Filamentation Process Research Articles

Transcriptomic Analysis Reveals Differential Expression of Genes between Lung Capillary and Post Capillary Venules in Abdominal Sepsis.

Lung endothelial cell dysfunction plays a central role in septic-induced lung injury. We hypothesized that endothelial cell subsets, capillary endothelial cells (capEC) and post capillary venules (PCV), might play different roles in regulating important pathophysiology in sepsis. In order to reveal global transcriptomic changes in endothelial cell subsets during sepsis, we induced sepsis in C57BL/6 mice by cecal ligation and puncture (CLP). We confirmed that CLP induced systemic and lung inflammation in our model. Endothelial cells (ECs) from lung capillary and PCV were isolated by cell sorting and transcriptomic changes were analyzed by bioinformatic tools. Our analysis revealed that lung capEC are transcriptionally different than PCV. Comparison of top differentially expressed genes (DEGs) of capEC and PCV revealed that capEC responses are different than PCV during sepsis. It was found that capEC are more enriched with genes related to regulation of coagulation, vascular permeability, wound healing and lipid metabolic processes after sepsis. In contrast, PCV are more enriched with genes related to chemotaxis, cell–cell adhesion by integrins, chemokine biosynthesis, regulation of actin filament process and neutrophil homeostasis after sepsis. In addition, we predicted some transcription factor targets that regulate a significant number of DEGs in sepsis. We proposed that targeting certain DEGs or transcriptional factors would be useful in protecting against sepsis-induced lung damage.

Comparison of Phenolic Contents and Scavenging Activities of Miang Extracts Derived from Filamentous and Non-Filamentous Fungi-Based Fermentation Processes.

The study investigated the impact of the fermentation process on the phenolic contents and antioxidant and anti-inflammatory activities in extracts of Miang, an ethnic fermented tea product of northern Thailand. The acetone (80%) extraction of Miang samples fermented by a non-filamentous fungi-based process (NFP) and filamentous fungi-based process (FFP) had elevated levels of total polyphenols, total tannins, and condensed tannins compared to young and mature tea leaves. The antioxidant studies also showed better the half-maximal inhibitory concentration (IC50) values for fermented leaves in both 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity assays as well as improved ferric reducing antioxidant power (FRAP) compared to young and mature tea leaves. Extracts of NFP and FFP samples at concentrations of 50 and 100 ppm showed better protective effects against hydrogen peroxide (H2O2)-induced intracellular reactive oxygen species (ROS) production in HT-29 colorectal cells without exerting cytotoxicity. Additionally, lipopolysaccharide (LPS)-induced production of nitric oxide (a proinflammatory mediator as well as a reactive nitrogen species) was also inhibited by these fermented Miang extracts with an IC50 values of 17.15 μg/mL (NFP), 20.17 μg/mL (FFP), 33.96 μg/mL (young tea leaves), and 31.33 μg/mL (mature tea leaves). Therefore, both NFP-Miang and FFP-Miang showed the potential to be targeted as natural bioactive functional ingredients with preventive properties against free radical and inflammatory-mediated diseases.

High-strength cellulose nanofiber/graphene oxide hybrid filament made by continuous processing and its humidity monitoring

Human-made natural-fiber-based filaments are attractive for natural fiber-reinforced polymer (NFRP) composites. However, the composites' moisture distribution is critical, and humidity monitoring in the NFRP composites is essential to secure stability and keep their life span. In this research, high strength and humidity sensing filament was developed by blending cellulose nanofiber (CNF) and graphene oxide (GO), wet-spinning, coagulating, and drying, which can overcome the heterogeneous mechanical properties between embedded-type humidity sensors and NFRP composites. The stabilized synthesis process of the CNF-GO hybrid filament demonstrated the maximum Young's modulus of 23.9 GPa and the maximum tensile strength of 439.4 MPa. Furthermore, the achieved properties were successfully transferred to a continuous fabrication process with an additional stretching process. Furthermore, its humidity sensing behavior is shown by resistivity changes in various temperature and humidity levels. Therefore, this hybrid filament has excellent potential for in-situ humidity monitoring by embedding in smart wearable devices, natural fiber-reinforced polymer composites, and environmental sensing devices.

Investigation of the Detailed AMPylated Reaction Mechanism for the Huntingtin Yeast-Interacting Protein E Enzyme HYPE.

AMPylation is a prevalent posttranslational modification that involves the addition of adenosine monophosphate (AMP) to proteins. Exactly how Huntingtin-associated yeast-interacting protein E (HYPE), as the first human protein, is involved in the transformation of the AMP moiety to its substrate target protein (the endoplasmic reticulum chaperone binding to immunoglobulin protein (BiP)) is still an open question. Additionally, a conserved glutamine plays a vital key role in the AMPylation reaction in most filamentation processes induced by the cAMP (Fic) protein. In the present work, the detailed catalytic AMPylation mechanisms in HYPE were determined based on the density functional theory (DFT) method. Molecular dynamics (MD) simulations were further used to investigate the exact role of the inhibitory glutamate. The metal center, Mg2+, in HYPE has been examined in various coordination configurations, including 4-coordrinated, 5-coordinated and 6-coordinated. DFT calculations revealed that the transformation of the AMP moiety of HYPE with BiP followed a sequential pathway. The model with a 4-coordinated metal center had a barrier of 14.7 kcal/mol, which was consistent with the experimental value and lower than the 38.7 kcal/mol barrier of the model with a 6-coordinated metal center and the 31.1 kcal/mol barrier of the model with a 5-coordinated metal center. Furthermore, DFT results indicated that Thr518 residue oxygen directly attacks the phosphorus, while the His363 residue acts as H-bond acceptor. At the same time, an MD study indicated that Glu234 played an inhibitory role in the α-inhibition helix by regulating the hydrogen bond interaction between Arg374 and the Pγ of the ATP molecule. The revealed sequential pathway and the inhibitory role of Glu234 in HYPE were inspirational for understanding the catalytic and inhibitory mechanisms of Fic-mediated AMP transfer, paving the way for further studies on the physiological role of Fic enzymes.

Modeling current and voltage peaks generation in complementary resistive switching devices

We propose a physical model of complementary resistive switching (CRS) based on the disruption and reformation process of a metallic filament inside each Oxyde Resistive Random Access Memory (OxRRAM) composing the CRS. The driving forces involved in this process are electromigration forces, electron phonon coupling and joule heating. The model accounts well for the experimental CRS current voltage characteristics. The stability of the CRS states and the CRS operation in pulse regime, including the current and voltage peaks generation are discussed.

Efficient point-by-point Bragg grating inscription in sapphire fiber using femtosecond laser filaments.

Sapphire fiber Bragg gratings (SFBGs) inscribed by using femtosecond laser point-by-point (PbP) technology typically have an extremely low reflectivity due to the limited cross-sectional area of refractive index modulations (RIMs) created in sapphire fiber. Hence, we propose and experimentally demonstrate a filamentation process for fabricating PbP SFBGs. This approach provides an efficient method for producing SFBGs at various Bragg wavelengths with a higher reflectivity, since the filament tracks could enlarge the cross-sectional area of RIMs. The influences of the pulse energy and the focal depth on the generation and morphology of the filament tracks were studied, and after optimizing these parameters, high-quality filament tracks with a length of 90 µm and a width of 1.4 µm were produced into sapphire fiber with a diameter of 100 µm. These filament tracks were precisely assembled in sapphire fiber, generating an SFBG with a reflectivity of 2.3%. The total fabrication time for this SFBG only requires ${\sim}{1.1}\;{\rm s}$. Subsequently, a wavelength-division-multiplexed (WDM) SFBG array consisting of five SFBGs was efficiently constructed. Moreover, the high-temperature response of the SFBG array was investigated and the experimental results showed that the SFBG array can withstand a high temperature of 1600°C. Such a WDM SFBG array could serve as quasi-distributed high-temperature sensor which will be promising in many areas, i.e., metallurgical, chemical, and aviation industries.

Dynamics of a contracting fluid compound filament with a variable density ratio

Introduction: Compound fluid filaments appear in many applications, e.g., drug delivery and processing or microfluidic systems. This paper focuses on the numerical simulation of an incompressible, immiscible, and Newtonian fluid for the contraction process of a fluid compound filament by solving the Navier-Stokes equations. The front-tracking method is used to solve this problem, which uses connected segments (Lagrangian grid) that move on a fixed grid (Eulerian grid) to represent the interface between the liquids.
 Methods: The interface points are advected by the velocity interpolated from those of the fixed grid using the area weighting function. The coordinates of the interface points are used to construct the indicators specifying the different fluids and compute the interfacial tension force.
 Results: The simulation results show that under the effects of the interfacial tension, the capsuleshaped filament can transform into a spherical compound droplet (i.e., non-breakup) or can break up into smaller spherical compound and simple droplets (i.e., breakup). When the density ratio of the outer to middle fluids increases, the filament changes from non-breakup to breakup upon contraction.
 Conclusion: Increasing the density ratio enhances the breakup of the compound filament during contraction. The breakup is also promoted by increasing the initial length of the filament.

Analysis of novel induction heating extruder for additive manufacturing using aluminum filament

Induction Heating (IH) method is gaining traction in the field of Additive Manufacturing (AM) as it is a low cost, clean, safe, and precise energy source. Wire as a feedstock material is highly efficient as compared to the powder form in terms of material utilization and economic viability. Thus, the combination of IH and wire feedstock delivery to additive manufacture a part has been explored on an in-house developed novel AM setup. The processing of aluminum wire (Al-5356) in semi-solid form from the extruder, heated using IH method has been performed. The approach adopted in this paper is to perform an in situ infrared imaging to analyze the evolution of thermal field during the extruder heating and metal deposition process. An effective thermal cartography has been undertaken to acquire temperature history of filament, extruder, and deposition process. The temperature profile plot is utilized to understand the temperature distribution and average temperature in the heating, extrusion, and layering process during layer fabrication. The presented work facilitates a priori anticipation to utilize IH as a potential energy source for the metal AM systems.

Properties and structure of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) filaments for fused deposition modelling

Fused deposition modelling (FDM) is a process of additive manufacturing allowing creating of highly precise complex three-dimensional objects for a large range of applications. The principle of FDM is an extrusion of the molten filament and gradual deposition of layers and their solidification. Potential applications in pharmaceutical and medical fields require the development of biodegradable and biocompatible thermoplastics for the processing of filaments. In this work, the potential of production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) filaments for FDM was investigated in respect to its thermal stability. Copolymer P(3HB-co-4HB) was biosynthesised by Cupriavidus malaysiensis. Rheological and mechanical properties of the copolymer were modified by the addition of plasticizers or blending with poly(lactic acid). Thermal stability of mixtures was studied employing thermogravimetric analysis and rheological analyses by monitoring the time-dependent changes in the complex viscosity of melt samples. The plasticization of P(3HB-co-4HB) slightly hindered its thermal degradation but the best stabilization effect was found in case of the copolymer blended with poly(lactic acid). Overall, rheological, thermal and mechanical properties demonstrated that the plasticized P(3HB-co-4HB) is a potential candidate of biodegradable polymer for FDM processes.

An Integrative 3D printing method for rapid additive manufacturing of a capacitive force sensor

With the rapid development of the three-dimensional printing (3D printing) technique, several electronic devices have been fabricated by 3D printing. Compared with the traditional micro electromechanical system (MEMS) manufacturing processes, the 3D printing technique provides a convenient method to meet the customers’ personalized demands. However, the applications of 3D printing are restricted by the electrically insulating properties of the commonly used polymers. Besides, additional alignment and assembling processes are still indispensable to fabricate the MEMS devices with geometrically complex structures using the conventional 3D printers. In order to solve these problems, an integrative 3D printing approach for rapid manufacturing is presented in this paper. With a triple-extruder 3D printer, the electrically insulating polylactic acid (PLA) filament, the electrically conductive PLA filament, and the soluble high impact polystyrene filament can be printed alternately in the 3D printing process. As an application of the method, a capacitive force sensor with a relatively complex suspended beam-plate structure was fabricated in a one-step 3D printing process without using any additional metallization process, unloading–reloading filament process, alignment process, and assembling process. With a good dynamic performance, the 3D printed force sensor was used to monitor human’s blood pulse. The results show that the integrative 3D printing method has potential to meet the emerging requirement for manufacturing of MEMS devices for personalized applications.

Microbial dynamics-linked properties and functional metabolites during Miang fermentation using the filamentous fungi growth-based process

The microbial community in ethnic fermented tea, “Miang” prepared from Camellia sinensis var. assamica in northern Thailand was investigated during the 10 days of a filamentous fungi growth-based process (FFP) using both culture-dependent and culture-independent techniques. During the aerobic phase (days 1–3), filamentous fungi were visually observed growing on steamed tea leaves during which yeast and lactic acid bacteria (LAB) viable cell numbers substantially increased up to 108 and 109 CFU/g Miang, respectively, and became the main microbial population both in semi-submerged fermentation (SSF) and submerged fermentation (SMF) processes. Next generation sequencing indicated the high diversity of the filamentous fungal population in the initial stage of aerobic fermentation. Aspergillus niger was the predominant fungus on day 3 and was the most important microbe in association with yeast, LAB and Bacillus sp. in both the SSF and SMF processes. Pectinases, β-mannanase and cellulases were mainly found during the aerobic fermentation phase, suggesting they were important during fermentation. The organic acids found in Miang were acetic, gallic, glucuronic, lactic, oxalic and succinic acids, while FFP Miang showed similar bioactive compounds including total tannin, total flavonoids and total polyphenols with both SSF and SMF processes. However, SMF resulted in higher antioxidant activity than SSF, while the hardness of both was similar. This study showed an important product processing platform for assessing the relationship between microbes, biotransformation and also functional metabolites accumulated in Miang fermented using the FFP.

Factors affecting properties of Ti-6Al-4V alloy additive manufactured by metal fused filament fabrication

This paper aims to break the current material-process-property tradeoffs in metal fused filament fabrication (MF3) to effectively fabricate Ti-6Al-4V alloy specimens beyond 90% relative density without any post-processing with consistent mechanical properties and microstructure, which are critical for aerospace and medical applications. Existing knowledge gaps in MF3 3D printing fail to address how properties scale from the filament processing stage to green part printing to sintering and what contributing factors cause significant deviation in mechanical properties in samples having the same sintered densities. To tackle these gaps, this work holistically investigates four key aspects specifically for MF3 of Ti-6Al-4V to address a) influence of filament extrusion conditions on filament density variance and diameter control, b) use of the design of experiments to identify factors influencing MF3 3D printed green sample density and dimensions, c) identifying sintering time and temperature conditions that yield densities beyond 90% and mechanical properties close to literature and d) powder attributes (size and interstitial concentrations) and its effect on sintered density and mechanical properties for MF3 samples.

Pre-eruption Splitting of the Double-decker Structure in a Solar Filament

Abstract Solar filaments often erupt partially. Although how they split remains elusive, the splitting process has the potential of revealing the filament structure and eruption mechanism. Here we investigate the pre-eruption splitting of an apparently single filament and its subsequent partial eruption on 2012 September 27. The evolution is characterized by three stages with distinct dynamics. During the quasi-static stage, the splitting proceeds gradually for about 1.5 hr, with the upper branch rising at a few kilometers per second and displaying swirling motions about its axis. During the precursor stage that lasts for about 10 minutes, the upper branch rises at tens of kilometers per second, with a pair of conjugated dimming regions starting to develop at its footpoints; with the swirling motions turning chaotic, the axis of the upper branch whips southward, which drives an arc-shaped extreme-ultraviolet front propagating in a similar direction. During the eruption stage, the upper branch erupts with the onset of a C3.7-class two-ribbon flare, while the lower branch remains stable. Judging from the well-separated footpoints of the upper branch from those of the lower one, we suggest that the pre-eruption filament processes a double-decker structure composed of two distinct flux bundles, whose formation is associated with gradual magnetic flux cancellations and converging photospheric flows around the polarity inversion line.

Computational Failure Analysis of Resistive RAM Used as a Synapse in a Convolutional Neural Network for Image Classification

Abstract Various NVM technologies are being explored for neuromorphic system realization, including resistive RAM, ferroelectric RAM, phase change RAM, spin transfer torque RAM, and NAND flash. This article discusses the potential of RRAM for such applications and evaluates key performance and reliability metrics in the context of neural network image classification. The authors conclude that the accuracy-power tradeoff may be further improved using alternative material stacks and multi-layer dielectrics so as to achieve better control of the oxygen vacancy or metallic filamentation process that governs RRAM switching characteristics.

Inhibition of the filamentation of Candida albicans by Borojoa patinoi silver nanoparticles

Candida albicans is fungus capable of changing from yeast to filamentous form when it’s transformed from a normal commensal to an opportunistic pathogen. The development of alternatives that interfere with this transition could be an effective way to reduce candidiasis. In this regard, evaluate the inhibitory effect of two Borojoa patinoi silver nanoparticles (AgNPs) produced by green synthesis at 5 °C and 25 °C on the process of filamentation of Candida albicans. The percentage of inhibition of filamentous forms of C. albicans ATCC10231 and C. albicans SC5314 with AgNPs was determined. Results showed that temperature of synthesis affected both the shape and size of silver nanoparticles synthesized using Borojoa patinoi extracts. The inhibition percentage of filamentous forms of Candida albicans ATCC10231 when treated with silver nanoparticles synthesized at 5 °C was 85.9% and at 25 °C it was 40%. C. albicans SC5314 when treated with AgNP synthesized at 5 °C was 97.2% and at 25 °C it was 64%. Cell toxicity assay showed that at 100ng/ml, AgNPs synthesized at 25 °C were safe in MES-OV CRL-3272 cell line. Our results showed that the silver nanoparticles obtained from Borojoa patinoi are inhibitors of the filamentous process of C. albicans.

The Cbk1-Ace2 axis guides Candida albicans from yeast to hyphae and back again

Since its description in S. cerevisiae, the Regulation of Ace2 and Morphogenesis (RAM) pathway has been studied for nearly 20 years in multiple model and pathogenic fungi. In pathogenic fungi, the RAM pathway carries out many functions through mechanisms that remain to be defined in detail. Recently, we reported that Cbk1-mediated phosphorylation of the transcription factor Ace2 functions to repress the hyphae-to-yeast transition in Candida albicans. This transition is understudied relative to the yeast-to-hyphae transition. Subapical hyphal cell compartments are arrested in G1 until the point at which lateral yeast emerge. Here, we discuss this model and report new data indicating that a second G1 associated protein, the mitotic exit regulator Amn1. In S. cerevisiae diploid cells, Amn1 negatively regulates Ace2 at both the gene expression level through a negative feedback loop and at the protein level by targeting Ace2 for degradation. In C. albicans, Amn1 and Ace2 also form a feedback loop at the level of gene expression. Deletion of AMN1 decreases lateral yeast formation relative to wild type in maturing hyphae and is associated with decreased expression of PES1, a positive regulator of lateral yeast formation. These data indicate that the regulation of mitotic exit plays a role in determining the timing of lateral yeast emergence from hyphae in C. albicans. We also propose an integrated model for the interplay between the Cbk1-Ace2 axis and other hyphal stage regulators during the process of filamentation and transition back to yeast.

Anatomical and surface ultrastructural investigation of the tongue in the straw-coloured fruit bat (Eidolon helvum, Kerr 1972).

The morphology of tongue in straw-coloured fruit bat from tropical forests was evaluated in relation to frugivorous diets and in comparison with other species that consumes other food types. Gross, stereomicroscopy, scanning electron microscope and histological methods were used. The tongue was relatively long with round tip, which closely fitted into oral cavity. Five types of mechanical papillae included crown-like and trifid filiform papillae. Also bulky, cone-shaped papillae and long conical papillae were identified. These mechanical types also showed variations in shape, size and number of processes of papillae. Transitional forms of these mechanical papillae were present. Fungiform papillae with taste pores were interposed amongst filiform types in apex and body; three ovoid-shaped vallate papillae were in triangular arrangement on root and displayed taste pores. Some bulky, cone-shaped papillae surrounded the vallate papillae. Histologically, mechanical filiform types showed highly keratinized stratified squamous epithelium and dense connective tissue core with secondary papillae. Taste buds appeared in fungiform and vallate papillae. Neutral and acidic secretions were identified in lingual glands of root. The presence of prominent filamentous processes of filiform papillae and conical papillae of the tongue in conjunction with gustatory papillae ensures adaptation to copious fruit diets. The gross morphometric and histometric parameters of the tongue did not differ remarkably from previous values obtained for some fruit bats with comparable weight. This investigation showed similarities with fruit bats such as large flying fox and Egyptian fruit bat and reflect common diet and feeding habits but varied from insectivorous and nectivorous bats.

In silico characterization of laccase gene isoforms of edible and medicinal basidiomycetes

Laccases are part of the family of ligninolytic enzymes and have played essential roles in several biological filamentous fungi processes, including fruiting body formation and lignin degradation. This study aimed to identify and characterize laccase genes in silico of several basidiomycete strains. The applied guaiacol oxidation test allowed the selection of seven out of 11 strains with ligninase activity, which were used for DNA extraction and amplification of the copper-binding region. A single amplicon of approximately 450 bp, was produced by all selected strains and they were further sequenced. Sequence analysis has suggested the presence of a new subdivision of the laccase genes. Clustering analysis confirmed the existence of two groups: cluster A with six strains and singleton B with U8-11 strain. The structural predictions of the U8-11 protein were dissimilar compared to other proteins described in our study due to the absence of the ALAVIN motif and, therefore, the U8-11 amino acid sequence was separated in a different cluster.

Phosphorus Catalytic Doping on Intrinsic Silicon Thin Films for the Application in Silicon Heterojunction Solar Cells.

Parasitic absorption and limited fill factor (FF) brought in by the use of amorphous silicon layers are efficiency-limiting challenges for the silicon heterojunction (SHJ) solar cells. In this work, postdeposition phosphorus (P) catalytic doping (Cat-doping) on intrinsic amorphous silicon (a-Si:H(i)) at a low substrate temperature was carried out and a P concentration of up to 6 × 1021 cm-3 was reached. The influences of filament temperature, substrate temperature, and processing pressure on the P profiles were systemically studied by secondary-ion mass spectrometry. By replacing the a-Si:H(n+er with P Cat-doping of an a-Si:H(i) layer, the passivation quality was improved, reaching an iVOC of 741 mV, while the parasitic absorption was reduced, leading to an increase in JSC by ∼1 mA/cm2. On the other hand, the open-circuit voltage and the FF of a conventional SHJ solar cell (with the a-Si:H(n) layer) can be improved by adding a Cat-doping process on the a-Si:H(i) layer, resulting in an increase in FF by 4.7%abs and in efficiency by 1.5%abs.

Designed nanomolar small-molecule inhibitors of Ena/VASP EVH1 interaction impair invasion and extravasation of breast cancer cells

Battling metastasis through inhibition of cell motility is considered a promising approach to support cancer therapies. In this context, Ena/VASP-depending signaling pathways, in particular interactions with their EVH1 domains, are promising targets for pharmaceutical intervention. However, protein-protein interactions involving proline-rich segments are notoriously difficult to address by small molecules. Hence, structure-based design efforts in combination with the chemical synthesis of additional molecular entities are required. Building on a previously developed nonpeptidic micromolar inhibitor, we determined 22 crystal structures of ENAH EVH1 in complex with inhibitors and rationally extended our library of conformationally defined proline-derived modules (ProMs) to succeed in developing a nanomolar inhibitor ([Formula: see text] Da). In contrast to the previous inhibitor, the optimized compounds reduced extravasation of invasive breast cancer cells in a zebrafish model. This study represents an example of successful, structure-guided development of low molecular weight inhibitors specifically and selectively addressing a proline-rich sequence-recognizing domain that is characterized by a shallow epitope lacking defined binding pockets. The evolved high-affinity inhibitor may now serve as a tool in validating the basic therapeutic concept, i.e., the suppression of cancer metastasis by inhibiting a crucial protein-protein interaction involved in actin filament processing and cell migration.