Antioxidant compounds and activities of Perilla frutescens var. crispa and its processed products

Perilla frutescens var. crispa 'Antisperill' has stronger anti-inflammatory effects than the original cultivar (red perilla), but studies on its bioactive compounds are limited. This study aimed to evaluate the antioxidant compounds and activity of red perilla and 'Antisperill', as well as their processed products using freeze drying (FD) and microwave-assisted low temperature vacuum drying (MVD). Red perilla had higher antioxidant compounds and activities than 'Antisperill'. MVD showed significantly greater antioxidant properties than FD among the processed products. Isoegomaketone, studied for its anti-obesity, antioxidant, anti-inflammatory, and anticancer properties, was only found in 'Antisperill' and its processed products, with the highest content in 'Antisperill' MVD samples. This study highlights that 'Antisperill' contains various antioxidants, and MVD is the optimal drying method to preserve and enhance its antioxidant content. As a result, 'Antisperill' could potentially serve as a natural antioxidant with both anti-inflammatory and antioxidant functions.

Comparative Analysis of Polyphenol Content and Antioxidant Activity of Different Parts of Five Onion Cultivars Harvested in Korea

Onions are typically consumed as the bulb, but the peel and root are discarded as by-products during processing. This study investigated the potential functional use of these by-products by analyzing the polyphenols, antioxidant compounds, and antioxidant activity contained in onions. In this study, the bulb, peel, and root of five onion cultivars ('Tank', 'Bomul', 'Gujji' 'Cobra', and 'Hongbanjang') harvested in Korea were investigated. Caffeic acid and quercetin were most abundant in the peel, whereas methyl gallate was the predominant polyphenol in the bulb. Both DPPH and ABTS radical scavenging activity were higher in onion peel and root than in the bulb. These findings suggest that onion peel and roots, which are often discarded, have abundant antioxidant substances and excellent antioxidant activity. This study provides basic data for the future use of onion peel and roots as functional ingredients with high added value.

APSIC dental infection prevention and control (IPC) guidelines

BACKGROUND

The Asia Pacific Society of Infection Control launched the Infection Prevention and Control Guidelines in July 2022. This document describes the guidelines and recommendations for safe practices in dental setting. It aims to highlight practical recommendations in a concise format designed to assist dental facilities at Asia Pacific region in achieving high standards in infection prevention and control practices, staff and patient safety.

METHOD

The guidelines were developed by an appointed workgroup comprising experts in the Asia Pacific region, following reviews of previously published international guidelines and recommendations relevant to each section.

RESULTS

It recommends standard precautions as a minimal set of preventive measures to protect staff and prevent cross transmission. Surgical aseptic technique is recommended when procedures are technically complex and longer in duration. Only trained staff are eligible to conduct reprocessing of dental instruments. The design, layout of the dental facility are important factors for successful infection prevention. The facility should also have a Pandemic Preparedness Plan.

CONCLUSIONS

Dental facilities should aim for excellence in infection prevention and control practices as this is part of patient safety. The guidelines that come with a checklist help dental facilities to identify gaps for improvement to reach this goal.

P02.01.B The telomere maintenance mechanism spectrum and its dynamics in gliomas

The activation of the telomere maintenance mechanism (TMM) is one of the critical drivers of cancer cell immortality. In gliomas, TERT expression and TERT promoter mutation are considered to reliably indicate telomerase activation, while ATRX mutation indicates alternative lengthening of telomeres (ALT). However, these relationships have not been extensively validated in tumor tissues. Here, we show through the direct measurement of telomerase activity and ALT in a large set of glioma samples that the TMM in glioma cannot be defined in the dichotomy of telomerase activity and ALT, regardless of TERT expression, TERT promoter mutation and ATRX mutation. Moreover, we observed that a considerable proportion of gliomas lack both telomerase activity and ALT (Neither group). And this Neither group exhibited evidence of slow growth potential. From a set of longitudinal samples from a separate cohort of glioma patients, we discovered that the TMM is not fixed but changes with glioma progression. Collectively, these results suggest that the TMM is a dynamic entity and that reflects the plasticity of the oncogenic biological status of tumor cells and that the TMM should be defined by the direct measurement of telomerase enzyme activity and evidence of ALT.

Characterization of rhodanine derivatives as potential disease-modifying drugs for experimental mouse osteoarthritis

OBJECTIVE

This study was performed to characterize selected rhodanine derivatives as potential preclinical disease-modifying drugs for experimental osteoarthritis (OA) in mice.

METHODS

Three rhodanine derivatives, designated rhodanine (R)-501, R-502, and R-503, were selected as candidate OA disease-modifying drugs. Their effects were evaluated by intra-articular (IA) injection in OA mouse models induced by DMM (destabilization of the medial meniscus) or adenoviral overexpression in joint tissues of hypoxia-inducible factor (HIF)-2α or zinc importer ZIP8. The regulatory mechanisms impacted by the rhodanine derivatives were examined in primary-culture chondrocytes and fibroblast-like synoviocytes (FLS).

RESULTS

All three rhodanine derivatives inhibited OA development caused by DMM or overexpression of HIF-2α or ZIP8. Compared to vehicle-treated group, for example, IA injection of R-501 in DMM-operated mice reduced median OARSI grade from 3.78 (IQR 3.00-5.00) to 1.89 (IQR 0.94-2.00, P = 0.0001). R-502 and R-503 also reduced from 3.67 (IQR 2.11-4.56) to 2.00 (IQR 1.00-2.00, P = 0.0030) and 2.00 (IQR 1.83-2.67, P = 0.0378), respectively. Mechanistically, the rhodanine derivatives inhibited the nuclear localization and transcriptional activity of HIF-2α in chondrocytes and FLS. They did not bind to Zn²⁺ or modulate Zn²⁺ homeostasis in chondrocytes or FLS; instead, they inhibited the nuclear localization and transcriptional activity of the Zn²⁺-dependent transcription factor, MTF1. HIF-2α, ZIP8, and interleukin-1β could upregulate matrix-degrading enzymes in chondrocytes and FLS, and the rhodanine derivatives inhibited these effects.

CONCLUSION

IA administration of rhodanine derivatives significantly reduced OA pathogenesis in various mouse models, demonstrating that these derivatives have disease-modifying therapeutic potential against OA pathogenesis.

Universal Early Coarsening of Quenched Bose Gases

We investigate the early coarsening dynamics of an atomic Bose gas quenched into a superfluid phase. Using a two-step quench protocol, we independently control the two cooling rates during and after passing through the critical region, respectively, and measure the number of quantum vortices spontaneously created in the system. The latter cooling rate regulates the temperature during the condensate growth, consequently controlling the early coarsening dynamics in the defect formation. We find that the defect number shows a scaling behavior with the latter cooling rate regardless of the initial cooling rate, indicating universal coarsening dynamics in the early stage of condensate growth. Our results demonstrate that early coarsening not only reduces the defect density, but also affects its scaling with the quench rate, which is beyond the Kibble-Zurek mechanism.

Defect Saturation in a Rapidly Quenched Bose Gas

We investigate the saturation of defect density in an atomic Bose gas rapidly cooled into a superfluid phase. The number of quantum vortices, which are spontaneously created in the quenched gas, exhibits a Poissonian distribution not only for a slow quench in the Kibble-Zurek (KZ) scaling regime but also for a fast quench, in which case the mean vortex number is saturated. This shows that the saturation is not caused by destructive vortex collisions, but by the early-time coarsening in an emerging condensate, which is further supported by the observation that the condensate growth lags the quenching in the saturation regime. Our results demonstrate that the defect saturation is an effect beyond the KZ mechanism, opening a path for studying critical phase transition dynamics using the defect number distribution.

Critical Energy Dissipation in a Binary Superfluid Gas by a Moving Magnetic Obstacle

We study the critical energy dissipation in an atomic superfluid gas with two symmetric spin components by an oscillating magnetic obstacle. Above a certain critical oscillation frequency, spin-wave excitations are generated by the magnetic obstacle, demonstrating the spin superfluid behavior of the system. When the obstacle is strong enough to cause density perturbations via local saturation of spin polarization, half-quantum vortices (HQVs) are created for higher oscillation frequencies, which reveals the characteristic evolution of critical dissipative dynamics from spin-wave emission to HQV shedding. Critical HQV shedding is further investigated using a pulsed linear motion of the obstacle, and we identify two critical velocities to create HQVs with different core magnetization.

Masking of High-Translucency Zirconia for Various Cores

CLINICAL RELEVANCE

Various core materials with different shades affect the final color of high-translucency monolithic zirconia restorations. The blue core shows the greatest color difference in final zirconia restorations followed by metal, A3 dentin-shade resin core, and white core.

SUMMARY

The purpose of this study was to evaluate the masking ability of high-translucency monolithic zirconia for various core materials. A computer-aided design-computer-aided manufacturing system was used to design a zirconia disc with a diameter of 10 mm and a thickness of 1.0 mm. Four groups of cores (n=15 each) were fabricated with blue-colored dual-cure resin, white-colored dual-cure resin, A3 dentin-shade composite resin, and titanium block with 10-mm diameter and 5-mm thickness.Dual-cure, self-adhesive resin cement discs with a thickness of 25.0 ± 0.02 μm were fabricated. The color was measured using a handheld spectrophotometer. Color measurements of all specimens were performed on a white background. To assess the masking ability of zirconia, the difference between the values measured with zirconia on a white background and the values measured with zirconia on each of the four types of core material as a background with the cement specimens interposed (zirconia + cement + core) was determined. To enhance the optical connection between the specimens, distilled water was applied between each layer during each measurement.The results showed that the value of ΔE was highest for the blue core followed by metal, A3 dentin-shade resin core, and white-resin core. No significant differences were observed between the metal core and the A3 dentin-shade resin core or between the A3 dentin-shade resin core and the white core. The blue core had the significantly highest ΔE value based on Tukey's honest significant difference test.Different core materials affect the final color of high-translucency monolithic zirconia restorations. Thus, our study showed that the final color of high-translucency monolithic zirconia restorations could be affected by the type of core material used.

Parental concerns during COVID-19-related school closures: Children’s behaviors and media usage

Introduction

While coronavirus disease 2019 (COVID-19) spreads across the globe, many countries have closed schools to ensure physical distancing to slow transmission and ease the burden on health systems. Concerns regarding Coronavirus Disease 2019 (COVID-19) school closures often increase stress levels in parents.

Objectives

This study examined whether higher levels of parental concerns were associated with children’s problematic behaviors and other factors during COVID-19-related primary school closures.

Methods

Participants were 217 parents who responded to a web-based questionnaire covering parental concerns, subjective stress, and depression; children’s sleep patterns, behavioral problems, and changes in activity level after COVID-19; previously received mental health services; and media usage during the online-only class period from community center in Suwon city.

Results

The number of parental concerns was associated with children’s behavioral problem index (BPI) score (Pearson correlation 0.211, p < 0.01), sleep problems (0.183, p < 0.01), increased smartphone usage (0.166, p < 0.05), increased TV usage (0.187, p < 0.01), parents’ subjective stress levels (0.168, p < 0.05), and parental depression (0.200, p < 0.01). In families with children who previously received mental health services, the children reportedly suffered from more sleep and behavioral problems but not increased media usage, and parents noted more stress and depression. Parental concerns are related to family factors such as change of caregiver, no available caregiver, decreased household income, and recent adverse life events.

Conclusions

Ongoing monitoring of mental health at risky group and multiple support systems should be considered for parents having difficulty in caring their children.

Application of purified porcine collagen in patients with chronic refractory musculoskeletal pain

Background

This study aimed to assess the potential efficacy of purified porcine atelocollagen (PAC) for the management of refractory chronic pain due to suspected connective tissue damage.

Methods

Patients treated with PAC were retrospectively evaluated. Patients with chronic refractory pain, suspected to have originated from musculoskeletal damage or defects with the evidence of imaging studies were included. Pain intensity, using the 11-point numerical rating scale (NRS), was assessed before the procedure, and 1 month after the last procedure.

Results

Eighty-eight patients were finally included for investigation. The mean NRS score was decreased from 5.8 to 4.1 after 1 month of PAC injection (P < 0.001). No independent factor was reported to be directly related to the decrease in NRS score by more than half.

Conclusions

Application of PAC may have potential as a treatment option for refractory chronic musculoskeletal pain. PAC might promote tissue recovery, act as a scaffold for repair, or directly reduce inflammation.

Assessment of Physicochemical Quality, Antioxidant Content and Activity, and Inhibition of Cholinesterase between Unripe and Ripe Blueberry Fruit

Five Korean blueberries (''Nelson'', ''Duke '', ''Bluejay '', ''Toro'', and ''Elliot '') were harvested at two maturity stages (unripe and ripe) to evaluate fruit quality and antioxidant activities. The Hunter L, a, and b color of ripe blueberries was lower than that of unripe fruit. Soluble solid concentration (SSC) and pH increased, and titratable acidity (TA) and firmness decreased as the blueberries matured. The ripe blueberry fruits showed a higher SSC/TA ratio than the unripe fruits. Although total anthocyanin, flavonoids, phenolics content, and antioxidant activity were higher in ripe blueberries than in unripe fruit, the unripe fruit had higher acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition activities than ripe fruit in all cultivars. Total antioxidant activity was highly correlated with total flavonoids and phenolics. The relationships between the total antioxidant activity and the AChE or BChE inhibitory activity are negative. There were several physicochemical quality and antioxidant activity differences in blueberries, depending on the cultivar and the maturity at harvest. Unripe fruits also contain potential health-promoting bioactive compounds as functional food ingredients.

Antibacterial and in vitro antidementia effects of aronia (Aronia melanocarpa) leaf extracts

This study investigated the antibacterial and in vitro antidementia effects of aronia (Aronia melanocarpa) leaf extracts from 3 cultivars (Nero, Viking, and McKenzie) collected at three different stages of maturity (young, harvest, and old). Bacillus cereus was susceptible to the old leaves of cultivars McKenzie and Nero, whereas Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua were not inhibited by any of the extracts. Growth of B. cereus was inhibited by cv. McKenzie, resulting in increased lag time, whereas Nero had both an inhibitory and an inactivation effect. Except for cv. Viking at harvest stage, the acetylcholinesterase and butyrylcholinesterase inhibitory activity of aronia leaf extracts were about 60-70 and 70-80%, respectively. Therefore, aronia leaf is a natural resource with a potentially potent antidementia effect, besides antibacterial activity.

Influence of ripening stage and cultivar on physicochemical properties, sugar and organic acid profiles, and antioxidant compositions of strawberries

The current study compared the physicochemical properties, antioxidant compounds and activities, of unripe and ripe fruits of three cultivars (Seolhyang, Janghee, and Maehyang) of strawberries grown in Korea. As fruits matured, their soluble solids content increased and their organic acid content decreased. Total phenolic content (TPC) and total flavonoid content (TFC) did not differ between Seolhyang and Maehyang fruits, regardless of maturity, whereas unripe Janghee fruits showed higher TPC and TFC than ripe fruits. Total anthocyanin content was higher in ripe fruits than in unripe fruits. For total antioxidant activity, ripe and unripe Seolhyang fruits showed no differences, whereas unripe Janghee fruits showed significantly higher activity than ripe fruits. TPC and TFC were highly correlated, as were DPPH and ABTS radical scavenging activities. Thus, antioxidant contents and total antioxidant activities differed with variety and fruit ripeness at harvest. Unripe fruits show strong potential for use in functional food manufacturing.

Influence of Ripening Stage and Cultivar on Physicochemical Properties and Antioxidant Compositions of Aronia Grown in South Korea

The present study investigated the fruits of aronia (Aronia melanocarpa) across different stages of maturity and analyzed their physicochemical properties, antioxidant compositions, and activities. The selected aronia cultivars (‘Viking’, ‘McKenzie’, and ‘Kingstar K1’ were categorized based on maturity into the immature stage (red tip), intermediary stage (red), and mature stage (dark purple). The key sugar components of aronia fruits were fructose, glucose, and sorbitol, while the main organic acid was found to be malic acid. The antioxidant content and activity of all three aronia cultivars showed significantly higher values for the red tip stage than the red or dark purple stages. However, the total anthocyanin content of aronia was the highest at the dark purple stage in three cultivars. The main polyphenols in aronia fruits were found to be catechol and chlorogenic acid, with a decreasing tendency as maturation progressed. As a result, the red tip stage of aronia fruits contains comparatively more abundant flavonoids, phenolic compounds and polyphenols than the dark purple stage, with higher antioxidant activity.

Observation of Wall-Vortex Composite Defects in a Spinor Bose-Einstein Condensate

We report the observation of spin domain walls bounded by half-quantum vortices (HQVs) in a spin-1 Bose-Einstein condensate with antiferromagnetic interactions. A spinor condensate is initially prepared in the easy-plane polar phase, and then, suddenly quenched into the easy-axis polar phase. Domain walls are created via the spontaneous Z_{2} symmetry breaking in the phase transition and the walls dynamically split into composite defects due to snake instability. The end points of the defects are identified as HQVs for the polar order parameter and the mass supercurrent in their proximity is demonstrated using Bragg scattering. In a strong quench regime, we observe that singly charged quantum vortices are formed with the relaxation of free wall-vortex composite defects. Our results demonstrate a nucleation mechanism for composite defects via phase transition dynamics.

Band Gap Closing in a Synthetic Hall Tube of Neutral Fermions

We report the experimental realization of a synthetic three-leg Hall tube with ultracold fermionic atoms in a one-dimensional optical lattice. The legs of the synthetic tube are composed of three hyperfine spin states of the atoms, and the cyclic interleg links are generated by two-photon Raman transitions between the spin states, resulting in a uniform gauge flux ϕ penetrating each side plaquette of the tube. Using quench dynamics, we investigate the band structure of the Hall tube system for a commensurate flux ϕ=2π/3. Momentum-resolved analysis of the quench dynamics reveals a critical point of band gap closing as one of the interleg coupling strengths is varied, which is consistent with a topological phase transition predicted for the Hall tube system.

Evaluation of the Microshear Bond Strength of MDP-containing and Non-MDP-containing Self-adhesive Resin Cement on Zirconia Restoration

OBJECTIVES

The purpose of this study was to measure the microshear bond strength (μSBS) of four different self-adhesive resin cements with/without 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing primer to zirconium ceramics and to evaluate the effect of zirconia primers on these self-adhesive resin cements (SARCs).

METHODS AND MATERIALS

Zirconia blocks (20 × 20 × 8 mm³) were prepared and divided into eight groups (n=20). They were sandblasted (50 μm Al₂O₃) and treated as follows: no primer or primer (Z-Primer Plus). Four self-adhesive resin cements (MDP-containing: Permacem 2.0 [PC], Clearfil SA luting [CS]; non-MDP-containing: Rely-X U200 [RU], Maxcem Elite [ME]) were bonded to the zirconia surface. After thermocycling, a μSBS test was performed. The failure mode was analyzed using light microscopy. Statistical analysis of μSBS was performed using one-way analysis of variance and two-sample t-test with post hoc Tukey test. The loss rate was evaluated using the Fisher's exact test and χ² test with post hoc Tukey test (p<0.05).

RESULTS

Within the no primer groups, the PC and CS groups showed higher bond strength than the RU and ME groups. Comparing the μSBS of the no primer and primer groups in the same SARCs, the RU/P group was higher than the RU group, and the ME/P group was higher than the ME group. No significant difference was observed between the PC and PC/P groups and between the CS and CS/P groups.

CONCLUSIONS

Non-MDP-containing SARC showed the increased bonding value with MDP-containing primer to zirconia ceramics. The bond strength of MDP-containing SARCs was not affected significantly by the use of zirconia primer.

Critical Vortex Shedding in a Strongly Interacting Fermionic Superfluid

We study the critical vortex shedding in a strongly interacting fermionic superfluid of ^{6}Li across the BEC-BCS crossover. By moving an optical obstacle in the sample and directly imaging the vortices after the time of flight, the critical velocity u_{vor} for vortex shedding is measured as a function of the obstacle travel distance L. The observed u_{vor} increases with decreasing L, where the rate of increase is the highest in the unitary regime. In the deep Bose-Einstein condensation regime, an empirical dissipation model well captures the dependence of u_{vor} on L, characterized by a constant value of η=-[d(1/u_{vor})/d(1/L)]. However, as the system is tuned across the resonance, a step increase of η develops about a characteristic distance L_{c} as L is increased, where L_{c} is comparable to the obstacle size. This bimodal behavior is strengthened as the system is tuned towards the BCS regime. We attribute this evolution of u_{vor} to the emergence of the underlying fermionic degree of freedom in the vortex-shedding dynamics of a Fermi condensate.

Realization of a Cross-Linked Chiral Ladder with Neutral Fermions in a 1D Optical Lattice by Orbital-Momentum Coupling

We report the experimental realization of a cross-linked chiral ladder with ultracold fermionic atoms in a 1D optical lattice. In the ladder, the legs are formed by the orbital states of the optical lattice and the complex interleg links are generated by the orbital-changing Raman transitions that are driven by a moving lattice potential superimposed onto the optical lattice. The effective magnetic flux per ladder plaquette is tuned by the spatial periodicity of the moving lattice, and the chiral currents are observed from the asymmetric momentum distributions of the orbitals. The effect of the complex cross-links is demonstrated in quench dynamics by measuring the momentum dependence of the interorbital coupling strength. We discuss the topological phase transition of the chiral ladder system for the variations of the complex cross-links.

The roughening kinetics of hydrogenated graphene

The roughness is a common property of all growing surfaces – however, the way the roughness of a growing surface changes with time and space is uniquely related to the underlying growth process, i.e. to how the atoms stick to the surface during the first stage of nucleation. This concept allows getting insights on the nucleation process of a growing surface by measuring two scaling exponents, α and β, known as roughness and growth exponents, respectively. In this work, we studied hydrogenation of graphene using the roughening kinetics. The coverage of graphene will depend on how the H ions stick on the surface, giving rise to a unique roughness evolution in time and space. We measured a roughness exponent of ~0.5 (derived from a Fourier index of ~3), and a growth exponent of ~0.3. The values of the growth and roughness exponents are close to those reported for clustered carbon, suggesting a roughening mechanism by clustering, in good agreement with the theory. We also compared our coverage data with a different model, used to describe the dynamics of graphene coverage, during chemical vapour deposition. Our data are in agreement with a nucleation-dominated growth, further confirming that hydrogenation is happening by clustering.

Critical Spin Superflow in a Spinor Bose-Einstein Condensate

We investigate the critical dynamics of spin superflow in an easy-plane antiferromagnetic spinor Bose-Einstein condensate. Spin-dipole oscillations are induced in a trapped condensate by applying a linear magnetic field gradient and we observe that the damping rate increases rapidly as the field gradient increases above a certain critical value. The onset of dissipation is found to be associated with the generation of dark-bright solitons due to the modulation instability of the counterflow of two spin components. Spin turbulence emerges as the solitons decay because of their snake instability. We identify another critical point for spin superflow, in which transverse magnon excitations are dynamically generated via spin-exchanging collisions, which leads to the transient formation of axial polar spin domains.

Molecular epidemiology and environmental contamination during an outbreak of parainfluenza virus 3 in a haematology ward

Background

Although fomites or contaminated surfaces have been considered as transmission routes, the role of environmental contamination by human parainfluenza virus type 3 (hPIV-3) in healthcare settings is not established.

Aim

To describe an hPIV-3 nosocomial outbreak and the results of environmental sampling to elucidate the source of nosocomial transmission and the role of environmental contamination.

Methods

During an hPIV-3 outbreak between May and June 2016, environmental surfaces in contact with clustered patients were swabbed and respiratory specimens used from infected patients and epidemiologically unlinked controls. The epidemiologic relatedness of hPIV-3 strains was investigated by sequencing of the haemagglutinin–neuraminidase and fusion protein genes.

Findings

Of 19 hPIV-3-infected patients, eight were haematopoietic stem cell recipients and one was a healthcare worker. In addition, four had upper and 12 had lower respiratory tract infections. Of the 19 patients, six (32%) were community-onset infections (symptom onset within <7 days of hospitalization) and 13 (68%) were hospital-onset infections (≥7 days of hospitalization). Phylogenetic analysis identified two major clusters: five patients, and three patients plus one healthcare worker. Therefore, seven (37%) were classified as nosocomial transmissions. hPIV-3 was detected in 21 (43%) of 49 environmental swabs up to 12 days after negative respiratory polymerase chain reaction conversion.

Conclusion

At least one-third of a peak season nosocomial hPIV-3 outbreak originated from nosocomial transmission, with multiple importations of hPIV-3 from the community, providing experimental evidence for extensive environmental hPIV-3 contamination. Direct contact with the contaminated surfaces and fomites or indirect transmission from infected healthcare workers could be responsible for nosocomial transmission.

Observation of vortex-antivortex pairing in decaying 2D turbulence of a superfluid gas

In a two-dimensional (2D) classical fluid, a large-scale flow structure emerges out of turbulence, which is known as the inverse energy cascade where energy flows from small to large length scales. An interesting question is whether this phenomenon can occur in a superfluid, which is inviscid and irrotational by nature. Atomic Bose-Einstein condensates (BECs) of highly oblate geometry provide an experimental venue for studying 2D superfluid turbulence, but their full investigation has been hindered due to a lack of the circulation sign information of individual quantum vortices in a turbulent sample. Here, we demonstrate a vortex sign detection method by using Bragg scattering, and we investigate decaying turbulence in a highly oblate BEC at low temperatures, with our lowest being ~0.5T _c , where T _c is the superfluid critical temperature. We observe that weak spatial pairing between vortices and antivortices develops in the turbulent BEC, which corresponds to the vortex-dipole gas regime predicted for high dissipation. Our results provide a direct quantitative marker for the survey of various 2D turbulence regimes in the BEC system.

Effect of Insufficient Light Exposure on Polymerization Kinetics of Conventional and Self-adhesive Dual-cure Resin Cements

Objectives: The purpose of this study was to investigate the influence of insufficient light exposure on the polymerization of conventional and self-adhesive dual-cure resin cements under ceramic restorations.

Methods: Two conventional dual-cure resin cements (Rely-X ARC, Duolink) and two self-adhesive resin cements (Rely-X U200, Maxcem Elite) were polymerized under different curing modes (dual-cure or self-cure), curing times (20 and 120 seconds), and thickness of a ceramic overlay (2 and 4 mm). Polymerization kinetics was measured by Fourier transform infrared spectroscopy for the initial 10 minutes and after 24 hours. Data were analyzed using mixed model analysis of variance (ANOVA), one-way ANOVA/Student-Newman-Keuls post hoc test, and paired t-test (α=0.05).

Results: When light-curing time was set to 20 seconds, the presence of the ceramic block significantly affected the degree of conversion (DC) of all resin cements. Especially, the DC of the groups with 20 seconds of light-curing time under 4 mm of ceramic thickness was even lower than that of the self-cured groups at 24 hours after polymerization (p&lt;0.05). However, when light-curing time was set to 120 seconds, a similar DC compared with the group with direct light exposure (p&gt;0.05) was achieved in all dual-cure groups except Maxcem Elite, at 24 hours after polymerization.

Conclusions: For both conventional and self-adhesive dual-cure resin cements, insufficient light exposure (20 seconds of light-curing time) through thick ceramic restoration (4 mm thick) resulted in a DC even lower than that of self-curing alone.

Observation of von Kármán Vortex Street in an Atomic Superfluid Gas

We report on the experimental observation of vortex cluster shedding from a moving obstacle in an oblate atomic Bose-Einstein condensate. At low obstacle velocities v above a critical value, vortex clusters consisting of two like-sign vortices are generated to form a regular configuration like a von Kármán street, and as v is increased, the shedding pattern becomes irregular with many different kinds of vortex clusters. In particular, we observe that the Stouhal number associated with the shedding frequency exhibits saturation behavior with increasing v. The regular-to-turbulent transition of the vortex cluster shedding reveals remarkable similarities between a superfluid and a classical viscous fluid. Our work opens a new direction for experimental investigations of the superfluid Reynolds number characterizing universal superfluid hydrodynamics.

EEG based image encryption via quantum walks

An electroencephalogram (EEG) based image encryption combined with Quantum walks (QW) is encoded in Fresnel domain. The computational version of EEG randomizes the original plaintext whereas QW can serve as an excellent key generator due to its inherent nonlinear chaotic dynamic behavior. First, a spatially coherent monochromatic laser beam passes through an SLM, which introduces an arbitrary EEG phase-only mask. The modified beam is collected by a CCD. Further, the intensity is multiply with the QW digitally. EEG shows high sensitivity to system parameters and capable of encrypting and transmitting the data whereas QW has unpredictability, stability and non-periodicity. Only applying the correct keys, the original image can be retrieved successfully. Simulations and comparisons show the proposed method to be secure enough for image encryption and outperforms prior works. The proposed method opens the door towards introducing EEG and quantum computation into image encryption and promotes the convergence between our approach and image processing.

Collisional Dynamics of Half-Quantum Vortices in a Spinor Bose-Einstein Condensate

We present an experimental study on the interaction and dynamics of half-quantum vortices (HQVs) in an antiferromagnetic spinor Bose-Einstein condensate. By exploiting the orbit motion of a vortex dipole in a trapped condensate, we perform a collision experiment of two HQV pairs, and observe that the scattering motions of the HQVs is consistent with the short-range vortex interaction that arises from nonsingular magnetized vortex cores. We also investigate the relaxation dynamics of turbulent condensates containing many HQVs, and demonstrate that spin wave excitations are generated by the collisional motions of the HQVs. The short-range vortex interaction and the HQV-magnon coupling represent two characteristics of the HQV dynamics in the spinor superfluid.