58 research outputs found
Text-Image Conditioned Diffusion for Consistent Text-to-3D Generation
By lifting the pre-trained 2D diffusion models into Neural Radiance Fields
(NeRFs), text-to-3D generation methods have made great progress. Many
state-of-the-art approaches usually apply score distillation sampling (SDS) to
optimize the NeRF representations, which supervises the NeRF optimization with
pre-trained text-conditioned 2D diffusion models such as Imagen. However, the
supervision signal provided by such pre-trained diffusion models only depends
on text prompts and does not constrain the multi-view consistency. To inject
the cross-view consistency into diffusion priors, some recent works finetune
the 2D diffusion model with multi-view data, but still lack fine-grained view
coherence. To tackle this challenge, we incorporate multi-view image conditions
into the supervision signal of NeRF optimization, which explicitly enforces
fine-grained view consistency. With such stronger supervision, our proposed
text-to-3D method effectively mitigates the generation of floaters (due to
excessive densities) and completely empty spaces (due to insufficient
densities). Our quantitative evaluations on the TBench dataset demonstrate
that our method achieves state-of-the-art performance over existing text-to-3D
methods. We will make the code publicly available
The Sediment Selectivity of Perinereis aibuhitensis Larvae: Active or Passive?
The selectivity of Perinereis aibuhitensis larvae on different sediment types was studied using an experimental behavioral device in the lab. There were six types of sediment with different organic matter content: 2.19, 2.30, 2.86, 3.25, 3.51, and 5.52%. The results indicated significant differences in the six treatments’ organic matter content (p < 0.05). When the P. aibuhitensis larvae initially attached to the sediment, the larvae’s density showed no significant difference among the six treatments. The density of larvae decreased gradually during the experimental period. It increased with the increasing organic matter content in sediment at every sampling time, but there was no significant difference (p > 0.05). The larvae’s specific growth rate in the first month was significantly higher than those in the second and third months (p < 0.05). The mortality showed no significance at different sediments in equal sampling times, but the mortality was lower in high organic matter content sediments. This study showed that the P. aibuhitensis larvae did not make an active selection; random selection happened when initially attached to the sediment with different organic matter contents. Higher organic matter content in the sediment was more conducive to larvae survival, and the organic matter content is the limitation factor on the mortality and the density. The different densities in the natural habitat of P. aibuhitensis might occur due to the passive selection by the environment
Protective Effect of Ocotillol, the Derivate of Ocotillol-Type Saponins in Panax Genus, against Acetic Acid-Induced Gastric Ulcer in Rats Based on Untargeted Metabolomics
Gastric ulcer (GU), a prevalent digestive disease, has a high incidence and is seriously harmful to human health. Finding a natural drug with a gastroprotective effect is needed. Ocotillol, the derivate of ocotillol-type saponins in the Panax genus, possesses good anti-inflammatory activity. The study aimed to investigate the gastroprotective effect of ocotillol on acetic acid-induced GU rats. The serum levels of endothelin-1 (ET-1) and nitric oxide (NO), the gastric mucosa levels of epidermal growth factor, superoxide dismutase and NO were assessed. Hematoxylin and eosin staining of gastric mucosa for pathological changes and immunohistochemical staining of ET-1, epidermal growth factor receptors and inducible nitric oxide synthase were evaluated. A UPLC-QTOF-MS-based serum metabolomics approach was applied to explore the latent mechanism. A total of 21 potential metabolites involved in 7 metabolic pathways were identified. The study helps us to understand the pathogenesis of GU and to provide a potential natural anti-ulcer agent
Label-Free Spectral Imaging Unveils Biochemical Mechanisms of Low-Level Laser Therapy on Spinal Cord Injury
Background/Aims: Low-level laser therapy (LLLT) leads to complex photochemical responses during the healing process of spinal cord injury (SCI). Confocal Raman Microspectral Imaging (in combination with multivariate analysis) was adopted to illustrate the underlying biochemical mechanisms of LLLT treatment on a SCI rat model. Methods: Using transversal tissue sections, the Raman spectra can identify areas neighboring the injury site, glial scar, cavity, and unharmed white matter, as well as their correlated cellular alterations, such as demyelination and up-regulation of chondroitin sulfate proteoglycans (CSPGs). Multivariate data analysis methods are used to depict the underlying therapeutic effects by highlighting the detailed content and distribution variations of the biochemical constituents. Results: It is confirmed that photon-tissue interactions might lead to a decay of the inhibitory response to remyelination by suppressing CSPG expression, as also morphologically demonstrated by reduced glial scar and cavity areas. An inter-group comparison semi-quantitatively confirms changes in lipids, phosphatidic acid, CSPGs, and cholesterol during SCI and its LLLT treatment, paving the way for in vitro and in vivo understanding of the biochemical changes accompanying pathobiological SCI events. Conclusion: The achieved results in this work not only have once again proved the well-known cellular mechanisms of SCI, but further illustrate the underlying biochemical variability during LLLT treatment, which provide a sound basis for developing real-time Raman methodologies to monitor the efficacy of the SCI LLLT treatment
Near-atomic cryo-electron microscopy structures of varicella-zoster virus capsids
VZV是一种广泛存在并且具有高度传染性的人类α-疱疹病毒。初次感染VZV可导致水痘,人群普遍易感(感染率约为61%~100%)。该病毒可在背根神经节潜伏感染,持续终生。夏宁邵教授团队长期开展VZV相关基础与新型疫苗研究,通过系统和精细探索建立了高效的VZV规模化培养和病毒颗粒纯化技术体系,成功获得高质量的VZV颗粒样品。首次揭示了疱疹病毒α家族的水痘-带状疱疹病毒(VZV)不同类型核衣壳的近原子分辨率结构,阐明了VZV核衣壳不同组成蛋白的相互作用网络与衣壳装配机制,可为进一步开展新型载体疫苗设计及抗病毒药物等研究提供重要支持。
我校博士后王玮、高级工程师郑清炳、博士生潘德全和俞海副教授为该论文共同第一作者,我校夏宁邵教授、程通副教授、李少伟教授以及美国罗格斯大学朱桦(Hua Zhu)教授、加利福尼亚大学洛杉矶分校周正洪(Z. Hong Zhou)教授为该论文的共同通讯作者。【Abstract】Varicella-zoster virus (VZV) is a medically important human herpesvirus that causes chickenpox and shingles, but its cell-associated nature has hindered structure studies. Here we report the cryo-electron microscopy structures of purified VZV A-capsid and C-capsid, as well as of the DNA-containing capsid inside the virion. Atomic models derived from these structures show that, despite enclosing a genome that is substantially smaller than those of other human herpesviruses, VZV has a similarly sized capsid, consisting of 955 major capsid protein (MCP), 900 small capsid protein (SCP), 640 triplex dimer (Tri2) and 320 triplex monomer (Tri1) subunits. The VZV capsid has high thermal stability, although with relatively fewer intra- and inter-capsid protein interactions and less stably associated tegument proteins compared with other human herpesviruses. Analysis with antibodies targeting the N and C termini of the VZV SCP indicates that the hexon-capping SCP—the largest among human herpesviruses—uses its N-terminal half to bridge hexon MCP subunits and possesses a C-terminal flexible half emanating from the inner rim of the upper hexon channel into the tegument layer. Correlation of these structural features and functional observations provide insights into VZV assembly and pathogenesis and should help efforts to engineer gene delivery and anticancer vectors based on the currently available VZV vaccine.This research was supported by grants from the National Science and Technology Major Projects for Major New Drugs Innovation and Development (no. 2018ZX09711003-005-003), the National Science and Technology Major Project of Infectious Diseases (no. 2017ZX10304402), the National Natural Science Foundation of China (no. 81871648, 81601762), the Research Unit of Frontier Technology of Structural Vaccinology of Chinese Academy of Medical Sciences (no. 2019RU022) and the US National Institutes of Health (DE025567/028583).
该研究获得了国家自然科学基金、新药创制国家科技重大专项和传染病防治国家科技重大专项等资助
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Revealing the crystalline packing structure of Y6 in the active layer of organic solar cells: the critical role of solvent additives
The bulk heterojunction (BHJ) morphology of photovoltaic materials is crucial to the fundamental optoelectronic properties of organic solar cells (OSCs). However, in the photoactive layer, the intrinsic crystalline packing structure of Y6, currently the hallmark molecule among Y-series non-fullerene acceptors (NFAs), has not been unambiguously determined. Here, employing grazing-incidence wide-angle X-ray scattering (GIWAXS), we managed to uncover the intrinsic crystalline packing structure of Y6 in the BHJ active layer of OSCs, which is found to be different from its single-crystal structure reported previously. Moreover, we find that solvent additive 1-chloronaphthalene (CN) can induce highly ordered packing of Y6 in BHJ thin films. With the help of atomistic molecular dynamics simulations, it is revealed that π-π interactions generally exist between naphthalene derivatives and IC terminals of Y6 analogues, which would essentially improve their long-range ordering. Our work reveals the intrinsic crystalline packing structure of Y6 in the BHJ active layer as well as its crystallization mechanism in thin films, thus providing direct correlations between this crystalline packing and the device characteristics and photophysical properties.Knut och Alice Wallenbergs StiftelseImmediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
The interplay between digital game co-play and parent-child relationship
The relationship between digital game co-play and the parent-child relationship has gained increasing attention in HCI research. Although plenty of work has focused on the one-way impact of co-play on the parent-child relationship, there is still room for research on the interrelationship between them. In this thesis, by interviewing 13 parents who regularly play digital games with their children, we investigated how digital game co-play influences the parent-child relationship, and how the parent-child relationship influences the co-play experience. The result suggests a clear mutual impact. On one hand, digital games promote communication and interaction between parents and children, helping them empathize with and learn about each other more deeply, creating an equal atmosphere for the family; on the other hand, the parent-child relationship affects the PX (player experience) of parents and children, making them pay more attention on each other than on the game. Based on these findings, we suggest some implications for parent-child games, which help them to increase their player experiences and enhance family relationships simultaneously
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