Stretchable ionic-electronic bilayer hydrogel electronics enable in situ detection of solid-state epidermal biomarkers.

Continuous and in situ detection of biomarkers in biofluids (for example, sweat) can provide critical health data but is limited by biofluid accessibility. Here we report a sensor design that enables in situ detection of solid-state biomarkers ubiquitously present on human skin. We deploy an ionic-electronic bilayer hydrogel to facilitate the sequential dissolution, diffusion and electrochemical reaction of solid-state analytes. We demonstrate continuous monitoring of water-soluble analytes (for example, solid lactate) and water-insoluble analytes (for example, solid cholesterol) with ultralow detection limits of 0.51 and 0.26 nmol cm-2, respectively. Additionally, the bilayer hydrogel electrochemical interface reduces motion artefacts by a factor of three compared with conventional liquid-sensing electrochemical interfaces. In a clinical study, solid-state epidermal biomarkers measured by our stretchable wearable sensors showed a high correlation with biomarkers in human blood and dynamically correlated with physiological activities. These results present routes to universal platforms for biomarker monitoring without the need for biofluid acquisition.

Atrial fibrillation cryoablation is an effective day case treatment: the UK PolarX vs. Arctic Front Advance experience.

AIMS: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF). There are limited data on the PolarX Cryoballoon. The study aimed to establish the safety, efficacy, and feasibility of same day discharge for Cryoballoon PVI. METHODS AND RESULTS: Multi-centre study across 12 centres. Procedural metrics, safety profile, and procedural efficacy of the PolarX Cryoballoon with the Arctic Front Advance (AFA) Cryoballoon were compared in a cohort large enough to provide definitive comparative data. A total of 1688 patients underwent PVI with cryoablation (50% PolarX and 50% AFA). Successful PVI was achieved with 1677 (99.3%) patients with 97.2% (n = 1641) performed as day case procedures with a complication rate of <1%. Safety, procedural metrics, and efficacy of the PolarX Cryoballoon were comparable with the AFA cohort. The PolarX Cryoballoon demonstrated a nadir temperature of -54.6 ± 7.6°C, temperature at 30 s of -38.6 ± 7.2°C, time to -40°C of 34.1 ± 13.7 s, and time to isolation of 49.8 ± 33.2 s. Independent predictors for achieving PVI included time to reach -40°C [odds ratio (OR) 1.34; P < 0.001] and nadir temperature (OR 1.24; P < 0.001) with an optimal cut-off of ≤34 s [area under the curve (AUC) 0.73; P < 0.001] and nadir temperature of ≤-54.0°C (AUC 0.71; P < 0.001), respectively. CONCLUSIONS: This large-scale UK multi-centre study has shown that Cryoballoon PVI is a safe, effective day case procedure. PVI using the PolarX Cryoballoon was similarly safe and effective as the AFA Cryoballoon. The cryoablation metrics achieved with the PolarX Cryoballoon were different to that reported with the AFA Cryoballoon. Modified cryoablation targets are required when utilizing the PolarX Cryoballoon.

Comparison of Ophiopogon japonicus and Liriope spicata var. prolifera from Different Origins Based on Multi-Component Quantification and Anticancer Activity.

The tuberous root of Ophiopogon japonicus (Thunb.) Ker-Gawl. is a well-known Chinese medicine also called Maidong (MD) in Chinese. It could be divided into "Chuanmaidong" (CMD) and "Zhemaidong" (ZMD), according to the geographic origins. Meanwhile, the root of Liriope spicata (Thunb.) Lour. var. prolifera Y. T. Ma (SMD) is occasionally used as a substitute for MD in the market. In this study, a reliable pressurized liquid extraction and HPLC-DAD-ELSD method was developed for the simultaneous determination of nine chemical components, including four steroidal saponins (ophiopojaponin C, ophiopogonin D, liriopesides B and ophiopogonin D'), four homoisoflavonoids (methylophiopogonone A, methylophiopogonone B, methylophiopogonanone A and methylophiopogonanone B) and one sapogenin (ruscogenin) in CMD, ZMD and SMD. The method was validated in terms of linearity, sensitivity, precision, repeatability and accuracy, and then applied to the real samples from different origins. The results indicated that there were significant differences in the contents of the investigated compounds in CMD, ZMD and SMD. Ruscogenin was not detected in all the samples, and liriopesides B was only found in SMD samples. CMD contained higher ophiopogonin D and ophiopogonin D', while the other compounds were more abundant in ZMD. Moreover, the anticancer effects of the herbal extracts and selected components against A2780 human ovarian cancer cells were also compared. CMD and ZMD showed similar cytotoxic effects, which were stronger than those of SMD. The effects of MD may be due to the significant anticancer potential of ophiopognin D' and homoisoflavonoids. These results suggested that there were great differences in the chemical composition and pharmacological activity among CMD, ZMD and SMD; thus, their origins should be carefully considered in clinical application.

Rapid Screening of Lipase Inhibitors from Ophiopogonis Radix Using High-Performance Thin Layer Chromatography by Two Step Gradient Elution Combined with Bioautographic Method.

In this study, a high-performance thin layer chromatography (HPTLC) method by two step gradient elution with two mobile phases was developed for the simultaneous analysis of seven constituents in Ophiopogonis Radix. The chromatography was performed on silica gel 60 F254 plate with dichloromethane-methanol-ethyl acetate-water (70:25:12:3, v/v/v/v) and dichloromethane-methanol (300:1, v/v) as the mobile phase for two step gradient elution. Then, the HPTLC profiles were observed after derivatization with 10% sulfuric acid in ethanol solution. The obtained HPTLC images were further analyzed by chemometric approaches and the samples could be clustered based on regions and/or growth years, which were two important factors affecting the constituents in Ophiopogonis Radix. Furthermore, five compounds including ophiopogonin D, ophiopojaponin C, ophiopogonin D', ophiopogonin C' and methylophiopogonanone B were screened as potential lipase inhibitors from Ophiopogonis Radix by the HPTLC-bioautographic method. The binding modes and interactions between the five compounds and lipase were further explored by molecular docking analysis. The developed HPTLC method could be used for quality control of Ophiopogonis Radix and screening of the potential lipase inhibitors.

The indications and safety of prolonged temporary pacing using active-fixation leads and externalized pulse generator.

BACKGROUND: Temporary cardiac pacing, conventionally achieved using a passive transvenous pacing wire, can be life-saving for unstable arrhythmias. However, they run the risk of complications, the longer they remain in-situ. Externalized prolonged temporary pacing (EPTP), using active-fixation lead and an externalized pulse generator; may be an alternative for transient pacing indications, concurrent illness or sepsis that precludes permanent pacing. METHODS: Sixty-seven patients (mean age 69 ± 14 years; 82% male) underwent EPTP between November 2011 and April 2019. EPTP was performed in a sterile facility, under fluoroscopy, using active-fixation leads anchored to the right ventricle septum. Externalized lead was connected to a re-sterilized pulse generator and secured to anterior chest wall with transparent dressings. EPTP indications and patient outcomes were evaluated. RESULTS: Pacing indications were high-grade atrio-ventricular (AV) block (73.2%), sinus arrest (14.9%), overdrive suppression of VT (5.9%) and pause-dependent VT (4.5%). Reasons for ETPT rather than permanent pacing included: sepsis (38.8%), CIED-related infection (8.9%), transient pacing indication (25%), to allow further investigations prior to decision on CIED type (22%), and over-drive arrhythmia suppression (6%). Sixty three percent patients were severely ill in an ICU. Mean duration of pacing was 16 ± 12 days. Sixty seven percent patients subsequently received a CIED and had no evidence of device-related infection at 1-year post-implant. There were three non-fatal complications during EPTP while no deaths were attributed to EPTP. CONCLUSION: EPTP is a safe and useful method of prolonged temporary pacing for patients who require chronotropic support, but in whom immediate permanent pacemaker implantation is contraindicated.

Determination of six polyynes in Oplopanax horridus and Oplopanax elatus using polyethylene glycol modified reversed migration microemulsion electrokinetic chromatography.

A PEG-modified reversed migration MEEKC method was developed for simultaneous determination of six polyynes, including oplopandiol, falcarindiol, oplopandiol acetate, (11S, 16S, 9Z)-9,17-octadecadiene-12,14-diyne-1,11,16-triol,1-acetate, oplopantriol B, and oplopantriol A, in Oplopanax horridus and Oplopanax elatus. The running buffer containing 0.8% v/v ethyl acetate, 3.8% w/v SDS, 6.6% v/v n-butanol in 20 mM phosphate buffer (pH 2.5), followed by mixing with propan-2-ol at 30% v/v and PEG-1000 at 15% w/v, was applied in the analysis. The proposed method was successfully applied to determine the six polyynes in five samples of Oplopanax horridus and one of O. elatus. The result showed that the types and amounts of polyynes present were obviously different when comparing the two herbs. Besides, the developed PEG-modified reversed MEEKC method might be suitable for the analysis of hydrophobic analytes in herbal medicines.

Nucleation dynamics of water nanodroplets.

The origin of the condensation of water begins at the nanoscale, a length-scale that is challenging to probe for liquids. In this work we directly image heterogeneous nucleation of water nanodroplets by in situ transmission electron microscopy. Using gold nanoparticles bound to a flat surface as heterogeneous nucleation sites, we observe nucleation and growth of water nanodroplets. The growth of nanodroplet radii follows the power law: R(t)~(t-t 0) ß , where ß~0.2-0.3.

Physical explanation of coupled cell-cell rotational behavior and interfacial morphology: a particle dynamics model.

Previous studies have reported persistent rotational behavior between adherent cell-cell pairs cultured on micropatterned substrates, and this rotation is often accompanied by a sigmoidal deflection of the cell-cell interface. Interestingly, the cell-cell rotation runs in the opposite reference frame from what could be expected of single cell locomotion. Specifically, the rotation of the cell pair consists of each individual cell protruding from the inwardly regressive arm of the cell-cell interface, and retracting from the other outwardly protrusive arm. To this author's knowledge, the cause of this elusive behavior has not yet been clarified. Here, we propose a physical model based on particle dynamics, accounting for actomyosin forcing, viscous dissipation, and cortical tension. The results show that a correlation in actomyosin force vectors leads to both persistent rotational behavior and interfacial deflection in a simulated cell cluster. Significantly, the model, without any artificial cues, spontaneously and consistently reproduces the same rotational reference frame as experimentally observed. Further analyses show that the interfacial deflection depends predominantly on cortical tension, whereas the cluster rotation depends predominantly on actomyosin forcing. Together, these results corroborate the hypothesis that both rotational and morphological phenomena are, in fact, physically coupled by an intracellular torque of a common origin.

A fluid model of pulsed direct current planar magnetron discharge.

We simulated a pulsed direct current (DC) planar magnetron discharge using fluid model, solving for species continuity, momentum, and energy transfer equations, coupled with Poisson equation and Lorentz force for electromagnetism. Based on a validated DC magnetron model, an asymmetric bipolar potential waveform is applied at the cathode at 50-200 kHz frequency and 50-80% duty cycle. Our results show that pulsing leads to increased electron density and electron temperature, but decreased deposition rate over non-pulsed DC magnetron, trends consistent with those reported by experimental studies. Increasing pulse frequency increases electron temperature but reduces the electron density and deposition rate, whereas increasing duty cycle decreases both electron temperature and density but increases deposition rate. We found that the time-averaged electron density scales inversely with the frequency, and time-averaged discharge voltage magnitude scales with the duty cycle. Our results are readily applicable to modulated pulse power magnetron sputtering and can be extended to alternating current (AC) reactive sputtering processes.

Oxygen Plasma Induced Nanochannels for Creating Bimetallic Hollow Nanocrystals.

Platinum-based metal catalysts are considered excellent converters in various catalytic reactions, particularly in fuel cell applications. The atomic structure at the nanocrystal surface and the metal interface both influence the catalytic performance, controlling the efficiency of the electrochemical reactions. Here we report the synthesis of Ag/Pt and Ag/Pd core/shell nanocrystals and insight into the formation mechanism of these bimetallic core/shell nanocrystals when undergoing oxygen plasma treatment. We carefully designed the oxidation treatment that determines the structural and compositional evolution. The accelerated oxidation-triggered diffusion of Ag toward the outer metal shell leads to the Kirkendall effect. After prolonged oxygen plasma treatment, most core/shell nanocrystals evolve into hollow spheres. At the same time, a minor fraction of the metal remains unchanged with a well-protected Ag core and a monocrystalline Pt or Pd shell. We hypothesize that the O2 plasma disturbs the Pt or Pd shell surface and introduces active O species that react with the diffused Ag from the inside out. Based on EDX elemental mapping, combined with several electron microscopic techniques, we deduced the formation mechanism of the hollow structures to be as follows: (I) the oxidation of Ag within the Pt or Pd lattice causes a disrupted crystal lattice of Pt or Pd; (II) nanochannels arise at the defect locations on the Pt or Pd shell; (III) the remaining Ag atoms pass through these nanochannels and leave a hollow crystal behind. Our findings deepen the understanding of interface dynamics of bimetallic nanostructured catalysts under an oxidative environment and unveil an alternative approach for catalyst pretreatment.

Variational quantum evolution equation solver.

Variational quantum algorithms offer a promising new paradigm for solving partial differential equations on near-term quantum computers. Here, we propose a variational quantum algorithm for solving a general evolution equation through implicit time-stepping of the Laplacian operator. The use of encoded source states informed by preceding solution vectors results in faster convergence compared to random re-initialization. Through statevector simulations of the heat equation, we demonstrate how the time complexity of our algorithm scales with the Ansatz volume for gradient estimation and how the time-to-solution scales with the diffusion parameter. Our proposed algorithm extends economically to higher-order time-stepping schemes, such as the Crank-Nicolson method. We present a semi-implicit scheme for solving systems of evolution equations with non-linear terms, such as the reaction-diffusion and the incompressible Navier-Stokes equations, and demonstrate its validity by proof-of-concept results.

Chemical Comparison of Monk Fruit Products Processed by Different Drying Methods Using High-Performance Thin-Layer Chromatography Combined With Chemometric Analysis.

Monk fruit, also named Luo Han Guo, is the fruit of Siraitia grosvenorii (Swingle) C. Jeffrey ex A. M. Lu et Z. Y. Zhang and has been used as both food and traditional Chinese medicine. Due to preservation concerns, monk fruit is usually processed by hot-air drying or using low-temperature techniques after harvest. In this study, high-performance thin-layer chromatography (HPTLC) method was developed for the analysis of 13 mogrosides, 1 flavonoid, and 3 sugars in monk fruit products. Then chemometric analysis was applied to investigate the chemical characteristics in the samples dried by different methods. The results showed that the contents of mogroside V, 11-oxo-mogroside V, isomogroside V, and sucrose in monk fruits dried at low temperature were much higher than those in traditional hot-air drying samples, which was also confirmed by HPTLC-scanning. These findings indicate that HPTLC combined with chemometric analysis provides a reliable tool to understand the chemical differences between the monk fruit products processed by different drying methods, which will be helpful for their quality evaluation.

Performing calculus: Asymmetric adaptive stimuli-responsive material for derivative control.

Materials (e.g., brick or wood) are generally perceived as unintelligent. Even the highly researched "smart" materials are only capable of extremely primitive analytical functions (e.g., simple logical operations). Here, a material is shown to have the ability to perform (i.e., without a computer), an advanced mathematical operation in calculus: the temporal derivative. It consists of a stimuli-responsive material coated asymmetrically with an adaptive impermeable layer. Its ability to analyze the derivative is shown by experiments, numerical modeling, and theory (i.e., scaling between derivative and response). This class of freestanding stimuli-responsive materials is demonstrated to serve effectively as a derivative controller for controlled delivery and self-regulation. Its fast response realizes the same designed functionality and efficiency as complex industrial derivative controllers widely used in manufacturing. These results illustrate the possibility to associate specifically designed materials directly with higher concepts of mathematics for the development of "intelligent" material-based systems.

Airborne dispersion of droplets during coughing: a physical model of viral transmission.

The Covid-19 pandemic has focused attention on airborne transmission of viruses. Using realistic air flow simulation, we model droplet dispersion from coughing and study the transmission risk related to SARS-CoV-2. Although this model defines most airborne droplets as 8-16 µm in diameter, we infer that larger droplets of 32-40 µm in diameter may potentially be more infectious due to higher viral content. Use of face masks is therefore recommended for both personal and social protection. We found social distancing effective at reducing transmission potential across all droplet sizes. However, the presence of a human body 1 m away modifies the aerodynamics so that downstream droplet dispersion is enhanced, which has implications on safe distancing in queues. At 1 m distance, we found that an average of 0.55 viral copies is inhaled for a cough at median loading, scalable up to 340 copies at peak loading. Droplet evaporation results in significant reduction in droplet counts, but airborne transmission remains possible even under low humidity conditions.

Risk assessment of airborne COVID-19 exposure in social settings.

The COVID-19 pandemic has led to many countries oscillating between various states of lock-down as they seek to balance keeping the economy and essential services running and minimizing the risk of further transmission. Decisions are made about which activities to keep open across a range of social settings and venues guided only by ad hoc heuristics regarding social distancing and personal hygiene. Hence, we propose the dual use of computational fluid dynamic simulations and surrogate aerosol measurements for location-specific assessment of risk of infection across different real-world settings. We propose a 3-tiered risk assessment scheme to facilitate classification of scenarios into risk levels based on simulations and experiments. Threshold values of <54 and >840 viral copies and <5% and >40% of original aerosol concentration are chosen to stratify low, medium, and high risk. This can help prioritize allowable activities and guide implementation of phased lockdowns or re-opening. Using a public bus in Singapore as a case study, we evaluate the relative risk of infection across scenarios such as different activities and passenger positions and demonstrate the effectiveness of our risk assessment methodology as a simple and easily interpretable framework. For example, this study revealed that the bus's air-conditioning greatly influences dispersion and increases the risk of certain seats and that talking can result in similar relative risk to coughing for passengers around an infected person. Both numerical and experimental approaches show similar relative risk levels with a Spearman's correlation coefficient of 0.74 despite differing observables, demonstrating applicability of this risk assessment methodology to other scenarios.

Quality standard of traditional Chinese medicines: comparison between European Pharmacopoeia and Chinese Pharmacopoeia and recent advances.

Traditional Chinese medicine (TCM) are becoming more and more popular all over the world. However, quality issues of TCM may lead to medical incidents in practice and therefore quality control is essential to TCM. In this review, the state of TCM in European Pharmacopoeia are compared with that in Chinese Pharmacopoeia, and herbal drugs that are not considered as TCM and not elaborated by TCM working party at European Directorate for the Quality of Medicines & Health Care (EDQM) but present in both European Pharmacopoeia and Chinese Pharmacopoeias are also discussed. Different aspects in quality control of TCM including origins, identification, tests and assays, as well as sample preparation, marker selection and TCM processing are covered to address the importance of establishing comprehensive quality standard of TCM. Furthermore, advanced analytical techniques for quality control and standard establishment of TCM are also reviewed.

Dispersion of evaporating cough droplets in tropical outdoor environment.

The ongoing Covid-19 pandemic has focused our attention on airborne droplet transmission. In this study, we simulate the dispersion of cough droplets in a tropical outdoor environment, accounting for the effects of non-volatile components on droplet evaporation. The effects of relative humidity, wind speed, and social distancing on evaporative droplet transport are investigated. Transmission risks are evaluated based on SARS-CoV-2 viral deposition on a person standing 1 m or 2 m away from the cougher. Our results show that the travel distance for a 100 µm droplet can be up to 6.6 m under a wind speed of 2 m/s. This can be further increased under dry conditions. We found that the travel distance of a small droplet is relatively insensitive to relative humidity. For a millimetric droplet, the projected distance can be more than 1 m, even in still air. Significantly greater droplets and viral deposition are found on a body 1 m away from a cougher, compared to 2 m. Despite low inhalation exposure based on a single cough, infection risks may still manifest through successive coughs or higher viral loadings.

The heparan sulfate proteoglycan (HSPG) glypican-3 mediates commitment of MC3T3-E1 cells toward osteogenesis.

Heparan sulfate (HS) sugar chains attached to core proteoglycans (PGs) termed HSPGs mediate an extensive range of cell-extracellular matrix (ECM) and growth factor interactions based upon their sulfation patterns. When compared with non-osteogenic (maintenance media) culture conditions, under established osteogenic culture conditions, MC3T3-E1 cells characteristically increase their osteogenic gene expression profile and switch their dominant fibroblast growth factor receptor (FGFR) from FGFR1 (0.5-fold decrease) to FGFR3 (1.5-fold increase). The change in FGFR expression profile of the osteogenic-committed cultures was reflected by their inability to sustain an FGF-2 stimulus, but respond to BMP-2 at day 14 of culture. The osteogenic cultures decreased their chondroitin and dermatan sulfate PGs (biglycan, decorin, and versican), but increased levels of the HS core protein gene expression, in particular glypican-3. Commitment and progress through osteogenesis is accompanied by changes in FGFR expression, decreased GAG initiation but increased N- and O-sulfation and reduced remodeling of the ECM (decreased heparanase expression) resulting in the production of homogenous (21 kDa) HS chain. With the HSPG glypican-3 expression strongly upregulated in these processes, siRNA was used to knockdown this gene to examine the effect on osteogenic commitment. Reduced glypican-3 abrogated the expression of Runx2, and thus differentiation. The reintroduction of this HSPG into Runx2-null cells allowed osteogenesis to proceed. These results demonstrate the dependence of osteogenesis on specific HS chains, in particular those associated with glypican-3.