Fine Strands Research Articles

Numerical simulations of turbulence in prominence threads induced by torsional oscillations

Context. Threads are the main constituents of prominences. They are dynamic structures that display oscillations, usually interpreted as magnetohydrodynamic (MHD) waves. Moreover, instabilities such as the Kelvin–Helmholtz instability (KHI) have also been reported in prominences. Both waves and instabilities may affect the thermodynamic state of the threads. Aims. We investigate the triggering of turbulence in prominence threads caused by the nonlinear evolution of standing torsional Alfvén waves. We study the heating in the partially ionized prominence plasma as well as possible observational signatures of this dynamics. Methods. We modeled a prominence thread as a radially and longitudinally nonuniform cylindrical flux tube with a constant axial magnetic field embedded in a much lighter and hotter coronal environment. We perturbed the flux tube with the longitudinally fundamental mode of standing torsional Alfvén waves. We numerically solved the three-dimensional (3D) MHD equations to study the temporal evolution in both ideal and dissipative scenarios. In addition, we performed forward modeling to calculate the synthetic Hα imaging. Results. The standing torsional Alfvén waves undergo phase-mixing owing to the radially nonuniform density. The phase-mixing generates azimuthal shear flows, which eventually trigger the KHI and, subsequently, turbulence. When nonideal effects are included, the obtained plasma heating is very localized in an annulus region at the thread boundary and does not increase the temperature in the cool core. Instead, the average temperature in the thread decreases owing to the mixing of internal and external plasmas. In the synthetic observations, first we observe periodic pulsations in the Hα intensity caused by the integration of the phase-mixing flows along the line of sight. Later, fine strands that may be associated with the KHI vortices are seen in the synthetic Hα images. Conclusions. Turbulence can be generated by standing torsional Alfvén waves in prominence threads after the triggering of the KHI, although this mechanism is not enough to heat such structures. Both the phase-mixing stage and the turbulent stage of the simulated dynamics could be discernible in high-resolution Hα observations.

Influence of amyloid fibril length and ionic strength on WPI-based fiber-hydrogel composites: Microstructural, rheological and water holding properties

One of the possible advantages of protein fibers in composites is that they can interact with the continuous gel matrix as active fillers at neutral pH. This study aimed to investigate the impacts of short (SAF) and long amyloid fibrils (LAF) and ionic strength (0–150 mM NaCl) on the whey protein isolate (WPI)-based fiber-hydrogel composites. The water holding capacity of the composite gels more depended on the gel coarseness rather than their elasticity. Significant differences were observed between the rheological data of the SAF-WPI and LAF-WPI composites, and the maximum elastic modulus (G′) was achieved at 100 mM NaCl where the LAF-WPI composites outperformed the SAF-WPI ones in enhancing G′ and hardness. Nevertheless, the elasticity and hardness of the composites dramatically dropped at 150 mM NaCl due to the change in the gel microstructure from fine strand to particulate, according to CLSM and SEM images. Interestingly, the trend in average particle size changed at 150 mM NaCl for the SAF- and LAF-WPI soluble aggregates compared to the WPI soluble aggregates. The effects of amyloid fibril and NaCl concentration on the protein aggregates as the initial building blocks of the gel were confirmed by size exclusion chromatography. These results indicated that the properties of composite gel were related to the balance between aggregate creation and the development of cross-links between them during gelation. The findings of the current study could be exploited to predict the functional behavior of globular protein gels containing amyloid fibrils with different lengths at various NaCl concentrations.

Development of Super Fine Strand Nb3Al Cable for SuperKEKB Superconducting Sextupole Magnet System

Along the beam lines of the SuperKEKB main rings, 218 conventional sextupole magnets are installed, and they are used for tuning the chromaticity of the accelerator rings. Especially, 16 sextupole magnets in the beam straight lines in the Tsukuba area are quite essential for the Crab Waist beam colliding. To make the beam tuning process finer, we are studying the superconducting sextupole magnet system with three types of the corrector magnets. From the operation temperature of the system, A15 compound superconductor is chosen as the cable material, and the development of the react and wind coil production has been tried with the Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al cable. The Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al super fine strand superconducting cable for the corrector magnets was manufactured, and its superconducting characteristics are being studied. In this paper, as the first test result of the development, the critical current characteristics of the straight cable as variables of temperature and magnetic field are reported. As the results, the critical current of the Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al cable was higher than the design values for the corrector magnets, and this level of cable performance also indicates the potential for the cable being used for the main sextupole magnet.

Antitumor Activity of Luteolin Against Ehrlich Solid Carcinoma in Rats via Blocking Wnt/β-Catenin/SMAD4 Pathway.

Background Ehrlich solid carcinoma (ESC) is characterized by rapid proliferation and a short survival time. Because Ehrlich ascites carcinoma (EAC) resembles human cancer cells, Ehrlich solid and ascetic forms are commonly used to determine the anticancer effects of various compounds. Luteolin is a flavonoid compound found in many dietary sources, including carrots, peppers, celery, olive oil, peppermint, and oregano. Luteolin has potent anti-inflammatory, antidiabetic, antitumor, and antiapoptotic activities. Aims This study aims to investigate the antitumor activity of luteolin against ESC in rats by affecting the Wnt/β-catenin/SMAD4 pathway. Methods We introduced 0.15 ml of Ehrlich cells (2 × 106) ESC into the left hind thighs of rats. After eight days of inoculation, the rats orally received 25 mg/kg of luteolin daily. We stained sections of tumor tissues with Masson's trichrome. We used another part of the tumor tissue to assess gene and protein expression of Wnt, β-catenin, E-cadherin, and SMAD4. Results Treatment of carcinoma rats with luteolin increased the mean survival time and reduced tumor volume and weight. In addition, examination of tumor tissue stained with Masson's trichrome showed loosely to densely packed collagen fibers in between neoplastic cells and scattered papillary expansion of a loose blue band of collagen expression along the covering adipose connective tissue and extending in a fine strand in between muscle fibers, which was ameliorated by treating rats with luteolin. Finally, treating ESC in rats with luteolin overexpressed E-cadherin and downregulated Wnt, β-catenin, and SMAD4. Conclusions We found luteolin has antineoplastic activity against ESC by reducing tumor size and weight while improving the structure of muscle cells. It works by suppressing Wnt, β-catenin, and SMAD4, resulting in decreased tumor cell proliferation and differentiation. Additionally, luteolin overexpresses E-cadherin, leading to reduced tumor cell invasion and metastasis.

A flexible 8.5 MHz litz wire receive array for field-cycling imaging

Objectives. Low frequency coils present unique challenges as loop losses, component losses, and the supporting electronics can significantly degrade the signal-to-noise ratio (SNR). SNR may already be a limiting factor with MRI at low field (and frequency), therefore the minimization of additional loss is particularly important. If interactions between loops are managed, array coils can provide increased SNR, coverage, and potentially imaging speed. In this work, we investigate methods to characterise and preserve SNR from a low frequency coil array, allowing a more geometrically conforming array for quick, no-tune application with various anatomies. Approach. Single and multi-turn, 16.2 cm diameter litz wire loops were constructed and characterised for losses under various loading conditions. Low noise preamplifiers were acquired and characterized, as well as interfacing electronics were developed and evaluated. A bench level SNR test was implemented to observe the effects of tuning and loading on individual coils. The results were used to select a design for construction of a 6-channel, flex array coil. Main results. Ultra fine strand litz wire exhibited lower losses than equivalent diameter solid wire which should translate to improved SNR and provides the mechanical flexibility needed in a conforming array. Single turn loop losses were dominant under all loading conditions; however, 2 and 3 turn loops were body loss dominated under modest loading conditions. Preamplifier blocking achieved was well short of our design goal and critical overlaps became necessary for coil-to-coil interaction control. Our finished array, a 3-channel posterior array coil and a 3-channel anterior array coil, conforms nicely to various anatomies and is providing consistent results in various volunteer study trials. Significance. Receive coils are challenging at low fields as loop losses often limit the final SNR. This is exacerbated in an array coil as loops may be smaller and not coupled well to the body. In this work we have demonstrated that body loss dominance is possible with 16.2 cm loops at 8.5 MHz. We have optimized, built, and tested low noise interfacing electronics and characterized the SNR penalties as the tuning and loading is varied, a key parameter in a geometrically flexible array designed for rapid setup. The resultant 6-channel, general-purpose array is supporting various Field-Cycling Imaging studies where body habitus and anatomies require a flexible, adaptable array coil which can be quickly positioned and utilized.

Volumetric High-Resolution X-Ray Phase-Contrast Virtual Histology of Breast Specimens With a Compact Laboratory System.

The assessment of margin involvement is a fundamental task in breast conserving surgery to prevent recurrences and reoperations. It is usually performed through histology, which makes the process time consuming and can prevent the complete volumetric analysis of large specimens. X-ray phase contrast tomography combines high resolution, sufficient penetration depth and high soft tissue contrast, and can therefore provide a potential solution to this problem. In this work, we used a high-resolution implementation of the edge illumination X-ray phase contrast tomography based on “pixel-skipping” X-ray masks and sample dithering, to provide high definition virtual slices of breast specimens. The scanner was originally designed for intra-operative applications in which short scanning times were prioritised over spatial resolution; however, thanks to the versatility of edge illumination, high-resolution capabilities can be obtained with the same system simply by swapping x-ray masks without this imposing a reduction in the available field of view. This makes possible an improved visibility of fine tissue strands, enabling a direct comparison of selected CT slices with histology, and providing a tool to identify suspect features in large specimens before slicing. Combined with our previous results on fast specimen scanning, this works paves the way for the design of a multi-resolution EI scanner providing intra-operative capabilities as well as serving as a digital pathology system.

Overdense Threads in the Solar Corona Induced by Torsional Alfvén Waves

Abstract High-resolution and high-cadence observations have shown that Alfvén waves are ubiquitous in the solar atmosphere. Theoretical works suggest their ability to transfer large energy fluxes from the photosphere to the corona and solar wind. In this proof-of-concept Letter we show that torsional Alfvén waves can induce the formation of filamentary plasma structures in the solar corona. We perform high-resolution 3D ideal MHD simulations in an initially uniform coronal plasma permeated by a line-tied twisted magnetic field. We find that torsional Alfvén waves develop Kelvin–Helmholtz instabilities as a result of the phase mixing process. The Kelvin–Helmholtz instability drives plasma compression that breaks the uniformity of density, creating elongated overdense threads aligned with the direction of the magnetic field. With synthetic modeling of SDO/AIA imaging we show that the overdense filaments could be seen in observations as fine strands that illuminate the underlying magnetic structure.

The Subgenual Organ Complex in Stick Insects: Functional Morphology and Mechanical Coupling of a Complex Mechanosensory Organ

Leg chordotonal organs in insects show different adaptations to detect body movements, substrate vibrations, or airborne sound. In the proximal tibia of stick insects occur two chordotonal organs: the subgenual organ, a highly sensitive vibration receptor organ, and the distal organ, of which the function is yet unknown. The distal organ consists of a linear set of scolopidial sensilla extending in the tibia in distal direction toward the tarsus. Similar organs occur in the elaborate hearing organs in crickets and bushcrickets, where the auditory sensilla are closely associated with thin tympanal membranes and auditory trachea in the leg. Here, we document the position and attachment points for the distal organ in three species of stick insects without auditory adaptations (Ramulus artemis,Sipyloidea sipylus, andCarausius morosus). The distal organ is located in the dorsal hemolymph channel and attaches at the proximal end to the dorsal and posterior leg cuticle by tissue strands. The central part of the distal organ is placed closer to the dorsal cuticle and is suspended by fine tissue strands. The anterior part is clearly separated from the tracheae, while the distal part of the organ is placed over the anterior trachea. The distal organ is not connected to a tendon or muscle, which would indicate a proprioceptive function. The sensilla in the distal organ have dendrites oriented in distal direction in the leg. This morphology does not reveal obvious auditory adaptations as in tympanal organs, while the position in the hemolymph channel and the direction of dendrites indicate responses to forces in longitudinal direction of the leg, likely vibrational stimuli transmitted in the leg’s hemolymph. The evolutionary convergence of complex chordotonal organs with linear sensilla sets between tympanal hearing organs and atympanate organs in stick insects is emphasized by the different functional morphologies and sensory specializations.

Elastic fibers: The missing key to improve engineering concepts for reconstruction of the Nucleus Pulposus in the intervertebral disc

The increasing prevalence of low back pain has imposed a heavy economic burden on global healthcare systems. Intense research activities have been performed for the regeneration of the Nucleus Pulposus (NP) of the IVD; however, tissue-engineered scaffolds have failed to capture the multi-scale structural hierarchy of the native tissue. The current study revealed for the first time, that elastic fibers form a network across the NP consisting of straight and thick parallel fibers that were interconnected by wavy fine fibers and strands. Both straight fibers and twisted strands were regularly merged or branched to form a fine elastic network across the NP. As a key structural feature, ultrathin (53 ± 7 nm), thin (215 ± 20 nm), and thick (890 ± 12 nm) elastic fibers were observed in the NP. While our quantitative analysis for measurement of the thickness of elastic fibers revealed no significant differences (p < 0.633), the preferential orientation of fibers was found to be significantly different (p < 0.001) across the NP. The distribution of orientation for the elastic fibers in the NP represented one major organized angle of orientation except for the central NP. We found that the distribution of elastic fibers in the central NP was different from those located in the peripheral regions representing two symmetrically organized major peaks (±45⁰). No significant differences in the maximum fiber count at the major angles of orientation (±45⁰) were observed for both peripheral (p = 0.427) and central NP (p = 0.788). Based on these new findings a structural model for the elastic fibers in the NP was proposed. The geometrical presentation, along with the distribution of elastic fibers orientation, resulting from the present study identifies the ultrastructural organization of elastic fibers in the NP important towards understanding their mechanical role which is still under investigation. Given the results of this new geometrical analysis, more-accurate multiscale finite element models can now be developed, which will provide new insights into the mechanobiology of the IVD. In addition, the results of this study can potentially be used for the fabrication of bio-inspired tissue-engineered scaffolds and IVD models to truly capture the multi-scale structural hierarchy of IVDs. Statement of SignificanceVisualization of elastic fibers in the nucleus of the intervertebral disk under high magnification was not reported before. The present research utilized extracellular matrix partial digestion to address significant gaps in understanding of nucleus microstructure that can potentially be used for the fabrication of bio-inspired tissue-engineered scaffolds and disk models to truly capture the multi-scale structural hierarchy of discs.

A recursive methodology for modelling multi-stranded wires with multilevel helix structure

Multi-stranded litz wires are commonly used in magnetic devices for power electronics applications at medium-high frequency range, from several kHz up to hundreds of kHz. For these applications, litz-wire structure favours the uniformity of driven current in the cross-sectional area of conductors, alleviating ac losses (skin and proximity effects) and improving the global efficiency of the application. These features are achieved by means of a special cable arrangement consisting of many isolated fine copper strands twisted together according to the manufacturing process. Often, the manufacturing process involves several twisting steps where bundles of moderate number of strands are successively twisted resulting in intricate cable structures. We present a mathematical description of the trajectories of copper strands with the purpose of obtaining the cable losses by means of Finite Element Analysis (FEA) simulation tools. Moreover, a nomenclature for this multilevel structures is also proposed. Parameters as the number of twisting steps, number of strands, strand diameter or pitch length, are included in this representation, allowing to compare the performance of different manufacturing solutions.

Evaluating the performance of a configurable finite element model as a tool in composite catheter design

Currently there are limited predictive modeling tools available for composite interventional catheter design. Most interventional catheter development involves iteration based design. Composite interventional catheters typically consist of a PTFE inner layer wrapped with a fine strand, metal reinforcement layer covered with a TPE (thermoplastic elastomer) outer layer. Fast reliable computational based techniques for early stage catheter design would limit the number of prototypes required to get to concept or design freeze stage therefore reducing development time. This paper’s goal is to examine how effective FEA is as a technique for predicting the performance of a composite catheter shaft. The steps taken and challenges overcome in creating a configurable FE model for a spirally reinforced composite catheter are outlined. The paper presents Finite Element (FE) generated data for tensile yield. This is a fundamental performance parameter in interventional catheter design. Catheters are designed to operate below their yield point. Models developed for simulating tensile yield can likely be adapted to simulate other performance characteristics such as flexural properties and torsion characteristics as part of future work. Data from FEA analysis is compared with data from physically testing catheters built to the same specification as that used in the FE model configuration.

Spontaneous unilateral hyphema from a strand of persistent pupillary membrane.

A 48-year-old female presented to us with sudden onset dimness of vision in her right eye (RE). There was no history of trauma. Her best corrected visual acuity (BCVA) was 6/9 (partial) (Snellen's) in her RE and 6/6 in her left eye (LE). Her RE showed strands of PPM crossing the pupil. There was active bleeding seen from a point source on one of the strands of the PPM resulting in hyphema formation, 3 mm in height [Fig. 1]. The patient was seen and pupillary dilatation had been done at a local clinic and thus her RE was pharmacologically dilated at presentation. Both eyes had nuclear sclerosis grade II cataract and the intraocular pressures (IOPs) were 16 mmHg and 14 mmHg in the RE and LE, respectively. Gonioscopy showed wide open angles without any new vessels at the angle in both eyes. Fundus examination of both eyes was normal.Figure 1: This is a photograph of the right eye of the patient showing clear cornea, dilated pupil with strands of PPM crossing the pupillary axis. Active bleeding can be seen from a point source on one of the strands of the PPM (white arrow). The resultant hyphema, 3 mm, due to the bleeding from the strand of PPM can be seen in the inferior aspect of the anterior chamber (white arrow with black outline). Plasmoid aqueous can also be noted in the anterior chamberHer systemic examination was normal with normal blood pressure and random blood sugar levels. Gentle compression of the right eye with a pinkie-ball for 3 min was done and the bleeding stopped completely. She was prescribed topical steroids (Loteprednol etabonate 0.5% w/v) four times daily and a mydriatic/cycloplegic eye drop twice daily in the RE for 7 days. She was advised routine blood tests: complete hemogram, fasting and post-prandial blood sugar, serum urea and creatinine, lipid profile and coagulation profile and advised follow-up after 1 week with the reports. At her follow-up after 1 week her BCVA was 6/6 in both eyes and there were no signs of hyphema or active bleeding. PPM in RE was noted as fine strands crossing the pupillary axis [Fig. 2]. Her blood work-up was normal. She refused to undergo an iris angiography since it was an invasive procedure. At her next follow-up visit after 1 month she was asymptomatic with no recurrence of bleeding from the PPM.Figure 2: These photographs show both the eyes of the patient at one week follow-up. In the right eye, strands of PPM can be seen crossing the pupillary axis (white arrows). There is no active bleeding noted from the PPM strands and the hyphema has completely resolved (a). The left eye is normal with no evidence of any PPM (b)The pupillary membrane is a transitory vascular connective tissue covering the anterior surface of the lens during embryonic development. By eight and a half months, the central arcades gets fragmented and disappear. Clinically the remnants of the pupillary membrane are often seen as white strands, in 17.6–31.9% of the cases, but persistent functional vessels are found in only 0.3% which may very rarely bleed.[1234] Our case presented with active bleeding from such a PPM strand. Spontaneous hyphema in the anterior chamber is rare and can occur due to certain reasons like intraocular neoplasms, blood disorders (leukemia, hemophilia), uveitis, rubeosis iridis, fibrovascular membranes in retrolental or zonular area (retrolental fibroplasia, persistent primary vitreous, retinoschisis), juvenile xanthogranuloma, occult trauma or trauma with late effect, hydrophthalmos, vascular anomalies of the iris, histiocytosis X, post-glaucoma surgery and very rarely from PPM.[1234] Literature search revealed that there are very few cases of bleeding from a strand of PPM in adults and it is extremely rare.[12345] Some case reports have documented an iris angiography which showed the anomalous vasculature or aneurysmal dilatation within the PPM strand.[2345] In most of the previously reported cases a predisposing factor, either strenuous effort immediately preceding the bleeding[12] or systemic hypertension[34] contributed in the causation of hyphema; however, Kotamarthi et al. reported the only case of truly spontaneous hyphema similar to our case.[5] This case illustrates that spontaneous bleeding may occur from a strand of PPM. To our knowledge, this is the first case of truly spontaneous bleeding from a strand of PPM being reported from India. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Clinical Profile of the Patients Undergoing Awake Fiberoptic Intubation Along with Airway Blocks in Cervical Discectomy Patients

Background: The optical characteristics of fine glass strands are what make fiberoptic technology possible. When glass rods are heated and stretched to diameters of 8 to 25µ, a flexible fiber capable of transmitting light is formed. Light that enters the distal end of the fiber is reflected off the walls until it emerges at the proximal end. To keep a fraction of the light from being lost during transmission, the fiber is clad in a layer of glass that has a different optical density. This process results in total internal reflection of light entering the fiber. The light transmitted along a single fiber emerges uniformly distributed over the cross-sectional area at the end. The resolution of a fiberoptic image is inversely proportional to the diameter of the glass fiber. Subjects and Methods: After overnight fasting, all patients under the study were premedicated with tab ranitidine 150mg orally and tab diazepam 10mg with sips of water 90 mins before shifting to operating theatre. Premedication with glycopyrrolate 0.2mg IM, administered 30-45 minutes prior to application of the local anesthetic. Results: At baseline, SO2 in both the groups were comparable. There were no significant differences between the groups with respect to changes in SO2 after bolus infusion, during intubation and after intubation clinically. Conclusion: Patients with study (D) group had a consciousness score of 2 (eyes open on command) in 41 patients out of 50 (82%), where as in control (P) group 17 patients (34%) had score of 2 (eyes open on command). 20 patients (40%) had score of 1 (response to ear pinching),in control (P) group compared to 3 patients in study(D) group.

A Three-dimensional Cell Culture Method with a Micromesh Sheet and Its Application to Hepatic Cells.

In vitro 3D cultures of hepatocytes are increasingly being used to assess human hepatic metabolism and toxicity in drug development. Here, we developed an in vitro 3D cell culture method with a microstructured mesh sheet and applied it to culturing human hepatoma HepG2 cells. The micromesh sheet is constituted of fine mesh strands and apertures that are each much larger than a single cell in size. Proliferating on a micromesh sheet, HepG2 cells spread out in a planar manner and then formed a multilayered cell sheet, so that cell-cell adhesion was dominant over cell-substrate adhesion as being different from 2D cultures. In micromesh cultures, the increase rate in thickness of the cell mass was visually slower than that in spheroid cultures, enabling us to clearly observe inside cells of the cell population by microscopy. Micromesh-cultured HepG2 cells showed higher viability compared with spheroid-cultured cells. The multilayered HepG2 cell sheet increased expression of hepatic marker genes and induced cell polarization with bile canalicular membranes. Furthermore, a combination of micromesh cultures with medium perfusion further induced expression of hepatic marker genes in HepG2 cells; especially CYP1A1 and CYP1A2 mRNA increased 86-fold and 43-fold compared with 2D controls, respectively, which were much higher than those in spheroid cultures. Thus, this simple and versatile micromesh culture method holds some advantages over traditional spheroid cultures and is expected to be instrumental in culturing more differentiated hepatic cells such as HepaRG cells and primary hepatocytes for future preclinical testing.

Possibility of Using Fine Wood Strands for the Production of P5 Type Building Boards

This paper investigated the possibility of using very fine wood chips for the production of P5 type building boards according to the EN 312 (2010) standard. Small wood chips are more evenly compressed during mat pressing because they have a high bulk density. Therefore, the beneficial effects of forming denser outer layers is lost. To achieve the desired shape of the density profile curve of a board, the moisture content of the chips used in the outer face layers was increased considerably (up to about 30%). As a result of the conducted tests, the mechanical properties of the manufactured boards met the EN 312 requirements for P5 boards above a density of 650 kg/m3. In cases when the additional conditions are being met, the standard requirements may be met at an even lower density level of approximately 550 kg/m3.

Difference of Irreversible Strain Limit in Technical RHQT Nb3Al Superconductors

Strain limit for critical current degradation in various technical rapid-heating, quenching, and transformation-processed Nb3Al strands has been studied with respect to the matrix material and filament diameter. This property is one important factor as well as the strain sensitivity to $J_{{\rm{c}}}$ characteristics, especially when we consider to apply the so-called react and wind technique to large magnets such as DEMO reactors. We compared five strands, including a standard Nb matrix, standard Ta matrix, Nb/Ag/Nb three-layered barrier structure, and other two fine filament diameter strands prepared by the restacking method. In normal Nb and Ta matrix strands with a filament diameter of more than 30 μ m, the irreversible strain limit is about 0.3%. Refinement of the filament diameter enables us to significantly improve the irreversible strain limit up to more than 0.7%. The Nb/Ag/Nb three-layered barrier structure appears more attractive from a practical point of view. The irreversible strain limit was improved up to nearly 0.6%, even if the filament diameter is more than 20 μ m. The Ag layer between the Nb3Al filaments seems to act as a cushion to mitigate the stress concentration in the wire. The Ag barrier also seems to be effective for current bypass in existence of cracks, resulting in suppressing $I_{{\rm{c}}}$ degradation in a higher strain range.

Minimization of cell-substrate interaction using suspended microstructured meshes initiates cell sheet formation by self-assembly organization

There is growing interest to achieve tissue fabrication by designing the architecture of the substrate. Here we present a mesh culture approach which enables fabrication of standalone cell sheets by cell–cell contact mediated self-assembly organization on highly porous and microstructured SU-8 polymer meshes (apertures size >100 μm in length, mesh strands 3–5 μm in width), which are set suspended in a culture medium to limit cell-substrate interaction only to the fine mesh strands. We demonstrate that ingression of cells into the wide mesh openings proceeds solely by cell–cell adhesion, resulting in the formation of a uniform cell sheet over the highly porous mesh scaffolds. A uniformly spread actin meshwork dotted with reinforcement structures including transverse actin cables was present in cell sheets of fibroblasts while ring-like cables of actin/E-cadherin architecture was confirmed in epithelial cell sheets, suggesting the requirement for mechanically stable cell–cell adhesion architecture to overcome substrate adhesion limitations. Expression of type I collagen suggested the deposition of collagen and other extracellular matrices. Moreover, cell sheets could be maintained for an extended period of time (>100 d) without noticeable loss of cell viability, owing to improved exposure of the cell layer to medium in a suspension setup. Thus, the mesh culture offers an alternative method for extended cell culture and fabrication of standalone cell sheets for easy integration into microfluidics platforms for organ-on-chip studies.

Morphology and clinical importance of epidural membrane and periradicular fibrous tissue in lumbar spinal stenosis.

Compared to the ligamentum flavum (LF), morphology of the epidural membrane (EM) and the periradicular fibrous tissue (PRFT) has been largely ignored in studies of lumbar spinal stenosis (LSS). The aim of this prospective study was to elucidate the morphologies and clinical importance of the EM and PRFT in LSS. Before starting this study, neural compressive EM (c-EM) and PRFT (c-PRFT) were defined as follows based on our microsurgical experience and a literature review. The c-EM is a constriction band or membrane obstructing dural tube expansion, and the c-PRFT is a fibrous tissue that compresses the nerve root and/or restricts its mobility. This study enrolled 134 patients who underwent microscopic decompression at L4/5. The morphologies of each patient's EM and PRFT were observed and recorded. Specimens were obtained from randomly selected patients for histological evaluation. The EM and PRFT exhibited a wide morphological spectrum, from a fine strand to a substantial membrane. The c-EM alone was observed in four cases, the c-PRFT alone in 37 cases, and both in three cases. The c-PRFT was more frequently observed in patients with degenerative spondylolisthesis than in those without olisthesis (P<0.05). Several cases exhibited interesting histological findings including many small arteries, chondrometaplasia, ganglion-like cyst formation, and hyalinized collagen fibers. Some EM and PRFT transform into degenerative and substantial fibrous tissues during the process of symptomatic LSS development. Such morphological and histological changes can cause dural tear, symptomatic epidural hematoma, and/or inadequate decompression.

Experimental investigation of inhomogeneities, nanoscopic phase separation, and magnetism in arc melted Fe-Cu metals with equal atomic ratio of the constituents

Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a magnetic moment being equal to about 2.13 μB/Fe atom and a bulk like negligible value of coercivity over the temperature range of 5–300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in magnetic character. However, for the annealed sample phase separated Fe exhibited homogenous strain.

Morphology, ciliary pattern and molecular phylogeny of Trachelophyllum brachypharynx Levander, 1894 (Litostomatea, Haptoria, Spathidiida)

We isolated a relatively unknown haptorian ciliate, Trachelophyllum brachypharynx , in brackish water from the mouth of the Taehwa River, South Korea. The morphology of this isolate was studied using in vivo observation and protargol impregnation, and its evolutionary history was revealed by phylogenetic analysis of the 18S rRNA gene. The main features of T. brachypharynx include (i) a very narrowly fusiform and slightly contractile body about 380 × 40 μm in size; (ii) two ellipsoidal macronuclear nodules typically connected by a fine strand; (iii) a single terminal contractile vacuole; (iv) filiform extrusomes that are typically 30 µm long; (v) an average of 24 ciliary rows, with two of them anteriorly differentiated into an isostichad dikinetidal dorsal brush; and (vi) hat-shaped lepidosomes. Based on the 18S rRNA gene phylogeny, T. brachypharynx clustered together with Trachelophyllum sp. within the order Spathidiida. Furthermore, phylogenetic trees and networks indicate some members from the genera Enchelyodon and Spathidium as the nearest relatives of trachelophyllids. Therefore, based on the present molecular and comparative-morphological analyses, we suggested a hypothesis explaining how trachelophyllids may have evolved from a spathidiid-like ancestor via an enchelyodonid-like stage.