Stable Drop Research Articles

Boiling heat transfer of water on smooth and square pin fins surfaces in minichannel

In this investigation, flow boiling heat transfer and hydrodynamic instability using deionized water in a minichannel with smooth and square pin fin surfaces was experimentally examined. The study is aimed to assess local and overall heat transfer coefficients, heat transfer coefficients, pressure drop and Nusselt number across various liquid mass flux ranges (50–93 kg m−2 s−1) and a constant heat flux of 46.91 kW/m2. The minichannel, with a hydraulic diameter of 2.85 mm, features a rectangular shape. Experimental testing was conducted on aluminum surface within a minichannel of dimensions 270 mm in length, 30 mm in width, and 1.5 mm height. The square pin fins are integrated at the base of the boiling surfaces, arranged in staggered form. The results revealed that the boiling heat transfer coefficient on square pin fin surfaces was approximately 88 % higher than that on smooth surfaces. Additionally, a notable increase in local heat transfer coefficient was observed for square pin fin surfaces (i.e., 34.64 kW/m2.K) compared to smooth surfaces (8.09 kW/m2.K) at the same mass flux of 50 kg/m2.s. Besides, the square pin fins surface exhibited a lower and stable pressure drop, particularly near annular flow regimes, compared to the smooth surface. Notably, the highest pressure drop observed was 4.8 kPa for the square pin fins surface, while the smooth surface experienced a higher pressure drop of 6.36 kPa, accompanied by more pronounced pressure fluctuations during annular flow.

Enhancing functional stability of NiTi tube for elastocaloric cooling through overstress training

Tubular NiTi is a promising candidate refrigerant for eco-friendly elastocaloric cooling, but its severe functional degradation during cyclic phase transition (PT) is a key concern in the technology development. Here, plastic deformation of 6.7% is applied to NiTi tube by overstress training under 1900 MPa for five cycles to improve the cyclic PT stability without losing cooling efficiency. It is found that after 106 compressive cycles under 1000 MPa, the overstress-trained NiTi tube exhibits small residual strain (0.5%), stable adiabatic temperature drop (ΔT = 11K) and improved coefficient of performance (COP = 55), showing high functional stability and good cooling performance. Transmission electron microscopy (TEM) observations show that the microstructure of the overstress-trained NiTi tube consists of 5–10 nm sized austenite (B2) and martensite (B19′) nanodomains with near-saturated dislocation density (ρ ≈ 5.153 × 1016 m−2). Such dislocation-enriched nanostructure effectively suppresses further formation and motion of dislocation during subsequent cyclic compression, thereby significantly enhancing the cyclic stability of the NiTi tube. The residual B19′ nanodomains and dense dislocations change the PT mode from nucleation-growth of the B19′ phase to direct growth of residual B19′ nanodomains, thereby reducing the dissipation of the PT process and increasing the COP of the NiTi tube. Our study provides an economic and effective method for to enhance the cyclic stability of bulk NiTi tubes for solid-state refrigeration.

Numerical simulation analysis of stable flow of hydrate slurry in gas-liquid-solid multiphase flow

The study of multiphase flow characteristics of hydrate slurry was crucial for controlling the risks associated with hydrate slurry transport in deep-water oil and gas operations. Currently, multiphase flow research on the hydrate slurry flow system focuses on two-phase (solid-liquid) flow studies in single short straight pipes or elbows. This paper established a geometric model based on an experimental loop of high-pressure natural gas hydrate slurry. The Euler model contained n momentum equations and continuity equations for each term, and the Euler model can couple the pressure term with the surface exchange coefficients. Therefore, Euler model was suitable to deal with complex fluid motion problems. Such as bubble flow problem, floating problem, particle suspension problem and fluidized bed problem. In this paper, the hydrate particles in the grout were set as regular round spheres and do not decompose, so the Euler model was suitable for the simulation of the gas-liquid-solid three-phase flow of hydrate grout in the loop. The Euler model was used to simulate the three-phase (gas-liquid-solid) expansion in the loop, focusing on the influence of hydrate slurry inlet flow rate, inlet hydrate volume fraction, liquid phase viscosity and pipe diameter on slurry flow characteristics. The results are as follows:1) Based on orthogonal experiments, pipe diameter has the most significant impact on the pressure drop of the entire pipe section, while liquid phase viscosity has the greatest impact on the average aggregation particle diameter of hydrate on the cross section.2) The distribution of hydrate phase is related to the direction of the loop. Under the influence of gravity, hydrates are primarily dispersed in the liquid phase, with a high concentration in the solid-liquid mixing zone, tend towards the gas phase zone. Hydrate particles are symmetrically distributed in the vertical cross-section, with smaller particle diameters in the solid-liquid mixing zone compared to the gas phase and liquid phase zone 3). In the elbow section, centrifugal force and density difference cause hydrate particles to aggregate towards the lower pipe wall on the outside of the elbow. This results in the disappearance of the liquid phase zone, higher hydrate concentration on the outside of the elbow, and smaller hydrate particle diameter in the solid-liquid mixing zone compared to the gas phase zone.4). Throughout entire loop, the viscosity of the slurry in the solid-liquid mixing zone was the highest, and the volume fraction of hydrate particles was symmetrical both vertically and horizontally. To validate the simulation results, high-pressure multiphase flow hydrate generation experiments were conducted in a 6 MPa hydrate slurry experimental loop. The stable flow pressure drop value of the slurry was compared to the simulation results. The relative error between the simulated and experimental pressure drops is less than 15%, falling within an acceptable range and matching the experimental results. This proved that the multiphase simulation technique of hydrate slurry gas-liquid-solid in the loop can effectively guide the safe transportation of hydrate slurry under actual working conditions.

In situ one-step production of hierarchical silicon nanofilaments/polyimide nonwovens for environmentally sustainable applications

Highly architectures with roughness and low surface energy reagent are the key toward developing superwetting materials. Silicon nanofilaments (SiNFs) had been grown on polyimide (PI) nonwovens by liquid deposition, which could enhance the hydrophobicity of the nonwovens without additives. These newly prepared nonwovens with micro/nano-scale secondary rough structures demonstrate outstanding air filtration and oil/water separation abilities. The in situ hybrid nonwoven shows extremely high efficiency air filtration function (the increase in filtration efficiency for PM1.0 by 63 % with stable pressure drop), stable particulate filtering effect after storage 15 months at ambient temperature, and good thermal stability at 350 °C. The oil/water separation test showed a separation efficiency of over 98 % and a high flux (above 40,000 Lm-2h−1) for different oil/water mixtures. Additionally, nonwovens prepared in this study demonstrated exceptional durability and stability when subjected to corrosive conditions, as evidenced by the results of realistic industrial simulations. The introduction of SiNFs on nonwoven, which combines the multiple capture and wettability properties, shows promise as a potential solution for large-scale air filtration and oil/water separation.

Multi-objective optimization of two-phase flow in the proton exchange membrane fuel cells based on a data driven surrogate model

Flooding is detrimental to Proton Exchange Membrane Fuel Cells (PEMFCs). Reducing two-phase pressure drop and flooding relief time alleviates the devastating effect of flooding. To this end, an innovative surrogate model based on Artificial Intelligence is developed for flooding conditions. Volume of Fluid is employed to capture two-phase flow during the flooding in the simulations. A dataset is generated by 3D two-phase CFD simulation. An Artificial Neural Network is developed based on the dataset to predict the dynamic behavior of two-phase during flooding in time series. Flooding criteria are formulated based on the time series. The results show that the model predicts two-phase flow behavior accurately. Low gas velocity compels small parasitic power, but flooding conditions are exacerbated by the low flow rate, especially in the geometries with corners and virtual bottlenecks. Two distinct methods are used to develop multi-objective optimization, fed by the presented formula. Features are cathode channel characteristics, and objectives are relief time and stabled two-phase pressure. The optimum case brings a time of 9.11 ms and a pressure drop of 27.44 Pa. Also, it reduces the stable pressure drop and the time by 83% and 90%, compared with the worst conditions.

Characterizations and Inkjet Printing of Carbon Black Electrodes for Dielectric Elastomer Actuators.

Dielectric elastomer actuators (DEAs) have been proposed as a promising technology for developing soft robotics and stretchable electronics due to their large actuation. Among available fabrication techniques, inkjet printing is a digital, mask-free, material-saving, and fast technology, making it versatile and appealing for fabricating DEA electrodes. However, there is still a lack of suitable materials for inkjet-printed electrodes. In this study, multiple carbon black (CB) inks were developed and tested as DEA electrodes inkjet-printed on acrylic membranes (VHB). Triethylene glycol monomethyl ether (TGME) and chlorobenzene (CLB) were selected to disperse CB. The inks' stability, particle size, surface tension, viscosity, electrical resistance, and printability were characterized. The DEA with Ink-TGME/CLB (mixture solvent) electrodes obtained 80.63% area strain, a new benchmark for the DEA actuation with CB powder electrodes on VHB. The novelty of this work involves the disclosure of a new ink recipe (TGME/CLB/CB) for inkjet printing that can obtain stable drop formations with a small nozzle (17 × 17 μm), high resolution (∼25 μm, approaching the limit of drop-on-demand inkjet printing), and the largest area strain of DEAs under similar conditions, distinguishing this contribution from the previous works, which is important for the fabrication and miniaturization of DEA-based soft and stretchable electronics.

A priori evaluation of the printability of water-based anode dispersions in inkjet printing

Inkjet printing represents a disruptive additive manufacturing technology that has emerged as an innovative approach to generate customized lithium-ion batteries by tailored dispersions. However, electrode dispersions cause a complex non-Newtonian behavior which hampers the processability. This paper demonstrates a novel procedure for an a priori evaluation of the printability of aqueous graphite dispersions. Therefore, dispersions with a varying active material content were prepared and the printability was examined through a characterization of the drop formation and the drop deposition behavior. While the drop formation was observed by in-situ monitoring, the drop deposition was analyzed in ex-situ test setups. The rheological properties were systematically determined to calculate nondimensional numbers that describe the dispensing behavior. Consequently, their capability to predict the stability of the drop formation was evaluated. The results revealed that a graphite dispersion with a content of 2 m% allowed for a stable drop formation. No splashing occurred on the substrate during the drop deposition and sufficient wetting can be assumed due to a contact angle of below 90∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ$$\\end{document}. Conclusions were drawn to further enhance the active material content. Due to the universality of the proposed approach, it is expected to be applicable to different dispersion systems.

A Clinical-Scale Microfluidic Respiratory Assist Device with 3D Branching Vascular Networks.

Recent global events such as COVID-19 pandemic amid rising rates of chronic lung diseases highlight the need for safer, simpler, and more available treatments for respiratory failure, with increasing interest in extracorporeal membrane oxygenation (ECMO). A key factor limiting use of this technology is the complexity of the blood circuit, resulting in clotting and bleeding and necessitating treatment in specialized care centers. Microfluidic oxygenators represent a promising potential solution, but have not reached the scale or performance required for comparison with conventional hollow fiber membrane oxygenators (HFMOs). Here the development and demonstration of the first microfluidic respiratory assist device at a clinical scale is reported, demonstrating efficient oxygen transfer at blood flow rates of 750mLmin⁻1 , the highest ever reported for a microfluidic device. The central innovation of this technology is a fully 3D branching network of blood channels mimicking key features of the physiological microcirculation by avoiding anomalous blood flows that lead to thrombus formation and blood damage in conventional oxygenators. Low, stable blood pressure drop, low hemolysis, and consistent oxygen transfer, in 24-hour pilot large animal experiments are demonstrated - a key step toward translation of this technology to the clinic for treatment of a range of lung diseases.

Experimental study on effect of structural parameters on pressure drop characteristics of multi-orifice plates

Owing to the advantages of rectification, low noise, low pressure loss, and more stable pressure drop signal compared with the characteristics of the conventional single-orifice plate, multi-orifice plates (MOPs) offer a wide range of application prospects in various industrial pipelines. However, owing to its various orifice shapes and orifice layouts, the pressure drop characteristics of MOPs are not fully understood. In this study, the pressure drop characteristics of single-phase flow across a multi-orifice plate, which implies a stable zone (turbulent flow) pressure loss coefficient and the minimum critical Reynolds number of the stable zone, are experimentally investigated in the Reynolds number range of 29,000–146,000 using water as the fluid. Nine MOPs with circular holes evenly arranged in an equilateral triangle are tested. Their structures differ in terms of the equivalent diameter ratio (0.30–0.60), orifice number (64–400), and relative orifice thickness (0.40–1.60). The results show that the minimum critical Reynolds number deceases as the equivalent diameter ratio decreases, the relative orifice thickness increases, and the orifice number increases, which allows an enlarged Reynolds number range for the stable zone. As the equivalent diameter ratio, orifice number, and relative orifice thickness increase, the stable zone pressure loss coefficient of MOPs initially decreases rapidly and gradually approaches a constant. Finally, based on the experimental results of this study, a correlation of the stable zone pressure loss coefficient of MOPs is proposed, which provides a reference for using MOPs in various industrial applications.

Field experiment of stress sensitivity effect in the Mabidong CBM block, southern Qinshui Basin, China

Coalbed methane (CBM) has made significant contributions to global energy supply and carbon neutrality. The stress sensitivity effect (SSE) is an important factor that influences CBM production, and it indicates that reservoir properties change with stress. Although there is abundant research on the SSE in CBM, most studies are based on theoretical analyses or laboratory physical simulations. Only few studies focused on the SSE of CBM during field production. Therefore, this study aims to investigate the SSE through a field experiment. To this end, a field well from the Mabidong CBM block in the southern Qinshui Basin is selected. Then, the corresponding experimental installations are set up. A parametric inversion method based on the Newman product method and type curve matching is established to interpret the experimental data. The entire experimental process includes six stages of pressure build tests, lasting for 290 days. The field experiment data are inverted using the parametric inversion method. The SSE in the CBM during production is revealed by analyzing the variations in the formation parameters of each stage. The results indicate that both the permeability and fracture half-length are related to the average pressure. The average pressure declines as the production proceeds, and this leads to an increase in the effective stress and a decrease in the permeability and fracture half-length. Relationships between permeability, fracture half-length, and average pressure are derived, and they can be used to better interpret the dynamic production data of CBM wells in the Mabidong Block. Moreover, these results indicate that decreasing the flow rate can mitigate the SSE, especially when the gas desorbs. Thus, during CBM production, the flow rate needs to be strictly controlled for maintaining a stable pressure drop and reducing reservoir damage caused by the SSE.

Simultaneous salt recovery and zwitterionic stachydrine purification from saline eluent via two-stage electrodialysis system

To date, saline eluent from the ion exchange process in the extraction of traditional Chinese medicine such as Leonurus japonicus Houtt was treated predominantly by the conventional processes such as evaporation, crystallization and ethanol elution. However, large amount of energy and fresh organic solvent need to be consumed in the above processes. In the present study, two-stage electrodialysis (ED) was proposed to simultaneously recover salt and purify zwitterionic stachydrine from the saline eluent. In the first stage ED, the membrane type and current density were optimized, and then the continuous twenty-batch operation in partial cyclic mode was carried out to increase the concentration of the recovered NaCl solution. Subsequently, the second stage ED was carried out to further purify the above desalinated saline eluent. Results indicate that, after the two-stage ED process, the concentrated NaCl solution can be directly recycled due to the high concentration of 2.9 mol/L; the recovery rate and purity of NaCl can reach to high values of 99.8% and 99.6%, respectively; the recovery rate and purity of stachydrine can reach to high values of 95.6% and 99.3%, respectively. In addition, a low energy consumption (∼8.34 kWh/m3) was required for the two-stage ED system. What’s more, the membrane fouling investigation indicated that there are as little as 0.5% of the total stachydrine in the saline eluent adsorbed into the CEM. Nonetheless, ED process can be operated stably due to the relatively stable membrane resistance and cell pair voltage drop. Hence, the two-stage ED system is a high-efficient, environmentally-friendly and economical process for simultaneous salt recovery and zwitterionic stachydrine purification from the saline eluent.

О стабильности капель катализатора на границе контакта пар-жидкость-кристалл в процессе роста нитевидных нанокристаллов

The paper provides a physical justification for the wettability conditions for a crystalline surface of a limited area by a small-volume catalytic liquid at the end of a growing nanowires (NW) characterized by a contact angle β, which contributes to a fundamental understanding of the nature of the contact angle of catalyst drops at the top of the NW. It is shown that under the conditions of stationary growth of NWs with a transverse singular face, there are only values of the angles β and γ (the angle of inclination of the side surface of the crystal to this face), which correspond to the minimum increment of the free energy of the three-phase system αLVcosβ + αSL = αSVcosγ and determine the stability of the catalyst drop at the top of the NW. With the growth of cylindrical NWs, the conditions of indifferent equilibrium are realized at the drop wetting perimeter. A drop, due to the dissolution of a crystallizing substance or its separation from a liquid solution, can take an equilibrium shape with a contact angle β that does not satisfy the equilibrium contact angle condition θ in the Young equation. A concentric break (rib) at the NW tip should increase the observed wetting angle θ and lead to contact angle hysteresis. The restrictions imposed on the value of the contact angle of a stable catalyst drop at the top of the NW are determined. The catalyst drop will take an equilibrium shape if the hysteresis angle β is in the range θ < β ≤ θ' + γ (θ' is the wetting angle of the NW side walls). For the growth of semiconductor NWs in the form of a straight cylinder, γ = 90° and therefore always β > 90°. It is shown that the direction of displacement of the three-phase line relative to the droplet surface is determined by the growth angle φ0: for the nonwetting growth mode of NWs (with a transverse face) φ0 = β – γ; for the wetting growth mode (with the end surface curved near the three-phase line)

Binder-integrated Bi/BiOI/TiO2 as an anti-chloride corrosion coating for enhanced photocathodic protection of 304 stainless steel in simulated seawater

Preparing Bi/BiOI catalysts for efficient photocathodic protection of metals in the marine environment has been always a tricky problem because of Bi oxidation and I- ion release under Cl- ion corrosion. Herein, by integrating sodium carboxymethyl cellulose (CMC) into the composites, petal-like Bi/BiOI-modified TiO2 (TBB) p-n heterostructure coatings with a "truncated schema" were successfully fabricated. The as-prepared coatings (CTBB) provided stable photocathodic protection for 304 stainless steel (304SS) in simulated seawater. Compared with TiO2, CMC integrated Bi/BiOI/TiO2 p-n heterostructure coatings showed enhanced photocathodic protection performance with a large photocurrent response of 43 μA cm−2 and a stable potential drop of − 250 mV in simulated seawater without the participation of hole scavengers, which was attributed to the improvement of visible-light utilization and fast electron-hole pair migration at the p-n heterojunction interface. Furthermore, CMC effectively protected Bi nanoparticles against oxidation and BiOI from corrosion of Cl- ions in the electrolyte due to electron density redistribution in the vicinity of I- ions. The as-fabricated CTBB coatings showed great potential as photoanodes for photocathodic protection of 304SS in simulated seawater.

Grain boundary and dislocation strengthening of nanocrystalline NiTi for stable elastocaloric cooling

We fabricate a nanocrystalline NiTi with an average grain size of 31 nm and high-density (4.7 × 1015 m−2) dislocations via cold rolling (38% thickness reduction) and annealing (310 ℃, 2 min) for elastocaloric cooling. It is found that the high-density-dislocation nanocrystalline NiTi shows a high yield strength of 2.09 GPa, a large and stable average temperature drop (ΔT) of 17.3 ℃ over 106 phase-transition cycles under the stress of 1.4 GPa at room temperature. The high cyclic stability originates from grain boundary and dislocation strengthening mechanisms, where the grain boundaries and the high-density dislocations suppress the nucleation of transformation-induced dislocations. The simple and effective processing route via cold rolling and low-temperature annealing is applicable to mass production of bulk nanostructured NiTi with stable elastocaloric cooling performances.

Development and Performance Evaluation of Polytetrafluoroethylene-Membrane-Based Automotive Cabin Air Filter.

A high-efficiency, long-life cabin filter unit is required for the effective purification of the air inside a vehicle. However, conventional cabin air filters that utilize electrostatic effects are less efficient and less effective owing to environmental factors. Polytetrafluoroethylene (PTFE) membranes exhibit a high porosity and surface-to-surface dust-removal performance, and maintain a stable pressure drop, indicating their good potential as filter materials. Therefore, in this study, the use of PTFE membranes for the fabrication of automobile filters and the filtration performance of the filters were examined. To this end, first, the properties of PTFE membranes mainly used in HEPA air conditioning filters and those of membranes used as vehicle cabin filters were compared. Next, the thickness, weight, stiffness, pore size, and filtration performance characteristics of filter media fabricated by blending melt-blown (MB) nonwoven, PTFE membranes, and supporting nonwoven into a total filtration layer were compared and analyzed. Lastly, the environmental change durability performance of the automobile cabin filter based on PTFE membrane and the results of the test after the installation of the filter in a vehicle were demonstrated.

CapCAM: A Multilevel Capacitive Content Addressable Memory for High-Accuracy and High-Scalability Search and Compute Applications

As one type of associative memory, content-addressable memory (CAM) has become a critical component in several applications, including caches, routers, and pattern matching. Compared with the conventional CAM that could only deliver a “matched or not-matched” result, emerging multilevel CAM (ML-CAM) is capable of delivering “the degree of match” with multilevel distance calculation. This feature has been desired in applications that need beyond-Boolean matching results. However, existing ML-CAM designs are limited by the bit-cell device discharging current mismatch and vulnerability to the timing of sensing operations for distance calculation. This inherent constraint makes it difficult to further improve the accuracy and scalability toward higher accuracy and higher dimension matching. In this work, we propose CapCAM, a multilevel Capacitive Content Addressable Memory. It could be implemented based on either static random-access memory (SRAM) or emerging technologies, e.g., the ferroelectric field-effect transistor (FeFET). CapCAM could provide linear and stable voltage drop scaled by the match degree and need no strict timing for result sensing, which embraces the high-accuracy and high-scalability search. The inherent enabler of CapCAM is the charge-domain computing mechanism. This article will present the basic concept, operating mechanisms, detailed circuit designs, and circuit-level simulations of CapCAM. Besides, we apply CapCAM to few-shot learning applications and compare CapCAM with the current-domain TCAM designs. Results show 99.2% accuracy for a five-way five-shot classification task with our proposed CapCAM design while considering 1-fF capacitors, 20-domain FeFETs, and 256 columns. In contrast, the prior work based on discharging dynamics requires strict timing controls and suffers from accuracy degradation under the same configuration, which demonstrates CapCAM’s capability of low-power, accurate, and scalable multilevel CAM (ML-CAM) computing.

Aqueous Prostaglandin Eye Drop Formulations.

Glaucoma is one of the leading causes of irreversible blindness worldwide. It is characterized by progressive optic neuropathy in association with damage to the optic nerve head and, subsequently, visual loss if it is left untreated. Among the drug classes used for the long-term treatment of open-angle glaucoma, prostaglandin analogues (PGAs) are the first-line treatment and are available as marketed eye drop formulations for intraocular pressure (IOP) reduction by increasing the trabecular and uveoscleral outflow. PGAs have low aqueous solubility and are very unstable (i.e., hydrolysis) in aqueous solutions, which may hamper their ocular bioavailability and decrease their chemical stability. Additionally, treatment with PGA in conventional eye drops is associated with adverse effects, such as conjunctival hyperemia and trichiasis. It has been a very challenging for formulation scientists to develop stable aqueous eye drop formulations that increase the PGAs’ solubility and enhance their therapeutic efficacy while simultaneously lowering their ocular side effects. Here the physiochemical properties and chemical stabilities of the commercially available PGAs are reviewed, and the compositions of their eye drop formulations are discussed. Furthermore, the novel PGA formulations for glaucoma treatment are reviewed.

Radiotherapy activity in the COVID 19 pandemic: Brazil's operational national-level study

PurposeDuring the COVID-19 pandemic, patients with cancer are at increased risk of not having timely diagnosis and access to cancer treatment. The present study evaluated the COVID-19 pandemic impact on radiotherapy activity in Brazil. MethodsA national-level study was performed to evaluate the RT utilization for prostate, breast, head & neck (HN), Gynecology (GYN), Gastrointestinal (GI), lung cancers, and bone/brain metastases. The data on the RT executed was extracted from the Brazilian Ministry of Health database. The NON-COVID period was considered the control group, and the comparison groups were COVID-2020 (without vaccine) and COVID-2021 (with vaccine). ResultsWe collected the data of 238,355 procedures executed on three periods. Significant difference in the RT utilization between NON-COVID and COVID-2020 were observed for prostate cancer, bone and brain metastases (−12.3 %, p = 0.02, +24 %, p = 0.02 and +14 %, p = 0.04, respectively). Comparing 2 equivalents months from NON-COVID-2019 (ref), COVID-2020, and COVID-2021, a significant increase was identified for bone and brain metastases (2020 +21 %, and 2021 +32 %), and (2020 +20 %, and 2021 +14 %). A stable drop occurred for prostate cancer (2020 −11 % and 2021 −10 %), and a variation was observed for breast (2020 +8 %, and 2021 −1 %) and lung cancer (2020 +10 %, and 2021 −3 %). For other cancers, non-significant changes were observed when comparing 2020 and 2021. ConclusionThe RT activity was heterogeneously affected with a substantial increase for bone and brain metastases and a meaningful decline for prostate cancer. Policy summaryWith a significant increase in the use of palliative radiotherapy for bone and brain metastases and a meaningful reduction in curative radiotherapy for prostate cancer, we hope these findings can help governments, RT services, medical communities, and other stakeholders develop strategies to mitigate the impact of the present and future pandemics. Finally, despite the changes imposed by the COVID pandemic, it is imperative to enhance screening, increase cancer diagnosis at an early stage, and improve access to all cancer treatments, including radiotherapy.

A system of real-time neural recording and stimulation and its potential application in blood pressure modulation.

Hypertension is one of the most prevalent chronic diseases that affects more than 20% of the adult population worldwide, but fortunately, most of their blood pressure can be effectively controlled via drug treatment. However, there still remains 5–30% of patients clinically who do not respond well to conventional medication, while the non-drug treatments currently existing are struggling with major drawbacks like irreversible nerve damage, huge side effects, and even non-effectiveness. In this study, based on the physiological regulation mechanism of blood pressure and state-of-the-art neuromodulation technique, we worked along with the vagus nerve stimulation scheme, developed, and explored whether and how a real-time neural recording and stimulation system could provide an insight into self-adaptive modulation in the blood pressure, in the hope to crack a crevice in the closed-loop treatment for resistant hypertension. Unlike traditional neuromodulation devices, additional signal recording and real-time wireless transmission functions are added to the same device to realize the features of a dynamic monitor and modulator. The system is tested both in vitro and in vivo, showing decent electrical performance of 8 kHz sampling rate and flexible stimulation outputs which sufficiently covers our needs in manipulating neural activities of interest. A relatively stable drop in the blood pressure resulting from stimulation was observed and specific patterns in the vagus nerve signals relating to blood pressure could also be primarily identified. This laid a solid foundation for further studies on the final realization of closed-loop automatic adjustment for resistive hypertension treatment.

Deep eutectic solvents-based headspace single-drop microextraction for the chromatographic determination of phenols and aliphatic alcohols in atmospheric air

In this work, the possibility for gas chromatography determination of volatile organic compounds in atmospheric air with preliminary microextraction into single drop of a deep eutectic solvent is presented for the first time. Highly toxic compounds (phenol, o-cresol) and aliphatic alcohols (methanol, n-butanol, n-pentanol) were selected as analytes for which low MPCs in the atmospheric air were established. A eutectic mixture of natural, environmentally friendly substances menthol and thymol was used as an extractant. The resulting eutectic solvent forms a stable drop that allows the rapid extraction of analytes from the gas phase. 30 min of sampling is enough to achieve sensitivity at the level of maximum permissible concentrations of these analytes in atmospheric air. At the same time, the volatility of the components of the eutectic compound themselves made it possible to introduce this solvent directly into the gas chromatograph without dilution. The developed procedure was used to analyze real air samples and standard gas mixtures. The limits of detection for analytes were in the range 0.001–0.01 mg L−1. The RSD for all analytes was <5 %. This sample preparation method can be easily and efficiently combined with subsequent chromatographic detection.