运筹学是什么

指出运筹学是一种探索最优化的文化.     

Development of a macro-scale model from a meso-scale model for cell culture population dynamics

In this paper, we present a novel macro-scale analytical model that allows the prediction of how the population size will change in a cell culture starting from an arbitrary initial value. General biological knowledge and some empirical observations are used to design an agent-based discrete-time model at the meso-scale, which then serves as a simulation environment and provides the necessary insights for the development of the continuous-time, differential equation-based, compact macro-scale model. This model can be parameter-tuned and employed for predicting how the population size changes. The paper gives a procedure for the estimation of parameter values of the macro-scale model via some simple tests to be conducted on the cell culture at hand. The performance of the macro-scale model is validated via simulation results that show how well the macro-scale model captures the population dynamics as obtained from the meso-scale model, while the biological plausibility of the meso-scale model is taken for granted.     

Covalent Attachment of Fibronectin onto Emulsion‐Templated Porous Polymer Scaffolds Enhances Human Endometrial Stromal Cell Adhesion,Infiltration, and Function

A novel strategy for the surface functionalization of emulsion‐templated highly porous (polyHIPE) materials as well as its application to in vitro 3D cell culture is presented. A heterobifunctional linker that consists of an amine‐reactive N‐hydroxysuccinimide ester and a photoactivatable nitrophenyl azide, N‐sulfosuccinimidyl‐6‐(4′‐azido‐2′‐nitrophenylamino)hexanoate (sulfo‐SANPAH), is utilized to functionalize polyHIPE surfaces. The ability to conjugate a range of compounds (6‐aminofluorescein, heptafluorobutylamine, poly(ethylene glycol) bis‐amine, and fibronectin) to the polyHIPE surface is demonstrated using fluorescence imaging, FTIR spectroscopy, and X‐ray photoelectron spectroscopy. Compared to other existing surface functionalization methods for polyHIPE materials, this approach is facile, efficient, versatile, and benign. It can also be used to attach biomolecules to polyHIPE surfaces including cell adhesion‐promoting extracellular matrix proteins. Cell culture experiments demonstrated that the fibronectin‐conjugated polyHIPE scaffolds improve the adhesion and function of primary human endometrial stromal cells. It is believed that this approach can be employed to produce the next generation of polyHIPE scaffolds with tailored surface functionality, enhancing their application in 3D cell culture and tissue engineering whilst broadening the scope of applications to a wider range of cell types.     

Investigating How Organic Solvents Affect Tissue Culture Polystyrene Surfaces through Responses of Mesenchymal Stem Cells

Polymer coating of tissue culture polystyrene (TCPS) surfaces promotes their biofunctionality, which can aid manipulation of cellular functions. However, the effect of the solvent used for polymer coating is yet to be elucidated. In this study, solvent‐treated TCPS surfaces using water, methanol, ethanol, 2‐propanol, and dimethyl sulfoxide are fabricated. Solvent treatment of TCPS surfaces is performed by spreading solvents onto the surfaces and allowing them to dry. Solvent treatment changes the surface roughness and wettability, depending on the kind of solvents. In addition, these surface property changes affected the extension, proliferation, and differentiation of human bone marrow–derived mesenchymal stem cells. These results suggest that solvent selection for polymer coating is crucial in the regulation of cell responses. Further, treatment with an appropriate solvent can result in a more suitable culture environment for modulating cellular functions.     

大处着眼，小处入手——基金委化学科学部2019年基金项目会议评审工作的几点尝试和思考

The National Natural Science Foundation of China (NSFC) is a vital government agency supporting basic research and people to create knowledge and meet major national needs, where a rigorous and objective merit-based peer review mechanism is the key to funding the most promising research proposals. This invited comment overviews some recent attempts aimed at bettering the academic evaluation environment at the Department of Chemical Science in 2019, through measures such as grouped panel committee meetings, standardized panel committee meeting procedures, and review process refinement to improve the project review at panel committee meeting levels.     

Photodegradation actuated shape-changing hydrogels

Hydrogels are attractive materials for generating 4D shapes due to their ability to undergo pronounced volume changes in response to several stimuli, including light. We previously reported shape-changing hydrogels actuated by long-wave UV and visible light in the presence of live cells using poly(ethylene glycol) macromers incorporating different photodegradable ortho-nitrobenzyl (o-NB) groups. In this comprehensive study, we determine the effect of chemical structure of different o-NB macromers (which influences molar absorptivity and rate constant of degradation), composition (macromer weight percent), fabrication design (initial gel thickness) and environment (ionic strength of solution) on light-induced hydrogel folding. We demonstrate successful photopolymerization and subsequent photodegradation of hydrogels, multistep folding, and live-cell encapsulation. This hydrogel system may be useful as new tool in stem cell differentiation and developmental biology research, facilitating the in vitro investigation of processes that are sensitive to both physical and temporal stimuli.     

Determination of lignans,phenolic acids and antioxidant capacity in transformed hairy root culture of Linum usitatissimum

Hairy root culture is a promising alternative method for the production of secondary metabolites. In this study, transformed root of Linum usitatissimum was established using Agrobacterium rhizogenes A4 strain from root cultures for lignans, phenolic acids and antioxidant capacity determination. Total lignin content (secoisolariciresinol diglucoside, secoisolariciresinol and matairesinol) was 55.5% higher in transformed root cultures than in the non-transformed root culture. Secoisolariciresinol was detected in higher concentration (2.107 μmol/g DM) in the transformed root culture than non-transformed culture (1.099 μmol/g DM). Secoisolariciresinol diglucoside and matairesinol were exclusively detected in the transformed root culture, but were not found in the non-transformed root culture. The overall production of phenolic acids in transformed roots was approximately 3.5 times higher than that of the corresponding non-transformed culture. Free radical scavenging DPPH˙ and ABTS˙⁺ assays showed 2.9-fold and 1.76-fold higher anti-oxidant activity in transformed root culture as compared to non-transformed.     

《茶经》中的中学化学课程资源

唐代陆羽撰写的《茶经》被誉为“茶叶百科全书”,是中国乃至世界上最早关于茶文化的史料,也是保留最完整、最全面的茶学专著。通过探析《茶经》中蕴含的育人价值,挖掘《茶经》中的化学课程资源。在化学教学中,将《茶经》中与化学知识契合的传统文化内容作为情境载体建立学习桥梁,从化学角度对传统文化内容进行再认识,从文化视角感受化学中蕴含的人文底蕴,帮助学习和理解化学知识,增强文化认同感和民族自豪感。依据新课标中的情境素材建议与要求,梳理了《茶经》中可与高中化学教科书相联系的内容,为创设真实的情境提供素材,利用古代茶器具与中学化学实验仪器之间的相似性创设情境。并且提出了关于中学化学教学中有效融入传统文化的几点建议。     

Formation and recovery of a cell sheet by a particle monolayer with the surface roughness

We studied the topographical effect of roughness displayed by a closely packed particle monolayer on formation of a cell monolayer (cell sheet). Particle monolayers were prepared by Langmuir-Blodgett deposition using particles, which were 527nm (SA053) and 1270nm (SA127) in diameter. Human umbilical vein endothelial cells (HUVECs) were seeded at a high density (2.0 x10(5)cells/cm(2)) onto particle monolayers. It was found that cells gradually became into contact with adjacent cells on the SA053 monolayer and the formed cell sheet could be readily detached from the particle monolayer by gentle pipetting. On the other hand, cells adhering onto the tissue culture polystyrene (TCPS) and the SA127 particle monolayer were difficult to peel off. At a low cell seeding density (5.0x10(4)cells/cm(2)), pre-coating with bovine plasma fibronectin (FN) allowed cell growth on an SA053 particle monolayer, and a confluent monolayer was able to be peeled as a cell sheet from the particle monolayer just by pipetting. By immunostaining of human fibronectin, we found that fibronectin was secreted and concentrated onto the substrate side of a cell sheet. The obtained cell sheet adhered and grew on the TCPS again within 20min.     

Gelation Kinetics and Mechanical Properties of Thiol-Tetrazole Methylsulfone Hydrogels Designed for Cell Encapsulation

Hydrogel precursors that crosslink within minutes are essential for the development of cell encapsulation matrices and their implementation in automated systems. Such timescales allow sufficient mixing of cells and hydrogel precursors under low shear forces and the achievement of homogeneous networks and cell distributions in the 3D cell culture. The previous work showed that the thiol-tetrazole methylsulfone (TzMS) reaction crosslinks star-poly(ethylene glycol) (PEG) hydrogels within minutes at around physiological pH and can be accelerated or slowed down with small pH changes. The resulting hydrogels are cytocompatible and stable in cell culture conditions. Here, the gelation kinetics and mechanical properties of PEG-based hydrogels formed by thiol-TzMS crosslinking as a function of buffer, crosslinker structure and degree of TzMS functionality are reported. Crosslinkers of different architecture, length and chemical nature (PEG versus peptide) are tested, and degree of TzMS functionality is modified by inclusion of RGD cell-adhesive ligand, all at concentration ranges typically used in cell culture. These studies corroborate that thiol/PEG-4TzMS hydrogels show gelation times and stiffnesses that are suitable for 3D cell encapsulation and tunable through changes in hydrogel composition. The results of this study guide formulation of encapsulating hydrogels for manual and automated 3D cell culture.