Ice quivers with potential arising from once-punctured polygons and Cohen-Macaulay modules

Given a tagged triangulation of a once-punctured polygon $P^*$ with $n$ vertices, we associate an ice quiver with potential such that the frozen part of the associated frozen Jacobian algebra has the structure of a Gorenstein $K[X]$-order $\Lambda$. Then we show that the stable category of the category of Cohen-Macaulay $\Lambda$-modules is equivalent to the cluster category $\mathcal{C}$ of type $D_n$. It gives a natural interpretation of the usual indexation of cluster tilting objects of $\mathcal{C}$ by tagged triangulations of $P^*$. Moreover, it extends naturally the triangulated categorification by $\mathcal{C}$ of the cluster algebra of type $D_n$ to an exact categorification by adding coefficients corresponding to the sides of $P$. Finally, we lift the previous equivalence of categories to an equivalence between the stable category of graded Cohen-Macaulay $\Lambda$-modules and the bounded derived category of modules over a path algebra of type $D_n$.Comment: 50 pages. Several improvements after refereeing. arXiv admin note: text overlap with arXiv:1307.067

Electrical Stimulation to Conductive Scaffold Promotes Axonal Regeneration and Remyelination in a Rat Model of Large Nerve Defect

BACKGROUND: Electrical stimulation (ES) has been shown to promote nerve regeneration when it was applied to the proximal nerve stump. However, the possible beneficial effect of establishing a local electrical environment between a large nerve defect on nerve regeneration has not been reported in previous studies. The present study attempted to establish a local electrical environment between a large nerve defect, and examined its effect on nerve regeneration and functional recovery. METHODOLOGY/FINDINGS: In the present study, a conductive scaffold was constructed and used to bridge a 15 mm sciatic nerve defect in rats, and intermittent ES (3 V, 20 Hz) was applied to the conductive scaffold to establish an electrical environment at the site of nerve defect. Nerve regeneration and functional recovery were examined after nerve injury repair and ES. We found that axonal regeneration and remyelination of the regenerated axons were significantly enhanced by ES which was applied to conductive scaffold. In addition, both motor and sensory functional recovery was significantly improved and muscle atrophy was partially reversed by ES localized at the conductive scaffold. Further investigations showed that the expression of S-100, BDNF (brain-derived neurotrophic factor), P0 and Par-3 was significantly up-regulated by ES at the conductive scaffold. CONCLUSIONS/SIGNIFICANCE: Establishing an electrical environment with ES localized at the conductive scaffold is capable of accelerating nerve regeneration and promoting functional recovery in a 15 mm nerve defect in rats. The findings provide new directions for exploring regenerative approaches to achieve better functional recovery in the treatment of large nerve defect

Compressive Failure Mechanism of Structural Bamboo Scrimber

Bamboo scrimber is one of the most popular engineering bamboo composites, owing to its excellent physical and mechanical properties. In order to investigate the influence of grain direction on the compression properties and failure mechanism of bamboo scrimber, the longitudinal, radial and tangential directions were selected. The results showed that the compressive load–displacement curves of bamboo scrimber in the longitudinal, tangential and radial directions contained elastic, yield and failure stages. The compressive strength and elastic modulus of the bamboo scrimber in the longitudinal direction were greater than those in the radial and tangential directions, and there were no significant differences between the radial and tangential specimens. The micro-fracture morphology shows that the parenchyma cells underwent brittle shear failure in all three directions, while the fiber failure of the longitudinal compressive specimens consisted of ductile fracture, and the tangential and radial compressive specimens exhibited brittle fracture. This is one of the reasons that the deformation of the specimens under longitudinal compression was greater than those under tangential and radial compression. The main failure mode of bamboo scrimber under longitudinal and radial compression was shear failure, and the main failure mode under tangential compression was interlayer separation failure. The reason for this difference was that during longitudinal and radial compression, the maximum strain occurred at the diagonal of the specimen, while during tangential compression, the maximum strain occurred at the bonding interface. This study can provide benefits for the rational design and safe application of bamboo scrimber in practical engineering

Effect of Salt on Dynamic Mechanical Behaviors of Polyampholyte Hydrogels

Understanding the dynamic mechanical behaviors of tough hydrogels with ionic dynamic bonds in saline solution is crucial for applications, particularly in the biomedical field. In this work, using polyampholyte hydrogels, dually crosslinked with a primary network from covalent crosslinkers and/or trapped entanglements, and a dynamic network from ionic bonds, as a model system, we investigate the salt effect on rheological response and mechanical behaviors. Through a systematic study on one gel without a chemical crosslinker and one gel with a chemical crosslinker, we demonstrate that the salt effect on mechanical properties, including small-strain moduli, large deformation energy dissipation, and fracture stretch ratio, can be effectively converted into frequency or strain rate dependences following the time–salt superposition principle. Accordingly, we access a wide range of observation time scales from 10–11 to 102 rad/s at room temperature, covering three regimes: (I) the high-frequency plateau regime from the dynamic and primary networks, (II) the viscoelastic regime from sticky Rouse motion of ionic associations, and (III) the low-frequency plateau regime from the primary network. Moreover, we disclose an in-depth understanding of the entanglement’s behavior in the long-timescale regime III. This work not only provides a guide to biological applications of hydrogels in saline environments but also gives important insights into the toughening mechanism via dynamic bonds in other systems with dually crosslinked structures

Ethnobotanical study on ritual plants used by Hani people in Yunnan, China

Abstract Background The Hani people, who reside in Yuanyang County, Honghe Hani and Yi Autonomous Prefecture, Yunnan Province, rely on rice terrace farming as their primary livelihood. They utilize plants in various traditional ritual practices. The Hani people have categorized the value of plants based on their natural attributes and have refined the ways of using different plants in specific rituals through practical observations and experiences derived from their agricultural culture. Although the plants used in these rituals hold significant cultural value, they have yet to be studied from the perspective of ethnobotany. This study aims to approach the ritual plants using ethnobotanical methods. Methods Ethnobotanical fieldwork was conducted in 10 villages in Yuanyang County between 2021 and 2023. Data were collected from the local Hani people through semi-structured interviews and participatory observations and 41 informants were interviewed during the field investigations. The frequency of citation (FC) and relative frequency of citation (RFC) were utilized to evaluate the relative importance of ritual plants among the local communities. Results A total of 36 plant species, belonging to 18 families and 34 genera, were recorded as being used in 11 ritual practices by the Hani people. Rosaceae, Poaceae, and Fabaceae were found to have the highest number of species. Most of the ritual plants used by the Hani people were collected from the wild. FC and RFC analysis showed that the preferred plants for Hani rituals were Rhus chinensis Mill, Oryza sativa L., Phyllostachys sulphurea (Carr.) A. et C. Riv. and Musa basjoo Siebold & Zucc. ex Iinuma. The 11 rituals are all centered around the performance of people, crops and livestock. The Hani people use plants in different rituals mainly based on their biological attributes. Conclusions Many rituals of the Hani people are closely related to their production and livelihood, and the plants used in these rituals are deeply rooted in Hani’s traditional ecological knowledge and beliefs. The Hani people’s reverence for nature, respect for life, gratitude towards ancestors, and seeking blessings and disaster prevention for their families, crops, and livestock are all reflected in these rituals and their utilization of ritual plants. The Hani people showcase their agricultural culture in the Honghe Hani Rice Terraces through plant-based ritual performances. Studying ritual plants in the core area of the Hani Rice Terraces is of great significance for protecting the Hani Terrace farming culture. In the future, it is essential to pay more attention to the role of traditional knowledge in biodiversity conservation

Evaluation of ScCO2-water performance on bituminous coal : insights from experiments and 3D CT image reconstruction

Evaluating the coupling of moisture content with supercritical CO2 (ScCO2) in coal is important for CO2 geological sequestration and enhanced coalbed methane recovery. Changes of minerals and microstructure in bituminous coal after ScCO2-water treatment were explored employing X-ray powder diffraction and micro-computed tomography (CT), and the seepage behavior evolution was further investigated by performing computational fluid dynamic analysis after 3D CT reconstruction. The results show that carbonate minerals dissolved remarkably after ScCO2-water treatment, but a reversible chemical reaction occurred in calcite minerals. The induced mineral dissolution, pore-fracture formation and expansion changed the pore-fracture structure in coal significantly. As a result, the amount and diameter of pores and throats obviously increased as the total volume and surface area of the pore-fracture increased to be nearly twice of the original coal. Additionally, the pore-fracture connectivity improved from 44.7 to 67.6% with a coordination number greater than 3 after ScCO2-water treatment. Pores of the equivalent radius of 75 μm were also found to contribute most to the permeability, rather than pores of the largest equivalent radius, as reported previously, indicating both the size and volume proportion of pores should be considered in permeability evaluation. Numerical modeling reveals that pore pressure decays faster along flow pathways after ScCO2-water treatment due to pore-fracture volume enhancement. The ScCO2-water treatment not only increased seepage channels in coal but also intensified the preferential flow. Along with the pore-fracture volume enhancement, the permeability heterogeneity in coal decreased after the ScCO2-water treatment, but the permeability enhancement along different directions varied