Number Of Different Cells Research Articles

Health monitoring of sandwich composites with auxetic core subjected to indentation tests using acoustic emission

The quasi-static indentation behavior of an eco-sandwich composite with auxetic core consisting of polylactic acid reinforced with flax fibers will be discussed in this article. The structures involved in the test were manufactured using 3D printing technique. Four configurations with different number of cells in the core, were tested. It is found that sandwiches with high number of cells are stiffer and dissipate more energy. Experimental tests were monitored with acoustic emission technique in order to detect the appearance and the evolution of damage behavior. An unsupervised pattern recognition algorithm was used to post process the acoustic emission signals. The classification is conducted using k-means algorithm. Results show that there are three different classes of events for each configuration, which are the core cracking, the matrix cracking and the fiber/matrix debonding. The evaluation of the contribution of each damage mechanism on the total amount of failure was deduced according to the amplitude range, the cumulative number of hits and the acoustic energy activity. Furthermore, macroscopic and microscopic observations were performed in order to correlate acoustic emission classes with the damage mechanisms observed.

Quantitative analysis of tumour spheroid structure.

Tumour spheroids are common in vitro experimental models of avascular tumour growth. Compared with traditional two-dimensional culture, tumour spheroids more closely mimic the avascular tumour microenvironment where spatial differences in nutrient availability strongly influence growth. We show that spheroids initiated using significantly different numbers of cells grow to similar limiting sizes, suggesting that avascular tumours have a limiting structure; in agreement with untested predictions of classical mathematical models of tumour spheroids. We develop a novel mathematical and statistical framework to study the structure of tumour spheroids seeded from cells transduced with fluorescent cell cycle indicators, enabling us to discriminate between arrested and cycling cells and identify an arrested region. Our analysis shows that transient spheroid structure is independent of initial spheroid size, and the limiting structure can be independent of seeding density. Standard experimental protocols compare spheroid size as a function of time; however, our analysis suggests that comparing spheroid structure as a function of overall size produces results that are relatively insensitive to variability in spheroid size. Our experimental observations are made using two melanoma cell lines, but our modelling framework applies across a wide range of spheroid culture conditions and cell lines.

Modular packaging effect on thermal performance of LiCoO2 lithium-ion cells: An experimental study

Thermal performance of lithium-ion cells plays a crucial role in terms of efficiency, safety, and residual lifetime management of many electrical devices. In this paper, a thermal management strategy for cooling-down 26650 LiCoO2 lithium-ion battery cells based on modular packaging is analyzed. Battery modules with different number of cells were arranged and experimentally discharged under natural convection followed by a cooling-down process by air forced convection until cells reached the ambient temperature. Surface temperature of each cell and ambient temperature were recorded and analyzed using a fractal time thermal model. Results show that modular packaging improves the thermal behavior of cells. As the modules became larger, the thermal time constant of the system significantly increased, i.e., heat transfer coefficient of module decreased and the furthest cells from the fans interchanged less heat to surrounding air. In addition, modular packaging improves the energy efficiency of the cooling system since it is more efficient to cool several small modules than cooling a larger one.

Effects of Sample Size on Plant Single-Cell RNA Profiling.

Single-cell RNA (scRNA) profiling or scRNA-sequencing (scRNA-seq) makes it possible to parallelly investigate diverse molecular features of multiple types of cells in a given plant tissue and discover cell developmental processes. In this study, we evaluated the effects of sample size (i.e., cell number) on the outcome of single-cell transcriptome analysis by sampling different numbers of cells from a pool of ~57,000 Arabidopsis thaliana root cells integrated from five published studies. Our results indicated that the most significant principal components could be achieved when 20,000–30,000 cells were sampled, a relatively high reliability of cell clustering could be achieved by using ~20,000 cells with little further improvement by using more cells, 96% of the differentially expressed genes could be successfully identified with no more than 20,000 cells, and a relatively stable pseudotime could be estimated in the subsample with 5000 cells. Finally, our results provide a general guide for optimizing sample size to be used in plant scRNA-seq studies.

Vimentin Cytoskeleton Architecture Analysis on Polylactide and Polyhydroxyoctanoate Substrates for Cell Culturing.

Polylactide (PLA), widely used in bioengineering and medicine, gained popularity due to its biocompatibility and biodegradability. Natural origin and eco-friendly background encourage the search of novel materials with such features, such as polyhydroxyoctanoate (P(3HO)), a polyester of bacterial origin. Physicochemical features of both P(3HO) and PLA have an impact on cellular response 32, i.e., adhesion, migration, and cell morphology, based on the signaling and changes in the architecture of the three cytoskeletal networks: microfilaments (F-actin), microtubules, and intermediate filaments (IF). To investigate the role of IF in the cellular response to the substrate, we focused on vimentin intermediate filaments (VIFs), present in mouse embryonic fibroblast cells (MEF). VIFs maintain cell integrity and protect it from external mechanical stress, and also take part in the transmission of signals from the exterior of the cell to its inner organelles, which is under constant investigation. Physiochemical properties of a substrate have an impact on cells’ morphology, and thus on cytoskeleton network signaling and assembly. In this work, we show how PLA and P(3HO) crystallinity and hydrophilicity influence VIFs, and we identify that two different types of vimentin cytoskeleton architecture: network “classic” and “nutshell-like” are expressed by MEFs in different numbers of cells depending on substrate features.

Context-aware synthetic biology by controller design: Engineering the mammalian cell.

The rise of systems biology has ushered a new paradigm: the view of the cell as a system that processes environmental inputs to drive phenotypic outputs. Synthetic biology provides a complementary approach, allowing us to program cell behavior through the addition of synthetic genetic devices into the cellular processor. These devices, and the complex genetic circuits they compose, are engineered using a design-prototype-test cycle, allowing for predictable device performance to be achieved in a context-dependent manner. Within mammalian cells, context effects impact device performance at multiple scales, including the genetic, cellular, and extracellular levels. In order for synthetic genetic devices to achieve predictable behaviors, approaches to overcome context dependence are necessary. Here, we describe control systems approaches for achieving context-aware devices that are robust to context effects. We then consider cell fate programing as a case study to explore the potential impact of context-aware devices for regenerative medicine applications.

The morphology and application of stem cells in digestive system surgery.

Stem cells constitute a group of cells which possess the ability to self-renew as well as the capacity to differentiate into a vast number of different cells within the human organism. Moreover, stem cells are able to undergo a potentially unlimited number of divisions and this characteristic is clinically essential. Specific fields of its application include treatment of diseases mainly in the field of haematology, orthopaedics, surgery, dentistry, and neurology. In the following work, the current knowledge concerning mechanisms of stem cell treatment in different parts of the digestive system with its diseases as well as adjacent therapy for surgery has been revised. Stem cells therapy may be used in the treatment of various diseases of different parts of the digestive system. This also applies to the end part of the digestive tract (proctological diseases) because stem cells can be used to treat fistulas. Liposuction allows more recovery of mesenchymal stem cells, compared to previous bone marrow harvesting methods. Despite the application of stem cells in the treatment of different diseases used for many years so far, the therapeutic use for the regeneration of the gastrointestinal tract is still rare and unfamiliar. Regenerative medicine seems to be a promising tool in medical research, especially when insulated cells and designed biomaterials are taken into consideration. Major points of discussion include types of stem cells, their origin or differentiation for the treatment of many diseases.

Mesh Dependency on a Partial Element Equivalent Circuit Model for an NI HTS Coil

In general, when evaluating a performance of a high-temperature superconductor (HTS) no-insulation (NI) magnet, current, voltage, and center magnetic field are considered as main parameters. To achieve detailed results of the main parameters of NI HTS magnet, distributed circuits which can analyze internal physical phenomena of the magnet are required. Among distributed circuits, a circuit that divides inside of each turn into several cells in azimuthal direction is called a Partial Element Equivalent Circuit (PEEC). In this paper, we compared the main parameters of simple NI HTS magnet according to different numbers of cells in PEEC. When the number of cells per turn is different, average azimuthal current and center magnetic field of each turn coincide with each other, but voltage does not. The result suggests that PEECs with different number of cells per turn may be different circuits for each others, and the main reason for this seems to be that an accurate discussion of the characteristic resistance according to the length was not made.

Comparative Study of Structural Behaviour of Reinforced Concrete Box Girder with Different Numbers of Cells

The aim of this research is to study the experimental effect of the number of cells on the structural behaviour of reinforced concrete box girder. Three simply supported box girder specimens with different numbers of cells were cast by using self-compacting concrete and experimentally tested under four-point load, the first reference specimen is with one cell, the second specimen is with two cells and the last specimen is with four cells. The testing results show that the ultimate load in the two-cell and four-cell specimens is higher compared with the one-cell specimen by (20.1% and 23.3%) respectively. Increasing the number of cells decrease the cracks width and increase the number of cracks, all the specimens failed with diagonal shear.

A Fast, Decentralized, Self-Aligned Carrier Method for Multicellular Converters

This paper proposes a fast, decentralized method for self-aligning the carriers of a multiphase/multilevel converter operating on the basis of phase-shifted pulse width modulation or level-shifted pulse width modulation. In the proposed method, each cell of the converter synchronizes and updates simultaneously its own carrier angle or carrier level based on the information shared with its neighboring cell, such as its angle/level, its index number, and the total number of activated cells of the converter. Different from the conventional decentralized method (with basic and modified updating rules), which requires some conditions in terms of cell number and initial carrier angles to start up and operate properly, the proposed method can be applied to the system with any number of cells and does not require special conditions of initial carrier angles. Further, while the conventional method needs an iteration process to adjust the inter-carrier phase-shifts and can be applied only to a multiphase converter which uses phase-shifted pulse width modulation, the proposed method offers an accurate and fast alignment of phases (for phase-shifted pulse width modulation) or levels (for level-shifted pulse width modulation) and thus can be applied to both multiphase and multilevel converter types. The simulations and the experimental results are presented in detail to show the validity and the effectiveness of the proposed methods. Further, thorough simulations on multiphase converters with different number of cells also show that the proposed method is much faster than the conventional method in both configuration and reconfiguration processes, especially in case the system has a large number of cells.

Stall Mode Transformation in the Wide Vaneless Diffuser of Centrifugal Compressors

A review on the rotating stall in the vaneless diffuser of centrifugal compressors is presented showing that different stall modes characterized by different numbers of cells can be detected within the diffuser even if the operating condition remains unchanged. The interaction between the inlet perturbation and the stall cells near the diffuser outlet is supposed to be the trigger of the stall mode transformation. In order to determine if the inlet perturbation will interact with the downstream stall cells, a characteristic time analysis is proposed to estimate the characteristic time of the perturbation in radial and tangential directions. An additional theoretical model which focused on the development of the vaneless diffuser rotating stall is presented to determine the propagation velocity of the cells. The comparison between the characteristic time in two directions shows that one stall mode is able to evolve into another stall mode if a critical condition is met, and the stall mode transformation is more likely to start from a mode with a higher number of cells and is more likely to occur in the diffuser with a large radius ratio. Experimental results are also employed to validate the proposed critical condition, and good agreements are obtained.

Multi-set Pre-processing of Multicolor Flow Cytometry Data

Flow Cytometry is an analytical technology to simultaneously measure multiple markers per single cell. Ten thousands to millions of single cells can be measured per sample and each sample may contain a different number of cells. All samples may be bundled together, leading to a ‘multi-set’ structure. Many multivariate methods have been developed for Flow Cytometry data but none of them considers this structure in their quantitative handling of the data. The standard pre-processing used by existing multivariate methods provides models mainly influenced by the samples with more cells, while such a model should provide a balanced view of the biomedical information within all measurements. We propose an alternative ‘multi-set’ preprocessing that corrects for the difference in number of cells measured, balancing the relative importance of each multi-cell sample in the data while using all data collected from these expensive analyses. Moreover, one case example shows how multi-set pre-processing may benefit removal of undesired measurement-to-measurement variability and another where class-based multi-set pre-processing enhances the studied response upon comparison to the control reference samples. Our results show that adjusting data analysis algorithms to consider this multi-set structure may greatly benefit immunological insight and classification performance of Flow Cytometry data.

Importance of standardizing the number of cells measured for coefficient of variation (COV) estimates of corneal endothelial cell area values as relevant to contact lens wear

PurposeTo assess the impact of using different numbers of cells in calculations of the coefficient of variation (COV) value for normal and polymegethous endothelia MethodsFour sets of 20 non-contact specular microscope images obtained from Caucasian individuals were assessed, and categorized according to the extent of polymegethism, i.e. grade 0 (none), grade 1 (mild), grade 2 (moderate) and grade 3 (substantial). Cell areas were measured manually and then values for between 2 and 100 cells were progressively added and averaged to generate COV estimates. These were then assessed in terms of their relative values (as percentages +/- SD) in relation to the value obtained on over 100 cells. ResultsFor the 4 sets of endothelia with group-mean COV values of 25.8, 33.1, 45.1 and 56.8%, the reliability of the COV estimates realized asymptotic values of close to ±1.0, ±2.7, ±3.6 and ±5.0% with 90 cells, but with greater uncertainty with few numbers of cells, e.g. only to within ±3.4, ±5.3, ±6.1 and ±7.9% with 75 cells. ConclusionsCOV estimates for the corneal endothelium are dependent on the number of cells used in the calculations. It is recommended that every effort should be made to not only assess 75–100 cells per endothelial image, but that this number should be the same or very similar for all endothelial images in a particular data set so that the uncertainly (or estimated proportional error) in the estimates is balanced.

Improvement of subcutaneous CDX model of lung cancer using A549 cell line.

e15618 Background: Lung cancer is a challenging cancer problem, despite significant progress in its therapy. The search of drugs for the treatment of lung cancer is an urgent task. The creation of animal models of lung cancer plays a key role in preclinical trials and in understanding the mechanisms of tumor pathogenesis. The purpose of the study was to create a subcutaneous cell line-derived xenograft (CDX) model of lung cancer using the human lung cancer cells A459 and to compare results of subcutaneous injections of a cell suspension with different numbers of cells in two groups of animals. Methods: A CDX model of lung cancer was created using the human lung cancer cells A459 and male BALB/c Nude mice divided into two groups (n = 4 and n = 6) with subcutaneous injections of a mix of a cell suspension with Matrigel (200 μl). The injection mix contained 5*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel (n = 4) and 10*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel (n = 6). Results: Animal models receiving a suspension of 10*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel were characterized by a higher tumor growth index compared to animals receiving 5*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel. Models created with the injections of 10*106 cells showed a larger volume of tumor nodes: 65.33±1, 39.2±1, 41.79±1, 36.64±1, 75.87±1 and 43.13±1 mm3. CDX models created with the injections of 5*106 cells were characterized by a division of the single tumor node by the 30th day of the experiment which complicated the measurement. Conclusions: The creation of a CDX model with injections of 5*106 cells is undesirable due to the nonlinear growth of the xenograft and its division into several tumor nodes. Subcutaneous CDX models of lung cancer created with injections of 10*106 cells showed the linear growth and the formation of the single tumor node.

Immunohistochemical Expression of KI-67 in Ovarian Surface Epithelial Tumors and its Correlation

The ovaries are unique in the variety of lesions that can arise from them. The complex anatomy and physiology of ovary with constant changes from puberty to menopausal age give rise to number of different cells, which are capable of giving rise to tumors. The present study is a two years, prospective study carried out in a tertiary care hospital. It is a descriptive study which included all specimens of ovarian tumors, diagnosed as surface epithelial origin on histopathological studies. Most patients presented with non-specific and vague symptoms over a period of time. Patient’s education and awareness among primary care physicians with timely attention and further investigations, can help in early detection of ovarian malignancies in this subset of cases, thereby reducing morbidity and mortality associated with diagnosis in advanced stages.

Clusters Tend to Be of Equal Size in a Negative Feedback Population Model of Cell Cycle Dynamics

We study a model of the cell cycles of a large ensemble of cells that was conceived to explain the coupling between metabolism and the cell cycle observed in cell cycle related, metabolic oscillations in yeast continuous culture. An essential feature of the model is that a negative feedback mechanism robustly produces temporal clustering: cohorts of cells proceeding through the cell cycle in phase synchrony, a phenomenon that was observed in the yeast experiments. In this paper we focus on the possibility of temporal clustering in which different cohorts are of unequal sizes. We observe in numerical simulations of the model that the clusters tend very strongly toward having nearly equal numbers of cells. This is consistent with the available experimental data. We study the case of two unequal clusters analytically and conclude that solutions with two unequal clusters are locally asymptotically stable in the clustered subspace. However, local asymptotic stability of unbalanced clusters in the full phase space depends delicately on the parameters of the model. The global dynamics reveal a more robust picture. If clusters become unbalanced, the influence of the larger cluster can radically shift the basins of attraction of individual clusters, making it more likely for an unclustered cell to join a smaller cluster. We propose that this points to a general principle: systems that form temporal clusters via nonlocal coupling tend to form nearly equal clusters. Finally, we describe an exception. When the number of clusters is a composite, we observe that groups of clusters may decouple with different numbers of cells in each group.

Short term effects of continuous lighting on the cornea of cage-reared laboratory rabbits

This study was to assess the impact on the cornea and eye blink activity of adapting rabbits to continuous lighting (CL) compared to a 14:10 light:dark cycle. Female New Zealand White rabbits (2 to 2.5 kg) were maintained under a light: dark (L:D) cycle or switched to continuous fluorescent lighting (CL) for an average of 17 +/− 2 days. Animal behaviour in their cages was manually recorded using an event marker and in vivo slitlamp biomicroscopy at 40× undertaken in mid-afternoon. Animals were then euthanized and the corneas prepared for scanning electron microscopy (SEM). From images taken at 500× from the central region of the corneas, the number of exfoliating (desquamating) cells and the relative number of different cells with light, medium or dark reflexes were assessed for the corneal epithelial surface, while the number of cells/unit area were assessed for both corneal epithelium and endothelium. Exposure to continuous lighting was associated with higher number of eye blink events (15.7 vs 8.2/15 min) and mild corneal surface alterations evident by biomicroscopy with higher numbers of intra-epithelial ‘granules’ (32 +/− 14 vs. 4 +/− 3/sq. mm). SEM revealed low numbers of exfoliating cells on the corneal epithelial surface in all CL-adapted animals, but not in L:D controls. Trends were observed for there to be slightly higher numbers of epithelial cells/unit area, higher numbers of small light reflex cells and lower numbers of larger dark reflex cells in CL animals. The corneal endothelium showed no obvious adverse effects in CL-adapted animals but the percentage of ‘hexagonal’ cells was slightly higher compared to L:D controls. The results indicate that even a short period of exposure of laboratory-raised rabbits to constant lighting can be associated with mild adverse effects on the corneal epithelial surface.

Development of a sensitive qPCR method for the detection of pelagophyte Aureococcus anophagefferens

AbstractBrown tides of pelagophyte Aureococcus anophagefferens have been recorded in the coastal waters of Qinhuangdao in the Bohai Sea (BS) since 2009. Current understandings on the dynamics and mechanisms of brown tides in the BS, however, are still quite limited due to the lack of accurate methods for detecting low‐abundance of A. anophagefferens cells. In this study, a Taqman qPCR method was developed, which targeted 28S rDNA D1‐D2 domain of A. anophagefferens. The specificity of the qPCR method was tested using 25 strains of microalgae commonly present in the coastal waters, and the targeted species A. anophagefferens was the only species that had reliable positive signal. The method was highly sensitive and reproducible, and the lower detection limit could reach 0.3 cells of A. anophagefferens. A calibration curve was established for A. anophagefferens using the DNA template extracted from different number of cells, and the lower and upper limits of detection for the qPCR assay is 0.3 cells and 1.2 × 105 cells, respectively. A high recovery rate ranged from 96.5% to 107% was achieved for A. anophagefferens at different cell densities. The qPCR assay has been successfully applied to the study on spatial and temporal variations of A. anophagefferens in the coastal waters of Qinhuangdao in 2014.

Sensitive detection of telomerase activity in cells using a DNA-based fluorescence resonance energy transfer nanoprobe

Telomerase activity is inhibited in normal somatic cells but abnormally high in the majority of cancer cells. Maintenance of active telomerase in cancer cells promotes proliferation and immortalization. With the difference in telomerase activity between cancer and normal cells in mind, we designed a nanoprobe based on quantum dot (QD) and fluorescence resonance energy transfer (FRET). The nanoprobe consisted of a specific sequence of DNA with the two ends labeled with QD as a fluorescent donor and Alexa488 as a fluorescent acceptor, respectively. FRET signal tracking was performed by adjusting the distance between donors and acceptors, and changes in the FRET signal shown to be related to telomerase activity. Incubation of cells with the nanoprobe facilitated sensing of intracellular telomerase activity, and consequent discrimination between normal and cancer cells. Our novel DNA nanoprobe based on QD-FRET achieved sensitive detection of telomerase in cells up to a detection limit of one cell, and quantitative detection of telomerase activity in different numbers of cells. The nanoprobe generated in this study is expected to allow dynamically monitoring of the changes in telomerase activity in cells under treatment with drugs, providing a potential basis for early diagnosis and management of cancer.

Simulation of turbulent wakes in model wind farm with arbitrary location for wind turbines

Wind energy is an important part of renewable energy sources in the Russian Federation. A new modern wind farm with 28 wind turbines was built on the territory of the Russian Federation, in the Ulyanovsk region in 2017-2018. When designing and operating a wind farm, it is necessary to assess correctly the power of each individual wind turbine. In this paper we used the open SOWFA library based on OpenFOAM 2.4.0 and URANS approach with k-e model of turbulence. The Actuator Line Model for the calculation of the forces from the wind turbines was used in pisoFoamTurbine.ALM solver. To set the boundary conditions at the input, the Precursor method was used. The unstructured grids with different number of cells were built. As a result of the calculation for 14 simulators of wind turbines, the values of the power coefficients Cp and thrust coefficients Ct were also determined. The maximum Cp value was in agreement with the Bets-Zhukovsky law for an ideal wind turbine. The new numerical case with 28 wind turbines was prepared for future simulations. The calculations were performed on a cluster of the UNICFD web-laboratory of ISP RAS. Each calculation was performed on 48-72 cpu cores.