Mirror Cell Research Articles

Isolation of circulating endothelial cells provides tool to determine endothelial cell senescence in blood samples

Circulating endothelial cells (CEC) are arising as biomarkers for vascular diseases. However, whether they can be utilized as markers of endothelial cell (EC) senescence in vivo remains unknown. Here, we present a protocol to isolate circulating endothelial cells for a characterization of their senescent signature. Further, we characterize different models of EC senescence induction in vitro and show similar patterns of senescence being upregulated in CECs of aged patients as compared to young volunteers. Replication-(ageing), etoposide-(DNA damage) and angiotensin II-(ROS) induced senescence models showed the expected cell morphology and proliferation-reduction effects. Expression of senescence-associated secretory phenotype markers was specifically upregulated in replication-induced EC senescence. All models showed reduced telomere lengths and induction of the INK4a/ARF locus. Additional p14ARF-p21 pathway activation was observed in replication- and etoposide-induced EC senescence. Next, we established a combined magnetic activated- and fluorescence activated cell sorting (MACS-FACS) based protocol for CEC isolation. Interestingly, CECs isolated from aged volunteers showed similar senescence marker patterns as replication- and etoposide-induced senescence models. Here, we provide first proof of senescence in human blood derived circulating endothelial cells. These results hint towards an exciting future of using CECs as mirror cells for in vivo endothelial cell senescence, of particular interest in the context of endothelial dysfunction and cardiovascular diseases.

A polarization conversion metasurface for reducing radar cross section and enhancing radiation performance of circularly polarized array antennas

In this paper, we present a metasurface for ultra-wideband polarization conversion. The unit structure of the PCM consists of a metallic pattern layer, an air layer, and a grounded dielectric layer, which can achieve a polarization conversion bandwidth (PCR) from 6.17 GHz to 19.5 GHz (103.9%). According to the phase cancellation principle, the PCM cells and their mirror cells are arranged in a checkerboard fashion to form a metasurface. Applying it to a circularly polarized patch array antenna for RCS reduction. With the addition of PCM, the impedance matching (S11) bandwidth of the antenna is broadened from 7.2 to 8.3 GHz (14.2%) to 6.2–8.4 GHz (30.1%), the axial ratio (AR) bandwidth is broadened from 6.9 to 8.25 GHz (17.8%) to 6.75–8.32 GHz (20.1%), the peak gain to 11.1 dBi and the antenna's monostatic RCS achieves more than 5 dB reduction from 6.4 to 18.6 GHz (97.6%) under x- and y-polarized plane wave irradiation.The current distribution of the antenna is used to explain the gain improvement. Finally, we fabricated and tested a prototype of the proposed metasurface antenna.

RF plugging of multi-mirror machines

One of the main challenges of fusion reactors based on magnetic mirrors is the axial particle loss through the loss cones. In multi-mirror (MM) systems, the particle loss is addressed by adding mirror cells on each end of the central fusion cell. Coulomb collisions in the MM sections serve as the retrapping mechanism for the escaping particles. Unfortunately, the confinement time in this system only scales linearly with the number of cells in the MM sections and requires an unreasonably large number of cells to satisfy the Lawson criterion. Here, it is suggested to reduce the outflow by applying a traveling radio frequency (RF) electric field that mainly targets the particles in the outgoing loss cone. The Doppler shift compensates for the detuning of the RF frequency from the ion cyclotron resonance mainly for the escaping particles resulting in a selectivity effect. The transition rates between the different phase space populations are quantified via single-particle calculations and then incorporated into a semi-kinetic rate equations model for the MM system, including the RF effect. It is found that for optimized parameters, the confinement time can scale exponentially with the number of MM cells, orders of magnitude better than a similar MM system of the same length but without the RF plugging, and can satisfy the Lawson criterion for a reasonable system size.

The dysregulation of circulating innate lymphoid cells is related to autoantibodies in pemphigus vulgaris.

Pemphigus vulgaris (PV) is a typical autoimmune disease caused by autoantibodies. Innate lymphoid cells (ILCs) are non-antigen-dependent populations composed of different subsets, also known as "mirror cells" of T cells, which play a crucial role in immune inflammatory diseases. However, the characteristics of ILCs in PV are unclear. Patients diagnosed with PV along with healthy controls in Second Xiangya Hospital of Central South University were studied. Flow cytometry was used to detect the proportion of ILC subsets in the peripheral blood. Anti-desmoglein (DSG) 1 and anti-DSG3 antibody levels of PV patients were detected. Thirty-eight PV patients and 37 healthy controls were enrolled. There were no differences in sex or age between the two groups. Compared with controls, ILCs/CD45+ lymphocytes were significantly decreased in patients with PV. The frequency of ILC1s increased in patients with PV and was positively correlated with anti-DSG3 antibodies. However, the frequency of ILC3s decreased in patients with PV and was negatively correlated with anti-DSG1 antibodies. After methylprednisolone treatment, ILC1/ILC levels significantly decreased. Circulating ILC subsets are associated with PV pathogenesis. Upregulated ILC1s seem to correlate positively with PV severity and can be restored after treatment.

Thermally reused solar energy harvesting using current mirror cells

AbstractThis paper implements a simultaneous solar and thermal energy harvesting system, as a hybrid energy harvesting (HEH) system, to convert ambient light into electrical energy through photovoltaic (PV) cells and heat absorbed in the body of PV cells. Indeed, a solar panel equipped with serially connected thermoelectric generators not only converts the incoming light into electricity but also takes advantage of heat emanating from the light. In a conventional HEH system, the diode block is used to provide the path for the input source with the highest value. In this scheme, at each time, only one source can be handled to generate its output, while other sources are blocked. To handle this challenge of combining resources in HEH systems, this paper proposes a method for collecting all incoming energies and conveying its summation to the load via the current mirror cells in an approach similar to the maximum power point tracking. This technique is implemented using off‐the‐shelf components. The measurement results show that the proposed method is a realistic approach for supplying electrical energy to wireless sensor nodes and low‐power electronics.

Review of song patterns and sound production in armoured ground crickets (Orthoptera: Tettigoniidae: Hetrodini) with karyological data and taxonomic notes.

In the mate finding system of bush-crickets, acoustical signals play a central role. Here we review and describe the bioacoustics of Hetrodini, a morphologically uniform group of Tettigonioidea with a distribution centered in Africa. The male calling songs are produced by tegmino-tegminal stridulation. In all species, these fore wings are completely covered by the pronotum (invisible in intact specimens) and lack the glossy mirror cells which are well-known from many other singing Ensifera. Concerning spectral composition, the broad frequency peak and the parts with the most energy lie in the high audio or low ultrasonic range. In amplitude modulation, the songs are relatively simply structured and contain only one type of syllables each. These syllables consist of heavily dampened impulses (non-resonant song) and are arranged in long series of echemes (chirps) or trills. As far as it is known, syntopic species differ in syllable and/or echeme repetition rates. In contrast to the uniform morphology, the karyotypes are surprisingly diverse with chromosome numbers ranging from 2n = 29 to 17 and one of two sex determination systems: X0 and neo-XY. In our opinion, taxonomically the group is at the moment at best considered as a tribe incertae sedis (without subfamily classification) within Tettigoniidae (not Tettigoniinae sensu OSF).

Loss channels affecting lithium niobate phononic crystal resonators at cryogenic temperature

We investigate the performance of microwave-frequency phononic crystal resonators fabricated on thin-film lithium niobate for integration with superconducting quantum circuits. For different design geometries at millikelvin temperatures, we achieve mechanical internal quality factors Qi above 105–106 at high microwave drive power, corresponding to 5×106 phonons inside the resonator. By sweeping the defect size of resonators with identical mirror cell designs, we are able to indirectly observe signatures of the complete phononic bandgap via the resonators' internal quality factors. Examination of quality factors' temperature dependence shows how superconducting and two-level system (TLS) loss channels impact device performance. Finally, we observe an anomalous low-temperature frequency shift consistent with resonant TLS decay and find that the material choice can help to mitigate these losses.

Mirroring Action Potentials: Label-Free, Accurate, and Noninvasive Electrophysiological Recordings of Human-Derived Cardiomyocytes.

The electrophysiological recording of action potentials in human cells is a long-sought objective due to its pivotal importance in many disciplines. Among the developed techniques, invasiveness remains a common issue, causing cytotoxicity or altering unpredictably cell physiological response. In this work, a new approach for recording intracellular signals of outstanding quality and with noninvasiveness is introduced. By taking profit of the concept of mirror charge in classical electrodynamics, the new proposed device transduces cell ionic currents into mirror charges in a microfluidic chamber, thus realizing a virtual mirror cell. By monitoring mirror charge dynamics, it is possible to effectively record the action potentials fired by the cells. Since there is no need for accessing or interacting with the cells, the method is intrinsically noninvasive. In addition, being based on optical recording, it shows high spatial resolution and high parallelization. As shown through a set of experiments, the presented methodology is an ideal candidate for the next generation devices for the reliable assessment of cardiotoxicity on human-derived cardiomyocytes. More generally, it paves the way toward a new family of in vitro biodevices that will lay a new milestone in the field of electrophysiology.

Supporting structure design for primary and tertiary mirror of off-axis TMA system

Supporting structure for primary and tertiary mirror is one of the most challenging technical points during development of off-axis three-mirror anastigmatism (TMA) biological imaging system. In order to minish the shape error of the mirror and meet the stability of the supporting structure which was working, the mirror supporting structure was designed and optimized with finite element method. First, based on requirement of optical design, materials and supporting mode for the mirror and its supporting structure were decided. Then, a weight reduction structure of the mirror cell was designed which had three-point backside and six-point lateral support structure. The flexible hinge with circular and cantilever beam was made according to the optimized mathematical model. The influence of the parameters on the precision of mirror surface were analyzed under the load conditions of gravity and uniform temperature rise of 4 ℃. Then, the static analysis and thermal analysis for the mirror subassembly were performed. The Finite Element Analysis (FEA) indicated that the surface error (RMS) was 1.529 nm at self-weight. RMS value was 2.426 nm when the temperature rised 4 ℃. Finally, the surface figure test and the wavefront aberrations test were carried out by using Zygo interferometer. The test RMS value of the surface figure is 0.025 λ and the wavefront aberrations of the optical system is 0.102 λ (RMS). The results show that this supporting system could meet the technical indicator requirements of biological imaging system (RMS value of the shape error ≤λ/40, RMS value of the wavefront aberrations≤λ/10).

Development of a 0.25 m f/10 reflecting telescope consisting of a thin primary mirror and a friction drive

Modern astronomical telescopes are comprised of high-quality optics and superior mounting designs to meet the standards and challenges of observational astronomy. Cost of commercial telescopes is a constraint for developing countries like Sri Lanka to be involved in astronomical related research. The objective of this research was to study the technological methods used in fabricating telescopes and to implement those methods to make economical telescopes locally. Therefore, a f/10 focal ratio Newtonian telescope consisting of a computerized friction drive alt-azimuth mount was fabricated with a locally ground thin telescope primary mirror made from Soda-lime glass plate having 0.25 m diameter and 0.012 m thickness. Deformation characteristics, profile formation and optical performance of the telescope primary mirror were investigated using finite element analysis, Polarization and Ronchi pattern analyses, respectively. Resolution, slew rate, torque and slippage of the fabricated friction drive were studied using a Computer Aided Design (CAD) model and an empirical approach. It was found that the profile of the mirror is a perfect parabola. The mirror was supported by a mirror cell with eighteen floating points and resultant root mean square wave-front error of the mirror due to the supporting points is 3.735x10-7m. The friction drive with the computer controller can position the telescope to a given angle with accuracies of 0.421 degrees on altitude axis and 0.03 degrees on azimuth axis. The total cost of production of the prototype telescope is about US$ 750.00. It is shown that there is a significant cost reduction and increased optical and mechanical performances of the telescope due to using the thin mirror and the friction drive mount. In this paper, the system design and the performance evaluation of the mechanical positioning and optical quality of the telescope are presented. Keywords: Newtonian telescope, mirror grinding, telescope driving system, thin telescope mirror.

Beschichtungstechnik auf dem Gipfel

SummaryCoating technology on the summit – Mirror Layers for the Large Synoptic Survey Telescope in ChileThis article focuses on mirror coating for the Large Synoptic Survey Telescope, which is being installed in Chile. The LSST coating system consists of a coating chamber for the deposition of highly reflective optical coatings and a cleaning and stripping station for the M1M3 and M2 mirrors. With the help of the sputtering process, bare and protected silver/aluminum coating recipes can be deposited. The cleaning and stripping station consists of a rotating washing/drying boom, perimeter platforms, and an effluent handling system within the M1M3 mirror cell. The article describes the status of the assembly work on the coating system. Furthermore, it provides information about the progress of factory testing, a about the basic design features and reflective/coating requirements and the coating results.

Magnetic mirror end-plugged by field-reversed configurations formed via rotating magnetic fields

A novel magnetic mirror concept with field-reversed configurations (FRCs) formed via rotating magnetic fields (RMFs) serving as end plugs is proposed to improve the mirror's axial confinement. Single-particle orbit calculations suggest that the FRCs in the end plugs can reflect ions back into the central cell if their parallel speeds are not so fast that they can overcome the magnetic field gradient force from the X-point of the FRC to the midplane outside of the FRC. However, this effect is limited and is no different from that of adding a weak mirror cell to the central cell. When the inward Hall electric field generated by the RMFs is considered, an additional Lorentz force emerges that pushes the incoming ions back to the central mirror, thereby dramatically improving the confinement. The Lorentz force is related to the azimuthal drift speed times the radial component of the magnetic field. By surveying the particle phase space of the speeds, we find that this Lorentz force can reflect back or trap >90% of ions escaping from the central mirror given a sufficient Hall electric field in the RMF region. Finally, preliminary experimental results from the Keda Mirror with AXisymmetricity RMF/FRC are reported and show that with the RMFs on, the axial mirror confinement can increase by a factor of ∼1.4 on average.

Spontaneous multi-keV electron generation in a low-RF-power axisymmetric mirror machine

X-ray emission shows the existence of multikilo-electron-volt electrons in low-temperature, low-power, capacitively coupled RF-heated magnetic-mirror plasmas that also contain a warm (300 eV) minority electron population. Though these warm electrons are initially passing particles, we suggest that collisionless scattering—μ nonconservation in the static vacuum field—is responsible for a minority of them to persist in the mirror cell for thousands of transits during which time a fraction is energized to a characteristic temperature of 3 keV, with some electrons reaching energies above 30 keV. A heuristic model of the heating by a Fermi-accelerationlike mechanism is presented, with μ nonconservation in the static vacuum field as an essential feature.

Ion losses induced by Alfvén ion-cyclotron instability in mirror machine with skew neutral beam injection

The dynamic of ions in an axisymmetric mirror cell with a perturbed field is investigated. The spatial distribution of the perturbation was found in the framework of an analysis of the linear stage of the Alfvén ion cyclotron instability in a mirror trap with skew neutral beam injection. It is demonstrated that unstable perturbations do not cause losses of ions with maximal energy driving the instability. Main anomalous losses are longitudinal losses of ions with low transversal energy due to stochastic diffusion by the magnetic moment.

Characterization of a medium-sized washer-gun for an axisymmetric mirror.

A new medium-sized washer gun is developed for a plasma start-up in a fully axisymmetric mirror. The gun is positioned at the east end of the Keda Mirror with AXisymmetricity facility and operated in the pulsed mode with an arc discharging time of 1.2 ms and a typical arc current of 8.5 kA with 1.5 kV discharge voltage. To optimize the operation, a systematic scan of the neutral pressure, the arc voltage, the bias voltage on a mesh grid 6 cm in front of the gun and an end electrode located on the west end of mirror, and the mirror ratio was performed. The streaming plasma was measured with triple probes in the three mirror cells and a diamagnetic loop in the central cell. Floating potential measurements suggest that the plasma could be divided into streaming and mirror-confined plasmas. The floating potential for the streaming plasma is negative, with an electric field pointing inwards. The mirror-confined plasma has a typical lifetime of 0.5 ms.

Quantitative feedback controller design and test for an electro-hydraulic position control system in a large-scale reflecting telescope

For the primary mirror of a large-scale telescope, an electro-hydraulic position control system (EHPCS) is used in the primary mirror support system. The EHPCS helps the telescope improve imaging quality and requires a micron-level position control capability with a high convergence rate, high tracking accuracy, and stability over a wide mirror cell rotation region. In addition, the EHPCS parameters vary across different working conditions, thus rendering the system nonlinear. In this paper, we propose a robust closed-loop design for the position control system in a primary hydraulic support system. The control system is synthesized based on quantitative feedback theory. The parameter bounds are defined by system modeling and identified using the frequency response method. The proposed controller design achieves robust stability and a reference tracking performance by loop shaping in the frequency domain. Experiment results are included from the test rig for the primary mirror support system, showing the effectiveness of the proposed control design.

Dynamic Loading Assembly for Testing Actuators of Segmented Mirror Telescope

Upcoming large telescopes are based on Segmented Mirror Telescope (SMT) technology which uses small hexagonal mirror segments placed side by side to form the large monolithic surface. The segments alignment needs to be maintained against external disturbances like wind, gravity, temperature and structural vibration. This is achieved by using three position actuators per segment working at few-nanometer scale range along with a local closed loop controller. The actuator along with a controller is required to meet very stringent performance requirements, such as track rates up to 300[Formula: see text]nm/s (90[Formula: see text]mN/s) with tracking errors less than 5[Formula: see text]nm, dynamical forces of up to [Formula: see text][Formula: see text]N, ability to reject disturbances introduced by the wind as well as by mechanical vibration generated in the mirror cell, etc. To conduct these performance tests in more realistic manner, we have designed and developed a Dynamic Loading Assembly (DLA) at Indian Institute of Astrophysics (IIA), Bangalore. DLA is a computer controlled force-inducing device, designed in a modular fashion to generate different types of user-defined disturbances in extremely precise and controlled manner. Before realizing the device, using a simple spring-mass-damper-based mathematical model, we ensured that the concept would indeed work. Subsequently, simple concept was converted into a detailed mechanical design and parts were manufactured and assembled. DLA has static and dynamic loading capabilities up to 250[Formula: see text]N and 18[Formula: see text]N respectively, with a bandwidth sufficient to generate wind disturbances. In this paper, we present various performance requirements of SMT actuators as well as our effort to develop a dynamic loading device which can be used to test these actuators. Well before using DLA for meaningful testing of the actuator, the DLA itself have gone through various tests and improvements phases. We have successfully demonstrated that DLA can be used to check the extreme performance of two different SMT actuators, which are expected to track the position/force with a few nanometer accuracy.

Tip-Tilt Tests by Using Eddy Current Measuring Sensors

Fast-steering Secondary Mirror (FSM) will be installed to the Giant Magellan Telescope (GMT) as a first generation secondary mirror. The FSM implements a tip-tilt mechanism which compensates image degradations caused by wind turbulence and structure jitter. A prototype segment of the FSM has been developed, which comprised of a dummy mirror, a mirror cell, axial and lateral supports, vacuum devices, etc. Several test-bed frames have been developed to hang the segment and to test tip-tilt functionalities. They have been designed, manufactured, assembled, and verified successfully step by step. Tip-tilt measurements were performed mainly by displacement measuring sensors which detect eddy currents precisely. The results proved that the prototype segment worked successfully, by complying the requirements of the FSM for the tip-tilt actuations.

Optical characterization of the active push–pull cell for the 21 m telescope at OAN SPM

Successful tests and results that confirm an efficient behavior of the new common-pull (controlled vacuum), multiple-push primary mirror cell for the 2.1 m telescope at OAN/SPM, are presented. An optical design program that reduces the information obtained from intra- and extra-focal Hartmann patterns, using the direction cosines of the rays that cross the sampled regions, is discussed. The intrinsic uncertainties of this method are evaluated.

Functional morphology of tegmina-based stridulation in the relict species Cyphoderris monstrosa (Orthoptera: Ensifera: Prophalangopsidae).

Male grigs, bush crickets and crickets produce mating calls by tegminal stridulation: the scraping together of modified forewings functioning as sound generators. Bush crickets (Tettigoniidae) and crickets (Gryllinae) diverged some 240million years ago, with each lineage developing unique characteristics in wing morphology and the associated mechanics of stridulation. The grigs (Prophalangopsidae), a relict lineage more closely related to bush crickets than to crickets, are believed to retain plesiomorphic features of wing morphology. The wing cells widely involved in sound production, such as the harp and mirror, are comparatively small, poorly delimited and/or partially filled with cross-veins. Such morphology is similarly observed in the earliest stridulating ensiferans, for which stridulatory mechanics remains poorly understood. The grigs, therefore, are of major importance to investigate the early evolutionary stages of tegminal stridulation, a critical innovation in the evolution of the Orthoptera. The aim of this study is to appreciate the degree of specialization on grig forewings, through identification of sound radiating areas and their properties. For well-grounded comparisons, homologies in wing venation (and associated areas) of grigs and bush crickets are re-evaluated. Then, using direct evidence, this study confirms the mirror cell, in association with two other areas (termed 'neck' and 'pre-mirror'), as the acoustic resonator in the grig Cyphoderris monstrosa Despite the use of largely symmetrical resonators, as found in field crickets, analogous features of stridulatory mechanics are observed between C. monstrosa and bush crickets. Both morphology and function in grigs represents transitional stages between unspecialized forewings and derived conditions observed in modern species.