Integrated dynamic wet spinning of core-sheath hydrogel fibers for optical-to-brain/tissue communications     

Guoyin Chen  Gang Wang  Xinrong Tan  Kai Hou  Qingshuo Meng  Peng Zhao  Shun Wang  Jiayi Zhang  Zhan Zhou  Tao Chen  Yanhua Cheng  Benjamin S Hsiao  Elsa Reichmanis  Meifang Zhu 《国家科学评论(英文版)》2021,8(9)

Hydrogel optical light-guides have received substantial interest for applications such as deep-tissue biosensors, optogenetic stimulation and photomedicine due to their biocompatibility, (micro)structure control and tissue-like Young''s modulus. However, despite recent developments, large-scale fabrication with a continuous synthetic methodology, which could produce core-sheath hydrogel fibers with the desired optical and mechanical properties suitable for deep-tissue applications, has yet to be achieved. In this study, we report a versatile concept of integrated light-triggered dynamic wet spinning capable of continuously producing core-sheath hydrogel optical fibers with tunable fiber diameters, and mechanical and optical propagation properties. Furthermore, this concept also exhibited versatility for various kinds of core-sheath functional fibers. The wet spinning synthetic procedure and fabrication process were optimized with the rational design of the core/sheath material interface compatibility [core = poly(ethylene glycol diacrylate-co-acrylamide); sheath = Ca-alginate], optical transparency, refractive index and spinning solution viscosity. The resulting hydrogel optical fibers exhibited desirable low optical attenuation (0.18 ± 0.01 dB cm⁻¹ with 650 nm laser light), excellent biocompatibility and tissue-like Young''s modulus (<2.60 MPa). The optical waveguide hydrogel fibers were successfully employed for deep-tissue cancer therapy and brain optogenetic stimulation, confirming that they could serve as an efficient versatile tool for diverse deep-tissue therapy and brain optogenetic applications.  相似文献   

Ancient covering plaster mortars from several convents and Islamic and Gothic palaces in Palma de Mallorca (Spain). Analytical characterisation     

Catalina Genestar  Carmen Pons 《Journal of Cultural Heritage》2003,4(4):291-298

Analysis of historic mortars including Islamic, Gothic and later ones taken from palaces, convents and mansions in Palma de Mallorca has been carried out. Scanning electron microscopy (SEM) coupled to energy dispersive X-ray spectrometer (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques were used to characterise the morphology and analytical composition of the samples analysed. Generally, covering plaster mortars presented a low percentage of small size aggregate. The reported results show that mixed and lime mortars have been used, thus, the establishment of a relationship between the type of mortar employed and its age is not feasible. In the painted mortars, polychromy has also been studied. The most common pigments to be found are natural earths.  相似文献   

Women students in engineering in Mexico: exploring responses to gender differences     

Carmen García Villa  Elsa M. González y González 《International journal of qualitative studies in education》2014,27(8):1044-1061

The percentage of women students in engineering in Mexico is still low compared to the percentage of women enrolled in higher education institutions in the country, which has achieved parity with male enrollment. It is thus important to understand how gender can shape the experiences of female college students in engineering programs, which was the focus of this study. Findings for this study are presented in two sections. We first describe how female students have an extra burden dealing with the possibility that their performance might confirm the stereotype of female inferiority in math and science and that they may be judged according to that stereotype. Secondly, we describe the challenges faced by female students in engineering colleges in Mexico, namely, a demanding academic curriculum, and competitive and individualistic environment. This study illustrates how successful female students negotiated the gendered expectations in engineering in Mexican engineering programs, and how they use resistance strategies like academic success to become accepted in the male-dominated engineering environment.  相似文献