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Chevron-shaped protrusions have been proposed in the literature for turbulent skin friction reduction. However, there is no consensus on the performance of this passive flow control technique; both an increase and a decrease in drag have been observed in previous studies. There is also no experimental evidence to support the working mechanism behind the drag reduction effect that has been postulated in the literature. In this study, direct force measurements were used to replicate experiments from the literature and, in addition, were used to test new array configurations to characterise the effect of individual design parameters on drag performance. A total of 23 different protrusion configurations were investigated in a turbulent boundary layer flow. In addition to the integral force measurements, particle image velocimetry was used to measure wall-parallel velocity fields in order to extract the statistical sizing and energy of the near-wall cycle turbulence. All configurations increased the drag between 2% and 10% for a friction Reynolds number of 1700. The drag reduction reported in the literature could not be replicated; however, these findings agreed with an experimental and numerical study that reported drag increase. The trend observed in the low-speed streak spacing from the PIV experiments was consistent with that observed in the balance data. Nevertheless, no evidence was found to support the working mechanism proposed in the literature. These results cast doubt on the proposed drag reduction potential of chevron-shaped protrusions. In the authors' view, the results of this study strengthen previous conclusions regarding their minor increase in drag. Future studies to further approach a consensus are proposed. [ABSTRACT FROM AUTHOR]

Abstract This research focuses on the study of pigment-medium interactions in the film forming, ageing and degradation mechanisms of modern white oil paints observed in the Neoplasticist painting Composition dans le cône avec couleur orange by G. Vantongerloo (1929), conserved in the Institut Valencià d’Art Modern (IVAM). The observation of selective vertical cracks and the significant presence of protrusions in the painting suggested that the observed degradation phenomena were specific to the coloured area. To understand the composition of pigments governing the film formation processes and later degradation phenomena in the oil paint films, a hybrid experimental approach was taken, aimed at understanding the physical, chemical and mechanical mechanisms involved. For this purpose, digital portable microscopy and multiband imaging analyses were carried out. Furthermore, the technical study involved the use of micro-invasive analysis such as μ-Raman, ATR-FTIR spectroscopy and GC–MS analysis for a more comprehensive understanding of the nature of the binding media and products resulting from the auto-oxidation, film-forming, hydrolysis, and degradation processes of the lipidic binding media. The results obtained suggest that on-going degradation phenomena are closely linked to the chemical interaction between pigment and binding medium.

Metastasisation occurs through the acquisition of invasive and survival capabilities that allow tumour cells to colonise distant sites. While the role of multicellular aggregates in cancer dissemination is acknowledged, the mechanisms that drive the formation of multiclonal cell aggregates are not fully elucidated. Here, we show that cancer cells of different tissue of origins can perform collective directional migration and can actively form heteroclonal aggregates in 3D, through a proliferation‐independent mechanism. Coalescence of distant cell clusters is mediated by subcellular actin‐rich protrusions and multicellular outgrowths that extend towards neighbouring aggregates. Coherently, perturbation of cytoskeletal dynamics impairs collective migration while myosin II activation is necessary for multicellular movements. We put forward the hypothesis that cluster attraction is mediated by secreted soluble factors. Such a hypothesis is consistent with the abrogation of aggregation by inhibition of PI3K/AKT/mTOR and MEK/ERK, the chemoattracting activity of conditioned culture media and with a wide screening of secreted proteins. Our results present a novel collective migration model and shed light on the mechanisms of formation of heteroclonal aggregates in cancer.

Metastasisation occurs through the acquisition of invasive and survival capabilities that allow tumour cells to colonise distant sites. While the role of multicellular aggregates in cancer dissemination is acknowledged, the mechanisms that drive the formation of multiclonal cell aggregates are not fully elucidated. Here, we show that cancer cells of different tissue of origins can perform collective directional migration and can actively form heteroclonal aggregates in 3D, through a proliferation‐independent mechanism. Coalescence of distant cell clusters is mediated by subcellular actin‐rich protrusions and multicellular outgrowths that extend towards neighbouring aggregates. Coherently, perturbation of cytoskeletal dynamics impairs collective migration while myosin II activation is necessary for multicellular movements. We put forward the hypothesis that cluster attraction is mediated by secreted soluble factors. Such a hypothesis is consistent with the abrogation of aggregation by inhibition of PI3K/AKT/mTOR and MEK/ERK, the chemoattracting activity of conditioned culture media and with a wide screening of secreted proteins. Our results present a novel collective migration model and shed light on the mechanisms of formation of heteroclonal aggregates in cancer. [ABSTRACT FROM AUTHOR]

One of the most effective technologies for recycling organic waste is its thermal destruction by pyrolysis methods to produce valuable products such as hydrogen and mixtures containing hydrogen. Increasing the thermal power of the flow helps to reduce the formation of secondary reactions, making the non-condensable hydrocarbon gas in the pyrolysis process cleaner, which simplifies further technology for the production of hydrogen and hydrogen-containing mixtures. In addition, the economic viability of pyrolysis depends on the energy costs required to decompose the organic feedstock. Using passive intensifiers in the form of discrete rough surfaces in heat exchanging channels is a widely used method of increasing heat transfer. This paper presents the results of numerical and experimental studies of heat transfer and hydraulic resistance in a channel with and without hemispherical protrusions applied to the heat transfer surface. The investigations were carried out for a reactor channel 150 mm long and 31 mm in diameter, with a constant pitch of the protrusions along the channels of 20 mm and protrusion heights h of 1 to 4 mm for 419 ≤ Re ≤ 2795. Compared to a smooth channel, a channel with protrusions increases heat transfer by an average of 2.23 times. By comparing the heat exchange parameters and the hydraulic resistance of the heat exchange channels, it was determined that h = 2 mm and 838 < Re < 1223 is the combination of parameters providing the best energetic mode of reactor operation. In general, an increase in h and coolant flow rate resulted in an uneven increase in heat transfer intensity. However, as h increases, the dead zone effect behind the protrusions increases and the rough channel working area decreases. Furthermore, increasing Re > 1223 is not advisable due to the increased cost of maintaining high coolant velocity and the reduced heat transfer capacity of the channel. [ABSTRACT FROM AUTHOR]

Metastasis is the main cause of death in cancer patients but remains a poorly understood process. Small cell lung cancer (SCLC) is one of the most lethal and most metastatic cancer types. SCLC cells normally express neuroendocrine and neuronal gene programs but accumulating evidence indicates that these cancer cells become relatively more neuronal and less neuroendocrine as they gain the ability to metastasize. Here we show that mouse and human SCLC cells in culture and in vivo can grow cellular protrusions that resemble axons. The formation of these protrusions is controlled by multiple neuronal factors implicated in axonogenesis, axon guidance, and neuroblast migration. Disruption of these axon-like protrusions impairs cell migration in culture and inhibits metastatic ability in vivo. The co-option of developmental neuronal programs is a novel molecular and cellular mechanism that contributes to the high metastatic ability of SCLC.

The cell migration cycle, well-established in 2D, proceeds with forming new protrusive structures at the cell membrane and subsequent redistribution of contractile machinery. Three-dimensional (3D) environments are complex and composed of 1D fibers, and 1D fibers are shown to recapitulate essential features of 3D migration. However, the establishment of protrusive activity at the cell membrane and contractility in 1D fibrous environments remains partially understood. Here the role of membrane curvature regulator IRSp53 is examined as a coupler between actin filaments and plasma membrane during cell migration on single, suspended 1D fibers. IRSp53 depletion reduced cell-length spanning actin stress fibers that originate from the cell periphery, protrusive activity, and contractility, leading to uncoupling of the nucleus from cellular movements. A theoretical model capable of predicting the observed transition of IRSp53-depleted cells from rapid stick-slip migration to smooth and slower migration due to reduced actin polymerization at the cell edges is developed, which is verified by direct measurements of retrograde actin flow using speckle microscopy. Overall, it is found that IRSp53 mediates actin recruitment at the cellular tips leading to the establishment of cell-length spanning fibers, thus demonstrating a unique role of IRSp53 in controlling cell migration in 3D. [ABSTRACT FROM AUTHOR]

Abstract The cell migration cycle, well‐established in 2D, proceeds with forming new protrusive structures at the cell membrane and subsequent redistribution of contractile machinery. Three‐dimensional (3D) environments are complex and composed of 1D fibers, and 1D fibers are shown to recapitulate essential features of 3D migration. However, the establishment of protrusive activity at the cell membrane and contractility in 1D fibrous environments remains partially understood. Here the role of membrane curvature regulator IRSp53 is examined as a coupler between actin filaments and plasma membrane during cell migration on single, suspended 1D fibers. IRSp53 depletion reduced cell‐length spanning actin stress fibers that originate from the cell periphery, protrusive activity, and contractility, leading to uncoupling of the nucleus from cellular movements. A theoretical model capable of predicting the observed transition of IRSp53‐depleted cells from rapid stick‐slip migration to smooth and slower migration due to reduced actin polymerization at the cell edges is developed, which is verified by direct measurements of retrograde actin flow using speckle microscopy. Overall, it is found that IRSp53 mediates actin recruitment at the cellular tips leading to the establishment of cell‐length spanning fibers, thus demonstrating a unique role of IRSp53 in controlling cell migration in 3D.

The paper proposes a compact-sized coronavirus-shaped Microstrip Patch Antenna (MPA) for wireless communication. A 15-20 GHz band of frequency is employed to analyze the effect of the shape on antenna's performance and characteristics. A low-cost FR4 dielectric substrate is used in the design and implementation of the coronavirus-shaped antenna, with suitable dimensions. The proposed antenna has six patterns depending upon the band of frequencies, and the same have been analyzed. The results show that the realized gain is better than -15 dB when using frequencies around 17 GHz, and total efficiency is about 70%. CST microwave software is used for designing and analysis. [ABSTRACT FROM AUTHOR]

The interaction of ultrahigh-performance concrete (UHPC) and normal-strength concrete (NSC) is one of the main issues for strengthening conventional concrete structures or other applications where NSC and UHPC are interrelated. UHPC stands out for its strength and durability, while NSC is significantly inexpensive and easier to work with. Efficiently designed structures can exploit the advantages of both mixtures. At the interface of these materials in newly designed structures, the formwork can be modified at the interface to give the concrete surface sufficient roughness and thus cohesion as required. This improves both the tensile and shear strength of the contact resulting in the enhanced capacity of the composite structure. In this study, a button foil was inserted into the formwork for the UHPC and then a part of NSC was made. The shear strength of the interface without any stress component in the transverse direction was measured on small-scale samples. It was to justify the possibility of the use of this interface in real constructions such as beams and columns. The main objective of further research is to design a composite beam using a UHPC shell as formwork for NSC and protrusions at the interface. It is expected that the U-shaped shell made of the UHPC could significantly contribute to the load-bearing capacity of the resulting composite NSC–UHPC structure and also to its enhanced durability. In addition, if the NSC is enclosed in a shell of UHPC, it can be made from various secondary materials, therefore it can decrease cement consumption by more than 50%. [ABSTRACT FROM AUTHOR]

One of the most effective technologies for recycling organic waste is its thermal destruction by pyrolysis methods to produce valuable products such as hydrogen and mixtures containing hydrogen. Increasing the thermal power of the flow helps to reduce the formation of secondary reactions, making the non-condensable hydrocarbon gas in the pyrolysis process cleaner, which simplifies further technology for the production of hydrogen and hydrogen-containing mixtures. In addition, the economic viability of pyrolysis depends on the energy costs required to decompose the organic feedstock. Using passive intensifiers in the form of discrete rough surfaces in heat exchanging channels is a widely used method of increasing heat transfer. This paper presents the results of numerical and experimental studies of heat transfer and hydraulic resistance in a channel with and without hemispherical protrusions applied to the heat transfer surface. The investigations were carried out for a reactor channel 150 mm long and 31 mm in diameter, with a constant pitch of the protrusions along the channels of 20 mm and protrusion heights h of 1 to 4 mm for 419 ≤ Re ≤ 2795. Compared to a smooth channel, a channel with protrusions increases heat transfer by an average of 2.23 times. By comparing the heat exchange parameters and the hydraulic resistance of the heat exchange channels, it was determined that h = 2 mm and 838 < Re < 1223 is the combination of parameters providing the best energetic mode of reactor operation. In general, an increase in h and coolant flow rate resulted in an uneven increase in heat transfer intensity. However, as h increases, the dead zone effect behind the protrusions increases and the rough channel working area decreases. Furthermore, increasing Re > 1223 is not advisable due to the increased cost of maintaining high coolant velocity and the reduced heat transfer capacity of the channel.

The colon is primarily responsible for absorbing fluids. It contains a large number of microorganisms including fungi, which are enriched in its distal segment. The colonic mucosa must therefore tightly regulate fluid influx to control absorption of fungal metabolites, which can be toxic to epithelial cells and lead to barrier dysfunction. How this is achieved remains unknown. Here, we describe a mechanism by which the innate immune system allows rapid quality-check of absorbed fluids to avoid intoxication of colonocytes. This mechanism relies on a population of distal colon macrophages that are equipped with “balloon-like” protrusions (BLPs) inserted in the epithelium, which sample absorbed fluids. In the absence of macrophages or BLPs, epithelial cells keep absorbing fluids containing fungal products, leading to their death and subsequent loss of epithelial barrier integrity. These results reveal an unexpected and essential role of macrophages in the maintenance of colon-microbiota interactions in homeostasis.

Cellular protrusions generated by the actin cytoskeleton are central to the process of building the body of the embryo. Problems with cellular protrusions underlie human diseases and syndromes, including implantation defects and pregnancy loss, congenital birth defects, and cancer. Cells use protrusive activity together with actin-myosin contractility to create an ordered body shape of the embryo. Here, I review how actin-rich protrusions are used by two major morphological cell types, epithelial and mesenchymal cells, during collective cell migration to sculpt the mouse embryo body. Pre-gastrulation epithelial collective migration of the anterior visceral endoderm is essential for establishing the anterior-posterior body axis. Gastrulation mesenchymal collective migration of the mesoderm wings is crucial for body elongation, and somite and heart formation. Analysis of mouse mutants with disrupted cellular protrusions revealed the key role of protrusions in embryonic morphogenesis and embryo survival. Recent technical approaches have allowed examination of the mechanisms that control cell and tissue movements in vivo in the complex 3D microenvironment of living mouse embryos. Advancing our understanding of protrusion-driven morphogenesis should provide novel insights into human developmental disorders and cancer metastasis. [ABSTRACT FROM AUTHOR]

For multiple intracellular bacterial pathogens, the ability to spread directly into adjacent epithelial cells is an essential step for disease in humans. For pathogens such as Shigella , Listeria , Rickettsia , and Burkholderia , this intercellular movement frequently requires the pathogens to manipulate the host actin cytoskeleton and deform the plasma membrane into structures known as protrusions, which extend into neighboring cells. The protrusion is then typically resolved into a double-membrane vacuole (DMV) from which the pathogen quickly escapes into the cytosol, where additional rounds of intercellular spread occur. Significant progress over the last few years has begun to define the mechanisms by which intracellular bacterial pathogens spread. This review highlights the interactions of bacterial and host factors that drive mechanisms required for intercellular spread with a focus on how protrusion structures form and resolve., Competing Interests: The authors declare no conflict of interest.

In a parameterized problem, every instance I comes with a positive integer k. The problem is said to admit a polynomial kernel if, in polynomial time, one can reduce the size of the instance I to a polynomial in k while preserving the answer. In this work, we give two meta-theorems on kernelization. The first theorem says that all problems expressible in counting monadic second-order logic and satisfying a coverability property admit a polynomial kernel on graphs of bounded genus. Our second result is that all problems that have finite integer index and satisfy a weaker coverability property admit a linear kernel on graphs of bounded genus. These theorems unify and extend all previously known kernelization results for planar graph problems. [ABSTRACT FROM AUTHOR]

To assess the effects of fabric take-up, yarn tension, feeder position, and yarn feeder material on the occurrence of snagging, fabrics produced with two different finishing processes, were subjected to longitudinal or transversal 100, 300, and 600 revolutions, and the degree of snagging was measured and compared afterwards with gray fabric. Our results showed that, during the knitting process, the use of ceramic yarn feeders resulted in significantly fewer snags compared with metal yarn feeders. The gray fabric, having no finishing, was fragile and easily snagged, whereas the fabric treated by a finishing process – either drying in relaxed condition (Treatment A) or under stress conditions (Treatment B) – was more resistant to snagging. Moreover, the snagging property of the gray fabric tended to increase with increasing longitudinal or transversal 100, 300, or 600 revolutions. Slight increases in snagging were also present in fabrics having Treatment A or Treatment B at the same revolutions, but the differences were not statistically important (P > 0.05). Frequency of snags was higher when revolutions were transversal rather than on longitudinal direction. Yarn tension and feeder position had no effect on snagging degree, while fabric take-up had limited effect. For acquiring a fabric resistant to snagging, the gray fabric produced with ceramic yarn guiders during the knitting process should be subjected to drying under relaxed condition. We also suggest that quality control tests be carried out taking the results of our study into consideration. [ABSTRACT FROM AUTHOR]

In the current research project, the thermal performance of a series of newly designed mixers has been investigated. Each mixer has two concentric cylinders comprising two annular slot flow channels around a solid cylindrical rod at the center. In each mixer, the first cylinder around the central solid rod has either spherical or pyramidal protrusions throughout the outer surface. It has been observed that with varying mass flow rate of cold and hot water (1 kg/m3-sec to 5 kg/m3-sec), 17% increase in rate of heat transfer for cold water & 73% for hot water has been observed with a variation in mass flow rate of 1-3 kg/m3-sec with all combination of angles of holes in spherical protrusions. In the case of pyramidal protrusions, the rate of heat transfer has been raised from 16% for cold water & 88% for hot water at varying a mass flow rate of 1-3 kg/m3-sec in all combinations of angles of the top vortex in each protrusion. The effect of imparting the centrifugal force has raised the rates of heat transfer in the range of 24-36% at varying rpm from 60-180 rpm of the central cylinder, with the highest with 120 rpm. A comparison of the heat transfer rates reveals that with increasing the mass flow rates, rpm, angle of the holes in spherical protrusions and angle of the traversed angle at the top corner of each pyramidal protrusion didn’t contribute linearly in terms of rising in the rate of heat transfer.

This paper presents the space charge impact on the inception and propagation of electrical trees in cross-linked polyethylene (XLPE) insulation via simulations and experimentation. A 3D finite element analysis (FEA)-based modeling is proposed to simulate electrical trees via a needle embedded on the XLPE insulation. The proposed FEA model demonstrates the influence of the space charge magnitude and polarity on the initiation of partial discharges (PD). Then the critical parameters at the tip of an 8 µm. tree are to be examined. Experimentation is necessary to verify the simulation results acquired and study the mechanism of electrical trees at the inception and propagation stage. Therefore, in the experiment, a needle with a curvature radius of 5 µm. is embedded in the XLPE as a method of simulating defects, such as protrusions, voids, or cracks found in cable insulation. The power source supplies several high AC voltages on the 20 kV (rated voltage) cable under test for observing the inception and propagation behavior of the electrical trees. Phase-resolved partial discharge (PRPD) patterns are extracted at the inception and propagation stages of the electrical tree to determine the severity of the PDs occurring. A relationship is obtained for the PD magnitude with respect to the applied AC voltage while considering the positive and negative polarities of the PDs. This relationship then allows for the acquisition of the maximum electric field-tree length characteristics. The goal of the simulation of electrical trees is to provide the reader with a better understanding about the effect of space charge magnitude and polarity to comprehend the behavior of the treeing inception and propagation mechanisms. The injection and extraction of space charges is a complex phenomenon that requires further visualization through simulations. Therefore, the results of both the simulation and experiment are compared with the aim of establishing a clear relationship between space charge distribution and tree initiation. [ABSTRACT FROM AUTHOR]

The generation of invasive fluctuating protrusions is a distinctive feature of tumor dissemination. During the invasion, individual cancer cells modulate the morphodynamics of protrusions to optimize their migration efficiency. However, it remains unclear how protrusion fluctuations govern the invasion of more complex multi‐cellular structures, such as tumors, and their correlation with the tumor metastatic potential. Herein, a reductionist approach based on 3D tumor cell micro‐spheroids with different invasion capabilities is used as a model to decipher the role of tumor‐associated fluctuating protrusions in cancer progression. To quantify fluctuations, a set of key biophysical parameters that precisely correlate with the invasive potential of tumors is defined. It is shown that different pharmacological drugs and cytokines are capable of modulating protrusion activity, significantly altering protrusion fluctuations, and tumor invasiveness. This correlation is used to define a novel quantitative invasion index encoding the key biophysical parameters of fluctuations and the relative levels of cell‐cell/matrix interactions, which is capable of assessing the tumor's metastatic capability solely based on its magnitude. Overall, this study provides new insights into how protrusion fluctuations regulate tumor cell invasion, suggesting that they may be employed as a novel early indicator, or biophysical signature, of the metastatic potential of tumors. [ABSTRACT FROM AUTHOR]

Upon inflammation, leukocytes rapidly transmigrate across the endothelium to enter the inflamed tissue. Evidence accumulates that leukocytes use preferred exit sites, alhough it is not yet clear how these hotspots in the endothelium are defined and how they are recognized by the leukocyte. Using lattice light sheet microscopy, we discovered that leukocytes prefer endothelial membrane protrusions at cell junctions for transmigration. Phenotypically, these junctional membrane protrusions are present in an asymmetric manner, meaning that one endothelial cell shows the protrusion and the adjacent one does not. Consequently, leukocytes cross the junction by migrating underneath the protruding endothelial cell. These protrusions depend on Rac1 activity and by using a photo-activatable Rac1 probe, we could artificially generate local exit-sites for leukocytes. Overall, we have discovered a new mechanism that uses local induced junctional membrane protrusions to facilitate/steer the leukocyte escape/exit from inflamed vessel walls.

This paper is focusing on 3D Finite Elements Analysis (FEA) based modelling of protrusions as defects or imperfections in the XLPE high voltage cable. This study is aiming to examine the impact, protrusions have on the initiation of partial discharges. Spherical and ellipsoidal protrusions with different sizes at the conductor screen of the high voltage cable is an essential content of this paper. In addition, a spherical gas-filled void is placed inside and outside the protrusions, and a water tree produced from protrusions is under consideration. The partial discharge influence taking place at the protrusions and the stress enhancement factor is determined for all the variations mentioned to quantify the rise in the inception of partial discharges due to the protrusions.

This paper is focusing on 3D Finite Elements Analysis (FEA) based modelling of protrusions as defects or imperfections in the XLPE high voltage cable. This study is aiming to examine the impact protrusions have on the initiation of partial discharges. Spherical and ellipsoidal protrusions with different sizes at the conductor screen of the high voltage cable is an essential content of this paper. In addition, a spherical gas-filled void is placed inside and outside the protrusions, and a water tree produced from protrusions is under consideration. The partial discharge influence taking place at the protrusions and the stress enhancement factor is determined for all the variations mentioned to quantify the rise in the inception of partial discharges due to the protrusions. [ABSTRACT FROM AUTHOR]

This paper focuses on the fabrication of high-quality novel products using a µEDM process variant called Reverse-µEDM. The tool plate required for the Reverse-µEDM is fabricated using Nd: YAG-based laser beam micromachining (LBµM) at the optimized process parameters. The Grey relation analysis technique is used for optimizing LBµM parameters for producing tool plates with arrayed micro-holes in elliptical and droplet profiles. Titanium sheets of 0.5 mm thickness were used for such micro-holes, which can be used as a Reverse-µEDM tool. The duty cycle (a combination of pulse width and frequency) and current percentage are considered as significant input process parameters for the LBµM affecting the quality of the micro-holes. A duty cycle of 1.25% and a current of 20% were found to be an optimal setting for the fabrication of burr-free shallow striation micro-holes with a minimal dimensional error. Thereafter, analogous protrusions of high dimensional accuracy and minimum deterioration were produced by Reverse-µEDM using the LBµM fabricated tool plates.

The nucleate pool is a useful technique of heat dissipation in a variety of thermal applications. This study investigates the effect of the gridded metal surface (GMS) with and without protrusions on the heat transfer from a surface maintained at a temperature above the saturation temperature of water. The experimental data have been collected pertaining to boiling heat transfer at atmospheric pressure by varying the grid size of gridded metal surface with protrusions from 6 mm to 22.5 mm placed over a boiling surface having microporous coating. The mean particle diameter of coating is varied as 11, 24, and 66 μm during the experimentation. It is observed that the increase in the boiling heat transfer coefficient of the aluminum disk with GMS with protrusions of grid size 11.5 mm compared to that of the smooth boiling surface is found to be 10.7%. Furthermore, the effect of GMS having protrusions with coated surface on the heat transfer is studied. The results showed that by using GMS having protrusions and with coated surface, the heat transfer is further enhanced. The boiling heat transfer coefficient obtained in case of GMS with protrusions (grid size = 11.5 mm) and microporous-coated surface (⁠dm = 66 μm) shows the maximum enhancement of 39.93% in comparison to the smooth surface. [ABSTRACT FROM AUTHOR]

Metastasis is the main cause of death in cancer patients but remains a poorly understood process. Small cell lung cancer (SCLC) is one of the most lethal and most metastatic cancer types. SCLC cells normally express neuroendocrine and neuronal gene programs but accumulating evidence indicates that these cancer cells become relatively more neuronal and less neuroendocrine as they gain the ability to metastasize. Here we show that mouse and human SCLC cells in culture and in vivo can grow cellular protrusions that resemble axons. The formation of these protrusions is controlled by multiple neuronal factors implicated in axonogenesis, axon guidance, and neuroblast migration. Disruption of these axon-like protrusions impairs cell migration in culture and inhibits metastatic ability in vivo. The co-option of developmental neuronal programs is a novel molecular and cellular mechanism that contributes to the high metastatic ability of SCLC.

Garnero et al. (2015) recently introduced a framework based on dynamic programming to make applications of the protrusion replacement technique constructive and to obtain explicit upper bounds on the involved constants. They show that for several graph problems, for every boundary size t one can find an explicit set R t of representatives. Any subgraph H with a boundary of size t can be replaced with a representative H ′ ∈ R t such that the effect of this replacement on the optimum can be deduced from H and H ′ alone. Their upper bounds on the size of the graphs in R t grow triple-exponentially with t. In this paper we complement their results by lower bounds on the sizes of representatives, in terms of the boundary size t. For example, we show that each set of planar representatives R t for Independent Set or Dominating Set contains a graph with Ω (2 t ∕ 4 t) vertices. This lower bound even holds for sets that only represent the planar subgraphs of bounded pathwidth. To obtain our results we provide a lower bound on the number of equivalence classes of the canonical equivalence relation for Independent Set on t -boundaried graphs. We also find an elegant characterization of the number of equivalence classes in general graphs, in terms of the number of monotone functions of a certain kind. Our results show that the number of equivalence classes is at most 2 2 t , improving on earlier bounds of the form (t + 1) 2 t . [ABSTRACT FROM AUTHOR]

Highly robust poly‐Si thin‐film transistor (TFT) on polyimide (PI) substrate using blue laser annealing (BLA) of amorphous silicon (a‐Si) for lateral crystallization is demonstrated. Its foldability is compared with the conventional excimer laser annealing (ELA) poly‐Si TFT on PI used for foldable displays exhibiting field‐effect mobility of 85 cm2 (V s)−1. The BLA poly‐Si TFT on PI exhibits the field‐effect mobility, threshold voltage (VTH), and subthreshold swing of 153 cm2 (V s)−1, −2.7 V, and 0.2 V dec−1, respectively. Most important finding is the excellent foldability of BLA TFT compared with the ELA poly‐Si TFTs on PI substrates. The VTH shift of BLA poly‐Si TFT is ≈0.1 V, which is much smaller than that (≈2 V) of ELA TFT on PI upon 30 000 cycle folding. The defects are generated at the grain boundary region of ELA poly‐Si during folding. However, BLA poly‐Si has no protrusion in the poly‐Si channel and thus no defect generation during folding. This leads to excellent foldability of BLA poly‐Si on PI substrate. [ABSTRACT FROM AUTHOR]

This paper experimentally introduces the electrostatic discharges generated from metal protrusions inside a silo during the loading of powders. An industrial-scale pneumatic powder transport facility including a silo and approximately 400 kg of polypropylene powder (PP, 2–3 mm in size) were used for this test. The PP powder loading speed was approximately 0.38 kg/s. Six different diameters (D: 1 cm to 6.3 cm) of metal protrusions were used. The metal protrusions were attached to the silo wall using a 30 cm support rod that was electrically grounded. The height from the accumulated PP powder to the protrusion in the silo varied from 10 cm to 50 cm. An image-intensifier unit was used in order to observe the electrostatic discharges generated from the metal protrusions and a current probe attached to an oscilloscope was used in order to measure the current of the discharges. As for the results, electrostatic discharges (such as brush discharges) from protrusions during the loading of PP powders were clearly observed. Specifically, the electrostatic discharge was the strongest in this paper when the diameter of the protrusion was 4 cm and the height from the accumulated powder was 30 cm. As an important finding, the value of the discharge amount was affected to a greater extent by the maximum discharge current. The maximum charge amount of electrostatic discharges generating from the metal protrusions in all of the test conditions was −122 nC, which is twice as high as the threshold for electrostatic risk assessment in the liquid painting process. These results suggest that, in the chemical process, sensitive powders with MIEs of less than 4 mJ, powders wetted with solvents, and the solvents themselves must be carefully handled, as these kinds of powders may be ignited by brush discharges. In order to prevent and reduce electrostatic accidents, it is important to make sure that no external material enters the silo. Unlabelled Image • Brush discharges from metal protrusions were clearly observed during the powder loading. • Brush discharge from protrusion with 4 cm in diameter was the strongest in this paper. • Protrusions within silo must be removed to prevent electrostatic accidents. [ABSTRACT FROM AUTHOR]

The facultative intracellular pathogen Listeria monocytogenes uses an actin-based motility process to spread within human tissues. Filamentous actin from the human cell forms a tail behind bacteria, propelling microbes through the cytoplasm. Motile bacteria remodel the host plasma membrane into protrusions that are internalized by neighboring cells. A critical unresolved question is whether generation of protrusions by Listeria involves stimulation of host processes apart from actin polymerization. Here we demonstrate that efficient protrusion formation in polarized epithelial cells involves bacterial subversion of host exocytosis. Confocal microscopy imaging indicated that exocytosis is up-regulated in protrusions of Listeria in a manner that depends on the host exocyst complex. Depletion of components of the exocyst complex by RNA interference inhibited the formation of Listeria protrusions and subsequent cell-to-cell spread of bacteria. Additional genetic studies indicated important roles for the exocyst regulators Rab8 and Rab11 in bacterial protrusion formation and spread. The secreted Listeria virulence factor InlC associated with the exocyst component Exo70 and mediated the recruitment of Exo70 to bacterial protrusions. Depletion of exocyst proteins reduced the length of Listeria protrusions, suggesting that the exocyst complex promotes protrusion elongation. Collectively, these results demonstrate that Listeria exploits host exocytosis to stimulate intercellular spread of bacteria. [ABSTRACT FROM AUTHOR]

Breast cancer nuclei have highly irregular shapes, which are diagnostic and prognostic markers of breast cancer progression. The mechanisms by which irregular cancer nuclear shapes develop are not well understood. Here we report the existence of vertical, apical cell protrusions in cultured MDA‐MB‐231 breast cancer cells. Once formed, these protrusions persist over time scales of hours and are associated with vertically upward nuclear deformations. They are absent in normal mammary epithelial cells (MCF‐10A cells). Microtubule disruption enriched these protrusions preferentially in MDA‐MB‐231 cells compared with MCF‐10A cells, whereas inhibition of nonmuscle myosin II (NMMII) abolished this enrichment. Dynamic confocal imaging of the vertical cell and nuclear shape revealed that the apical cell protrusions form first, and in response, the nucleus deforms and/or subsequently gets vertically extruded into the apical protrusion. Overexpression of lamin A/C in MDA‐MB‐231 cells reduced nuclear deformation in apical protrusions. These data highlight the role of mechanical stresses generated by moving boundaries, as well as abnormal nuclear mechanics in the development of abnormal nuclear shapes in breast cancer cells. [ABSTRACT FROM AUTHOR]

Many tumors recapitulate the developmental and differentiation program of their tissue of origin, a basis for tumor cell heterogeneity. Although stem-cell-like tumor cells are well studied, the roles of tumor cells undergoing differentiation remain to be elucidated. We employ Drosophila genetics to demonstrate that the differentiation program of intestinal stem cells is crucial for enabling intestinal tumors to invade and induce non-tumor-autonomous phenotypes. The differentiation program that generates absorptive cells is aberrantly recapitulated in the intestinal tumors generated by activation of the Yap1 ortholog Yorkie. Inhibiting it allows stem-cell-like tumor cells to grow but suppresses invasiveness and reshapes various phenotypes associated with cachexia-like wasting by altering the expression of tumor-derived factors. Our study provides insight into how a native differentiation program determines a tumor's capacity to induce advanced cancer phenotypes and suggests that manipulating the differentiation programs co-opted in tumors might alleviate complications of cancer, including cachexia. [Display omitted] • The native cell differentiation program is co-opted in yki 3S/A intestinal tumors • The native cell differentiation program fosters intestinal tumor cell heterogeneity • Blocking tumor cell differentiation halts tumor cell invasion • Blocking tumor cell differentiation rescues certain cachexia phenotypes Pranoto et al. reveal that the native cell differentiation program is aberrantly recapitulated in intestinal tumors, resulting in a pronounced heterogeneity within tumor cell populations. The study discovers the essential roles of the tumor cells undergoing differentiation in inducing tumor cell invasion and certain cachexia phenotypes, such as tissue wasting. [ABSTRACT FROM AUTHOR]

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The paper considers the origin of hydrocarbon accumulations within the Pre-Cenozoic basement of the Vietnam shelf. It is shown that the formation of hydrocarbon deposits is associated with protrusive granite massifs that underwent structural–tectonic reworking at the prototectonic and posthumous (postmagmatic) tectonic stage. Together, the posthumous structure-forming processes led to changes in the viscosity properties of rocks, their tectonic and material inhomogeneity, lamination, and, as a result, vertical and lateral spatial redistribution with the formation of granite protrusions. The mechanisms by which voids and oil and gas traps formed within protrusions are considered. A conclusion on the organic nature of petroleum in the basement of the Vietnam shelf is drawn, based on the similarity of the geochemical characteristics and biomarkers of the petroleum and organic parameters in the Oligocene–Miocene sedimentary cover and basement rocks. Possible mechanisms for hydrocarbon migration and accumulation in basement rocks are considered. It is confirmed that the formation of hydrocarbon deposits occurred due to lateral and downward migration of hydrocarbons via contact zones from Oligocene and Miocene oil source rocks into crystalline massifs: into voids and increased fracture zones in the protrusion body. [ABSTRACT FROM AUTHOR]

Abstract Cell migration is part of many important in vivo biological processes and is influenced by chemical and physical factors such as substrate topography. Although the migratory behavior of different cell types on structured substrates has already been investigated, up to date it is largely unknown if specimen's age affects cell migration on structures. In this work, we investigated age-dependent migratory behavior of human endothelial cells from young (≤ 31 years old) and old (≥ 60 years old) donors on poly(dimethylsiloxane) microstructured substrates consisting of well-defined parallel grooves. We observed a decrease in cell migration velocity in all substrate conditions and in persistence length perpendicular to the grooves in cells from old donors. Nevertheless, in comparison to young cells, old cells exhibited a higher cell directionality along grooves of certain depths and a higher persistence time. We also found a systematic decrease of donor age-dependent responses of cell protrusions in orientation, velocity and length, all of them decreased in old cells. These observations lead us to hypothesize a possible impairment of actin cytoskeleton network and affected actin polymerization and steering systems, caused by aging. [ABSTRACT FROM AUTHOR]

Abstract Heat transfer enhancement in parallel plate-fin heat exchanger is examined by performing three-dimensional numerical simulations of longitudinal vortex generators (VG) with protrusions. The turbulence is modeled using the shear-stress transport (SST) κ-ω model and validated with correlations and experimental data at Reynolds number equal to 4600. Hemi-spherical protrusions are inserted downstream two VG configurations: delta winglet type (DWP) and a new VG configuration named inclined projected winglet pair (IPWP), in various locations, leading to the definition of six different configurations. Based on the streamwise distribution of Nusselt number and friction coefficient criteria in addition to vorticity, the local performance is analyzed. Some VGs with protrusions are examined and show better performance relative to VGs standing alone. The present study highlights the different mechanisms involved in the convective heat transfer intensification by generating multiple interacting vortices while adding protrusions with low pressure drop penalty. Finally, it is found that the IPWP with protrusions, set downstream in the middle, bestows the best global performance with about 7.1% heat transfer enhancement compared to DWP configuration. Highlights • A new vortex generator configuration (IPWP) and delta winglet type (DWP) are simulated in a channel. • Hemi-spherical protrusions are inserted downstream the two types of vortex generators. • Effect on the flow structure and heat transfer mechanisms are analyzed. [ABSTRACT FROM AUTHOR]

Charge transportation expressed as a Lissajous figure usually is a standard method for the analysis of discharge power and energy in surface dielectric barrier discharge (SDBD). In this paper, the charge transportation characteristics under different parameters of power supply and actuator configurations are investigated, and the mechanisms of two typical Lissajous figures are discussed theoretically. Experimental results show that when the plasma distribution is quasi-diffuse mode, the Lissajous figure is almond shape correspondingly, while the plasma distribution looks like separated-channel mode, the Lissajous figure presents a parallelogram shape. Based on an improved time-varying lumped-element circuit model, two equivalent circuits of SDBD under two plasma distributions are built, and the Lissajous figures are calculated theoretically. Calculations and analysis results indicate that the two kinds of Lissajous figures under different plasma distribution modes are due to the current pulse durations and equivalent dielectric capacitances caused by plasma distributions acting together. The protrusions of Lissajous figures are caused by the current narrow pulses in the characteristics of separated-channel mode, while Lissajous figures under quasi-diffuse mode have no protrusions. [ABSTRACT FROM AUTHOR]

Surface textures have been demonstrated to have a positive effect on the friction reduction. However, sharp edges of the normally textured patterns usually cause stress concentration and severe wear during sliding, especially for non-conformal contacting pairs. In this study, protrusion-type textures were fabricated at different area ratios on stainless steel discs and edge profiling was performed for the protrusions, and friction tests were conducted in water to investigate the tribological properties. The results show that the friction was reduced markedly by edge profiling due to the formation of wedge contact and improvement of lubricant supply to the contact interfaces under low load. Under high load, severe wear destroyed the wedge contact resulting in high friction as those of the normally textured pairs. High area ratio exhibited better friction reduction effect. The stress analysis via ANSYS indicated that much high stress concentrated at the edges of the protrusions and could be reduced significantly by edge profiling.