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Maintaining the integrity of articular cartilage is paramount to joint health and function. Under constant mechanical stress, articular cartilage is prone to injury that often extends to the underlying subchondral bone. In this study, we incorporated arginine–aspartate–glycine (RGD) peptide into chondroitin sulfate-based cryogel for hyaline cartilage regeneration. Known to promote cell adhesion and proliferation, RGD peptide is a double-edged sword for cartilage regeneration. Depending on the peptide availability in the microenvironment, RGD may aid in redifferentiation of dedifferentiated chondrocytes by mimicking physiological cell-matrix interaction or inhibit chondrogenic phenotype via excessive cell spreading. Here, we observed an increase in chondrogenic phenotype with RGD concentration. The group containing the highest RGD concentration (3 mM; RGD group) experienced a 24-fold increase in COL2 expression in the 1st week of in vitro culture and formed native cartilage-resembling ectopic tissue in vivo. No sign of dedifferentiation (COL1) was observed in all groups. Within the concentration range tested (0–3 mM RGD), RGD promotes chondrocyte redifferentiation after monolayer expansion and thus, formation of hyaline cartilage tissue.

Currently time-domain astronomy can scan the entire sky on a daily basis, discovering thousands of interesting transients every night. Classifying the ever-increasing number of new transients is one of the main challenges for the astronomical community. One solution that addresses this issue is the robotically controlled Spectral Energy Distribution Machine (SEDM) which supports the Zwicky Transient Facility (ZTF). SEDM with its pipeline PYSEDM demonstrates that real-time robotic spectroscopic classification is feasible. In an effort to improve the quality of the current SEDM data, we present here two new modules, BYECR and CONTSEP. The first removes contamination from cosmic rays, and the second removes contamination from non-target light. These new modules are part of the automated PYSEDM pipeline and fully integrated with the whole process. Employing BYECR and CONTSEP modules together automatically extracts more spectra than the current PYSEDM pipeline. Using SNID classification results, the new modules show an improvement in the classification rate and accuracy of 2.8% and 1.7%, respectively, while the strength of the cross-correlation remains the same. Improvements to the SEDM astrometry would further boost the improvement of the CONTSEP module. This kind of robotic follow-up with a fully automated pipeline has the potential to provide the spectroscopic classifications for the transients discovered by ZTF and also by the Rubin Observatory's Legacy Survey of Space and Time., 9 pages, 6 figures, 2 tables, accepted for publication in PASP

CANDLES(CAlcium fluoride for the study of Neutrinos and Dark matters by Low Energy Spectrometer) is the experiment to search for the neutrino-less double beta decay(0vββ) of 48Ca with CaF2 scintillator. 48Ca has the highest Q ββ -value (4.3 MeV) among all isotope candidates for 0vββ. It enables us to measure signals with very low background condition. After rejection analysis with 131 days × 86 kg data for background events from radioactive contaminations in the CaF2 scintillators, no events are observed in the Q ββ -value region. As a result, the half-life of 48Ca is greater than 6.2 × 1022 yr (90% confidence level). For further high sensitive measurement of 48Ca 0vββ search, we have been developing the 48Ca enrichment and CaF2 scintillating bolometer techniques. In this paper, the latest result for CANDLES and the status of scintillating bolometer development are described.

Scintillating bolometer is a powerful tool to search neutrinoless double beta decay. We established a large scintillating bolometer using a 312 g CaF2(Eu) crystal with a readout technology of metallic magnetic calorimeters. A set of successful measurements were carried out for simultaneous detection for heat and light signals at 10-40 mK in an above-ground laboratory. We found large light signals with clear difference in scintillation yields between electron- and alpha-induced events. The comparison of relative amplitudes of heat and light signals obtained about 10 σ discrimination power. We also found the heat signals experiencing strong position dependence from the event location. This position dependence can be interpreted by the spin-lattice interaction of paramagnetic Eu ions in the CaF2 crystal.

There is an urgent need to improve system design of calibration equipment which allows us to determine parameters and characteristics of medical electrodes. Technical characteristics of a hardware and software system for researching medical electrodes are depending on amplitude–frequency responses of a measurement analog channel. This channel consists of an instrumentation amplifier, a cascaded chain of operational amplifiers including programmable-gain amplifiers and a low-pass filter, therefore calculating amplitude–frequency responses of a measurement channel is a multiparameter problem. This problem can be solved efficiently by simulation with help of Matlab. Simulink-model of a hardware and software system for researching medical electrodes is suggested. The model provides the correct design of a measurement channel. It is subject to design criteria such as accuracy of frequency band and a reduction in gain.

Thin films of ferroelectric materials are potential candidates to be implemented in the unfolding of a new paradigm in high-density memory devices. As the thickness of these films reaches the sub-10 nm level, the interface properties between the electrode and ferroelectric material undergo significant changes that play a crucial role in governing the ferroelectric behavior. The present state-of-the-art approach presents a detailed investigation of different high pressure annealing (HPA) conditions through simulation studies. The simulation studies were performed using Landau-Khalatnikov equations, with Landau's parameters calculated using the least regression method as described in the Method S1. The extracted coefficients were used to determine various relationships (free energy, ferroelectric potential and negative capacitance) with which to observe the impact of HPA on the negative capacitance (NC) effect on account of the majority ferroelectric phase. To verify the simulation results, pulse transient switching measurements were conducted using Pt/Ti/TiN/Hf0.5Zr0.5O2/TiN-based metal-ferroelectric-metal (MFM) devices to study the coercive field, interfacial capacitance and load resistance behavior. The results suggest that the non-ferroelectric portion (t-phase) coexists with the ferroelectric (o-phase) within the thin layer of the MFM capacitor adjacent to TiN electrode, which undergoes a phase transformation from the t-phase to the o-phase when exposed to different HPA conditions as well as electric field cycling during PS measurements. The simulation and experimental results confirm that the 550 °C at 50 atm N2 environment provides the best possibility of achieving the highest ferroelectric characteristics with the lowest proportion of the non-ferroelectric phase and thus the maximum NC effect as well.

There is a growing demand for wearable sensing devices to perceive and respond to vital biological signals or human activities. In this work, a carbon nanotube ink drop-coated textile resistive pressure sensor on a typical three-dimensional (3D) spacer textile was developed to detect human health and motion through scalable, cost-effective, and simple processing. A 3D spacer textile comprises two outer layers interconnected with a monofilament spacer with robust compression resistance and high air circulation with open-hole structures, which demonstrates the potential for use in a wearable pressure sensing device. The textile pressure sensor unit shows a wide range of sensing performance of 200 Pa–50 kPa, which facilitates the detection of physiological signal acoustic vibrations and hand motion, and it exhibits stable cycling performances up to 10 000 cycles, along with a fast response time of 20 ms. Furthermore, large-area sensor arrays are successfully demonstrated for the spatial distribution of pressure mapping, suggesting significant potential in smart textiles or wearable electronics.

We report the recent progress on critical temperature switch development for metallic magnetic calorimeters (MMCs). The superconducting planar coil of a micro-fabricated MMC is charged with a persistent current, which serves as the stable field current to magnetize the sensor material. Part of the Nb superconducting circuit is fabricated with an alloy of Nb and Ta (NbTa), another superconducting material with a transition temperature (T C ) that is lower than that of Nb. A persistent current can be injected into the loop while lowering the temperature from above to below the T C of the NbTa switch. Resistance measurements of a sputtered film of a NbTa alloy with a Ta concentration of 62% showed a clear superconducting transition at 5.29 K. Using one of the completed MMC devices, the ability to use the T C switch for charging with a persistent current up to 120 mA was tested by means of magnetization measurements. The magnetization measurements recorded with a DC-SQUID were in good agreement with the calculated values in all tested cases with four different currents. These results indicate that an MMC can be charged with a persistent current as expected using the T C switch. This work is the first demonstration of the proposed T C switch in a complete MMC setup. Based on the present progress, future studies will investigate multi-channel operation and the development of a hybrid setup with an on-chip heater.

Specific problems arising in the use of the method of renormalization group and e expansion in the theory of developed turbulence are discussed: the necessity to take into account the dependence of the model parameters on the expansion parameter e and the large magnitude of the physical value of the expansion parameter. It is shown that quantities independent of the amplitude of the correlation function of the random force possess a uniquely defined e expansion. On the example of the two-loop calculation of the Kolmogorov constant and the turbulent Prandtl number, effectiveness of the improved expansion is demonstrated, which uses an approximate summation of the high-order terms of the e expansion.

Starting from investigation of feasibility and basic studies, KEPCO/KEPRI has carried an enterprising project for HTS cable system since 2002. The objectives of this project are to demonstrate HTS cable system and evaluate the feasibility in electricity utility's view. The installation of 100m/3phase/22.9kV/50MVA HTS cable system is undergoing in KEPCO's test yard, located in Gochang, Korea. The HTS cable system consists of 100m long cable, two terminations and a cooling system. To simulate the actual cable installation, the 55m section of the 100m long cable was installed into an underground tunnel. Commissioning test is scheduled at the end of September, 2005 and followed by long term operation test. In this paper, the installation of HTS cable system and initial results of system operation will be summarized

Metallic magnetic calorimeters (MMCs) are highly sensitive temperature sensors that use the paramagnetic nature of erbium in a metallic host and superconducting electronics usually composed of a superconducting niobium coil and a current sensing superconducting quantum interference device. This article discusses the applicability of MMCs in experimental searches for rare events in particle physics. A detector module using two MMCs was built to perform low-temperature measurements of heat and scintillation light generated by particle interaction in a 340 g 40Ca100MoO4 crystal. The energy transfer mechanism, from incident particles to the components of the heat and light sensors, is described through a thermal model. MMCs, with gold films collecting athermal phonons, can be used over wide ranges of operating temperature and crystal volume without a significant change in detector performances. Rare event searches could thus benefit from MMC-based detectors presenting such flexibility as well as excellent energy resolution and particle discrimination power.

Metallic magnetic calorimeters (MMCs) are highly sensitive temperature sensors that operate at millikelvin temperatures. An energy deposit in a detector can be measured using an MMC through the induced temperature increase. The MMC signal, i.e., a variation in magnetization can then be measured using a superconducting quantum interference device. MMCs are used in particle physics experiments searching for rare processes as their high sensitivity and fast response provide high energy and timing resolutions and good particle discrimination. Low-temperature detectors consisting of molybdenum-based scintillating crystals read out via MMCs were designed and built to perform simultaneous measurements of heat and light signals at millikelvin temperatures. These detectors have been used in the advanced Mo-based rare process experiment (AMoRE) that searches for the neutrinoless double beta decay of 100Mo. This article provides a detailed description of the MMC-based low-temperature detector system of the AMoRE-Pilot experiment which currently uses five crystals.

We report on a systematic study for maximising the signal size of metallic magnetic calorimeters (MMCs) used for large-area light detectors operating at milli-Kelvin temperatures. These light detectors are to be used for phonon-scintillation detection using a scintillating crystal for rare event search experiments. The light detector is composed of a 2 inch wafer as an absorber for scintillation light from a crystal, and an MMC as its sensor. A systematic calculation for the expected signal size is made with different SQUID selections, Er concentrations of an MMC sensor, dimensions of the meander-shaped pick-up coil, field currents and operating temperatures. The optimisation study finds that more than five times larger signals can be achieved compared with that of a reference condition in which 90 eV root-mean-squared threshold is obtained. We also describe the inductance measurement for several MMC devices with different size of the pick-up coil to be applied for an optimal condition. This optimisation protocol is also valid for MMC applications of x-ray, alpha and beta spectroscopies.

This paper presents the details of a recent study on the removal of the screening-current-induced field (SCIF) in a pancake-type non-insulated high-temperature superconductor coil (NI coil). To determine the SCIF in the NI coil, the magnetic flux density (B z ) was calculated using the equivalent circuit model of the coil and compared to the B z obtained empirically. The experimental results indicate that the SCIF elimination in the NI coil was enhanced upon increasing the amplitude and frequency of the AC current being supplied to the background coil. Moreover, the SCIF in the NI coil was successfully removed by applying the appropriate external AC magnetic field intensity. This is because the magnetization direction of the SCIF changed completely from radial to spiral, a phenomenon termed the 'vortex shaking effect.' Overall, this study confirmed that the SCIF in a pancake-type NI coil can be effectively removed by exposing the coil to an external AC magnetic field.

We used a single-energy x-ray method and an image processing system to measure the amount of calcium salts deposited in 60 human aortas (41 male and 19 female) of ages 15-88 y. The aortas were removed at autopsy, slit lengthwise and preserved in formalin. The aortas were x-rayed while flat, together with a calibration block containing known amounts of CaHPO4. We determined the amount of calcium salt, referenced to CaHPO4, from the x-ray film with a personal computer using a frame-grabbing board. There was less calcium in the thoracic than the abdominal aorta both in males and females and those of ages less than 50 y. The coefficient of correlation for abdominal aortic calcium mass versus age in 19 females was 0.557 and in 41 males was 0.321. The higher correlation of mass with age for females may be related to differences in calcium metabolism between sexes.

This paper reports the transient characteristics of two types of magnetically coupled GdBCO racetrack pancake coils: (1)?a pair of insulated coils (INS?INS coils) and (2)?a pair of non-insulated coils (NI?NI coils). In order to investigate the electromagnetic behavior of the INS?INS and NI?NI coils, charging/sudden discharging tests were performed with respect to the distance between primary and secondary coils of the coil pairs. The charging/sudden discharging test results show that the amount of induced current and measured axial magnetic field decreased with increasing distance between the primary and secondary coils. Additionally, charge and discharge delays were clearly observed in the NI?NI coils. The simulated results show good agreement with the experimental results, which validates the proposed approach involving an equivalent circuit model.

In this study, empirical and numerical analyses on the screening current-induced field (SCIF) characteristics of a non-insulated (NI) GdBCO-coated conductor single-pancake coil were conducted. Charge and discharge tests were carried out to induce an SCIF in the NI test coil. The SCIF in the NI coil was identified by comparison between the measured and calculated magnetic fields. The experimental results exhibit an increase of the SCIF with increasing an operating current, as well as a logarithmic decay of the SCIF as a function of time. Moreover, the SCIF was not affected by the slow discharge of the NI coil. The estimation of the SCIF based on the critical-state model in a thin film using the finite element method was in fairly good agreement with the experimental results.

The thermal and electrical characteristics of two GdBCO-coated conductor racetrack coils, one insulated with Kapton insulation and the other without turn-to-turn insulation, were investigated by typical voltage–current measurement, charge–discharge, sudden discharge, and over-current tests with respect to external pressures applied to the straight sections of the coils. The test results show that the thermal and electrical stabilities of the racetrack coil without insulation were enhanced considerably with increasing external pressure up to 0.5 MPa, whereas those of the insulated coil were not affected by the pressure. The non-insulated HTS racetrack-type coil with improved turn-to-turn thermal contact in the straight sections may have the potential to be manufactured into field coils for HTS wind turbine generators with highly enhanced thermal and electrical stabilities.

GdBCO single-pancake coils wound with Kapton insulation every 3, 6, 9 turns, and without insulation, were characterized by charge–discharge and over-current tests. The magnetic field saturation at higher currents than the critical current was affected by the portion of the insulated turns that restricted the surplus current flow away from the azimuthal current path. The charge–discharge delay decreased with the increase of the portion of the insulated turns, which suggested that partial insulation winding may be effective for use in HTS power applications. Magnetic field loss of the coils with reduced insulation at excessive high currents was mainly affected by the decrease in ampere-turns due to the electrically shorted-circuits between the non-insulated turns, which resulted in the over-current flow bypass through the turn-to-turn contacts.

We investigate the electrical reliability of nanoscale lines of highly aligned, networked, metallic/semiconducting single-walled carbon nanotubes (SWCNTs) fabricated through a template-based fluidic assembly process. We find that these SWCNT networks can withstand DC current densities larger than 10 MA cm(-2) for several hours and, in some cases, several days. We develop test methods that show that the degradation rate, failure predictability and total device lifetime can be linked to the initial resistance. Scanning electron and transmission electron microscopy suggest that fabrication variability plays a critical role in the rate of degradation, and we offer an empirical method of quickly determining the long-term performance of a network. We find that well-fabricated lines subject to constant electrical stress show a linear accumulation of damage reminiscent of electromigration in metallic interconnects, and we explore the underlying physical mechanisms that could cause such behavior.

A cooling system that uses solid nitrogen (SN2) as an effective heat capacity enhancer was recently introduced to enhance the thermal stability of the HTS SMES. Since SN2 has a large enthalpy with minimal weight, it enables a portable system by increasing the recooling to recooling time period (RRTP). However, contact between the SN2 and HTS SMES magnet can be broken by repeated thermal disturbances (thermal 'dry-out' phenomena). Therefore, it is essential to improve thermal contact to allow full use of the heat capacity of SN2. This study evaluated the effect of using a mixture containing SN2 and a small amount of a liquid cryogen as a cooling system in the HTS SMES system. The performance of the cooling system was evaluated using the mixed cryogen and compared with that of SN2 alone. In addition, the role of liquid neon (Ne) as a heat exchanger between SN2 and the HTS SMES magnet is discussed.

The superconducting properties of YBCO (yttrium barium copper oxide) coated conductors (CCs) are strongly dependent on their oxygen content. Degradation of the superconducting properties of a YBCO CC can occur due to a phase/structure transition caused by the oxygen diffusion out of the YBCO during heat-treatment or soldering, which is an inevitable process during the creation of a superconducting joint. Such variations in phase/structure are generally functions of temperature and oxygen partial pressure (PO2). Therefore, in order for a superconducting joint of YBCO CC to be feasible, it is important to examine the changes in the microstructure and oxygen diffusion behavior for YBCO CCs. This study examined the superconducting properties of YBCO CCs before and after a heat-treatment under a reduced PO2 followed by an oxygenation annealing process in an oxygen rich environment. Partial melting of YBCO without melting of the silver stabilizer layer was obtained for a sample heat treated for 60?s at 820??C and ?Torr. The superconducting properties of the sample heat treated at 820??C were fully restored by an oxygenation annealing treatment for 15?h at 600??C.

The field theoretic renormalization group is applied to the stochastic Navier-Stokes equation with the stirring force correlator of the form k^(4-d-2\epsilon) in the d-dimensional space, in connection with the problem of construction of the 1/d expansion for the fully developed fluid turbulence beyond the scope of the standard epsilon expansion. It is shown that in the large-d limit the number of the Feynman diagrams for the Green function (linear response function) decreases drastically, and the technique of their analytical calculation is developed. The main ingredients of the renormalization group approach -- the renormalization constant, beta function and the ultraviolet correction exponent omega, are calculated to order epsilon^3 (three-loop approximation). The two-point velocity-velocity correlation function, the Kolmogorov constant C_K in the spectrum of turbulent energy and the inertial-range skewness factor S are calculated in the large-d limit to third order of the epsilon expansion. Surprisingly enough, our results for C_K are in a reasonable agreement with the existing experimental estimates., Comment: 30 pages with EPS figures