电磁场法向分量边界条件非独立性的微分法证明

电磁场的法向分量边界条件不独立 ,但先前关于这一命题的微分法证明有局限性 .文中指出了这一局限性 ,给出了对任何光滑界面普遍适用的微分证明法 .     

Quantitative and reliable in vitro method combining scanning electron microscopy and image analysis for the screening of osteotropic modulators

The increased generation and up-regulated activity of bone resorbing cells (osteoclasts) play a part in the impairment of bone remodeling in many bone diseases. Numerous drugs (bisphosphonates, calcitonin, selective estrogen receptor modulators) have been proposed to inhibit this increased osteoclastic activity. In this report, we describe a pit resorption assay quantified by scanning electron microscopy coupled with image analysis. Total rabbit bone cells with large numbers of osteoclasts were cultured on dentin slices. The whole surface of the dentin slice was scanned and both the number of resorption pits and the total resorbed surface area were measured. Resorption pits appeared at 48 h and increased gradually up to 96 h. Despite the observation of a strong correlation between the total resorption area and the number of pits, we suggest that area measurement is the most relevant marker for osteoclastic activity. Osteotropic factors stimulating or inhibiting osteoclastic activity were used to test the variations in resorption activity as measured with our method. This reproducible and sensitive quantitative method is a valuable tool for screening for osteoclastic inhibitors and, more generally, for investigating bone modulators.     

Low-temperature X-ray microanalysis of the differentiating vascular tissue in root tips of Lemna minor L

The fracture faces of bulk-frozen tissue offer a number of advantages for the analysis of diffusible elements. They are easy to prepare, remain uncontaminated, and, unlike most frozen-hydrated sections, can be shown to exist in a fully hydrated state throughout examination and analysis. Root tips of Lemna minor briefly treated with a polymeric cryoprotectant are quench frozen in melting nitrogen. Fractures are prepared using the AMRAY Biochamber, lightly etched if necessary to reveal surface detail and carbon coated while maintaining the specimen at 110 K. The frozen-hydrated fracture faces are analysed at 110 K using the P/B ratio method which is less sensitive to changes in surface geometry and variations in beam current. The method has been used to investigate the distribution of seven elements (Na+, Mg⁺⁺, P, S, Cl^?, K+ and Ca⁺⁺) in the developing vascular tissue of the root tip. The microprobe can measure relative elemental ratios at the cellular level and the results from this present study reveal important variations in different parts of the root. The younger, more actively dividing cells, appear to have a slightly higher concentration of diffusible ions in comparison to the somewhat older tissues which have begun to differentiate into what are presumed to be functional vascular elements.     

领导-部属交换对组织负面影响机制研究——印象管理的研究视角

在34个团队共688份问卷的基础上,从资源为导向的发展观出发,探讨领导-部属交换水平对员工职业成长的影响机制,并检验了领导-部属交换差异性在上述资源分配影响过程中的调节作用。通过跨层次的研究方法,研究发现领导-部属交换水平对员工职业成长有正向相关作用,并且对员工的迎合行为有正向影响,员工迎合行为在上述影响过程中起到中介作用。在探讨领导-部属交换差异性对上述影响机制的调节作用时,通过数据发现,领导-部属交换差异性在领导-部属交换水平对员工职业成长的影响中有调节作用。阐述了上述研究结论所产生的原因,探讨了领导-部属交换过程领导所面临的双重困境。     

Mitotic Diversity in Homeostatic Human Interfollicular Epidermis

Despite decades of skin research, regulation of proliferation and homeostasis in human epidermis is still insufficiently understood. To address the role of mitoses in tissue regulation, we utilized human long-term skin equivalents and systematically assessed mitoses during early epidermal development and long-term epidermal regeneration. We now demonstrate four different orientations: (1) horizontal, i.e., parallel to the basement membrane (BM) and suggestive of symmetric divisions; (2) oblique with an angle of 45°–70°; or (3) perpendicular, suggestive of asymmetric division. In addition, we demonstrate a fourth substantial fraction of suprabasal mitoses, many of which are committed to differentiation (Keratin K10-positive). As verified also for normal human skin, this spatial mitotic organization is part of the regulatory program of human epidermal tissue homeostasis. As a potential marker for asymmetric division, we investigated for Numb and found that it was evenly spread in almost all undifferentiated keratinocytes, but indeed asymmetrically distributed in some mitoses and particularly frequent under differentiation-repressing low-calcium conditions. Numb deletion (stable knockdown by CRISPR/Cas9), however, did not affect proliferation, neither in a three-day follow up study by life cell imaging nor during a 14-day culture period, suggesting that Numb is not essential for the general control of keratinocyte division.     

Advances and Perspectives in Dental Pulp Stem Cell Based Neuroregeneration Therapies

Human dental pulp stem cells (hDPSCs) are some of the most promising stem cell types for regenerative therapies given their ability to grow in the absence of serum and their realistic possibility to be used in autologous grafts. In this review, we describe the particular advantages of hDPSCs for neuroregenerative cell therapies. We thoroughly discuss the knowledge about their embryonic origin and characteristics of their postnatal niche, as well as the current status of cell culture protocols to maximize their multilineage differentiation potential, highlighting some common issues when assessing neuronal differentiation fates of hDPSCs. We also review the recent progress on neuroprotective and immunomodulatory capacity of hDPSCs and their secreted extracellular vesicles, as well as their combination with scaffold materials to improve their functional integration on the injured central nervous system (CNS) and peripheral nervous system (PNS). Finally, we offer some perspectives on the current and possible future applications of hDPSCs in neuroregenerative cell therapies.     

Mechanical and biological evaluation of 3D printed 10CeTZP-Al2O3 structures

Three-dimensional structures were robocasted from a 10 mol% ceria-stabilized zirconia and alumina composite (10CeTZP-Al₂O₃). A hydrogel-based printable ink was developed using a unique non-ionic copolymer surfactant. Self-supporting and free-standing structures, including round lattices with interconnected pores (200–600 μm pores; 30–50% porosity), rectangular bars (95% density on average) and cones were successfully printed. The round lattices of 200 μm pores and 30% porosity showed compression strengths similar to those of cortical bone, reaching almost 200 MPa. The maximum flexural strength value attained for the rectangular bars was 575 MPa. In vitro biological studies demonstrated that the samples allow for practically 100% cell viability, confirming their non-cytotoxic nature. Cell differentiation tests were performed using osteoblasts incubated for 7 days in supplemented cell culture medium. Quantification of specific osseous differentiation genes showed that the robocasted structures induced a higher degree of osseous differentiation than tissue culture polystyrene.     

城市树木致伤风险可视化评估：以武汉市 中山公园为例

城市中的树木能提供多种生态系统服务，但树木倒 伏、树枝坠落也可能致人伤害，评估城市树木风险能有效地预 防伤害发生、保障人身安全。但当前研究的评估维度多聚焦于 树木自身，对城市人群致伤可能性的考量较少。建构了风险严 重性、风险可能性和致伤潜力3个维度的城市树木致伤风险指 数(I UTIR)评估方法，以武汉市中山公园为例展开树木致伤风险 评估，并分析了树木自身风险、致伤潜力与致伤风险之间的空 间关系。研究发现：68.7%的区域中，树木自身风险与致伤潜 力之间的空间关系呈现正相关性，25.1%的区域呈现负相关 性。在此基础上，提出了预防树木致伤风险的管理建议。为公 园规划设计和树木风险管理策略提供参考，从而减弱树木致伤 风险对人体健康的影响。     

Framework of emergence: from chain of value to value constellation

ABSTRACT

For academic design programmes and research councils, finding mechanisms to measure impact and valuate co-design research projects is very difficult. The metric parameters – number of attendees, volume, shape, length – have shown to be insufficient. The subject matter, the subjects and matters, do not easily fit within these parameters, which fail to translate the value of a ‘constellation of affections’ that emerge throughout co-design processes. Emphasis on quantifiable impact derives from particular ways of understanding production, reproduction, and dissemination of knowledge. This paper understands academic design programmes as a technology to discuss axiology in co-design practices. This paper re-configures a techno-logic of value; from chain of value to value constellation, intersecting a co-design case study with readings of Simondon’s philosophy of technology and Barad’s agential realism. Ageing Playfully was a knowledge exchange project from The Creative Exchange programme, that involved people living with dementia and their caregivers co-designing interventions to boost mobility and well-being. At the core, this paper, explores an axiological move that informs a framework of emergence, a way of thinking in methods to account for the value of co-design as site of emergence.