Strain-stiffening properties derived from biological tissue have been widely observed in biological hydrogels and are essential in mimicking natural tissues. Although strain-stiffening has been studied in various protein-based hydrogels, effective approaches for tuning the strain-stiffening properties of protein hydrogels have rarely been explored. Here, we demonstrated a new method to tune the strain-stiffening amplitudes of protein hydrogels. By adjusting the surface charge of proteins inside the hydrogel using negatively/positively charged molecules, the strain-stiffening amplitudes could be quantitively regulated. The strain-stiffening of the protein hydrogels could even be enhanced 5-fold under high deformations, while the bulk property, recovery ability and biocompatibility remained almost unchanged. The tuning of strain-stiffening amplitudes using different molecules or in different protein hydrogels was further proved to be feasible. We anticipate that surface charge adjustment of proteins in hydrogels represents a general principle to tune the strain-stiffening property and can find wide applications in regulating the mechanical behaviors of protein-based hydrogels. Strain-stiffening behaviors are normally observed in natural soft tissues and are defined as an increase in stiffness under applied strains, thus protecting the system from large deformations ,2. StraiMoment by moment, our articular cartilage bears the great load brought by daily exercise. Articular cartilage is a matrix exquisitely weaved by collagen and proteoglycans and embedded with chondrocytes, which would especially benefit strain-stiffening behaviors under deformations . Due to Inspired by the electrorepulsive interaction in highly stress-tolerant cartilage, we demonstrated a new method to tune the strain-stiffening properties of protein-based hydrogels without affecting hydrogel networks. By adjusting the surface charge of BSA using charged molecules, the strain-stiffening could be tuned while the bulk property, microstructure and recovery ability were barely affected. Furthermore, this method of tuning strain-stiffening was demonstrated to be feasible using different molecules or applicable for different protein hydrogels. Finally, the outstanding biocompatibility of protein hydrogels was also proved to be unchanged. We expect that the surface charge modification of proteins in hydrogels can be widely applied to tune the strain-stiffening behaviors without affecting the bulk properties and biocompatibilities.As shown in −3. Obviously, the hydrogel exhibited relatively higher mechanical strength at BSA and PEG concentrations of 10 mM and 5 mM, indicating the optimized hydrogel network . However, the reason for the decrease of zeta potential at high glyoxylic acid concentrations remains unknown, and needs to investigated in the future.To investigate the effects of surface charge modification on the structure of BSA, modified BSA was studied using circular dichroism (CD) spectroscopy and thiol detection. As shown in Next, the mechanical properties of BSA-PEG hydrogels with BSA surface charge modified by glyoxylic acid were studied in detail by compression tests. The typical stress–strain curves corresponding to modified and unmodified hydrogels almost overlapped in the region of low strains (<10%), indicating the mild effects of BSA modification on hydrogels under small deformations A. The neThe stress–strain curves for the compression–relaxation cycle at the strain of 50% for hydrogels modified with different ratios of glyoxylic acid and BSA are shown in The mechanical properties of hydrogels prepared using the modified BSA were also evaluated for comparison, and similar results to those of the hydrogels modified after the gelation were observed . The incFurthermore, the recovery properties of the hydrogels were investigated by applying compression and relaxation cycles to the same hydrogel without any waiting time E. The noTo demonstrate the universality of tuning the strain-stiffening property of protein hydrogels by charge modification, BSA-PEG hydrogels modified using bromoacetic acid and hemoglobin-PEG hydrogels modified with glyoxylic acid were also studied. For BSA-PEG hydrogels modified with bromoacetic acid, the strain-stiffening property was also significantly enhanced, with the porosity, swelling ratios and pore size remaining unchanged . The difMoreover, the mechanical properties of the hemoglobin-PEG hydrogels modified with glyoxylic acid are shown in Finally, the cytotoxicity of BSA-PEG hydrogels modified with glyoxylic acid was studied, since protein-based hydrogels are widely used in cell culture, drug release and tissue engineering. Human high-metastatic liver cancer cells 97H (MHCC-97H) and kidney-2 cells (HK-2) were chosen to be cultured on hydrogels modified at different ratios of glyoxylic acid and BSA. After being cultured for 48 h, the cells were stained using calcein-AM and propidium iodide (PI). As shown in 2O was produced by a Milli-Q® integral water purification system . All other chemical reagents, unless otherwise stated, were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. . All reagents were used without further purification.Materials: BSA and hemoglobin were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. . Succinimidyl glutamate-terminated 4-armed polyethylene glycol (M.W. = 20 kDa) (4-armed PEG-SG) was purchased from Sinopeg Co., Ltd. . Glyoxylic acid, bromoacetic acid, and DTNB were purchased from Shanghai Sigma–Aldrich Co., Ltd. . ddH2O for 48 h to remove the unreacted molecules and lyophilized. The modification of BSA using bromoacetic acid and the modification of hemoglobin using glyoxylic acid were achieved using the same methods.Surface charge modification of proteins: For the modification of BSA using glyoxylic acid, glyoxylic acid was dissolved in BSA solutions to different concentrations (0–3.6 mM). Then, the solutions were stirred for more than 24 h at room temperature. The mixtures were dialyzed in ddH2O to 15 μM, and then the suspension solutions were measured using a Zetasizer Nano ZS . The same protein solutions were measured at least three times to guarantee reproducibility.Measurement of zeta potentials: Different proteins were dissolved in ddHUV-Vis spectroscopy: UV-Vis spectra of all samples were recorded using a V-550  spectrophotometer. The cuvette width was 1 cm, and the bandwidth was 0.2 nm.2O to concentrations of 20 mM and 10 mM, respectively. Then, the two kinds of solutions were quickly mixed at a volume ratio of 1:1. Transparent BSA-PEG hydrogels formed minutes after mixing. Then, the hydrogels were dialyzed in ddH2O for 24 h to remove the unreacted BSA and PEG. For the charge modification of the BSA-PEG hydrogels, BSA-PEG hydrogels were prepared as described above and immersed in glyoxylic acid solutions with varying proportions for more than 24 h. Finally, the hydrogels were dialyzed in ddH2O for 24 h to remove the unreacted glyoxylic acid. The modification of BSA-PEG hydrogels using bromoacetic acid and the modification of hemoglobin-PEG hydrogels using glyoxylic acid were achieved using the same methods. The preparation and modification of hemoglobin-PEG hydrogels were achieved using the same method as described above. The concentrations of hemoglobin and 4-armed PEG-SG were 1.5 and 5 mM, respectively. For the preparation of the hydrogels using modified protein, BSA was modified using glyoxylic acid as previously described before gelation.Preparation and charge modification of the BSA-PEG and hemoglobin-PEG hydrogels: four-armed PEG-SG and BSA were dissolved in ddHScanning electron microscope (SEM) imaging: SEM images were obtained using a Quanta Scanning Electron Microscope  at 20 kV. The hydrogels were lyophilized and coated with Pt prior to the measurement. More than 3 samples of each hydrogel were used in the SEM imaging and more than 4 images were randomly taken for each sample. The meshes were marked with ImageJ and the size was measured according to the image scale.Thiol detection using 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB): The unfolding of BSA was characterized by detecting the exposed thiol in the proteins. Typically, hydrogels were prepared as described above and soaked in deionized water for 24 h. DTNB was then diluted into the solution, and the concentration of the reaction product of thiol and DTNB, 3-carboxy-4-nitrophenyl disulfide, was monitored by monitoring the UV absorbance at 412 nm.2O to a concentration of 1.5 μM. Then, CD spectra of all samples were recorded using a J-815  spectrophotometer. The cuvette width was 1 cm, and the bandwidth was 0.2 nm.Circular Dichroism Spectra (CD): Typically, modified BSA was suspended in ddH−1 with respect to the original height of the hydrogel, roughly in the range of 1.6–2.0 mm min−1. In the compression–relaxation cycle test, the rate of compression was also kept constant at 20% min−1 with respect to the original height of the hydrogel. The mechanical recovery percentage of each cycle was caudated as the highest stress in the current cycles divided by the highest stress in the first cycles. The fracture energy (fE) was measured based on the force-distance curves of the hydrogels that were compressed until fracture. The stress (σ) was calculated as the compression force divided by the cross-section area. fE was calculated by the integration of the area below the compression force-distance curves until the fracture point. The equation used in the calculation was as follows: x0 and fx correspond to the starting distance and the fracture distance of the compression, respectively. The Young’s modulus was the approximate linear fitting value of the stress–strain curve in the strain range of ~10%. The differential moduli were calculated as the slope of the stress–strain curve.Compressive test: The compressive stress–strain measurements were performed using a tensile-compressive tester (Instron-5944 with a 2 kN sensor) in air. In the compression–crack test, the rate of compression was kept constant at 20% minIn summary, we demonstrated a universal method to tune the strain-stiffening property of protein-based hydrogels. By modifying the surface charge of the protein in BSA-PEG hydrogels, compressive strain-stiffening was significantly enhanced, while the bulk property, microstructure and recovery property remained unchanged. Due to the enhanced electrorepulsive interactions, the differential modulus of the modified BSA-PEG hydrogels increased by more than 3300% in the strain range of 0–60%, significantly higher than the ~1100% of the unmodified hydrogels. Furthermore, enhancements and weakening of strain stiffening were observed in BSA-PEG hydrogels modified using bromoacetic acid and hemoglobin-PEG hydrogels modified using glyoxylic acid, demonstrating the universal feasibility of charge modification on the regulation of the strain-stiffening property. We anticipate that this new method can be widely applied to independently tune the strain-stiffening performance of protein hydrogels without affecting the bulk properties, microstructures and biocompatibility.


Aortic pulse wave velocity (PWV) enables the direct assessment of aortic stiffness, which is an independent risk factor of cardiovascular (CV) events. The aim of this study is to evaluate the association between aortic PWV and CV risk model classified into three groups based on the Framingham risk score (FRS), i.e., low-risk (<10%), intermediate-risk (10~20%) and high-risk (>20%).To noninvasively estimate local PWV in an abdominal aorta, a high-spatiotemporal resolution PWV measurement method (>1 kHz) based on wide field-of-view ultrafast curved array imaging (ufcPWV) is proposed. In the ufcPWV measurement, a new aortic wall motion tracking algorithm based on adaptive reference frame update is performed to compensate errors from temporally accumulated out-of-plane motion. In addition, an aortic pressure waveform is simultaneously measured by applanation tonometry, and a theoretical PWV based on the Bramwell-Hill model (bhPWV) is derived. A total of 69 subjects (aged 23–86 years) according to the CV risk model were enrolled and examined with abdominal ultrasound scan.r = 0.847, p < 0.01), and it showed a statistically significant difference between low- and intermediate-risk groups , and low- and high-risk groups  while there is no significant difference between intermediate- and high-risk groups . Moreover, it showed a significant difference between two evaluation groups [low- (<10%) vs. higher-risk group (≥10%)]  when the intermediate- and high-risk groups were merged into a higher-risk group.The ufcPWV was significantly correlated with bhPWV (This feasibility study based on CV risk model demonstrated that the aortic ufcPWV measurement has the potential to be a new approach to overcome the limitations of conventional systemic measurement methods in the assessment of aortic stiffness. The elasticity of proximal large arteries is determined by a high elastin to collagen ratio, and the increase in arterial stiffness is mostly caused by the progressive elastic fiber degeneration , 2. The The PWV is defined by the speed at which a forward pressure wave is transmitted from the aorta through the vascular tree. To estimate PWV , the propagating distance and the time of the arterial waveform passing between the two sites are measured, and the carotid-femoral PWV is currently being regarded as the gold standard method –10. HoweCardiovascular magnetic resonance (CMR) based PWV assessment substantially reduces errors by using accurate aortic length and transit times between flow waves , 14. DopFrom the previous studies, a local PWV measurement technique based on high spatiotemporal resolution is strongly required, and the ultrafast PWV measurement for aortic segments in human abdomen are still rarely studied due to low accessibility and technical limitations, such as a deep and wide field-of-view (FOV). Here, we propose a high spatiotemporal resolution aortic PWV measurement method based on wide FOV ultrafast curved array imaging  using di2).The CV risk model was classified into three groups based on the Framingham risk score (FRS), i.e., low-risk (<10%), intermediate-risk (10~20%) and high-risk (>20%). The study was approved by the Institutional Review Board of the Clinical Trials Center of Yonsei University Health System, and the written informed consent was obtained from all patients. 31 patients for each risk group  were recruited, but a few patients in the intermediate- and high-risk groups were excluded due to the poor image quality or incomplete scanning of the abdominal aorta. The study population's characteristics of the remaining 69 patients were presented in To assess pulse wave velocities (PWVs) in aortas, the recently proposed ultrafast curved array imaging technique , which pFor PWV measurements, vessel wall motion tracking (speckle correlation) is usually conducted, and the selection of a reference frame is crucial to accurately estimate arterial wall motion. In addition, the out-of-phase motion or unexpected noise may disrupt highly accurate motion estimation, and the unwanted errors  are typically accumulated with a common fixed reference or interframe-based motion estimation methods –33. As iBased on the ultrafast curved array imaging and ARFD-based speckle correlation algorithm, the aortic ultrafast PWV (ufcPWV) imaging and measurement was conducted. To do this, a high-spatiotemporal resolution pulse wave-induced wall displacement was estimated. Anterior or posterior vessel wall segmentation was first performed, and the distance of the vessel wall was calculated. Then, the wall velocity waveform was derived from the estimated displacement using a 9-point Savitzky-Golay digital differentiator for the temporal derivative . TherefoTo investigate the association and agreement between the direct PWV measurement (ufcPWV) and theoretical PWVs derived from arterial distensibility, a local aortic PWV was obtained with the Bramwell-Hill equation (bhPWV) . The BraAd is the cross-sectional area in diastole, and A is the difference of the cross-sectional area between systole and diastole in the cardiac cycle. To measure the cross-sectional area of aortic vessel, the envelope image in the transversal view was utilized and the diameter was calculated assuming a circular shape. ρ is the blood density (1060 kg/m3), and PP is the local pulse pressure. To noninvasively measure the local PP in aorta, the arterial applanation tonometry  was performed and the central blood pressure waveform was obtained.where n = 31) and higher-risk ]. The signal and image processing were externally conducted with MATLAB R2019b . The coefficient of determination (r2) in linear regression was evaluated to indicate the reliability of PWV calculation .Data from a total of 69 patients were processed, and a statistical analysis was performed to examine differences between each risk groups. The initial three evaluation groups were further classified into two evaluation groups by merging the intermediate- and the high-risk groups into a higher-risk group [i.e., low-risk . Th. Thn = 3n = 69). As illustrated in r = 0.85, p < 0.01). The association between the ufcPWV and the bhPWV was evaluated for all subjects (n = 31), intermediate- (n = 22) and high-risk (n = 16); p < 0.01), low- and high-risk groups  and intermediate- and high-risk group , respectively, as illustrated in p < 0.01), and low- and high-risk groups  while there is no significant difference between intermediate- and high-risk group .In the analysis of the three evaluation groups (low- (n = 31) and the higher-risk group , were analyzed in the same manner. p < 0.01) and the ufcPWV measurements .To further analyze the differences between the CV risk models, two modified evaluation groups consisting of the low-risk group  as described in A significant correlation was found between the ufcPWV and FRS (n = 69), and it showed a significant correlation  between the two clinical parameters. To further analyze the association according to the CV risk model, systolic blood pressures for the three evaluation groups were respectively evaluated. As shown in r = 0.47 and r = 0.45, all p < 0.05) while the low-risk group showed no significant association .The relation of ufcPWV to systolic blood pressure , which iPulse waves are propagated through arteries, and PWV is affected by the mechanical properties in the pathological process of arterial wall changes along the arterial system. Therefore, PWV is not constant and varies from one location to another since the geometrical and mechanical properties vary along the arterial tree, and there are differences between central elastic arteries and more peripheral, muscular arteries. For these reasons, the importance of measuring local PWV is increasing in contrast to measuring systemic PWV, which can only be estimated an averaged PWV. For example, aortic PWV, which is one of the most reliable clinical parameters for evaluating arterial stiffness, has been generally measured in two different sites . The carotid-femoral PWV measurement is currently accepted as the gold-standard technique for arterial stiffness assessments. For carotid-femoral PWV measurements, several tonometry techniques based on pressure sensors with ECG gating  have been widely used in research and clinical settings . HoweverA major advantage of the local measurement of PWV is that a direct measurement of local vessels is strongly related to wall stiffness. In the early stage of arterial stiffness, the elastic properties are affected by locally scattered fibrous spots on the arterial wall, and the heterogeneous structure of arterial walls at different sites produces different functional properties between vessel segments. Regarding strongly localized wall heterogeneity, arterial wall mechanical properties can be dramatically altered within a small region (from a few millimeters to a few centimeters), e.g., abdominal aortic aneurysms or arterial plaques. However, the most current PWV measurements  cannot assess biomechanical properties in local vessels, and they cannot directly evaluate the arterial stiffness of vessel segments due to the accessibility and the limited temporal resolution of the techniques. The temporal resolution  is the most significant technical factor in the PWV measurements. To properly snapshot the accelerated pulse wave (5~10 m/s), data acquisition rates must be increased relative to the PWV. However, the accuracy and reliability of the PWV measurement approaches usually suffer from an inherent technical tradeoff between spatial resolution  and temporal resolution (frame rate). Inaccurate measurements imposed by frame-rate limitations can increase errors as the PWV increases by arterial stiffening. Therefore, a high-frame-rate-based accurate PWV measurement technique is still required.The FRS, which estimates the 10-year CV risk of an individual, is calculated based on a variety of risk factors such as age, smoking history, diabetes mellitus, systolic blood pressure, HDL-C concentration. The FRS is considered as a useful tool for quantitative assessment of the risk for CV disease in the general populations , 41–43 aIn this article, we investigated the association between the Framingham risk model classified with FRS and aortic PWV. To measure local PWV in a specific aortic segment  with high spatiotemporal resolution (>1 kHz), wide field-of-view ultrafast curved array imaging based PWV measurement method (ufcPWV) was proposed . In the The association between aortic PWV and systolic blood pressure among the clinical parameters  was addin = 9) and the high-risk (n = 15) groups  groups  were excFor the future PWV measurements, relatively inexpensive techniques with fewer approximations, leading to an accurate evaluation, will be needed for the more efficient diagnostic tool in detecting CV diseases in early stages. In addition, highly accurate PWV measurements and direct arterial stiffness assessments may also improve the management of the process of CV risks or the monitoring of therapy in patients with conditions such as isolated systolic hypertension. In future work, aortic PWVs in different segmental regions  will be measured and evaluated in various clinical settings .In this paper, a high-spatiotemporal resolution aortic PWV measurement method based on ultrafast curved array imaging (ufcPWV) was proposed and it showed the association with Framingham risk model. This feasibility study demonstrated that the ufcPWV measurement has the potential to be a new approach to overcome the limitations of conventional systemic measurement methods in the assessment of aortic stiffness.The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.The studies involving human participants were reviewed and approved by Institutional Review Board of the Clinical Trials Center of Yonsei University Health System (IRB number: 1-2019-0065). The patients/participants provided their written informed consent to participate in this study.the in vivo study. JH and G-RH designed the clinical study protocol and obtained data from patients. G-RH and YY supervised the study. JK, G-RH, and YY wrote the manuscript. All authors contributed to the article and approved the submitted version.JK and KH performed the theoretical and experimental analyses and implementation of This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (NRF-2021R1A2C3006264) and the Korea Medical Device Development Fund grant funded by the Korea government  (Project Number: 202011A01).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Gravity waves play essential roles in the terrestrial atmosphere because they propagate far from source regions and transport momentum and energy globally. Gravity waves are also observed in the Venus atmosphere, but their characteristics have been poorly understood. Here we demonstrate activities of small-scale gravity waves using a high-resolution Venus general circulation model with less than 20 and 0.25 km in the horizontal and vertical grid intervals, respectively. We find spontaneous gravity wave radiation from nearly balanced flows. In the upper cloud layer (~70 km), the thermal tides in the super-rotation are primary sources of small-scale gravity waves in the low-latitudes. Baroclinic/barotropic waves are also essential sources in the mid- and high-latitudes. The small-scale gravity waves affect the three-dimensional structure of the super-rotation and contribute to material mixing through their breaking processes. They propagate vertically and transport momentum globally, which decelerates the super-rotation in the upper cloud layer (~70 km) and accelerates it above ~80 km. Gravity waves are observed in Venus atmosphere, but their characteristics are not well-known. Here, the authors show spontaneous generation of gravity waves from the thermal tides in the Venus atmosphere as small-scale gravity waves are resolved in high-resolution general circulation model. The non-orographic gravity waves are also generated spontaneously from jet/front systems2, although the large-scale motions are almost balanced4. Since small-scale gravity waves appear at jet-exit regions, they are often called Jet-Exit Region Emitted (JEREmi) waves2. The spontaneous generation of gravity waves for the terrestrial atmosphere has traditionally been investigated in horizontally two-dimensional shallow water system7 , and extended to three-dimensional models9. Theoretically, two mechanisms are possible to explain small-scale JEREmi waves10. One is the velocity-variation mechanism in which strong divergence/convergence of the flow generates vertical motions, which lead to gravity waves. The other is the mountain-wave-like mechanism in which the deformation of isentropic surfaces acts as a mountain; the flow over isentropic surfaces produces upward/downward motions of gravity waves.In the terrestrial atmosphere, gravity waves generated in the troposphere—most of which are orographically forced waves and non-orographic waves associated with convection—drive the general circulation of the middle atmosphere11. It has been suggested using idealistic vertical convection models that the gravity waves could be generated by convective motions in the cloud layer14, and by cloud feedback radiative heating15. Radio occultation measurements of the Venus Express16 and Akatsuki observed temperature perturbations, indicating gravity waves with vertical wavelengths less than 4 km. While these temperature perturbations are eminent around the cloud layer (~60 km), their magnitudes decrease around the cloud-top (~70 km) and increase above the cloud-top (~80 km), suggesting another source of gravity waves other than the cloud layer convection or cloud feedback radiative heating. Visible and Infra-red Thermal Imaging Spectrometer-Mapper (VIRTIS-M) onboard the Venus Express also suggested that small-scale gravity waves with horizontal wavelengths in the range of 90–400 km exist in the upper atmosphere in the range of 110–140 km altitudes17. Further, at the cloud tops (62–70 km), many types of small-scale gravity wave whose horizontal wavelengths are tens of kilometres were observed by the Venus Monitoring Camera19 (VMC) and VIRTIS-M20 onboard the Venus Express. Following the experiences on the terrestrial atmosphere, possible effects of those gravity waves have also been incorporated as parameterised schemes in general circulation models (GCMs) for the Venus thermosphere22. Nevertheless, the characteristics of gravity waves in the Venus atmosphere, such as their generation, propagation, and geographical distribution are poorly understood. Especially, the spontaneous gravity wave radiation from the super-rotation has not been investigated because the resolutions of the typical Venus GCMs so far have been, for instance, around T10 or T2123 , which is insufficient to resolve the abovementioned issues. Recently, it has been highlighted that the medium-scale gravity waves appear in moderate resolution Venus GCMs25 . However, the details remain unclear due to the lack of resolution in previous studies.The gravity waves are also expected to play essential roles in the Venus atmosphere26 and named AFES-Venus for a Venus version of AFES. Starting from an idealised super-rotating flow, AFES-Venus reproduced baroclinic waves27, the super-rotation with planetary-scale waves28 and thermal tides29 under the realistic distributions of solar heating and static stability, polar and equatorial temperature distributions consistent with observation31 and planetary-scale streak structure32.Recently, we developed a Venus GCM modified from an Atmospheric GCM optimised For the Earth Simulator (AFES)34, on small-scale gravity waves is examined by conducting two experiments with and without the thermal tides. The atmospheric motions are driven by the solar heating with and without the diurnal component in the nominal and Qz  cases, respectively. Since the thermal tides are excited by the diurnal component of the solar heating36, they are excluded in the Qz case. Our main goal is to demonstrate that gravity waves are spontaneously radiated from the thermal tides in the super-rotation and their activities in the atmosphere are not small.In this study, we resolve small-scale gravity waves and investigate the spontaneous gravity wave radiation in high-resolution simulations of AFES-Venus. The impact of thermal tides, which significantly affects the super-rotation−1 and with weak mid-latitude jets at the cloud-top (~70 km) level reached a quasi-equilibrium state, which was similar to those reported in previous Venus GCM studies25. For Qz, because equatorward momentum transport due to the thermal tides disappeared, the equatorial wind speed decreased and the mid-latitudes jets were intensified near the cloud-top compared with the nominal case , Ek and Ep for the nominal and Qz cases, respectively.The vertical structure of TWE obtained for the nominal case Fig.  also ind10 at jet-exit regions  seemed to work in the present results. The former was expected in regions close to the local minimum of zonal flow , is frequently used as a diagnostic tool to detect the source of spontaneous gravity waves radiation; it is given by40. Although it is difficult to compute Eq.  observed by radio occultation measurements of the Venus Express16 and Akatsuki are comparable to those in this study. Although it has been argued that these gravity waves are generated by cloud layer convection14 and cloud feedback radiative heating15, our result strongly suggested that spontaneous generation from the thermal tides and baroclinic/barotropic waves is also one of the important sources. It was also suggested by the radio occultation measurements of the Venus Express that the amplitude of unsaturated gravity waves increases with height in the range of 75–90 km compared with 65–80 km46. Therefore, small-scale gravity waves in the upper atmosphere (110–140 km) observed by VIRTIS-M17 are possibly related to spontaneous generation. Since spontaneous generation produces small-scale gravity waves due to wave-capture mechanism47, especially for large-scale motions varying slowly in time, some small-scale gravity waves at the cloud-top (62–70 km) observed by VMC19 and VIRTIS-M20 may also be due to the present radiation processes.Several observations have suggested that the gravity waves appear in and above the cloud layer48. Contrary to the terrestrial atmosphere in geostrophic balance , it is expected that the spontaneous gravity wave generation from large-scale motions would be enhanced in the Venus atmosphere as in cases of large Rossby number9. Actually, the estimate of the Lagrangian Rossby number in the Venus atmosphere tended to be large compared with that in the terrestrial atmosphere. The gravity wave parameterisation in Venus GCMs should be improved in light of the spontaneous generation. Investigating the gravity waves generated by topography and convection, and quantifying the effects of gravity waves are crucial future works. More future observations such as radio occultation are also required to determine the source and statistical properties of gravity waves.Although the Venus rotation is slow (then the Coriolis parameter due to Venus rotation can be ignored), cyclostrophic balance  has been established in the super-rotation with stable stratification above the cloud layer27. So far, spontaneous gravity wave generation in the terrestrial atmosphere has mainly been investigated via hydrostatic models39, because it is unrelated to vertical convection and vertical shear instability. Therefore, we investigated small-scale gravity waves generated at jet-exit regions in the present GCM. The physical processes were simplified for Venus, and there was no topography. The horizontal resolution was T639 , which was the highest resolution in GCM simulations of the Venus atmosphere and probably close to the limit of hydrostatic approximation. Note that vertical convection, which, if any, was supposed to be substituted by the dry convective adjustment scheme, possibly began to be explicitly represented in the present model. The atmosphere from the ground to ~120 km was divided into 260 levels in height at non-uniform spacing. The vertical intervals were less than 0.25 km around the cloud layer from 50 to 90 km. The vertical and horizontal eddy diffusion was used in the model. The vertical eddy viscosity coefficient was set to 0.15 m2 s−1, and the second-order hyper-viscosity  harmonics, with zonal wave 1 and 2 structures, were excited by the diurnally-varying component of the solar heating . In addition, we performed a simulation without thermal tides by excluding the diurnal component of the solar heating (Qz case) to elucidate the effect of thermal tides on small-scale gravity waves. We used Newtonian cooling for the infra-red radiative process; relaxation time was chosen by the work50 and relaxation field is a horizontally uniform temperature prepared by Venus international reference atmosphere (VIRA)51. Note that an equator–pole thermal contrast is produced by the solar heating in both the nominal and Qz cases.The atmosphere is driven by the prescribed solar heating based on observations−1 and was constant afterward. The vertical profile of the initial temperature, which included a weakly stratified layer observed in the ranges of 55–60 km52, was produced by VIRA. The latitudinal distribution of the initial temperature was prepared to be in gradient wind balance with this idealised super-rotating flow. With this initial state, nonlinear numerical simulations were performed for 4 Earth years with T159L260. The simulations were extended for 1 Earth year with T319L260, and 0.5 Earth years with T639L260 to spin up and obtain quasi-equilibrium steady states. We analysed the data for 30 Earth days sampled every Earth day. We set the directions of planetary rotation and basic zonal flow to be eastward (positive).An idealised super-rotating flow in solid-body rotation was used for the initial condition. At the equator, zonal velocity increased linearly with height from the ground to 70 km up to 100 m sSupplementary InformationPeer Review FileDescription of Additional Supplementary FilesSupplementary Movie 1Supplementary Movie 2Supplementary Movie 3Supplementary Movie 4


The coronavirus disease 2019 (COVID-19) has become a serious global health issue, especially for people with pre-existing health conditions. Patients dealing with asthma are presumed to be at higher risk as COVID-19 may cause severe respiratory distress.From the initial stage of the pandemic, several clinical trials and studies have assessed the association between COVID-19 and asthma; however, no significant association was reported. This may be due to the fact that most of the asthma cases remained undiagnosed and overlapping respiratory features make it difficult to differentiate between these two diseases. The pathomechanism of the conditions and the immune response generated in response to the conditions suggest that the presence of any of the conditions is very likely to influence the presence or severity of the other condition. So far, no specific treatments are known for COVID-19; however, the use of plasma therapy and broad-spectrum antiviral drugs during the initial phase of the pandemic and widespread vaccination during the latter phase has given positive outcomes in reducing COVID-19 cases as well as disease severity.Taking asthma as an increased risk factor for COVID-19 morbidity, this article aims to provide comprehensive insights into the risk and proper management of asthma patients during this COVID-19 pandemic. The common medications of asthma patients suppress their respiratory immune response that might facilitate cytokine storm in COVID-19 patients. Similarly, there are risks of viral-induced asthma exacerbations. Besides, different social issues such as shortage of medicines, SDOH, and delayed clinical trials put asthma patients through inconvenience. The primary focus at this point should be to reduce probable asthma attacks and severity to prevent hospitalization of asthma patients. Moreover, for better management of asthma patients maintaining an asthma action plan and healthy lifestyle, ensuring a nutritious diet, and developing self-management interventions can play a crucial role. The pandemic coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has become a serious public health issue all over the world .–27.24–27Proper understanding of distinct clinical features of COVID-19 and asthma is crucial to avoid any misinterpretation and ensure an accurate diagnosis. Patients of both COVID-19 and asthma show overlapping features including coughing, fatigue, and shortness of breath, which makes diagnosis and proper management of both diseases quite challenging. However, literature studies reveal that some symptoms such as diarrhea, myalgia, loss of smell and taste, headache, and prolonged fever are the distinctive features of COVID-19 and are not evident in asthma. On the other hand, an asthma patient may experience wheezing, which is not evident in COVID-19. The comparative features of COVID-19 and asthma are presented in Table SARS-CoV-2 follows a lytic replication cycle and employs the host metabolic machinery to replicate itself. The virus invades human respiratory host cells in five steps: attachment, penetration, biosynthesis, maturation, and release Fig.  32, 33], 3332, 3SARS-CoV-2 enters the host cell using angiotensin-converting enzyme-2 (ACE-2) receptors, which are highly expressed in the apical mucosal membranes of the lung, kidney, heart, ileum, small intestine, and bladder of mammals . The virEvidence from severe COVID-19 patients suggests the mechanism of "cytokine storms" are due to exceptionally high levels of interleukin (IL)-1β, IL-1Rα, IL-7, IL-8, IL-9, IL-10, basic fibroblast growth factor (FGF), granulocyte-colony stimulating factor (G-CSF), granulocyte–macrophage colony-stimulating factor (GM-CSF), IFN-γ, interferon-γ-inducible protein (IP-10), monocyte chemo-attractant protein (MCP-1), macrophage inflammatory protein 1 alpha (MIP-1α), macrophage inflammatory protein 1 beta (MIP-1β), platelet-derived growth factor (PDGF), tumor necrosis factor (TNF-α), and vascular endothelial growth factor (VEGF) . CriticaThe application of new molecular and biological techniques allowed the evaluation of phenotypic aspects and complex interacting pathways in asthma, revealing a variety of factors incurring the recurrent airflow limitation of the condition .Bronchoconstriction is a prominent feature in asthma, which leads to the narrowing of the airway. Allergy-specific immunoglobulin E (IgE) reacts to stimuli like allergens and irritants, mediating the release of histamine, tryptase, prostaglandins, and leukotrienes that causes bronchoconstriction Fig. . Some noAsthma is mostly mediated by type-2 immune response comprising type-2 B cells, group 2 innate lymphoid cells, helper T cells, NK cells, basophils, eosinophils, mast cells, and NKT cells . EvidencBesides, mucosal mast cells in the airway are activated by the allergens. These immune cells release cytokines and other mediators to promote inflammation and acute bronchospasm. The severity of this situation correlates with an increased number of eosinophils, releasing a wide range of pro-inflammatory cytokine and inflammatory enzymes . HoweverNumerous studies have claimed that COVID-19 is not a significant threat to asthma patients, while some research has shown that asthma patients might be under increased risk of contracting COVID-19 . AccordiOn the contrary, several studies have debunked the idea of asthma patients being at increased risk during the COVID-19 pandemic. The prevalence of asthma patients with COVID-19 is most likely to be lower than expected from population levels based on the data from both USA and China . Data frMoreover, asthma is not listed in the top ten comorbid health conditions present in COVID-19 patients . Many ofAlthough there is mixed opinion on the impact of asthma in COVID-19, some of the reported results together with the previous SARS-CoV outbreak suggested that asthma may have a potential impact on the susceptibility and severity of COVID-19 due to the impaired immune response against viral infection in asthmatic patients . Since tAs of now, studies suggesting a probable association between asthma and ACE2 expression are insufficient; however, there are several studies on the impact of lessened ACE-2 expression in asthmatic COVID-19 patients. These studies suggested that the expression of ACE2 is most likely regulated reciprocally by IFN levels and type-2 cytokines in the blood, especially in allergic asthma . This coEosinophil plays a central role in asthma and has a potential role in antiviral host defense . A recenHuman coronaviruses can inhibit IFN signaling, a significant pathway to activate the host innate immune system . SeveralA significant dilemma for COPD patients is whether or not to continue consuming their regular prescribed asthma medications during the pandemic. Since SARS-CoV-2 is a respiratory virus, patients are concerned about their prescribed medicines .Nebulization therapy directly transfers drugs in the form of mists or droplets to the site of action in the lung, but a portion of this aerosol might return to the reservoir tube , increasThe National Institute for Health and Care Excellence (NICE) states that the fluid inside the nebulizer chamber will not have any virus particles from patients. Still, it is recommended to avoid the use of nebulizers and consider alternatives such as metered-dose inhalers (MDIs), dry powder inhalers (DPIs), or spacers. However, asthma patients with COVID-19 might be allowed to use a nebulizer under three conditions: (1) if they are suffering from life-threatening conditions; (2) if they have an inadequate response to the alternatives while using minimal oxygen flow rate to drive the nebulizer; and (3) if the patient is unable to manage alternatives other than nebulization .Inhaled corticosteroids (ICS) are the most effective and comprehensive asthma controllers. Even in low doses, the drug can suppress inflammation and reduce inflammation-mediated lung injury .There is much confusion regarding the use of ICS during this pandemic. Some studies have revealed that the use of ICS alone or in a combination of bronchodilators can have some positive impact on reducing viral infection . HoweverThere is some evidence of ICS being helpful, such as pretreatment of human respiratory epithelial cells with a combination of medications like glycopyrronium, formoterol, and budesonide may inhibit SARS-CoV-2 replication and reduce cytokine production , 78. A sBased on previous experiences with Influenza, SARS, and the MERS epidemic, organizations like WHO and CDC have recommended stopping the use of oral corticosteroids (OCS) to treat COVID-19 patients. It is highly suspected that the use of OCS can prolong viral replication, complicate viral clearance, increase the risks of ventilation, cause secondary infections, and raise mortality rates .Corticosteroid prednisone, a widespread recommended asthma medication, is not suspected to compromise the immune system or increase susceptibility to COVID-19 infection when used in a brief course. Thus, asthma patients without experiencing COVID-19 symptoms should continue to treat their exacerbations using the drug. However, if the patient is suspected of being infected by the virus, prednisone cannot be considered safe as it might prolong viral replication . Front lOn the other hand, a report by WHO shows dexamethasone, an OCS used for asthma and some other complications, can be lifesaving for severe COVID-19 patients. The WHO Director-General stated that it was the first treatment to be shown to reduce mortality in patients with COVID-19 using ventilation support .Biologics like anti-IgE and anti-IL5 monoclonal antibodies are very useful in reducing the frequency of asthma exacerbations. Studies including long-term follow-ups indicate no signs of the impaired immune system or increased risks of viral infection due to the use of these biologics . The useRecent studies have reported that blocking IgE can reduce the possibility of being infected by respiratory viruses because IgE is responsible for weakening anti-viral response in asthma patients. Besides, anti-IgE monoclonal antibodies can upregulate IFN-α signaling in dendritic cells and decrease viral infection duration along with levels of IL-33 that induce pro-inflammatory cytokines . All theAllergen immunotherapy (AIT) has been deemed as one of the best approaches to "personalized medicine" in allergic diseases . AIT canDuring the initial stage of the pandemic, programs established by FDA such as expanded access (EA) and emergency use authorization (EUA) allowed clinicians to gain access to investigational therapies to find any drug effective in reducing COVID-19 severity .Remdesivir, an inhibitor of the viral RNA-dependent RNA polymerase, was the most widely used drug to treat COVID-19 patients due to its promising outcome against the SARS-COV-1 and MERS-CoV –91. ClinChloroquine (CQ) and hydroxychloroquine (HCQ), two of the synthetic drugs used in the treatment of acute attacks of malaria, can inhibit glycosylation of the ACE-2 receptor and interrupt the binding of SARS-CoV-2 to the host cell . BesidesThe anti-inflammatory drug azithromycin has been widely evaluated for its efficacy against COVID-19 . The immThere is an ongoing debate regarding the possibility of worsening asthma symptoms while receiving the COVID-19 vaccines; however, no evidence to support such a hypothesis exists as of now. The effect of COVID-19 vaccination in asthma patients is entirely unexplored, raising concerns regarding the probable long-term effect such vaccines can induce in asthmatic patients. There are also concerns that asthma might increase the chances of allergic reaction to the COVID-19 vaccines; however, no such evidence has been found.The rates of allergic reactions to COVID-19 vaccines are extremely low and there is no evidence of asthma patients being more susceptible to such allergic reactions. As per a weekly report of CDC, among the recipients of the Pfizer vaccine, 11.1 out of 1 million doses reported the case of anaphylaxis, the most severe type of allergic reaction. The rate of Moderna-induced anaphylaxis was 2.5 per 1 million doses. Among the 8 million doses of the Janssen vaccine, 4 anaphylaxis cases could be reported , 102.Some studies have reported that mRNA vaccines are likely to induce IFN-1 production . HyperacAs of now, it is suggested that asthma patients should receive the full doses of COVID-19 vaccines if no significant side effect is reported after the first dose of the vaccine. According to the American College of Allergy, Asthma, and Immunology (ACAAI), even asthma patients prescribed with ICS or OCS must receive the vaccine if no severe side effect is reported .The current pandemic has severely affected the production and supply chain of medicine. Besides, stocking medicine much more than needed is creating artificial scarcity and increasing price . In someFinancial distress, physical environment, food and housing insecurity, and inability to access health care services, all these social determinants of health (SDOH) are being influenced due to the current pandemic situation. Especially for low-income families with no permanent job security or insurance benefits, it is difficult to maintain necessary physical distancing as there are concerns regarding food arrangements for the family. In such situations, taking care of an asthma patient becomes challenging, as they cannot afford to stockpile medicines or access telehealth programs . AlthougMedication adherence in asthma includes a variety of factors including visits to the health care provider and routine follow-ups. The interaction between health care providers and asthma patients may boost their treatment adherence and eventually have a positive effect on asthma control . Due to Asthma exacerbation is defined as a reduction in the forced expiratory volume of more than 20% from baseline, or a decrease in peak expiratory flow of > 30% from baseline for two consecutive days at any time frame during the course of treatment . It is aDiagnosis of asthma follows a critical analysis of patient history as well as physical, biochemical, and radiological examinations, which can be difficult in this current pandemic , 116. ToTelecommunications and virtual patient encounters can be viable alternatives to in-person checkups during this SARS-CoV-2 pandemic. Asthma and several other COPD patients can be diagnosed using automated computer-based methods. Researchers have suggested the diagnosis of asthma and COPD using artificial neural networks (ANNs), fuzzy logic (FL), and an expert system (ES). Based on these suggestions, some facilities in combination such as a portable spirometer that can be connected to a mobile phone via Bluetooth, a well-developed android operating system installed in that mobile phone, and an expert system stored on the mobile server could provide a precise diagnosis of asthma as well as other COPDs .Telemedicine can provide supportive care to asthma patients and help them diagnose the disease without leaving their houses and also predict any probable asthma exacerbations. Systematic and meta-analysis of 2019 found telemedicine could improve asthma control compared to usual care . HoweverDifferent online resources from professional societies and regulatory agencies are being developed to overcome such barriers and make people familiar with the telehealth program . Since tUncontrolled asthma and severe exacerbations can be fatal in the current pandemic. Thus, it is highly recommended to continue taking asthma medications as before, even if the person is suspected to be COVID-19 positive. There is no sufficient data regarding the harmful impacts of consuming asthma drugs or contributions of asthma medications in COVID-19 susceptibility. Besides, several asthma medicines like corticosteroids and bronchodilators are being used in coronavirus treatment , suggestMaintaining an asthma action plan can ensure better control of asthma and reduce the need to visit the healthcare facilities amidst this pandemic . CDC sugCOVID-19 pandemic has changed our lifestyle and pattern of daily activities. The practice of isolation and lockdown has put a drastic impact on our day-to-day life, as well as our physical and mental health. This sudden change in surroundings can provoke uncontrolled asthma in patients. It has been reported that the most common barriers to asthma self-management include mood disorders and anxiety, social support, and access to health care . Such faPotential asthma triggers including allergens, irritants, pet dander, and dust should be avoided as much as possible. Exercising every day can be good practice and may help reduce breathing difficulties, but strenuous exercise should be avoided due to the chance of getting exercise-induced bronchoconstriction. A nutritious and balanced diet can improve overall health and asthma control. A healthy diet plan can also help to maintain body weight, which is essential as asthma tends to be worse in overweight patients. Especially for immune-compromised asthma patients, a well-balanced meal can boost immunity and significantly expand the body's ability to fight against COVID-19 .The global pandemic caused by SARS-CoV-2 has affected all classes of people from all over the world, but patients with COPD including asthma were presumed to be the worst sufferers. In addition, overlapping representations of asthma and COVID-19 make these conditions difficult to distinguish. However, some unique features of COVID-19 including fever, muscle pain, loss of smell and taste, myalgia, and diarrhea can be used to make differentiate from asthma, but asymptotic COVID-19 patients make it more complex. In addition, wheezing is commonly present in asthma but rarely found in COVID-19 patients. Thus, examining symptoms can play a crucial role in differentiating asthma from COVID-19.It has been an ongoing debate if asthma patients are at increased risk of getting infected with COVID-19. Asthma patients suppress their immune system by taking different drugs to avoid allergens stimulation. This immune suppression might facilitate viral-induced damage to the airway. The majority of the sources suggest that asthma is not among the risk factors of COVID-19 and might even have a positive influence on this disease susceptibility. However, it should be noted that asthma is under-diagnosed and under-reported due to this pandemic, and also differentiation of symptoms is fierce between the two.Although there is another debate regarding the possible adverse impact the COVID-19 vaccines may have on asthma patients, no such evidence to such claim is present and it is recommended that in absence of any serious complication or side effects after the first dose everyone must receive the vaccines to ensure protection against the virus.Different ongoing challenges during the pandemic like shortage of medicines, impact of SDOH, delayed clinical trials are likely to put asthma patients through inconvenience. The primary focus should be to reduce probable asthma attacks as uncontrolled asthma may lead to hospitalization and increase the risk of viral infection. There are also risks regarding the possibility of viral-induced exacerbations, but most of the evidence related to this information comes from human rhinoviruses and no other viruses.Whether or not to continue consuming asthma medications has been a significant issue as asthma drugs can suppress the airway immune response. There is no certainty to the risks associated with the consumption of such medicines; thus, it is recommended to continue consuming the prescribed medications to manage asthma. However, it is suggested to stop the practice of nebulization, which can increase the risk of viral contamination in both the asthma patients and the bystander hosts. It is also recommended to keep a peak flow meter in the house to diagnose asthma from home and maintain a peak flow diary for better asthma management. Necessary apparatus like thermometers should also be kept in every house so that health care providers can better understand the condition through telehealth facilities. Although there are some barriers to be addressed for better telehealth facilities, most of the organizations are working to reduce such lacking and promote telehealth practice among patients. Moreover, it is recommended that all the clinical trials be shifted to virtual visits, and visiting a hospital should only be considered in extreme conditions.Management of asthma is the most crucial need during this pandemic. Uncontrolled asthma can be even more dangerous than COVID-19 infection. It is recommended to follow the individualized asthma action plan and to develop self-management interventions to avoid the potential asthma triggers. Additionally, it is extremely important to avoid potential maintain a healthy lifestyle and practice safe hygiene to avoid getting asthma exacerbations from our surroundings and lifestyle choices. A healthy lifestyle and a nutritious diet plan may further boost the immune response to fight off COVID-19 as well as help to manage asthma attacks better.COVID-19 has created challenges for regular treatment including asthma. As the COVID-19 is the highest priority and is a threat for other patients to be infected; lockdown, break of the medicine supply chain may cause asthma patients at higher risk. However, there are overlapping respiratory features between asthma and COVID-19, but the modifying effect of asthma in increasing severity of COVID-19 remained unclear. Asthma patients should continue their existing treatment and arrange some small diagnostic devices for a routine check. It is also advised to take telehealth care if necessary, and follow an asthma action plan. Further, self-care and management with a healthy diet and exercise can ensure good immune health of asthma patients during the COVID-19 pandemic.


In-hospital mortality was significantly higher in older adults with MIN at admission versus those without it (71 (31%) versus 11 (12%); p < 0.001). In a logistic regression model adjusting by age, sex, severity, and Charlson Comorbidity Index, the OR for in-hospital mortality was 2.1  among those older adults with MIN at admission. Older adults with acute myocardial injury had greater time to clinical recovery, as well as higher odds of in-hospital mortality. Myocardial involvement during SARS-CoV-2 infection has been reported in many prior publications. We aim to study the prevalence and the clinical implications of acute myocardial injury (MIN) during SARS-CoV-2 infection, particularly in older patients. The method includes a longitudinal observational study with all consecutive adult patients admitted to a COVID-19 unit between March–April 2020. Those aged ≥65 were considered as older adult group. MIN was defined as at least 1 high-sensitive troponin (hs-TnT) concentration above the 99th percentile upper reference limit with different sex-cutoff. Results. Among the 634 patients admitted during the period of observation, 365 (58%) had evidence of MIN, and, of them, 224 (61%) were older adults. Among older adults, MIN was associated with longer time to recovery compared to those without MIN (13 days (IQR 6-21) versus 9 days (IQR 5-17);  Myocardial involvement has been reported as one of the clinical presentations of individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection ,2. CardiIt is key to understand whether MIN during the acute COVID-19 episode is a bystander epi-phenomenon or has a relevant clinical role in the outcome of the infection.A consistent risk for myocardial injury is age . Aging hHowever, no consistent data looking into this specific issue has been reported in older adults with SARS-CoV-2 infection. During the first COVID-19 wave, the largest proportion of patients was over 65 years old ) versus 11 (12%); p < 0.001).MIN showed longer time to clinical recovery compared to those without it (median 13 days (IQR 6–21) versus 9 days (IQR 5–17); p = 0.043) among those older adults with myocardial injury at admission  highly expressed by myocardial cells . During There is a wide range of hypotheses trying to discern the causes of troponin rise during SARS-CoV-2 infection, as well as the role it plays in the evolution of the disease . An inteConversely, according to our results, we entertain the hypothesis that inflammatory pathways put in place by the immune response against the virus collaterally affect the myocardium. We found a positive correlation between inflammation measured by inflammatory markers and troponin levels. In addition, we consistently found that individuals with MIN showed significantly higher inflammatory markers than those individuals without it. Older adults might be more susceptible to increased inflammation in the context of a viral infection as a result of a process called immunosenescence. This consists of the aging of the immune system  that leaOur study has some limitations since it was conducted in a single center during the first wave of the COVID-19 outbreak. It has a mid-size sample, and we were not able to conduct cardiac ultrasound or MRI; as a consequence, we were only able to define myocardial injury by troponin elevation, without detailing myocardial tissue characteristics and hemodynamic function. Moreover, during this first wave, many older adults with SARS-CoV-2 infection remained in long term care facilities. In that case, we can say that our hospital was the reference center for many long-term care facilities of the area and received frequent referrals from them, even in the moments with the highest incidence. This study was conducted during the first wave of the pandemic, where individuals had no prior contact with the virus, and the immune response was naïve. The impact of vaccination in this condition, especially its incidence or its prognosis value, remains to be elucidated in the new scenario and might constitute future research. However, we find that a key strength of our study is that it is a representative sample of an older adult population, belonging to a large city with high incidence of SARS-CoV-2 infection, which makes the results directly relevant to the clinical practice. We can conclude that MIN was frequent in older adults with SARS-CoV-2 infection, especially in patients with pre-existing comorbidities and with higher inflammatory levels. We can also conclude that MIN impacted the clinical outcomes of individuals that experienced it, being associated with greater time to clinical recovery, more severe presentation of the disease, and higher odds of in-hospital mortality. The consistent association that we found between inflammation and MIN makes the hypothesis of an inflammatory insult as responsible for heart damage plausible. This is more relevant in a group with higher inflammatory levels due to immune dysregulation linked to aging and may deserve further attention. Ultimately, due to its widespread presence, and its likely role in prognosis, it is advisable that we direct attention to this matter.


The molecules in these condensates remain highly mobile, readily exchange with the surrounding environment and grow/coarsening over time , often towards the round structures to minimize the surface tension.The accumulating evidence suggests that cytosol represents a complex emulsion where multiple membrane-bound organelles and biomolecular condensates co-exist together.3 Failure to regulate this maturation process often leads to insoluble aggregates, a characteristic of many neurodegenerative diseases and cancers. For example, some biomolecular condensates in cells—such as P granules in developing C. elegans embryo—are shown to have fluid-like properties but refrain from coalescing into a single large condensate despite the timescale of hours or even days.4 Several key questions emerge as to how nature evolved to regulate the stability of multiple condensates and yet prevent their maturation into insoluble aggregates.The fluid nature of condensates suggests that molecules maintain high diffusion within these condensates and readily exchange between the condensate and the surrounding medium. However, data across many studies show that these condensates can evolve into less dynamic states where molecules binding within condensates increases over time, forming so-called aging Maxwell fluids.1 Pickering emulsion is stabilized by solid particles that adsorb on the interface of two phases, often used in material science,5 drug, and food industry.6 P granules show remarkable dynamics during oocyte maturation and zygote polarization with rounds of dissolution and assembly, as well as the spatial patterning within the zygote. P granules are heterotypic condensates assembled by PGL proteins (PGL-1 and PGL-3) and regulated by disordered proteins MEGs (MEG-3 and MEG-4), MBK-2 , and MEX-5, an RNA-binding protein.Recently, the lab of Geraldine Seydoux discovered that nanoscale protein clusters can act as Pickering agents and stabilize P granules, a class of RNA-containing granules in the germline.C. elegans zygote  in wild-type and animals lacking MEG-3 and MEG-4, suggests that MEGs stabilize many small PGL-3 emulsions during oocyte-to-zygote transition.While PGL-3 alone is coarsening into larger droplets in vitro, the addition of MEG-3 prevents this process resulting in PGL-3 condensates being stable over hours, resembling their stability observed in ote Fig. . To quanSymmetry breaking and transitioning of the zygote from unpolarized to polarized is tightly accompanied by the formation of cytosolic gradients of RNAs and protein factors. PGL-3 condensates are considered to accumulate at the posterior side in response to MEX-5-driven RNA accumulation at the anterior of the zygote inducing the saturation gradient. However, Folkmann and colleagues experimentally show that MEX-5 alone is not sufficient for this patterning and that MEGs are essential for positioning and accumulation of PGL-3 condensates at the posterior of the zygote. MEG nanoclusters at the surface of PGL-3 condensates act as molecular beacons recruiting MBK-2/DYRK3 kinase that is required for P granule dissolution during polarization Fig. .The experimental observations of P granule dynamics in oocytes and during polarization of zygote were used to build a theoretical model, which took into account three important elements. In the model, the conversion rate of soluble PGL-3 molecules to PGL-3 molecules engaged in the condensates depends on the availability of MEG nanoclusters and recruited MBK-2/DYRK3 kinase. The heterogenous distribution of RNAs  affects the positioning of PGL-3 condensates. Finally, the differences in chemical potential at the condensates in the posterior end of the zygote depend on the asymmetry of the MEGs, as necessary surface stabilizers. Indeed, such a theoretical framework recapitulated the dual nature of MEGs at supersaturated concentrations of PGL-3 molecules: they both act as Pickering reagents stabilizing the condensate and are necessary to recruit MBK-2 kinase that solubilizes PGL-3 granules, thus allowing for their growth and recruitment of new molecules.C. elegans oocyte development. This concept puts forward several testable hypotheses that protein nanoclusters that accumulate at the interface of biomolecular condensates can stabilize the condensates across different time scales and act as molecular beacons for recruitment of enzymes able to couple the metabolic state of the cell with the condensate dis/assembly.The discovery that biomolecular nanoclusters adsorbed at the surface of condensates can act as Pickering agents goes beyond P granules in


Background: It is unclear what factors clinicians consider when deciding about endovascular thrombectomy (EVT) in acute ischemic stroke patients with a pre-existing disability. We aimed to explore international practice patterns and preferences for EVT in patients with a pre-stroke disability, defined as a modified Rankin score (mRS) ≥ 2.Methods: Electronic survey link was sent to principal investigators of five major EVT trials and members of a professional interventional neurology society.Results: Of the 81 survey-responding clinicians, 57% were neuro-interventionalists and 33% were non-interventional stroke clinicians. Overall, 64.2% would never or almost never consider EVT for a patient with pre-stroke mRS of 4-5, and 49.3% would always or almost always offer EVT for a patient with pre-stroke mRS 2-3. Perceived benefit of EVT (89%) and severity of baseline disability (83.5%) were identified as the most important clinician-level and patient-level factors that influence EVT decisions in these patients.Conclusion: In this survey of 80 respondents, we found that EVT practice for patients with pre-stroke disability across the world is heterogenous and depends upon patient characteristics. Individual clinician opinions substantially alter EVT decisions in pre-stroke disabled patients. The American Heart Association/American Stroke Association national practice guidelines for management of acute ischemic stroke only recommend offering endovascular thrombectomy (EVT) to patients with an acute ischemic stroke involving a large anterior cerebral vessel occlusion without a pre-stroke disability, defined as pre-stroke modified Rankin Score (mRS) of 0 or 1 , 3. SmalA 20-item survey was developed by the authors based on factors most frequently cited in prior literature as influential in the EVT decision-making process. A pilot version was completed by 24 physicians at two institutions. Feedback from respondents was used to improve survey readability and accuracy. The final survey questionnaire in its entirety is provided in the Invitations to complete the final survey were emailed to all author-investigators of the first five international pivotal EVT trials of stent retrievers and to members of the Society of Vascular and Interventional Neurology (SVIN) –11. For Survey responses were de-identified. Survey respondent characteristics were characterized using frequencies (numerator/denominator) for each response option. Ordinal three-level frequency distributions of physician likelihood of pursuing EVT  were calculated separately for the two scenarios of patients with pre-stroke disability of mRS 2-3 and patients with pre-stroke disability of 4-5 and separately for non-interventionalists and interventionalists. Frequencies of physician selection of multiple-choices among 14 response options for general, patient-specific, and stroke-specific features most important to EVT decision-making in patients with pre-stroke disability were calculated and reported in rank order from most to least frequent.Completed survey responses were received from a total of 81 physician-experts, including 33 from among the international EVT trial authors and 48 from among the SVIN society members. The response rate among the international EVT trial authors total was 33/119 (28%). The denominator for the SVIN survey recipients was unavailable due to use of email listserv technical constraints.The characteristics of survey physician respondents is shown in The frequency with which physicians indicated they would ever consider EVT for an otherwise eligible patient was: 97.5% for pre-stroke mRS 2; 79% for mRS 3; and 74% for mRS 4-5.The degrees of physician likelihood of considering, performing, or offering EVT for patients with pre-stroke disability of mRS 2-3 and patients with pre-stroke disability of 4-5 are shown in Most respondents considered the complication risk  and the likelihood of recanalization  to be the same between patients with vs. without pre-stroke disability. However, most physicians thought patients with pre-existing disability had a lower rate of return to baseline disability .Respondents were asked to identify among 14 general, patient-specific, and stroke-specific features those that were most important to their decision-making regarding offering EVT to individual patients with pre-stroke disability. Among the 79 respondents who indicated they would ever offer EVT to a patient with pre-stroke mRS 2-5, A substantial majority of physicians  responded that their institution had general guidance on how to select patients for EVT. Of those reporting institutional guidance, most indicated that protocols did not take a stand on how to treat patients with pre-existing disability and left the decision up to individual physicians . Only five institutions had explicit guidance on how to treat patients with pre-existing disability with three recommending to never treat and two recommending to always treat patients with pre-existing disability. The remaining 24 organizations providing any direction advised that patients with pre-stroke disability were sometimes candidates for EVT.We observed considerable individual clinician and institutional-level heterogeneity in EVT practice among acute ischemic stroke patients with a pre-existing disability in this survey of 80 respondents. Disposition to pursue treatment was strongly influenced by the level of patients' pre-existing disability. While nearly half of the survey respondents noted that they would always or almost always treat patients with mild-to-moderate pre-existing disability, a preponderance of respondents noted they would almost never or never do so for patients with severe disability. In addition to the wide variation in overall propensity to treat, physicians varied substantially when identifying which general, patient-specific, and stroke-specific characteristics were important to them when making treatment decisions in individual patients with pre-stroke disability.The current AHA/ASA guidelines only recommend offering EVT to acute ischemic stroke patients who do not have a pre-existing disability . This guThe present study not only highlights heterogeneity in EVT practice among patients with pre-stroke disability, but offers some insights into factors influencing individual clinician reasoning in this practice. While most of the survey respondents believed that the complication risks and success of recanalization were the same for patients with pre-stroke disability as those without pre-stroke disability, the majority also believed that patients with pre-stroke disability would be less likely to return to their baseline disability. Almost 90% of physicians considered their own valuation, or perception, of benefit to patient as a major factor in deciding whether to offer EVT to patients with disability. It is important to note that, in the absence of comparative data on benefits and risks of EVT compared with medical management, clinician perception is based on physiologic reasoning  and personal experience, rather than definitive randomized clinical trial evidence. Accordingly, the findings of this study reflect the current range of opinion and intuition among individual clinicians making EVT decisions for pre-stroke disabled patients and underscore the need for more reliable, formal evidence.Importantly, large variation in institutional guidance for EVT in patients with pre-existing disability is highlighted in our study. The majority of institutional protocols remain silent on EVT specifically pertaining to pre-stroke disable patients and leave clinical decision making up to individual clinicians. Of the 6% of institutions with strict guidance on offering EVT to patients with existing disability, half recommended to always offer and half recommended to never offer EVT to pre-stroke disabled patients, highlighting inter-institutional heterogeneity in practice.Our study has several limitations. First, respondents of our survey were drawn from lead investigators in international EVT trials and members of a US professional society largely populated by interventional neurologists. Therefore, our results may not be generalizable to the entire population of physicians that perform endovascular interventions for acute ischemic stroke. Second, the response rate to survey invitations was moderate and it is possible that the views of non-respondents would have differed from those of respondents. The strengths of our study include responses from physicians in nine different subspecialties with a good mix of practice experience, academic rank, and geographic diversity.In this International survey of 80 respondents, we found considerable individual clinician and institutional-level heterogeneity in EVT practice among acute ischemic stroke patients with a pre-existing disability. Likelihood to offer EVT differed according to baseline disability as well as patient and stroke characteristics. Further research into effects of EVT among patients with a pre-stroke disability is warranted. Such research should utilize novel study methodologies and outcome measures to overcome challenges of studying this patient population.The raw data supporting the results of this study will be made available upon a reasonable request.Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. Written informed consent from the participants was not required to participate in this study in accordance with the national legislation and the institutional requirements.SS contributed to data collection, analysis, and drafting of the manuscript. JN contributed to data collection. AH contributed to data collection and critical revision of the manuscript. CL, PK, JM, and JS contributed to conceptualization and critical revision of the manuscript. EM contributed to data collection, drafting of manuscript, and conceptualization. All authors contributed to the article and approved the submitted version.EM received salary support from NIH/NINDS (K23NS113858) for this work.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.