardiac histopathology, myocardial infarction size, levels of cardiac troponin T (cTNT), myeloperoxidase (MPO) and interleukin-1β (IL-1β), protein expressions of apoptosis-associated speck-like protein containing a CARD (ASC), Nod-like receptor protein 3 (NLRP3), caspase-1 and Gasdermin D (GSDMSD), and left ventricular performance were studied respectively. Our results showed that administration of β-Asarone significantly improved the heart outcome after myocardial ischemia and reperfusion in terms of less infarction size and lower serum cTNT concentration. Further, β-Asarone treatment evidently inhibited inflammatory response with less granulocyte infiltration, mild tissue edema and lower tissue MPO content, it also suppressed NLRP3 signal pathway and cardiac cell’s pyroptosis for less protein expressions of ASC and NLRP3, lower level cleavage activation of caspase-1 and GSDMSD, and lower serum IL-1β concentration. Finally, β-Asarone treatment well preserved the left ventricular performance with higher ejection fraction and fractional shortening. The experimental results suggested that β-Asarone was protective against myocardial ischemia–reperfusion injury, in which inhibition of inflammatory response and suppression of NLRP3 inflammasome mediated pyroptosis were supposed to play a vital role.
Research on materials with pure organic room temperature phosphorescence (RTP) and their application as organic single-molecule white light emitters is a hot area and relies on the design of highly ...efficient pure organic RTP luminogens. Herein, a facile strategy of heavy-atom-participated anion-π
interactions is proposed to construct RTP-active organic salt compounds (1,2,3,4-tetraphenyloxazoliums with different counterions). Those compounds with heavy-atom counterions (bromide and iodide ions) exhibit outstanding RTP due to the external heavy atom effect via anion-π
interactions, evidently supported by the single-crystal X-ray diffraction analysis and theoretical calculation. Their single-molecule white light emission is realized by tuning the degree of crystallization. Such white light emission also performs well in polymer matrices and their use in 3D printing is demonstrated by white light lampshades.
The transient characteristics of wind farms in groups are quite different; in addition, there is a strong coupling between the wind farms and the grid, and these factors make the fault analysis of ...the grid with wind farm groups complicated. In order to solve this problem, a mathematical model of the converter is established based on the input-output external characteristics of the converter, and a transient model of a doubly fed wind turbine (DFIG) is presented considering the influence of the low-voltage ride-through control (LVRT) of the converter, and the effect mechanism of the LVRT strategy on the short-circuit current is analyzed. Finally, a short-circuit current calculation model of a doubly fed wind turbine with low-voltage crossing control is established. The interaction mechanism between wind farms during the fault is analyzed, and a short-circuit current calculation method of doubly fed wind farm groups is proposed. RTDS is used to verify the accuracy of the proposed short-circuit current calculation method for doubly fed field groups. On this basis, a method of power grid fault analysis after doubly fed field group access is discussed and analyzed.
With the development of near-eye display technology, optical distortion is often introduced into the design of near-eye optical system to meet people's requirements for high definition and large ...field of view. However, the larger the field of view, the greater the distortion of the projected image. In order to correct distorted images, this paper proposes an image pre-distortion algorithm based on nonlinear fitting and forward mapping interpolation. The radial basis function fitting algorithm is used to get a more precise mapping relationship between the original image and the pre-distorted image. The compactly supported radial basis function (CSRBF) interpolation algorithm based on forward mapping is used for image gray reconstruction to obtain better correction effect of image distortion. The experimental results show that the fitting error of the radial basis function fitting algorithm can be reduced to less than 1 pixel, reaching sub-pixel level. The pre-distortion algorithm has a good correction effect on the non-rotational symmetry distortion produced by the near-eye optical system, which makes the display image clear and complete.
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