Widespread subsonic turbulence in Ophiuchus North 1

Supersonic motions are common in molecular clouds. (Sub)sonic turbulence is usually detected toward dense cores and filaments. However, it remains unknown whether (sub)sonic motions at larger scales ($\gtrsim$1~pc) can be present in different environments or not. Located at a distance of about 110 pc, Ophiuchus North 1 (Oph N1) is one of the nearest molecular clouds that allows in-depth investigation of its turbulence properties by large-scale mapping observations of single-dish telescopes. We carried out the $^{12}$CO ($J=1-0$) and C$^{18}$O ($J=1-0$) imaging observations toward Oph N1 with the Purple Mountain Observatory 13.7 m telescope. The observations have an angular resolution of $\sim$55\arcsec (i.e., 0.03~pc). Most of the whole C$^{18}$O emitting regions have Mach numbers of $\lesssim$1, demonstrating the large-scale (sub)sonic turbulence across Oph N1. Based on the polarization measurements, we estimate the magnetic field strength of the plane-of-sky component to be $\gtrsim$9~$\mu$G. We infer that Oph N1 is globally sub-Alfv{\'e}nic, and is supported against gravity mainly by the magnetic field. The steep velocity structure function can be caused by the expansion of the Sh~2-27 H{\scriptsize II} region or the dissipative range of incompressible turbulence. Our observations reveal a surprising case of clouds characterised by widespread subsonic turbulence and steep size-linewidth relationship. This cloud is magnetized where ion-neutral friction should play an important role.Comment: 16 pages, 12 figures, accepted for publication in A&

A Relational Intervention Approach for Unsupervised Dynamics Generalization in Model-Based Reinforcement Learning

The generalization of model-based reinforcement learning (MBRL) methods to environments with unseen transition dynamics is an important yet challenging problem. Existing methods try to extract environment-specified information $Z$ from past transition segments to make the dynamics prediction model generalizable to different dynamics. However, because environments are not labelled, the extracted information inevitably contains redundant information unrelated to the dynamics in transition segments and thus fails to maintain a crucial property of $Z$: $Z$ should be similar in the same environment and dissimilar in different ones. As a result, the learned dynamics prediction function will deviate from the true one, which undermines the generalization ability. To tackle this problem, we introduce an interventional prediction module to estimate the probability of two estimated $\hat{z}_i, \hat{z}_j$ belonging to the same environment. Furthermore, by utilizing the $Z$'s invariance within a single environment, a relational head is proposed to enforce the similarity between $\hat{{Z}}$ from the same environment. As a result, the redundant information will be reduced in $\hat{Z}$. We empirically show that $\hat{{Z}}$ estimated by our method enjoy less redundant information than previous methods, and such $\hat{{Z}}$ can significantly reduce dynamics prediction errors and improve the performance of model-based RL methods on zero-shot new environments with unseen dynamics. The codes of this method are available at \url{https://github.com/CR-Gjx/RIA}.Comment: ICLR2022 accepted pape

pH-Mediated Antibacterial Dyeing of Cotton with Prodigiosins Nanomicelles Produced by Microbial Fermentation

This study developed a novel pH-mediated antimicrobial dyeing process of cotton with prodigiosins nanomicelles produced by microbial fermentation. The average diameter of the pigment nanomicelles was 223.8 nm (range of 92.4–510.2 nm), and the pigment concentration was 76.46 mg/L. It was found that the superior dyeing effect of cotton fabric was achieved by adjusting the dye bath pH. When the pH was three, dyed cotton under 90 °C for 60 min exhibited the greatest color strength with good rubbing, washing and perspiration color fastness. By the breaking strength test and XRD analysis, it was concluded that the cotton dyed under the optimum condition almost suffered no damage. In addition, due to the presence of prodigiosins, dyed cotton fabric under the optimal process showed outstanding bacteriostatic rates of 99.2% and 85.5% against Staphylococcus aureus and Escherichia coli, respectively. This research provided an eco-friendly and widely-applicable approach for antimicrobial intracellular pigments with the property of pH-sensitive solubility in water to endow cellulose fabric with color and antibacterial activity

Preparation of Biocolorant and Eco-Dyeing Derived from Polyphenols Based on Laccase-Catalyzed Oxidative Polymerization

Natural products have been believed to be a promising source to obtain ecological dyes and pigments. Plant polyphenol is a kind of significant natural compound, and tea provides a rich source of polyphenols. In this study, biocolorant derived from phenolic compounds was generated based on laccase-catalyzed oxidative polymerization, and eco-dyeing of silk and wool fabrics with pigments derived from tea was investigated under the influence of pH variation. This work demonstrated that the dyeing property was better under acidic conditions compared to alkalinity, and fixation rate was the best when pH value was 3. Furthermore, breaking strength of dyed fabrics sharply reduced under the condition of pH 11. Eventually, the dyeing method was an eco-friendly process, which was based on bioconversion, and no mordant was added during the process of dyeing

Construction and application of cellulose-based hydrogel

Hydrogel is a cross-linked three-dimensional network hydrophilic polymer material, which can absorb and retain a large amount of water and maintain a certain shape. In recent years, with the depletion of petroleum resources and the increasing attention of human beings to environmental issues, natural or modified polymer synthetic polymer hydrogels have become a research hotspot. Cellulose and its derivatives are a large class of renewable natural polymer materials, which have the characteristics of rich resources, wide variety, non-toxic and renewable, etc. The synthesized cellulose-based hydrogel has good water absorption, water retention, biocompatibility and biodegradability, etc., which can be used in medical, environment, agriculture and other fields. The research progress of the construction and application of cellulose-based hydrogels in recent years was reviewed in this paper. The microscopic network structure is combined with the macroscopic properties of the hydrogel. The mechanical properties, swelling properties and adsorption properties of the single network, interpenetrating network and semi-interpenetrating network cellulose-based hydrogels were summarized, and their applications in medical, environmental, agricultural and electronic fields were introduced. The development of cellulose-based hydrogels with both mechanical properties and biocompatibility, and the development of more green economic methods for the synthesis of cellulose-based hydrogels for industrial applications were proposed

Nitrogen, Phosphorus and Sulfur Co-Doped Pyrolyzed Bacterial Cellulose Nanofibers for Supercapacitors

Heteroatom doping is an effective way to raise the electrochemical properties of carbon materials. In this paper, a novel electrode material including nitrogen, phosphorus, and sulfur co-doped pyrolyzed bacterial cellulose (N/P/S-PBC) nanofibers was produced. The morphologies, structure characteristics and electrochemical performances of the materials were investigated by Scanning electron microscopy, Fourier transform infrared spectra, X-ray diffraction patterns, X-ray photoelectronic spectroscopy, N2 sorption analysis and electrochemical measurements. When 3.9 atom% of nitrogen, 1.22 atom% of phosphorus and 0.6 atom% of sulfur co-doped into PBC, the specific capacitance of N/P/S-PBC at 1.0 A/g was 255 F/g and the N/P/S-PBC supercapacitors’ energy density at 1 A/g was 8.48 Wh/kg with a power density of 489.45 W/kg, which were better than those of the N/P-PBC and N/S-PBC supercapacitors. This material may be a very good candidate as the promising electrode materials for high-performance supercapacitors

Bio-Preparation and Regulation of Pyrrole Structure Nano-Pigment Based on Biomimetic Membrane

Microbial pigments, regarded as the most potential biomass pigments, have lately attracted increasing attention in textile dyeing due to their sustainability and cleaner production. The pyrrole structure microbial pigment, called prodigiosin, recently have become a research hotspot for its bright colors and antibacterial function. However, in most case the extraction and preparation are time-consuming and expensive processes since these kinds of microbial pigments are intracellular metabolites. In order to promote the application of microbial pigments in textile dyeing, a novel idea of preparing dye liquid of pyrrole structure pigments based on fermentation broth was put forward via increasing the proportion of extracellular pigments. A model membrane platform was established with a planar lipid bilayer to investigate transmembrane transport of microbial pigments and permeability barrier of cell membrane. The nano-dispersion of pigments was produced as the dye liquor owing to high-throughput transmembrane transfer of intracellular pigments and the increase of extracellular pigments proportion. The results indicated that the size and surface electrical properties of the pigments had contributed much to the mass transfer. It is also showed that transmembrane transmission of the intracellular pigments could be regulated by physical and chemical methods. With the improvement of transmembrane transfer efficiency of microbial pigments and the proportion of extracellular pigments, the complicated biological separation process could be avoided and the application of microbial pigments in textile dyeing can be promoted

Research progress in hydrogel microneedle

Microneedles (MN) as a minimally invasive device consisting of a micro-raised array, can penetrate the cuticle to the epidermis and dermis, and which has the advantages of safety, painless, minimally invasive, self-administration and convenience. As a new kind of microneedles, hydrogel microneedles have attracted more attentions in the medical field due to its excellent performance. Hydrogel microneedles have good biocompatibility and mechanical properties, and can be completely removed after skin action without residual polymer in the body. Its unique swelling property can realize minimally invasive extraction of human detection substance and slow release of drugs, which can play a huge role in the field of personal health monitoring and drug controlled release in the future. The mechanism of action, design, preparation and application of hydrogel microneedles were reviewed in this paper, focusing on the current design parameters of hydrogel microneedles and their applications in drug delivery, extraction monitoring and wound healing, and the problems of hydrogel microneedles in skin infection risk, pharmacokinetics and wearing comfort were pointed out. In the future, the key research direction is to combine with intelligent devices to realize both human body monitoring and intelligent drug controlled release on the microneedle patch

Biodegradation of Microplastic Derived from Poly(ethylene terephthalate) with Bacterial Whole-Cell Biocatalysts

At present, the pollution of microplastic directly threatens ecology, food safety and even human health. Polyethylene terephthalate (PET) is one of the most common of microplastics. In this study, the micro-size PET particles were employed as analog of microplastic. The engineered strain, which can growth with PET as sole carbon source, was used as biocatalyst for biodegradation of PET particles. A combinatorial processing based on whole-cell biocatalysts was constructed for biodegradation of PET. Compared with enzymes, the products can be used by strain growth and do not accumulated in culture solution. Thus, feedback inhibition of products can be avoided. When PET was treated with the alkaline strain under high pH conditions, the product concentration was higher and the size of PET particles decreased dramatically than that of the biocatalyst under neutral conditions. This shows that the method of combined processing of alkali and organisms is more efficient for biodegradation of PET. The novel approach of combinatorial processing of PET based on whole-cell biocatalysis provides an attractive avenue for the biodegradation of micplastics