581 research outputs found
Bionic Duplication of Fresh Navodon septentrionalis
Biomimetic superhydrophobic surface was fabricated by replicating topography of the fresh fish skin surface of Navodon septentrionalis with polydimethylsiloxane (PDMS) elastomer. A two-step replicating method was developed to make the surface structure of the fresh fish skin be replicated with high fidelity. After duplication, it was found that the static contact angle of the replica was as large as 173°. Theoretic analysis based on Young's and Cassie-Baxter (C-B) model was performed to explain the relationship between structure and hydrophobicity
Vector Quantized Diffusion Model with CodeUnet for Text-to-Sign Pose Sequences Generation
Sign Language Production (SLP) aims to translate spoken languages into sign
sequences automatically. The core process of SLP is to transform sign gloss
sequences into their corresponding sign pose sequences (G2P). Most existing G2P
models usually perform this conditional long-range generation in an
autoregressive manner, which inevitably leads to an accumulation of errors. To
address this issue, we propose a vector quantized diffusion method for
conditional pose sequences generation, called PoseVQ-Diffusion, which is an
iterative non-autoregressive method. Specifically, we first introduce a vector
quantized variational autoencoder (Pose-VQVAE) model to represent a pose
sequence as a sequence of latent codes. Then we model the latent discrete space
by an extension of the recently developed diffusion architecture. To better
leverage the spatial-temporal information, we introduce a novel architecture,
namely CodeUnet, to generate higher quality pose sequence in the discrete
space. Moreover, taking advantage of the learned codes, we develop a novel
sequential k-nearest-neighbours method to predict the variable lengths of pose
sequences for corresponding gloss sequences. Consequently, compared with the
autoregressive G2P models, our model has a faster sampling speed and produces
significantly better results. Compared with previous non-autoregressive G2P
methods, PoseVQ-Diffusion improves the predicted results with iterative
refinements, thus achieving state-of-the-art results on the SLP evaluation
benchmark
Superconductivity in boron-doped carbon nanotube networks
By using the five Angstrom diameter pores of calcined zeolite as the
template, we have fabricated boron doped carbon nanotube networks via the
chemical vapor deposition method. Raman data indicate the network to comprise
segments of interconnected carbon nano tubes. Transport measurements showed a
superconducting transition initiating at 40K, with a sharp downturn around 20K
to a low resistance state at 2K, accompanied by a low resistance plateau in the
current voltage characteristic, fluctuating around zero resistance. Magnetic
measurements exhibited the Meissner effect characteristic of thin
superconducting wire networks in which the superconducting wire radius is much
smaller than the London penetration length. At low magnetic field, the negative
diamagnetic susceptibility was observed to persist beyond 200K. The transport
and magnetic data are reconciled on the basis of a physical model based on weak
links comprising short, one-dimensional superconducting nano tubes, that govern
the global transport behavior.Comment: 22 pages, 6 figures in the main text, 2 figures in appendices, 37
reference
In vitro and in vivo evaluation of folate receptor-targeting amphiphilic copolymer-modified liposomes loaded with docetaxel
Xiang Li1, Xin Tian2, Jing Zhang3, Xu Zhao1, Xiaohui Chen1, Youhong Jiang2, Dongkai Wang1, Weisan Pan11Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang; 2The Second Laboratory of Cancer Research Institution, The First Hospital of China Medical University, Shenyang; 3Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Traditional Chinese Medicine, Nanchang, ChinaBackground: The purpose of this study was to develop folate-poly (PEG-cyanoacrylate-co-cholesteryl cyanoacrylate) (FA-PEG-PCHL)-modified freeze-dried liposomes for targeted chemotherapy using docetaxel as a model drug.Methods: FA-PEG-PCHL was synthesized and its cytotoxicity was evaluated by CCK-8 assay in L929. Docetaxel-loaded liposomes modified by FA-PEG-PCHL were prepared by an organic solvent injection method and lyophilized to obtain freeze-dried FA-PEG-PCHL-docetaxel liposomes (FA-PDCT-L). Two carcinoma cell lines (MCF-7 and A-549 cells) were cultured with docetaxel solution, conventional docetaxel-loaded liposomes, or FA-PDCT-L, and the cytotoxicity and apoptosis was evaluated for each preparation. The uptake of the docetaxel preparations into MCF-7 cells was studied by confocal laser scanning microscopy. Liquid chromatography-mass spectrometry was used to study the pharmacokinetics and tissue distribution characteristics of the preparations.Results: The existence of an enlarged fixed aqueous layer on the surface of the liposomes was affirmed by zeta potential analysis. The entrapment efficiency and particle size distribution were almost the same as those of docetaxel-loaded liposomes. The drug release profile showed that the release rate was faster at higher molecular weight of the polymer. Compared with docetaxel solution and docetaxel-loaded liposomes, FA-PDCT-L demonstrated the strongest cytotoxicity against two carcinoma cell lines, the greatest intracellular uptake especially in the nucleus, as well as the most powerful apoptotic efficacy. In pharmacokinetic studies, the area under the plasma concentration-time curve of FA-PDCT-L was increased 3.82 and 6.23 times in comparison with the values for the docetaxel-loaded liposomes and docetaxel solution, respectively. Meanwhile, a lower concentration of docetaxel was observed for FA-PDCT-L in the liver and spleen, and a significantly higher concentration of FA-PDCT-L in tumors suggested that the presence of FA-PEG-PCHL on the liposomes resulted in greater accumulation of the drug in tumor tissue.Conclusion: Liposomes modified by FA-PEG-PCHL could be one of the promising suspensions for the delivery of antitumor drugs in cancer.Keywords: folate-poly (PEG-cyanoacrylate-co-cholesteryl cyanoacrylate), docetaxel, freeze-dried liposomes, tumor targetin
Recommended from our members
Collaborative interactions of heterogenous ribonucleoproteins contribute to transcriptional regulation of sterol metabolism in mice.
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a group of functionally versatile proteins that play critical roles in the biogenesis, cellular localization and transport of RNA. Here, we outline a role for hnRNPs in gene regulatory circuits controlling sterol homeostasis. Specifically, we find that tissue-selective loss of the conserved hnRNP RALY enriches for metabolic pathways. Liver-specific deletion of RALY alters hepatic lipid content and serum cholesterol level. In vivo interrogation of chromatin architecture and genome-wide RALY-binding pattern reveal insights into its cooperative interactions and mode of action in regulating cholesterogenesis. Interestingly, we find that RALY binds the promoter region of the master metabolic regulator Srebp2 and show that it directly interacts with coactivator Nuclear Transcription Factor Y (NFY) to influence cholesterogenic gene expression. Our work offers insights into mechanisms orchestrating selective promoter activation in metabolic control and a model by which hnRNPs can impact health and disease states
Recommended from our members
Dissociate lattice oxygen redox reactions from capacity and voltage drops of battery electrodes.
The oxygen redox (OR) activity is conventionally considered detrimental to the stability and kinetics of batteries. However, OR reactions are often confused by irreversible oxygen oxidation. Here, based on high-efficiency mapping of resonant inelastic x-ray scattering of both the transition metal and oxygen, we distinguish the lattice OR in Na0.6[Li0.2Mn0.8]O2 and compare it with Na2/3[Mg1/3Mn2/3]O2. Both systems display strong lattice OR activities but with distinct electrochemical stability. The comparison shows that the substantial capacity drop in Na0.6[Li0.2Mn0.8]O2 stems from non-lattice oxygen oxidations, and its voltage decay from an increasing Mn redox contribution upon cycling, contrasting those in Na2/3[Mg1/3Mn2/3]O2. We conclude that lattice OR is not the ringleader of the stability issue. Instead, irreversible oxygen oxidation and the changing cationic reactions lead to the capacity and voltage fade. We argue that lattice OR and other oxygen activities should/could be studied and treated separately to achieve viable OR-based electrodes
Quantitative detection and attribution of groundwater level variations in the Amu Darya Delta
In the past few decades, the shrinkage of the Aral Sea is one of the biggest ecological catastrophes caused by human activity. To quantify the joint impact of both human activities and climate change on groundwater, the spatiotemporal groundwater dynamic characteristics in the Amu Darya Delta of the Aral Sea from 1999 to 2017 were analyzed, using the groundwater level, climate conditions, remote sensing data, and irrigation information. Statistics analysis was adopted to analyze the trend of groundwater variation, including intensity, periodicity, spatial structure, while the Pearson correlation analysis and principal component analysis (PCA) were used to quantify the impact of climate change and human activities on the variabilities of the groundwater level. Results reveal that the local groundwater dynamic has varied considerably. From 1999 to 2002, the groundwater level dropped from -189 cm to -350 cm. Until 2017, the groundwater level rose back to -211 cm with fluctuation. Seasonally, the fluctuation period of groundwater level and irrigation water was similar, both were about 18 months. Spatially, the groundwater level kept stable within the irrigation area and bare land but fluctuated drastically around the irrigation area. The Pearson correlation analysis reveals that the dynamic of the groundwater level is closely related to irrigation activity within the irrigation area (Nukus: -0.583), while for the place adjacent to the Aral Sea, the groundwater level is closely related to the Large Aral Sea water level (Muynak: 0.355). The results of PCA showed that the cumulative contribution rate of the first three components exceeds 85%. The study reveals that human activities have a great impact on groundwater, effective management, and the development of water resources in arid areas is an essential prerequisite for ecological protection
- …