Buoyancy

浮力
  • 文章类型: Journal Article
    质体是在塑料碎片表面生长的微生物群落,通常与塑料生物膜或生物污染塑料互换使用。它可以以多种方式影响塑料碎片的性质。本文旨在系统地介绍塑料球对微塑料理化性能的影响。它强调了塑料球通过增加微塑料的密度来改变它们的浮力和运动,导致他们下沉并安顿下来。由于更大的表面积和更高的生物污染率,较小的和薄膜的微塑料可能会更快地沉降。由于质体生长的昼夜和季节性变化,生物污染的微塑料在沉降时可能会在水体中显示振荡运动,直到它们接近水体底部并被沉积物截留。塑料球增强了微塑料对金属和有机污染物的吸附,并将吸附机制从颗粒内扩散转移到膜扩散。塑料球还增加了表面粗糙度,减小孔径,并改变了微塑料的整体用量。电荷变化主要归因于微塑料表面上官能团的变化。塑料球引入羰基,胺,酰胺,羟基,和磷酰基到微塑料上,导致其表面亲水性增加,这可能会改变它们对重金属的吸附行为。塑料球可以充当增强极性添加剂的浸出的反应性屏障。它可能会锚定可以分解塑料添加剂的细菌,导致微塑料的结晶度降低。这篇评论有助于更好地理解质体如何改变命运,运输,以及微塑料对环境的影响。它指出了改造塑料球以改善微塑料生物降解的可能性。
    The plastisphere is the microbial communities that grow on the surface of plastic debris, often used interchangeably with plastic biofilm or biofouled plastics. It can affect the properties of the plastic debris in multiple ways. This review aims to present the effects of the plastisphere on the physicochemical properties of microplastics systematically. It highlights that the plastisphere modifies the buoyancy and movement of microplastics by increasing their density, causing them to sink and settle out. Smaller and film microplastics are likely to settle sooner because of larger surface areas and higher rates of biofouling. Biofouled microplastics may show an oscillating movement in waterbodies when settling due to diurnal and seasonal changes in the growth of the plastisphere until they come close to the bottom of the waterbodies and are entrapped by sediments. The plastisphere enhances the adsorption of microplastics for metals and organic pollutants and shifts the adsorption mechanism from intraparticle diffusion to film diffusion. The plastisphere also increases surface roughness, reduces the pore size, and alters the overall charge of microplastics. Charge alteration is primarily attributed to changes in the functional groups on microplastic surfaces. The plastisphere introduces carbonyl, amine, amide, hydroxyl, and phosphoryl groups to microplastics, causing an increase in their surface hydrophilicity, which could alter their adsorption behaviors for heavy metals. The plastisphere may act as a reactive barrier that enhances the leaching of polar additives. It may anchor bacteria that can break down plastic additives, resulting in decreased crystallinity of microplastics. This review contributes to a better understanding of how the plastisphere alters the fate, transport, and environmental impacts of microplastics. It points to the possibility of engineering the plastisphere to improve microplastic biodegradation.
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  • 文章类型: Journal Article
    语言教师免疫的概念是在语言教师心理学领域引入的一个相对较新的概念。教师必须加强其固有的免疫力,因为他们从来没有受到内在的保护,免受意外和无法控制的波动。为了实现这一目标,本研究采用定量的方法来探讨教师免疫力对心理健康的可能影响,浮力,和订婚。本研究是通过向384名小学语文教师发放三份问卷进行的。根据调查结果,结论是,教师免疫力有可能作为英语作为外语(EFL)教师的心理健康的重要预测指标,浮力,和订婚。这项研究的结论可能对教育在促进心理健康方面具有重要意义,浮力,和订婚。
    The concept of language teacher immunity is a relatively new notion that has been introduced in the field of language teacher psychology. It is imperative that teachers have their inherent immunity strengthened since they have never been intrinsically protected against fluctuations that are unanticipated and beyond their control. In order to achieve this goal, the present research used a quantitative approach in order to investigate the possible effects of teacher immunity on their psychological well-being, buoyancy, and engagement. This study was conducted by sending out three questionnaires to a total of 384 primary language teachers. On the basis of the findings, it was concluded that teacher immunity has the potential to serve as a significant predictor of English as a foreign language (EFL) teachers\' psychological well-being, buoyancy, and engagement. The research\'s conclusions may have substantial implications for education in terms of advancing psychological well-being, buoyancy, and engagement.
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  • 文章类型: Journal Article
    在过去的十年里,微机器和纳米机器(MNMs)在靶向给药领域取得了突出的成就,肿瘤治疗,显微外科,生物检测,以及环境监测和修复。研究人员做出了巨大的努力,以加速能够通过不同能源(化学反应,超声,光,电力,磁性,热,或其组合)。然而,MNM的运动主要在有限的二维(2D)水平设置中进行研究。此外,三维(3D)运动控制仍然具有挑战性,特别是垂直运动和控制,大大限制了其在货物运输中的潜在应用,环境修复,和生物治疗。因此,迫切需要开发能够克服自重力并在3D空间中可控移动的MNM。这篇综述深入研究了在不同操纵方法下具有3D运动功能的MNM的最新进展,讨论了潜在的运动机制,探索受自然启发的潜在设计概念,用于MNM中可控的3D运动,并介绍了可用的3D观察和跟踪系统。
    In the past decade, micro- and nanomachines (MNMs) have made outstanding achievements in the fields of targeted drug delivery, tumor therapy, microsurgery, biological detection, and environmental monitoring and remediation. Researchers have made significant efforts to accelerate the rapid development of MNMs capable of moving through fluids by means of different energy sources (chemical reactions, ultrasound, light, electricity, magnetism, heat, or their combinations). However, the motion of MNMs is primarily investigated in confined two-dimensional (2D) horizontal setups. Furthermore, three-dimensional (3D) motion control remains challenging, especially for vertical movement and control, significantly limiting its potential applications in cargo transportation, environmental remediation, and biotherapy. Hence, an urgent need is to develop MNMs that can overcome self-gravity and controllably move in 3D spaces. This review delves into the latest progress made in MNMs with 3D motion capabilities under different manipulation approaches, discusses the underlying motion mechanisms, explores potential design concepts inspired by nature for controllable 3D motion in MNMs, and presents the available 3D observation and tracking systems.
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  • 文章类型: Journal Article
    在本研究中,我们开发了新型胃滞留双层片剂,有望用于候选药物MT-1207的每日一次口服给药.胃滞留层由亲水和疏水聚合物的组合组成,即聚环氧乙烷和Kollidon®SR。进行了阶乘实验,结果揭示了一个非泡腾的胃滞留层,与文献中报道的大多数胃滞留层不同,很容易准备,并提供即时片剂浮力(平均浮动滞后时间1.5秒),在禁食状态下持续超过24小时模拟胃液(FaSSGF)pH1.6,与药物层无关,从而允许MT-1207从片剂的药物层持续释放24小时。此外,在不同pH值(1.0、3.0、6.0)介质中优化的双层片剂的体外浮力测试期间,显著差异(单向方差分析,在各自的总漂浮时间之间的p<0.001)表明,在非泡腾胃滞留制剂的开发和给药方案的选择过程中,必须考虑胃pH对片剂浮力的影响。据我们所知,这以前没有报道过,在设计给药方案时,它可能应该被考虑在内。最后,在Beagle犬中进行的一项药代动力学研究表明,MT-1207在24小时时间点从优化的胃滞留双层片剂中成功地在体内24小时持续释放,药物血浆浓度保持在估计的最小有效浓度1ng/mL以上,并且还证明了亲水性和疏水性聚合物组合的胃滞留能力.优化的配方将被转发到临床开发。
    In the present study, novel gastroretentive bilayer tablets were developed that are promising for the once-a-day oral delivery of the drug candidate MT-1207. The gastroretentive layer consisted of a combination of hydrophilic and hydrophobic polymers, namely polyethylene oxide and Kollidon® SR. A factorial experiment was conducted, and the results revealed a non-effervescent gastroretentive layer that, unlike most gastroretentive layers reported in the literature, was easy to prepare, and provided immediate tablet buoyancy (mean floating lag time of 1.5 s) that lasted over 24 h in fasted state simulated gastric fluid (FaSSGF) pH 1.6, irrespective of the drug layer, thereby allowing a 24-hour sustained release of MT-1207 from the drug layer of the tablets. Furthermore, during in vitro buoyancy testing of the optimised bilayer tablets in media of different pH values (1.0, 3.0, 6.0), the significant difference (one-way ANOVA, p < 0.001) between the respective total floating times indicated that stomach pH effects on tablet buoyancy are important to be considered during the development of non-effervescent gastroretentive formulations and the choice of dosing regimen. To the best of our knowledge, this has not been reported before, and it should probably be factored in when designing dosing regimens. Finally, a pharmacokinetic study in Beagle dogs indicated a successful in vivo 24-hour sustained release of MT-1207 from the optimised gastroretentive bilayer tablet formulations with the drug plasma concentration remaining above the estimated minimum effective concentration of 1 ng/mL at the 24-hour timepoint and also demonstrated the gastroretentive capabilities of the hydrophilic and hydrophobic polymer combination. The optimised formulations will be forwarded to clinical development.
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  • 文章类型: Journal Article
    各类放射性核素具有不同的大气扩散特性,如轻气体和重颗粒的浮力和重力沉积现象,分别。高斯羽流模型被广泛用于描述放射性流出物的大气扩散行为,特别是用于工程环境影响评估或核应急支持的目的。尽管如此,浮力和重力沉积在以前的工作中很少报道,特别是氚,这可能会导致对公众评估近地表浓度分布和辐射剂量的偏差。基于多种形式的氚案例,我们对浮力和重力沉积现象进行了定量描述,并讨论了建立改进的高斯羽流模型来预测近地表浓度分布的可行性。首先,通过使用计算流体动力学方法(CFD)和标准高斯羽流模型来预测表面附近的tri浓度分布,以达到一致性,而无需考虑浮力和重力沉积效应。其次,通过气态tri的物种迁移模型和液滴tri的离散相模型,结合气态tri的密度变化引起的浮力和足够大小的液滴tri的重力,确定了浮力和重力沉积的影响。第三,获得了浮力和重力沉积校正因子,以修改标准高斯羽流模型。最后,将改进高斯羽流模型的预测结果与CFD方法进行了比较。事实证明,改进的校正方法可以更准确地预测具有密度变化的气态污染物或具有重力沉积特性的颗粒的大气浓度分布。
    Various types of radionuclides have different atmospheric dispersion characteristics, such as buoyancy and gravitational deposition phenomenon of light gas and heavy particles, respectively. Gaussian plume model was widely used to describe atmospheric dispersion behaviors of radioactive effluents, particularly for the purpose of engineering environmental impact assessment or nuclear emergency support. Nonetheless, buoyancy and gravitational deposition were rarely reported in previous work for tritium in particular, which might cause a deviation in evaluating near-surface concentration distribution and radiation dose to the public. Based on the multi-form tritium case, we made a quantitative description for the buoyancy and gravitational deposition phenomenon and discussed the feasibility of developing an improved Gaussian plume model to predict near-surface concentration distribution. Firstly, tritium concentration distribution near to the surface was predicted by using computational fluid dynamics method (CFD) and standard Gaussian plume model to reach consistency without consideration of buoyancy and gravitational deposition effects. Secondly, effects of buoyancy and gravitational deposition were identified by species transport model for gaseous tritium and discrete phase model for droplet tritium with integrating the buoyancy force caused by density variation of gaseous tritium and gravitational force of droplet tritium with enough size. Thirdly, buoyancy and gravitational deposition correction factors were obtained to modify the standard Gaussian plume model. Lastly, predictive results by improved Gaussian plume model were compared with CFD method. It was proved the improved correction method enables higher accuracy in predicting the atmospheric concentration distribution of gaseous pollutants with density variation or particles with gravitational deposition properties.
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  • 文章类型: Journal Article
    光是藻类生长和表面水华形成的重要驱动力。微囊藻菌落的长期浮力维持对于它们在水面的聚集和随后的藻华发展至关重要。然而,光介导的菌落形态变化对微囊藻菌落浮力调节的影响尚不清楚。在这项研究中,生长参数,确定了微囊藻菌落的菌落形态和漂浮/下沉性能,以探索在不同光照条件下菌落形态的变化如何影响菌落的浮力。我们通过细胞体积与菌落体积之比(VR)来量化菌落紧密度,并发现在不同光强度下菌落大小和VR的不同响应。在低光照条件下,VR较高的微囊藻菌落可以在水面停留更长时间,有利于长期生长和浮力维持。然而,在相对较高的光强度下,在较晚的生长阶段观察到菌落大小增加和紧密度降低(即,>108μmol光子m-2s-1)。有趣的是,我们发现在高光照强度下,微囊藻的菌落大小与浮力之间存在违反直觉的负相关。此外,我们发现,在高光照强度下,菌落形态对浮力的影响更强。这些结果表明,光可以通过菌落形态调节浮力,并且在可变环境条件下的进一步研究中需要考虑菌落形态在浮力调节中的作用。
    Light is an important driver of algal growth and for the formation of surface blooms. Long-term buoyancy maintenance of Microcystis colonies is crucial for their aggregation at the water surface and the following algal bloom development. However, the effect of light-mediated variations of colony morphology on the buoyancy regulation of Microcystis colonies remains unclear. In this study, growth parameters, colony morphology and floatation/sinking performance of Microcystis colonies were determined to explore how variations in colony morphology influence the buoyancy of colonies under different light conditions. We quantified colony compactness through the cell volume to colony volume ratio (VR) and found different responses of colony size and VR under different light intensities. Microcystis colonies with higher VR could stay longer at the water surface under low light conditions, which was beneficial for the long-term growth and buoyancy maintenance. However, increased colony size and decreased compactness were observed at a later growth stage under relatively higher light intensity (i.e., >108 µmol photons m-2 s-1). Interestingly, we found a counterintuitive negative correlation between colony size and buoyancy of Microcystis under high light intensity. Additionally, we found that the influence of colony morphology on buoyancy was stronger at high light intensity. These results indicate that light could regulate the buoyancy via colonial morphology and that the role of colony morphology in buoyancy regulation needs to be accounted for in further studies under variable environmental conditions.
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  • 文章类型: Journal Article
    作为英语学习者成就和智力发展不可或缺的一部分,好的语言教师需要熟悉阻碍或促进他们成功的影响因素。关注积极特质的积极心理学突出了提高绩效的因素。在这行,通过成为一名成功教师的支持者,本研究的目的是考虑中国英语教师职业成功之间的相互作用,工作场所浮力,和认知灵活性。然后,人们认为英语教师的浮力和认知灵活性是否可以预测成功。因此,328名中国英语教师被方便地选择参加这项研究。为了分析收集的数据,采用多元回归分析和SpearmanRho相关指数以及方差分析。这些发现表明了EFL教师认知灵活性之间的直接和显著的相关性和协同作用,工作场所浮力,专业的成功。此外,结果表明,英语教师的认知灵活性可以成为其职业成功的重要预测因素之一。我们的发现暗示,教师需要增强其积极的人格特质,例如认知灵活性和浮力,才能在职业中取得成功。
    As integral to the EFL learners\' achievement and intellectual development, good language teachers need to be familiar with the influential factors hindering or promoting their success. Positive psychology paying attention to positive traits highlights the factors that boost performance. In this line, by taking boosters of being a successful teacher, the aim of the current study is to consider the interplay between Chinese EFL instructors\' professional success, workplace buoyancy, and cognitive flexibility. Then, it is considered whether EFL teachers\' buoyancy and cognitive flexibility can predict success. Accordingly, 328 Chinese EFL teachers were conveniently selected to participate in this study. To analyze the collected data, multiple regression analysis and Spearman Rho correlation index as well as ANOVA were employed. The findings are an indication of a direct and significant correlation and coaction among EFL teachers\' cognitive flexibility, workplace buoyancy, and professional success. Additionally, the results indicate that the cognitive flexibility of EFL teachers can be one of the significant predictors of success in their profession. Our findings imply that teachers need to enhance their positive personality traits such as cognitive flexibility and buoyancy to be successful in their profession.
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  • 文章类型: Journal Article
    Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids. However, the molecular mechanisms underlying the regulation of spawning habits are not well understood. We recently identified zona pellucida (Zp) as the top differentially expressed protein between East Asian cyprinids that produce adhesive and semi-buoyant eggs, suggesting that Zp protein may play important roles in the regulation of egg type. In this work, we generated transgenic zebrafish in which oocyte-specific expression of zp genes from rare minnow ( Gobiocypris rarus), an East Asian cyprinid laying adhesive eggs, was driven by a zebrafish zp3.2 gene promoter. We found that the transgenic eggs obtained partial adhesiveness and exhibited alteration in hydration and buoyancy. Abnormal metabolism of vitellogenin (VTG) may contribute to enhanced hydration and/or buoyancy. Our work shows that expression of the exogenous zp3a gene from an adhesive-egg producing fish is sufficient to induce changes in both egg adhesiveness and buoyancy in zebrafish, emphasizing the important role of zp genes in the regulation of spawning habits. Our results thus provide new insights into how endemic East Asian cyprinids may have adapted to the Yangtze river-lake system via changes in spawning habits.
    繁殖策略和产卵习性对于鲤科鱼类东亚特有类群的演化具有重要意义。然而,调控产卵习性的分子机制尚未明确。我们近期的研究发现,在产黏性卵和半浮性卵的东亚鲤科鱼类中,Zp蛋白的表达量差异最大,提示其在卵型调控中可能具有重要作用。稀有鮈鲫( Gobiocypris rarus)是一种产黏性卵的东亚特有理科鱼类,在该研究中,我们利用斑马鱼 zp3.2基因的启动子,构建了能表达稀有鮈鲫卵巢特异性Zp蛋白的转基因斑马鱼品系。我们发现转基因品系所产鱼卵获得了部分黏性并且水合作用以及浮性也出现变化。过去有研究指出,卵黄蛋白原代谢异常可能导致鱼卵水合作用和/或浮性发生改变。我们的研究表明,在斑马鱼中内源性表达产黏性卵鱼类的 zp3a基因,就足以引起其鱼卵的黏性及浮性都发生变化,暗示着 zp基因在调控鱼卵类型中具有重要作用。我们的结果为鲤科鱼类东亚特有类群如何通过改变产卵习性适应长江江湖复合生态系统提供了新见解。.
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  • 文章类型: Journal Article
    Tritium contributes majority to the total airborne radioactive effluents from the nuclear facility because of its considerable production and difficulty in separation. Tritium inventory in the fusion reactor would reach an unprecedented magnitude which brings new safety concern. After being released into the atmosphere, inconsistent atmospheric dispersion behaviors might appear regarding different physicochemical forms such as gaseous state HT, gaseous-aerosol-droplet state HTO. In this study, atmospheric dispersion characteristics of multi-form tritium were investigated based on the computational fluid dynamics method validated by multi-fan type wind tunnel experiments. Species transport model and discrete phase model were used to describe atmospheric dispersion of gaseous and aerosol-droplet state tritium, respectively. Deposition velocity was predicted for gaseous and aerosol-droplet state tritium with different particle sizes. Conditions for describing the changes of particle diameter and its influencing on near-surface tritium distribution due to condensation were provided. The results show that buoyancy effect would strengthen along with the increasing gaseous tritium mass fraction in the airborne effluents. We also indicated that obvious gravitational deposition would appear once gaseous HTO was transformed into droplet state HTO with the particle diameter larger than 20 μm. Both the atmospheric buoyancy and deposition phenomenon would result in a quite different near-surface tritium distribution.
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  • 文章类型: Journal Article
    教师通过在教育空间中的努力,在培养社区未来成员方面发挥着主要作用,事实上,没有热情和忠诚的教育工作者的最终决定,教育质量就不会实现。从今以后,有必要对教师承诺的概念和影响教师承诺的方面进行更多的调查。教育者承诺在影响教育者的陈述方面具有重要的功能;因此,有必要确定有助于教育者承诺的基本要素。此外,浮力是心理教育环境中的另一个基本构造,可以帮助人们应对学术挑战。心理健康是另一个被认为是学术环境中一个重要维度的术语。本综述试图使用积极心理学的理论议程和社会认知理论来关注影响教育工作者工作承诺的心理健康和浮力。简洁地,这篇文献综述对学者们有启示,理论家,和从业者寻求检查浮力和心理健康对教师专业承诺的作用。
    Teachers have the main role in cultivating the future members of the community by their effort in the educational space, and indeed, the quality of education would not be accomplished without the ultimate determinations of enthusiastic and committed educators. Henceforth, there is a need for more investigation regarding the conception of teacher commitment and the aspects that affect it. Educator commitment has an important function in influencing educators\' presentation; thus, it is necessary to determine the fundamental elements that contribute to educator commitment. Moreover, buoyancy is another fundamental construct in a psycho-educational environment helping people with academic challenges. Psychological health is another term considered as a significant dimension in an academic environment. The present review tries to focus on psychological health and buoyancy that affect educators\' job commitment using the theoretical agenda of positive psychology and the sociocognitive theory. Succinctly, this review of the literature has implications for scholars, theorists, and practitioners seeking for inspecting the roles of buoyancy and psychological health on teachers\' professional commitment.
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