Photopolymerized maleilated chitosan/methacrylated silk fibroin micro/nanocomposite hydrogels as potential scaffolds for cartilage tissue engineering

Hydrogels composed of natural materials exhibit great application potential in artificial scaffolds for cartilage repair as they can resemble the extracellular matrices of cartilage tissues comprised of various glycosaminoglycan and collagen. Herein, the natural polymers with vinyl groups, i.e. maleilated chitosan (MCS) and methacrylated silk fibroin (MSF) micro/nanoparticles, were firstly synthesized. The chemical structures of MCS and MSF micro/nanoparticles were investigated using Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Then MCS/MSF micro/nanocomposite hydrogels were prepared by the photocrosslinking of MCS and MSF micro/nanoparticles in aqueous solutions in the presence of the photoinitiator Darocur 2959 under UV light irradiation. A series of properties of the MCS/MSF micro/nanocomposite hydrogels including rheological property, equilibrium swelling, sol content, compressive modulus, and morphology were examined. The results showed that these behaviors could be tunable via the control of MSF content. When the MSF content was 0.1%, the hydrogel had the compressive modulus of 0.32±0.07MPa, which was in the range of that of articular cartilage. The in vitro cytotoxic evaluation and cell culture of the micro/nanocomposite hydrogels in combination with mouse articular chondrocytes were also investigated. The results demonstrated that the micro/nanocomposite hydrogels with TGF-β1 was biocompatible to mouse articular chondrocytes and could support cells attachment well, indicating their potential as tissue engineering scaffolds for cartilage repair.This study was supported by National Natural Science Foundation of China (Grant No. 51203123, 51403165, 51503161) and the National Key Research and Development Program of China (No.2016YFA0101102)

Six DOF tactile stimulator for psychophysical investigations

The design of a high performance tactile stimulator with six degrees of freedom for psychometric investigations is the subject of this thesis.In order to design this device, a new mechanism is put forward, which is fully parallel and string driven. It achieves kinematic and dynamic isotropy. From the kinematic and dynamic analysis, the conditions for obtaining the best performance results are derived. These form the basis for the design and lead to a high performance device, which has wide bandwidth, low friction and which is free from backlash. The input and output is fully decoupled, which lead to simple control

A Teaching Experiment of Chinese College Students’ English Idioms Comprehension

An English idiom is a special combination of words, the meaning of which is not the simple addition of its constituents but a special meaning. English idioms are widely used by English native speakers, which are very important for English as a second language learners. Chinese learners are poor in English idioms comprehension, and they need to adopt a new method for improving their English idioms comprehension. S-S-P-C model means analyzing an English idiom from syntactic, semantic, pragmatic, and cultural perspective, which was applied in a teaching experiment among college students for one semester. The teaching experiment shows that S-S-P-C model is an efficient method for Chinese learners to help improve their English idioms comprehension

Kinematic Decoupling in Mechanisms and Application to a Passive Hand Controller Design

Observations regarding the kinematics of mechanisms are applied to the synthesis of a passive hand controller. It is argued that stiffness (and damping) properties are central to the effectiveness of such devices and in particular that the simplicity of these proper-ties is crucial. What simple means is analyzed and it is shown that only certain types of manipulators can appropriately be used. In effect, decoupling is shown to be architec-ture and configuration dependent. The properties of parallel mechanisms are reviewed and found appropriate for restricted-workspace hand controllers. A particular kinematic design is then derived and a practical implementation described. 0 1993 John Wiley & Sons, Inc. 1

MTG: A Benchmark Suite for Multilingual Text Generation

We introduce MTG, a new benchmark suite for training and evaluating multilingual text generation. It is the first-proposed multilingual multiway text generation dataset with the largest human-annotated data (400k). It includes four generation tasks (story generation, question generation, title generation and text summarization) across five languages (English, German, French, Spanish and Chinese). The multiway setup enables testing knowledge transfer capabilities for a model across languages and tasks. Using MTG, we train and analyze several popular multilingual generation models from different aspects. Our benchmark suite fosters model performance enhancement with more human-annotated parallel data. It provides comprehensive evaluations with diverse generation scenarios. Code and data are available at \url{https://github.com/zide05/MTG}.Comment: NAACL2022 finding

Review of resource utilization of Fe-rich sludges: purification, upcycling, and application in wastewater treatment

This paper discusses the resource utilization of Fe-rich sludges generated as waste products from water treatment, hydromet-allurgy, surface finishing, and dye chemical industries. Apart from the conventional landfill disposal of such sludges, the work focuses on sludge purification for new commercial products, including iron red/black dyes, an iron concentrate powder, a polyferric flocculant, a catalyst, and a magnetic adsorbent. Among such purifications, a new strategy was developed to recycle Fe-rich sludges for a new Fe/S-bearing flocculant. Given that Fe-rich sludges may contain rare and/or heavy metals, the purification of sludges as high-purity hematite nanoparticles and other valuable products is detailed as a new insight. Accordingly, the mechanisms for the phase transformation of Fe-bearing minerals and the purification of valuable Fe oxides are deeply considered. The work summarizes the pilot-and/or field-scale application for recycling of Fe-rich sludge and proposes the development of a new Fe/S flocculant and a high-purity hematite product

Resource utilization of hazardous Cr/Fe-rich sludge: synthesis of erdite flocculant to treat real electroplating wastewater

Cr/Fe-bearing sludge is a hazardous solid waste, produced at mass production in smelting, plating and surface finishing industries. Such waste is commonly treated by chemical detoxification and safety landfill, whereas only a few Cr-rich sludge is recycled as a tanning reagent. In this study, a novel route was developed to recycle Cr/Fe-bearing sludge as erdite-bearing flocculant for wastewater treatment. Results showed that two sludges were irregular aggregates, one of which contained 1.6 wt.% Cr (short for LS) and the other contained 4.2 wt.% Cr (HS). After hydrothermal treatment, stable Cr(III)/S-bearing product was formed from the Cr(VI) reduction in the sludges. Conversely, erdite was generated in nanorod form with diameter and length of 200 nm and 0.5–1 μm from LS, respectively, whereas grew radially to 1.5–2.5 μm for HS. The two erdite-bearing products were spontaneously hydrolysed to Fe/S-bearing flocs and showed similar performance in the treatment of real electroplating effluent with 91.55, 1.94 and 0.25 mg/L of Zn, Ni and Cr, respectively. For instance, by adding 1 g/L product of LS, the release of Cr from the products did not occur, and the residual Zn, Ni and Cr in the effluent was 0.25, 0.65 and 0.17 mg/L, respectively, which met the discharge standard of the electroplating industry. With the two converted products, the residual Zn/Ni/Cr concentrations were apparently lower than those of the raw sludges and other common reagents (e.g. polymeric ferric sulphate, activated carbon and diatomite). Thus, such erdite-bearing products could serve as a flocculant and then be applied in electroplating wastewater treatment