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

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.     

Unfolding polyelectrolytes in trivalent salt solutions using dc electric fields: A study by Langevin dynamics simulations

We study the behavior of single linear polyelectrolytes condensed by trivalent salt under the action of electric fields through computer simulations. The chain is unfolded when the strength of the electric field is stronger than a critical value. This critical electric field follows a scaling law against chain length, and the exponent of the scaling law is −0.77(1), smaller than the theoretical prediction, −3ν∕2 [R. R. Netz, Phys. Rev. Lett. 90, 128104 (2003)], and the one obtained by simulations in tetravalent salt solutions, −0.453(3) [P.-Y. Hsiao and K.-M. Wu, J. Phys. Chem. B 112, 13177 (2008)]. It demonstrates that the scaling exponent depends sensitively on the salt valence. Hence, it is easier to unfold chains condensed by multivalent salt of a smaller valence. Moreover, the absolute value of chain electrophoretic mobility increases drastically when the chain is unfolded in an electric field. The fact that the mobility depends on electric field and on chain length provides a plausible way to impart chain-length dependence in free-solution electrophoresis via chain unfolding transition induced by electric fields. Finally, we show that, in addition to an elongated structure, a condensed chain can be unfolded into a U-shaped structure. The formation of this structure in our study is purely a result of the electric polarization, not of the elastohydrodynamics dominated in sedimentation of polymers.     

A leap to the digital era—what are lower and upper secondary school students’ experiences of distance education during the COVID-19 pandemic in Serbia?

European Journal of Psychology of Education - The aim of this paper is to thoroughly examine how students in Serbia experienced their education through distance learning during the 2020 Spring...     

The impact of SSCI and SCI on Taiwan’s academy: an outcry for fair play

The increasing importance of the competition in global university ranking has resulted in a paradigm shift in academic governance in East Asia. Many governments have introduced different strategies for benchmarking their leading universities to facilitate global competitiveness and international visibility. A major trend in the changing university governance is the emergence of a regulatory evaluation scheme for faculty research productivity, reflected by the striking features of the recent changing academic profile of publication norms and forms that go beyond the territories of nation-states in the East and West. With the expansion of the Taiwanese higher education system in the last two decades, the maintenance of quality to meet the requirements for international competitiveness has become a key concern for policy makers. Since 2005, the Ministry of Education has introduced a series of university governance policies to enhance academic excellence in universities and established a formal university evaluation policy to improve the competitiveness and international visibility of Taiwanese universities. In so doing, the government has legalized a clear link between evaluation results and public funding allocation. Research performance is assessed in terms of the number of articles published in journals indexed by the Science Citation Index (SCI), the Social Science Citation Index (SSCI), and the Arts and Humanities Citation Index and in terms of citation rates and associated factors. Therefore, evaluation has taken on a highly quantitative dimension. Despite the efforts of concerned parties to encourage academic excellence, the abovementioned quantitative evaluation indicators have resulted in bitter complaints from the humanities and social sciences, whose research accomplishments are devalued and ignored by the current quantitative indicators. In this paper, the authors describe the recent petition for collective action initiated by university faculty to protest the privileging of SSCI and SCI publications as critical indicators for academic performance regardless of faculty discipline and specialization. The article concludes its argument with a group petition calling for more diverse and reliable indicators in recognizing the research of different natures and disciplines while creating culturally responsive evaluation criteria for social sciences and humanities in the Taiwanese academe. The article not only sheds light on academic evaluation literature, especially on the uncertain paradox of globalization and market economy, but also proposes alternatives to the evaluation system for humanities and social sciences in higher education.     

From "Simply Bad Luck" to "Seeking State Compensation"

This article describes Taiwan's recent progress against sexual violations in schools, using the author's personal experience with case investigation work to observe changes in the sexual violation prevention landscape. Fifteen years ago, schools in Taiwan were either at a loss about how to handle sexual violation cases, or they engaged in passive avoidance. Now they are forced to actively address such cases according to the law. Families of victims have progressed from withdrawing and resigning themselves to their bad luck to actively seeking state compensation. In addition to enacting and amending legislation, government entities have more recently ruled on five state compensation cases. This article attempts to convey the significance of these events.     

Microanalytic case studies of individual participation patterns in an asynchronous online discussion in an undergraduate blended course

This study presents three case studies of students' participation patterns in an online discussion to address the gap in our current understanding of how individuals experience asynchronous learning environments. Cases were constructed via microanalysis of log-file data, post contents, and the evolving discussion structure. The first student was Thorough, reading all the posts in the forum in sequence, revisiting different posts multiple times, and creating posts outside of the discussion tool. The second student was Self-Monitoring, revisiting his own posts multiple times, checking the discussion frequently for replies, and replying to or editing his posts in response. Finally, the third student was Independent, using the forum as a tool for her own individual reflection. The behaviors found for these cases are aligned with a theoretical taxonomy for participation proposed by Knowlton (2005). The value and limitations of the microanalytic case study approach are discussed, and implications for research and practice are suggested.