Tip End Research Articles

Free Vibration Analysis of Tapered Composite Aircraft Wing via the Finite Element Method

The responses of the structures used in engineering applications under the effects of static and dynamic forces are significant in the design phase. Determination of the response of dynamic forces for a structure is initially performed by the evaluation of free vibration characteristics that are mode shape of the structure and vibration frequencies. This paper presents modal analyses of tapered aircraft wing structures that consist of NACA4415 design and different common materials used in the aviation industry. Furthermore, the effect of winglets on natural frequencies is examined. The main wing structures as ribs and shells are drawn using CATIA and imported to ANSYS Workbench. Analyses have been carried out considering the aircraft wing as a three-dimensional cantilever beam by fixing one end (root chord) of the aircraft wing while the other end (tip chord) is free. The first ten modes of free vibration with their respective natural frequencies and mode shapes of the wing structures of the aircrafts are obtained. The results show that the winglets decrease the natural frequency noticeably and the shell material as Carbon Epoxy UD has been observed to have higher natural frequency compared with Kevlar Epoxy.

Energy harvesting from charged conical nanopore with salinity and temperature gradient

• An energy harvesting system from charged conical nanopore with coupled salinity and temperature gradient is proposed. • An interesting completive mechanism between the concentration gradient and temperature gradient effect was found, which determined the output performance. • The enhancement of negative temperature difference on output power is more significant compared with positive temperature difference. • The research results provide useful information for the design and optimization of energy devices. Renewable energy has been received more attention with the increasingly serious energy crisis. In this paper, an energy harvesting system from charged conical nanopore with coupled salinity and temperature gradient is proposed. The results show that the obtained maximum power increases first and then decreases as the concentration difference increases. Particularly, the enhancement of negative temperature difference (NTD) on maximum output power and the corresponding energy conversion efficiency is more significant compared with positive temperature difference (PTD) due to the simultaneous increase of short circuit current and open circuit voltage. Besides, the maximum output power is larger when the low concentration reservoir is connected to the tip end of the conical nanopore. The obtained maximum optimal value is about 0.22 pW. In the further investigation of a temperature gradient, we found that the short circuit current, open circuit voltage, and maximum output power show the approximately linear thermal response characteristics as the temperature difference is increased. Besides, an interesting competive mechanism between the concentration gradient effect and temperature gradient effect is found, which determines the prior conical nanopore orientation. The related research results provide useful information for the design and optimization of energy devices.

Simulation and experimental investigation of an ultrasound system with cavitation in concentric zone

Nowadays, ultrasonic cavitation has been successfully used for the degradation of organic pollutants. However, many sonotrodes employed for wastewater treatment are excited to present a longitudinal vibration mode. Thus, the strongest cavitation generally occurs at the tip end of the sonotrodes or the inner walls of ultrasound baths, resulting in severe erosion of the vibrating metal surface caused by ultrasonic cavitation, even though the sonotrodes are made of titanium alloy. In addition, recontamination is possible due to corrosion of the sonotrode. To avoid the above issues, a novel ultrasound system composed of a cylindrical sonotrode and a Langevin-type transducer, is proposed for generating cavitation only in the concentric zone of the cylindrical sonotrode. The first-order longitudinal vibration and the radial vibration are simultaneously stimulated in the Langevin transducer and the cylindrical sonotrode, respectively, to produce the focused cavitation at the concentric zone of the sonotrode. At first, the finite element simulation is conducted to confirm the planned vibration of the ultrasound system and to compute its sound pressure. Subsequently, the prototype of the proposed ultrasound system is manufactured and assembled for vibration measurements. Finally, experimental investigations are carried out on the ultrasound system prototype. By the aluminum foil experiments, the cavitation bubbles occurred in the center of the cylindrical sonotrode. The erosion area increased with the increase of the working power and processing time. After treating the methyl violet solution by ultrasonic cavitation for 60 min, the methyl violet in the solution is reduced by 60%, which certainly will help the development of an appropriate flow system for dye degradation. • An ultrasound system for dye wastewater treatment without re-contamination is proposed, simulated, and experimental investigated. • Cavitation bubbles were only produced at the center of the ring sonotrode. • Concentration of methyl violet solution after ultrasonic treatment decreased significantly.

Nanofabrication mechanism of [formula omitted]/20 features achieved by coupling field tip enhancement induced with nanosecond laser irradiating AFM probe tip

The nanofabrication mechanism of coupling field tip enhancement induced by laser-irradiated probe tip was investigated theoretically and experimentally. The coupling mechanisms and distribution characteristics of the enhanced electric, thermal, and stress fields were studied at wavelengths of 400–800 nm and tip-sample distances of 1–20 nm for 9 material combinations. The simulation results demonstrated that the electro-thermal coupling effect and thermal–mechanical coupling effect are the basic principles of this technique, independent of the materials. It was also demonstrated that probe damage due to mechanical scratching can be avoided through the estimation of probe displacement. The superposition of electromagnetic energy and thermal energy generates an extremely constrained total energy of up to 10–12 orders of magnitude near the tip end. The nano-line structures were processed at each tip-sample distance, and nanostructures with a feature size of approximately λ/20 were obtained. The experimental results and the total energy distribution demonstrated that the interaction of the coupling field tip enhancement with samples is in the form of total energy deposits on materials. The significance of this study will not only enable a refined understanding of the fundamental physics of surface nanostructuring but will also advance the scientific and industrial applications of the technology.

In-situ mapping characterization of structure and electrical property of grain boundary in polycrystalline ZnO using nanorobot in SEM

Different from the existing methods of individual characterization of structure or electrical property, a unique approach for in-situ mapping characterization of single grain boundary using nanorobot in SEM is proposed to simultaneously realize the characterization of structure and electrical property in micro-area polycrystalline ZnO. Z-direction height differences constructed by multiple adjacent grains relative to a single target grain can be individually probed by the nanorobot single end tip and correspondingly virtually reconstructed. Electrical impedances complex planes of grain boundaries in-situ detected by nanorobot dual probes can be fitted by equivalent circuits. Experimental results illustrate that in-situ mapping characterization of structure and electrical property of single grain boundary using nanorobot in SEM can be verified. A single grain boundary layer, composed of adjacent multi-grains, seems to be nonlinear and unequal height along the Z direction. Z-direction relative height differences probed by the nanorobot can actually be regarded as the Z-direction projected lengths of surrounding grain boundary interfaces of single target grain. A three dimensional stereogram of single target grain boundary can be virtually reconstructed based on 3D software. It is deduced that schottky barrier existing in grain boundary interface exhibits larger height difference, basically proportional to the thickness of grain boundary in plane X–Y. Furtherly, it can promote an advance in in-situ mapping characterization of structure-property of single/multi micro area in other bulk inorganic polycrystalline bulk materials.

Spin-selective tunneling from nanowires of the candidate topological Kondo insulator SmB6.

Incorporating relativistic physics into quantum tunneling can lead to exotic behavior such as perfect transmission through Klein tunneling. Here, we probed the tunneling properties of spin-momentum-locked relativistic fermions by designing and implementing a tunneling geometry that uses nanowires of the topological Kondo insulator candidate samarium hexaboride. The nanowires are attached to the end of scanning tunneling microscope tips and used to image the bicollinear stripe spin order in the antiferromagnet Fe1.03Te with a Neel temperature of about 50 kelvin. The antiferromagnetic stripes become invisible above 10 kelvin concomitant with the suppression of the topological surface states in the tip. We further demonstrate that the direction of spin polarization is tied to the tunneling direction. Our technique establishes samarium hexaboride nanowires as ideal conduits for spin-polarized currents.

Record on Nematode <I>Tanqua tiara</I> Infection on Snakehead Fish <I>Channa striata</I> in South Kalimantan Indonesia

Highlight Research The parasitic disease has been record in snakehead fish (Channa striata) from South Kalimantan The nematodes with needle shape on both tip end with approximately 1 mm length and moving inside of wall cysts were found in in abdomen cavity and flesh of fish The morphology of the nematode was observed by light- and scanning electron-microscope The analysis on 18S rRNA showed that this parasite is belonging to nematode Tanqua tiara Abstract Snakehead fish (Channa striata) is an important commodity in South Kalimantan Indonesia. The snakehead fish production was increased due to the capture and intensive culture. The disease is one of the obstacles for production that may happened in cultured- and wild-fishes. The aims of this study were to record and to identify parasite which infected on wild snakehead fish from Kandangan Lama, Panyipatan, Tanahlaut, South Kalimantan. The parasite identification was conducted based on the morphology and the molecular characters. The morphology was observed by light microscope and scanning electron microscope. The 18S rRNA of parasite was amplified using designed primers and followed by sequencing. Spherical cysts were found in abdomen cavity and flesh of snakehead fish. The cylindrical worm with needle shape on both tip end with approximately 1 mm length were moving inside of wall cysts. Alignment analysis of 18S rRNA showed the highest homology at 99.83% with Tanqua tiara. Phylogenic tree showed that this worm is located at distance clade with the nematodes that have been reported to infect snakehead fish. The morphology and molecular results verified that and first report the parasite found in snakehead fish in South Kalimantan was T. tiara species. This nematode parasite may be served as intermediate host.

Innovative energy sources for Hyperloop high-speed transport

This article describes an innovative design of a solar-wind generator for a distributed energy Hyperloop high-speed system. The knowhow of this development is to mount flexible silicon solar panels (SP) on wind turbine blades, thus optimizing the thermal efficiency of solar panels. The basic dimensions of the wind turbine blades and the maximum internal flow velocities at the blade outlet (tips) are presented. At low wind velocities, it is rational to locate solar panels on the outer end (or the tip) of a blade, rather than along the blade length.The cooling effect can be increased by using materials with low thermal resistance for the SP and blades, or by reducing their thickness.To increase the heat transfer coefficient, it is recommended to use the airflow turbulence on the solar panel surface. In practice, this can be achieved both by changing the operating parameters and by introducing innovative design solutions.For better cooling of solar panels, it is recommended to use the technology of a wind flow sucked into the blade inner cavity. Changing the geometry of the outer end (tip) of the blades and the use of deflectors also give a better panel cooling parameters.

3D Generation of Multipurpose Atomic Force Microscopy Tips

In this work, 3D polymeric atomic force microscopy (AFM) tips, referred to as 3DTIPs, are manufactured with great flexibility in design and function using two‐photon polymerization. With the technology holding a great potential in developing next‐generation AFM tips, 3DTIPs prove effective in obtaining high‐resolution and high‐speed AFM images in air and liquid environments, using common AFM modes. In particular, it is shown that the 3DTIPs provide high‐resolution imaging due to their extremely low Hamaker constant, high speed scanning rates due to their low quality factor, and high durability due to their soft nature and minimal isotropic tip wear; the three important features for advancing AFM studies. It is also shown that refining the tip end of the 3DTIPs by focused ion beam etching and by carbon nanotube inclusion substantially extends their functionality in high‐resolution AFM imaging, reaching angstrom scales. Altogether, the multifunctional capabilities of 3DTIPs can bring next‐generation AFM tips to routine and advanced AFM applications, and expand the fields of high speed AFM imaging and biological force measurements.

Investigation on the impact of the leaf trailing effect using the Halcyon integrated platform system.

The double-stacked design of the Halcyon multileaf collimator (MLC) presents new challenges for treatment planning systems (TPSs). The leaf trailing effect has recently been described as the result of the interplay between the fluence transmitted through the leaf tip ends of each MLC layer. This effect makes the dosimetric leaf gap (DLG) dependent on the distance between the leaves of different layers (trailing distance) and is not adequately modeled by the Eclipse TPS. The purpose of our study was to investigate and report the dose discrepancies produced by these limitations in clinical plans and to explore how these discrepancies can be mitigated and avoided. The integrated platform with the Halcyon v2 system, Eclipse and Aria v15.6, was used. The dose discrepancies were obtained with electronic portal imaging device (EPID) images and the portal dosimetry software and validated using radiochromic film dosimetry. The results for the AIDA commissioning test and for nine selected clinical beams with the sliding window intensity modulated radiotherapy (dIMRT) technique were thoroughly analyzed and presented. First, the digital imaging and communications in medicine radiotherapy (DICOM RT) plans were exported and the fluences were computed using different leaf tip models, and then were compared. Second, the detailed characteristics of the corresponding leaf sequences were investigated. Finally, modified DICOM RT plans were created in which the noncollimating (backup) leaves were retracted 2mm to increase the leaf trailing distance, the modified plans were imported back into the TPS and the measurements were repeated. Dedicated in-house tools were developed in Python to carry out allanalyses. Dose discrepancies greater than 10% and regions of gamma failure were found in both the AIDA test and clinical beams using static-gantry dIMRT. Fluence analysis highlighted that the discrepancies were due to limitations in the MLC model implemented in the TPS. Analysis of leaf sequences indicated that regions of failure were associated with very low leaf speeds and virtually motionless leaves within the beam aperture. Some of these discrepancies were mitigated by increasing the trailing distance of the noncollimating leaves without affecting the beam aperture, but this strategy was not possible in regions where the leaves from both layers actively defined the beamaperture. Current limitations of the MLC model in Eclipse produced discrepancies between calculated and delivered doses in clinical beams that caused plan-specific quality assurance failures and interruptions in the clinical workflow. Careful evaluation of the clinical plans produced by Eclipse for the Halcyon is recommended, especially for static gantry dIMRT treatments. Some characteristics of leaf sequences are problematic and should be avoided in clinical plans and, in general, a better leaf tip model is needed. This is particularly important in adaptive radiotherapy treatments, where the accuracy and reliability of TPS dose calculations are of the utmostimportance.

Sigmoidal Auxiliary Tendon-Driven Mechanism Reinforcing Structural Stiffness of Hyper-Redundant Manipulator for Endoscopic Surgery.

The overtube of an endoscopic surgery robot is fixed when performing tasks, unlike those of commercial endoscopes, and this overtube should have high structural stiffness after reaching the target lesion so that sufficient tension can be applied to the lesion tissue with the surgical tool and there are fewer changes in the field of view of the endoscopic camera from this reaction force. Various methods have been proposed to reinforce the structural stiffnesses of hyper-redundant manipulators. However, the safety, rapid response, space efficiency, and cost-effectiveness of these methods should be considered for use in actual clinical environments, such as the gastrointestinal tract. This study proposed a method to minimize the positional changes of the overtube end tip due to external forces using only auxiliary tendons in the optimized path without additional mechanical structures. Overall, the proposed method involved moving the overtube to the target lesion through the main driving tendon and applying tension to the auxiliary tendons to reinforce the structural stiffness. The complete system was analyzed in terms of energy, and the sigmoidal auxiliary tendons were verified to effectively reinforce the structural stiffness of the overtube consisting of rolling joints. In addition, the design guidelines of the overtube for actual endoscopic surgery were proposed considering hollowness, retroflexion, and high structural stiffness. The positional changes due to external forces were confirmed to be reduced by 60% over the entire workspace.

Comparative evaluation of fracture resistance of hyflex edm, neolix neo niti, protaper next and protaper gold files- an in-vitro study

Aim: The purpose of the present research was to assess the comparison of the fracture resistance ability of various endodontic files like- Hyflex EDM, Neolix Neo NiTi, Protaper Next and Protaper Gold. Methodology: All the instruments were subjected to fracture test using a stainless-steel artificial canal. Time required for fracture as well as number of cycles to failure was calculated at 5 and 8 mm distance from the end of root canal tip. The fractured surfaces were then visualized using electron microscope. The data was analysed using student t-test and Weibull reliability estimation. Results: Hyflex EDM OneFile instruments showed significantly greater cyclic fatigue resistance than protaper Gold Primary instruments as well as protaper next and neolix NiTi. A significant difference was found between the groups for the length of the fracture 5 mm from the tip (P < 0.01). No significant difference was found between the groups for the length of the fracture 8 mm from the tip (P > 0.01). Conclusion: Hyflex EDM OneFile demonstrated the highest performance in terms of cyclic fatigue resistance.

Root Cap to Soil Interface: A Driving Force Toward Plant Adaptation and Development.

Land plants have developed robust roots to grow in diverse soil ecosystems. The distal end of the root tip has a specialized organ called the 'root cap'. The root cap assists the roots in penetrating the ground, absorbing water and minerals, avoiding heavy metals and regulating the rhizosphere microbiota. Furthermore, root-cap-derived auxin governs the lateral root patterning and directs root growth under varying soil conditions. The root cap formation is hypothesized as one of the key innovations during root evolution. Morphologically diversified root caps in early land plant lineage and later in angiosperms aid in improving the adaptation of roots and, thereby, plants in diverse soil environments. This review article presents a retrospective view of the root cap's important morphological and physiological characteristics for the root-soil interaction and their response toward various abiotic and biotic stimuli. Recent single-cell RNAseq data shed light on root cap cell-type-enriched genes. We compiled root cap cell-type-enriched genes from Arabidopsis, rice, maize and tomato and analyzed their transcription factor (TF) binding site enrichment. Further, the putative gene regulatory networks derived from root-cap-enriched genes and their TF regulators highlight the species-specific biological functions of root cap genes across the four plant species.

Tip-end fusion of a rod-shaped secretory organelle

Weibel–Palade bodies (WPB) are elongated, rod-like secretory organelles unique to endothelial cells that store the pro-coagulant von-Willebrand factor (VWF) and undergo regulated exocytosis upon stimulation with Ca2+- or cAMP-raising agonists. We show here that WPB preferentially initiate fusion with the plasma membrane at their tips and identify synaptotagmin-like protein 2-a (Slp2-a) as a positive regulator of VWF secretion most likely mediating this topological selectivity. Following secretagogue stimulation, Slp2-a accumulates at one WPB tip before fusion occurs at this site. Depletion of Slp2-a reduces Ca2+-dependent secretion of highly multimeric VWF and interferes with the formation of actin rings at WPB–plasma membrane fusion sites that support the expulsion of the VWF multimers and most likely require a tip-end fusion topology. Phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] binding via the C2A domain of Slp2-a is required for accumulation of Slp2-a at the tip ends of fusing WPB, suggesting that Slp2-a mediates polar exocytosis by initiating contacts between WPB tips and plasma membrane PI(4,5)P2.

Electric-Field and Mechanical Vibration-Assisted Atomic Force Microscope-Based Nanopatterning

Abstract Atomic force microscope (AFM)-based nanolithography is a cost-effective nanopatterning technique that can fabricate nanostructures with arbitrary shapes. However, existing AFM-based nanopatterning approaches have limitations in the patterning resolution and efficiency. Minimum feature size and machining performance in the mechanical force-induced nanofabrication process are limited by the radius and sharpness of the AFM tip. Electric-field-assisted atomic force microscope (E-AFM) nanolithography can fabricate nanopatterns with features smaller than the tip radius, but it is very challenging to find the appropriate input parameter window. The tip bias range in E-AFM process is typically very small and varies for each AFM tip due to the variations in tip geometry, tip end diameter, and tip conductive coating thickness. This paper demonstrates a novel electric-field and mechanical vibration-assisted AFM-based nanofabrication approach, which enables high-resolution (sub-10 nm toward sub-5 nm) and high-efficiency nanopatterning processes. The integration of in-plane vibration with the electric field increases the patterning speed, broadens the selectable ranges of applied voltages, and reduces the minimum tip bias required for nanopatterning as compared with E-AFM process, which significantly increases the versatility and capability of AFM-based nanopatterning and effectively avoids the tip damage.

Feeding Behavior of Riptortus pedestris (Fabricius) on Soybean: Electrical Penetration Graph Analysis and Histological Investigations.

Simple SummaryRiptortus pedestris (Fabricius) (Hemiptera: Alydidae) is a major soybean pest with the peak population occurrence during the seed maturity stage from pod filling to harvest. Soybean pods and/or seeds are required for R. pedestris development. However, the feeding strategies employed by this stink bug to feed on soybean are still not clear. In the present study, we recorded the feeding behaviors of R. pedestris on soybean using electropenetrography (EPG). The biological meaning of each waveform was confirmed by histological examination of plant tissues containing stylets or salivary sheath. In total, five phases of waveforms were identified: non-probing, pathway (Rp1), xylem sap ingestion (Rp2), salivation and ingestion (Rp3), and interruption (Rp4). Xylem ingestion (Rp2) was observed during R. pedestris feeding on soybean leaflets, stems, and pods, demonstrating that the stink bug was ingesting xylem sap from vascular tissue. Cell rupture (salivation/ingestion, Rp3) was only recorded during R. pedestris feeding on cotyledon and pods. Histological images showed that stylet tips and the salivary sheath were positioned in the tissues of cotyledon and pods. Taken together, our results demonstrate that R. pedestris uses a cell-rupture strategy to acquire nutrients from soybean pods and/or seeds while utilizing salivary sheath tactics to obtain water from xylem sap. These findings provide insightful information to understand the interactions between R. pedestris and the soybean plant. Riptortus pedestris (Fabricius) is a major agricultural pest feeding on soybean pods and seeds. The large populations occur during seed maturity stages from pod filling to harvest. Its infestation results in shriveled and dimpled seeds while vegetative structures (leaflet and stem) remain green, known as “Stay Green” syndrome. Additional evidence also demonstrates that soybean pods and seeds are required for Riptortus pedestris development. However, the feeding behavior strategies employed by this stink bug to feed on soybean plants are still not clear. In the present study, the feeding behaviors of R. pedestris on soybean plants were recorded by electropenetrography (EPG), and a waveform library was created for this species. A total of five phases of waveforms—nonprobing, pathway (Rp1), xylem sap ingestion (Rp2), salivation and ingestion (Rp3), and interruption (Rp4)—were identified. Non-probing waveforms Z and NP and pathway (Rp1) were found in all tested plant structures (leaflet, stem, cotyledon, and pods). Waveform Rp2 (xylem sap ingestion, xylem ingestion) was primarily recorded during R. pedestris feeding on leaflets and stems, while Rp3 (salivation/ingestion) was only observed during feeding on cotyledon and pods. Histological examinations confirmed that correlation between Rp2 and stylet tip positioning in the xylem vessel in leaflets and stems. Stylet tips end in the tissues of cotyledon and pods when Rp3 is recorded. Taken together, our results demonstrate that R. pedestris ingests xylem sap from vegetative tissues of soybean (leaflet and stem) via a salivary sheath strategy to obtain water. It mainly acquires nutrients from soybean pods and/or seeds using cell-rupture tactics. This study provided insightful information to understand the field occurrence patterns of “Stay Green” syndrome, which may have important implications for pest control.

Spontaneous and Selective Potassium Transport through a Suspended Tailor-Cut Ti3C2Tx MXene Film.

Biological ion pumps selectively transport target ions against the concentration gradient, a process that is crucial to maintaining the out-of-equilibrium states of cells. Building an ion pump with ion selectivity has been challenging. Here we show that a Ti3C2Tx MXene film suspended in air with a trapezoidal shape spontaneously pumps K+ ions from the base end to the tip end and exhibits a K+/Na+ selectivity of 4. Such a phenomenon is attributed to a range of properties of MXene. Thanks to the high stability of MXene in water and the dynamic equilibrium between evaporation and swelling, the film keeps a narrow interlayer spacing of ∼0.3 nm when its two ends are connected to reservoirs. Because of the polar electrical structure and hydrophilicity of the MXene nanosheet, K+ ions experience a low energy barrier of ∼4.6 kBT when entering these narrow interlayer spacings. Through quantitative simulations and consistent experimental results, we further show that the narrow spacings exhibit a higher energy barrier to Na+, resulting in K+/Na+ selectivity. Finally, we show that the spontaneous ion transport is driven by the asymmetric evaporation of the interlayer water across the film, a mechanism that is similar to pressure driven streaming current. This work shows how ion transport properties can be facilely manipulated by tuning the macroscopic shape of nanofluidic materials, which may attract interest in the interface of kirigami technologies and nanofluidics and show potential in energy and separation applications.

Enhanced Isolation of Single Myofibers in Flexor Digitorum Brevis Dissociation

IntroductionThe isolation of single myofibers from the Flexor Digitorum Brevis (FBD) has been a well‐established model in skeletal muscle physiology research. The use of isolated single‐fibers has led to advancements in the understating of the excitation – contraction (E‐C) coupling mechanisms in skeletal muscle, calcium transients, the role of mitochondria, and much more. However, these experiments rely on the quality of the dissociation of myofibers and their attachment to the imaging dish which can be difficult and time exhaustive. The purpose of this study was to build upon previously established methodologies to improve the yield of intact‐alive myofibers in a time efficient manner.Methods and MaterialsEuthanasia and experimental protocols were approved by the University of Texas at Arlington’s IACUC. Based upon previously established dissociation techniques (1–3), we modified the protocol as follows: the intact FDB was dissected out and placed in 2 mL of Ringer’s solution (142 mM NaCl2, 5 mM KCl, 1.8 mM MgCl2, 10 mM Hepes, 10 mM Glucose). Under the dissection microscope the whole muscle was separated into 4 muscle bundles; separated by the distal tendons. The muscle bundles were transferred to the digestion media (DMEM with glutamine, 2% sterile filtered fetal bovine serum (FBS), 0.1% gentamycin, and 4 mg ml‐1 Collagenase A). The muscle bundles were incubated for 30‐45 minutes at 37° C in 5% CO2. Following incubation, the bundles were transferred to 1mL of Ringer’s solution in a 24‐well plate and gently titrated with the cut end of a P1000 pipette tip. The solution was transferred to laminin coated glass bottom dishes and incubated for 15‐30 minutes for fiber attachment. Following fiber attachment, the fibers were either stained with the LIVE/DEAD™ Viability/Cytoxicity kit or loaded with Fura‐2 AM fluorescent dye for measurement of maximal calcium depolarization response induced with 100mM Potassium Chloride (KCl) using a PTI spectrophotometry system.Results and ConclusionWe found that using an increased concentration of collagenase and a reduced time of digestion successfully increased the number of fibers in the field of vision.. Laminin coated glass bottom dishes produced quick and strong attachment, allowing for optimal stimulation conditions. The use of cell culture media with FBS protected the sarcolemma increasing the viability of the fibers. This is shown in both the LIVE/DEAD imaging and the response to KCl stimulation. This study demonstrates that the change of dissociation media and the decrease in dissociation time allow for protection of the myofiber for an increased yield and viability. This protocol will allow for improved experimental outcomes in which mature myofibers are subjected to electrical or chemical stimulations.

Effect of vorticity transport on flow structure in the tip region of axial compressors

Numerical simulations are carried out to investigate the flow structure in the blade tip region of axial compressors. Various tip clearance heights and end wall motion conditions in a linear compressor cascade are studied to assess the effect of vorticity transport on the tip leakage flow (TLF). Moreover, the effect of vorticity transport on the TLF in a compressor rotor at different operating conditions is studied using delayed detached eddy simulation. The results show that the vorticity transport at both the blade tip and the end wall plays an important role in the roll-up and evolution of the tip leakage vortex (TLV), resulting in great impacts on the loss and stability of the TLV. It is found that the TLV is composed of a two-layer structure. The inner vortex core region formed by the vorticity transport from the blade tip shear layer to the TLV has a great effect on the strength and loss of the vortex, and the structure of the outer shear layer is altered by the secondary vortex formed by the vorticity transport from the end wall shear layer and thus affects the stability of the TLV. By the mechanism of the vorticity transport, the effects of the clearance height, the end wall motion, and the non-uniform clearance as a control method can be explained uniformly. The new understanding of the TLF structure and the vorticity transport mechanism helps to improve the performance of axial compressors by controlling the vorticity transport of the TLF.

Bottom, Top, or in Between: Combining Plasmonic Nanohole Arrays and Hydrogel Microgels for Optical Fiber Sensor Applications

AbstractAttractive label‐free plasmonic optical fiber sensors can be developed by cleverly choosing the arrangement of plasmonic nanostructures and other building blocks. Here, the final response depends very much on the alignment and position (stacking) of the individual elements. In this work, three different types of fiber optic sensing geometries fabricated by simple layer‐by‐layer stacking are presented, consisting of stimulus‐sensitive poly‐N‐isopropylacrylamide (polyNIPAM) microgel arrays and plasmonic nanohole arrays (NHAs), namely NHA/polyNIPAM, polyNIPAM/NHA, polyNIPAM/NHA/polyNIPAM. Their optical response to a representative stimulus, namely temperature, is investigated. NHA/polyNIPAM monitors the volume phase transition of polyNIPAM microgels through changes in the spectral position and the amplitude of the reflection minimum of plasmonic NHA. In contrast, polyNIPAM/NHA shows a more complex response to the swelling and collapse of polyNIPAM microgels in their reflectance spectra. The most pronounced changes in optical response are observed by monitoring the amplitude of the reflectance minimum of this sensor during heating/cooling cycles. Finally, the triple stack of polyNIPAM/NHA/polyNIPAM at the end of a optical fiber tip combines the advantages of the NHA/polyNIPAM, polyNIPAM/NHA double stacks for optical sensing. The unique layer‐by‐layer stacking of microgel and nanostructure is customizable and can be easily adopted for other applications.