Natural killer (NK) cells make only a small fraction of immune cells in the human body, however, play a pivotal role in the fight against cancer by the immune system. They are capable of eliminating ...abnormal cells via several direct or indirect cytotoxicity pathways in a self-regulating manner, which makes them a favorable choice as a cellular therapy against cancer. Additionally, allogeneic NK cells, unlike other lymphocytes, do not or only minimally cause graft-versus-host diseases opening the door for an off-the-shelf therapy. However, to date, the production of NK cells faces several difficulties, especially because the critical process parameters (CPPs) influencing the critical quality attributes (CQAs) are difficult to identify or correlate. There are numerous different cultivation platforms available, all with own characteristics, benefits and disadvantages that add further difficulty to define CPPs and relate them to CQAs. Our goal in this contribution was to summarize the current knowledge about NK cell expansion CPPs and CQAs, therefore we analyzed the available literature of both dynamic and static culture format experiments in a systematic manner. We present a list of the identified CQAs and CPPs and discuss the role of each CPP in the regulation of the CQAs. Furthermore, we could identify potential relationships between certain CPPs and CQAs. The findings based on this systematic literature research can be the foundation for meaningful experiments leading to better process understanding and eventually control.
In this paper, the process of expansion of wet water vapor in a piston long-stroke low-speed drive of a low-flow compressor unit is considered. The study is carried out on the basis of the developed ...mathematical model, which includes both the basic thermodynamic equations and the equations describing the process of heat exchange of the working substance with the walls of the working chamber during the expansion process. The results of the calculations carried out reflect the dependences of pressure, temperature and degree of dryness on changes in the volume of the working cavity at various values of the initial degree of dryness in the process of expansion and the duration of the process. An analysis of the results obtained shows that an increase in the cycle time and a decrease in the initial degree of dryness lead to an intensification of the process of condensation of wet steam in the process of expansion and the possibility of obtaining complete condensation of the working fluid.
A component model synthesis (CMS) has been explored by carrying out model updating with neural networks. Structural system identification was achieved by applying the degree of freedom (DOF)-based ...reduction method and the inverse perturbation method. Experimental vibration data were restored to a full finite element model to update the numerical model. The experimental data were obtained using the specific sensor location selection method. The system identification was improved using the system equivalent reduction-expansion process by carrying out proper orthogonal decomposition. The proposed CMS was applied for a tank bracket model by simplifying the bolt assembly. Top and bottom parts of the tank bracket were each constructed to have a modally equivalent model. The convolutional neural network was adopted by training the density, Young's modulus and contact properties to improve the computational efficiency.
Vibration-based structural damage identification through optimization techniques has become an interesting research topic in recent years. Dynamic characteristics such as frequencies and mode shapes ...are used to construct the objective function. The objective functions based on only frequencies are not very sensitive to damage in large structures. However, objective functions based on both mode shapes and frequencies are very effective. In real measurement condition, the number of installed sensors is limited, and there are no economic reasons for measuring the mode shapes at all degrees of freedom. In this kind of circumstances, mode expansion methods are used to address the incompleteness of mode shapes. In this article, the system equivalent reduction and expansion process is applied to determine the unmeasured mode shapes. Two experimental examples including a cantilever beam and a truss tower are investigated to show system equivalent reduction and expansion process’ efficiency in estimating unmeasured mode shapes. The results show that the technique used for expansion is influential. Damage identification is formulated as an optimization problem, and the residual force vector based on expanded mode shapes is considered as an objective function. In order to minimize the objective function, grey wolf optimization and Harris hawks optimization are used. Numerical studies on a 56-bar dome space truss and experimental validation on a steel frame are performed to demonstrate the efficiency of the developed approach. Both numerical and experimental results indicate that the combination of the grey wolf optimization and expanded mode shapes with system equivalent reduction and expansion process can provide a reliable approach for determining the severities and locations of damage of skeletal structures when it compares with those obtained by Harris hawks optimization.
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•A novel cold hole expansion method called HCREP is proposed.•The parameters of the LTP are optimized to strengthen the sleeve used in HCREP.•The surface integrity state after HCREP ...is systematically analyzed.•The effect of expansion degree on the CRS distribution is revealed.•Grain refinement is the fundamental reason for improving the surface integrity.
Preferred surface integrity around the hole wall is one of the key parameters to ensure the optimized performance of hole components for nickel-based superalloy. The novel hole cold expansion technique introduced in this work involves the laser texturing process (LTP) followed by the Hertz contact rotary expansion process (HCREP), where the cylindrical sleeve is the critical component connecting the above-mentioned two processes. The purpose of LTP is to obtain the most optimized strengthened cylindrical sleeve surface, preparing for the following HCREP. Hereafter, the HCREP acts on the nickel-based hole components by the rotary extruding movements of the strengthened sleeve and conical mandrel tools. As compared to the as-received GH4169 material, the surface integrity characterization for the strengthened hole shows that a plastic deformation layer with finer grains, higher micro-hardness, deeper compressive residual stress (CRS) distribution and lower surface roughness is formed at the hole wall. In addition, transmission electron microscope (TEM) observations reveal the microstructure evolution mechanism in the strengthened hole. Grain refinement near the hole wall is regarded as the fundamental reason for improving the surface integrity, where the aggregated dislocations and recombined dislocation walls can be clearly observed.
A catalytic domino, three‐component reaction has been developed for the transformation of carbon dioxide into functionalized six‐membered cyclic carbonates. The catalytic process combines an initial ...carboxylative cyclization of β‐epoxy alcohols followed by an oxa‐Michael reaction affording an unparalleled scope of heterocyclic structures. The wide range of functional groups, including free‐alcohols, empowers the access to a range of products including C11‐oxo‐based bicyclic heterocycles. The versatility of these functionalized carbonates is further complemented by a series of synthetic diversifications. Control experiments are consistent with the first step of this domino process being promoted by a binary Lewis acid/base catalyst, while the second stage only requires catalytic base.
A catalytic domino process has been developed for larger‐ring, functionalized cyclic carbonates with various types of functional groups and involves the intermediacy of a free‐alcohol based six‐membered cyclic carbonate. The domino protocol is propelled by a combination of an Al(III) complex and N‐methyl‐morpholine as supported by various control experiments.
Hyperspectral image classification faces various levels of difficulty due to the use of different types of hyperspectral image data. Recently, spectral-spatial approaches have been developed by ...jointly taking care of spectral and spatial information. This paper presents a completely different approach from a subpixel target detection view point. It implements four stage processes, a preprocessing stage, which uses band selection (BS) and nonlinear band expansion, referred to as BS-then-nonlinear expansion (BSNE), a detection stage, which implements constrained energy minimization (CEM) to produce subpixel target maps, and an iterative stage, which develops an iterative CEM (ICEM) by applying Gaussian filters to capture spatial information, and then feeding the Gaussian-filtered CEM-detection maps back to BSNE band images to reprocess CEM in an iterative manner. Finally, in the last stage Otsu's method is applied to converting ICEM-detected real-valued maps to discrete values for classification. The entire process is called BSNE-ICEM. Experimental results demonstrate BSNE-ICEM, which has advantages over support vector machine-based approaches in many aspects, such as easy implementation, fewer parameters to be used, and better false classification and precision rates.
Expanding into new product areas is an important part of the growth strategy of many firms, but there is still more to learn about how it affects firm performance. We believe that as the top ...management team (TMT) is responsible for coordinating product expansion, looking there can yield valuable clues. We argue that diversification entails significant additional information processing and that this strains top managerial resources. We hypothesize that task-related faultlines within the TMT may help it cope with product expansion while bio-demographic faultlines may hinder it. We find support for these hypotheses on a longitudinal sample of 2,730 expansion steps made by 61 German firms between 1985 and 2007: task related faultline strength increases performance when diversifying, while bio-demographic faultline strength decreases it.
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In this study, the formation and structure of a single-particle layer of organo-zinc oxide are investigated using surface-pressure-area (π-A) isotherms, out-of-plane X-ray diffraction ...(XRD) analysis, and atomic force microscopy (AFM). Further, techniques for achieving the solubilization of inorganic fine particles in general solvents have been proposed, and a single-particle layer has been formed using such an inorganic solution as a “spreading solution” for an interfacial film. Surface modification of ZnO is performed using a long-chain carboxylic acid. Accordingly, a regular arrangement of ZnO can be easily achieved in order to overcome the relatively weak van der Walls interactions between inorganic materials. A condensed Langmuir monolayer of these particles is also formed. A multiparticle layered structure is constructed by the Langmuir–Blodgett (LB) technique. Out-of-plane XRD measurement results for a single-particle layer of organo-ZnO clearly show a sharp peak at 42Å. This peak is attributed to the distance between ZnO layers. The AFM image of this single-particle layer of organo-ZnO shows a particle assembly with a uniform height of 60nm. These aggregated particles form large two-dimensional crystals. In other words, a regular periodic structure along the c-axis and a condensed single-particle layer had been fabricated using Langmuir and LB techniques.
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•We proposed novel indices to characterize urban expansion structure and form.•The centrality and aggregation of urban expansion were explicitly quantified.•The proposed approaches ...fill a gap of dynamic assessment by global perspective.
A quantitative description is the basis for correctly understanding the urban expansion process. Previous approaches were dedicated to identifying expansion types based on the boundary sharing rate, thereby depicting the evolution of urban expansion. These methods, however, focused on describing neighborhood relations and ignored urban global expansion structure and form information. In this study, we first propose a new index, the location centrality index (LCI), to capture the expansion structure characteristics by incorporating an “area-inverse distance” weighting algorithm and geometric features. Then, we propose another index, the location centrality aggregation index (LCAI), to depict the heterogeneous evolution of urban form by considering the attribute of the new patch. The location centrality and location aggregation types are identified to reflect the effect of new patches on the urban expansion structure and form based on LCI and LCAI, respectively. Two variants of LCI and LCAI are also proposed to reflect the global bottom-up characteristics of urban expansion. The LCI and LCAI were verified using four periods of Landsat images (1995, 2000, 2005, and 2010) of the Wuhan metropolitan area, China. The results show that the overall development trend of the expansion structure in the Wuhan metropolitan area was toward decentralization. The urban form had become generally separated, but tended toward aggregation from 2005 to 2010. Our findings also reveal that the LCI fills the gap in the dynamic assessment of urban expansion with previous indices by explicitly uncovering global structure characteristics. The LCAI achieves better performance than previous indices in identifying heterogeneous aggregation.
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